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What is the brain?

Paul Grobstein's picture

Welcome to the on-line forum associated with the Biology 202 at Bryn Mawr College. Its a way to keep conversations going between course meetings, and to do so in a way that makes our conversations available to other who may in turn have interesting thoughts to contribute to them. You're welcome to post here any thoughts that have arisen during the course this week (and to respond to thoughts others have posted).

One issue worth thinking about this week is that the notion of the brain as a stimulus/response device should probably be replaced with that of the brain as an input/output device, one which is capable of generating outputs on its own and in which inputs have somewhat unpredictable effects.  Another is the idea that the brain is a nested set of input/output boxes, and that it is the organization of these boxes that is responsible for behavior.   Are these good summaries of observations? stories? What observations do they not incorporate? What new questions do they raise?

Lyndsey C's picture

brainstorming about the neocortex (pun intended!

Today we ended class with a discussion about "wrinkled stuff" in the brain, aka the neocortex, which all mammals possess and other animals do not. We all seemed to agree that this distinction must logically result in a difference in behavior between mammals and all other animals, in following with our conclusion that changes or differences in brain physiology ultimately result in changes in behavior. So our ending question to ponder until our next class (thursday) is to consider "what is the difference in behavior between animals with and without a neocortex?" Prof Grobstein left us with a few ideas to begin with (mammals = hair, warm blood, milk, birthing process, ect) but of course refused to spoil the fun and give us the answer, which is why i thought it would be interesting to sort of think out loud on this post and try to come up with at least an educated guess or three. (and this counts towards my "being wrong at least 3x per day" requirement for this class!)

1. since the cortex links the right and left hemispheres of the brain, maybe the neocortex in mammals has something to do with increased, more sophisticated communication and thus behavioral processes.
2. hormones are what control complex processes specific to mammals (such as producing milk or growing hair) so perhaps there is a connection between hormone processing and neocortex functioning, which in turn can affect behavior.
3. the cortex contains sulci and fulci which in part act to maximize surface area of the brain, which in turn increases number of and communication between neurons. maybe this physiological phenomenon is what allows mammals to behave differently from other animal classes.

I realized all of the guesses i posed attempt to answer the question of "why mammals behave differently" but none of my points account for "how mammals behave differently." Any other ideas? I'm curious!

and here's my final thought of the day:
Molly Pieri's picture

one idea...

I can't really think of any single mammalian behavior that universally differs in kind from the rest of vertebrate behavior, only in degree. For example, while mammals in general may communicate to a greater degree of complexity than do amphibians/reptiles/birds in general, amphibians/reptiles/birds do communicate.

One aspect of mammalian behavior that seems to be isolated to mammals and birds is parental investment behavior... while some reptiles will guard nests or even give birth to live juveniles,


there isn't really an infancy period during which these animals are nurtured or cared for by parents. This infancy period (and the resulting parental investment) is seen in mammals, and birds. (Even precocial birds like quail or chickens are cared for by a parent) If the jury is still out on the question of bird-neocortex existence, then perhaps this aspect of behavior could be attributed to that portion of the brain.

On the idea of parental investment/maternal instinct, I'd like to leave you with this video. (If this link doesn't work, try googling "Hippo Saves Impala" and checking the video search results.)


Simone Shane's picture

Other thoughts

I was just thinking that circadian rhythm could be a form of output with no input. When surrounded by pitch dark and no cues for day and night, we still follow similar patterns as we would with the changing patterns of the sky.

Also, I was hoping we could start thinking about another problem with our even newest model. Namely, I do not think that it accounts for top-down processing and the way our previous knowledge shapes and even tunes out or tunes in different inputs. Can this be accounted for in a box or do we need an arrow going backwards somewhere in the model?

Molly Pieri's picture

Late posting re: sensory deprivation...

Hey. Sorry for not getting around to this earlier... it seems my fate to not post on serendip until the discussion for the week is pretty much over. But maybe I'll do better next week...

Anyway, the thing that interested me most about the "output with no input" or "self-generated output" idea was constructing an environment in which the mind might be totally deprived of stimulus (or input. or both if you would like to distinguish between the two). I purposefully make use of the word mind rather than brain, I don't want to confuse the two for those who like the Cartesian dualistic model of thought and body. I think that we agree that most of the actions we consider "meaningful" and "important" are produced or in some way processed by our conscious mind. That is to say, they are voluntary actions we make a choice to preform. (Not to imply that our smooth muscle functions aren't important, but rather they aren't significant in the way that I would like to investigate here...) If we focus on these sorts of actions, those that are determed by a choice of the mind, (or a physiological response of the brain, if you consider there to be a difference between the two phrasings) then what would it take the deprive our consciousness of any sort of input? Would that also imply depriving the brain/mind of memory? Or would memory beconsidered an internal aspect of the input-output box, even though it is at least in part the result of collective external experience?

I suppose a question which must be investigated prior to any of these musings would be the difference between conscious and unconscious (might non-consciousness play a role here too?) Any way, those are my thoughts for the week. Hope every one had a wonderful superbowl weekend.



Simone Shane's picture

The Internal and External

I'm also inclined to agree with rdelacruz that the lack of output when an output is generally expected should be considered a type of output, as there must be some reason for the output's absence. For example, a neuron, or input/output box, may still receive the message to do the output, but also be receiving a stronger inhibitory message. Thus, it is not as if the input elicited nothing, its elicitation just did not go as far to cause the end behavior, or output. As people were arguing for internal inputs above, can we have internal outputs as well? Would a type of internal output be unconscious learning, such as muscle memory? Indeed, learning is the growing and strengthening of neuronal connections, but do we consider that a behavior? Moreover, perhaps these outputs which were inhibited before they could result in an external output messed with the output of some other input? Therefore, could you not say that the internal output affected an external output? Sorry if this isn't coherent.

Another idea: Maybe a female cricket did not turn towards the male's chirp because she saw a scary spider in his direction and then learned to fear that specific male's chirp through conditioning. Could we then say that there was an output, albeit delayed and the result of other factors as well?

I'm not so sure how I feel about internal inputs. I'm curious as to what makes previous thoughts that have nothing to do with your current environment pop into consciousness? Could it be a delayed output and therefore the effect of an external output, or something purely internal? I cannot, however, think of what this internal something might be. Jessica Krueger spoke to the importance of ontogenetic and phylogenetic histories when analyzing behavior. Could these histories be enough to cause behavior without an even latent external cue? I have difficulty thinking so, but I'd be eager to hear others' thoughts!

Rica Dela Cruz's picture

I am intrigued by the first

I am intrigued by the first comment written by Emily Alspector because I too am not fully convinced that the brain alone is the reason for behavior and believe that the mind has an equal influence for behavior. Aware of this, I tried to think of reasons for how this model of input/output boxes could also relate to the mind and not just to the nervous system. If this model were correct, where do these inputs come from then? There must be something provoking inputs, which then produce outputs, or no outputs. Are these inputs due to the brain or the mind? Also, how is it that our brains, according to this model, can produce an output without having an input? Could this be a result of the mind? One problem with the model for me is that we are assuming that inputs and outputs are produced from the brain and it seems to neglect the mind.

In addition, I do not like that this model says that there can be an input that produces no output. I feel that when an input is made, one is conscious of that input and therefore can make a conscious decision to produce an output or no output at all. Since one is most likely conscious of the input made, one should be able to produce some form of output. I feel that there must always be a decision made when an input enters. Therefore, the decision of creating no output can be an output within itself. Can't we say "no output" is another type of output? Even if we were not conscious of the input, wouldn't it still be somewhere stored in our brains or minds? I feel that this too can be a type of output. 

gflaherty's picture

nervous system complexity

The numbers thrown around at the end of the class last week impressed me.  The high percentage of interneurons really put the nervous system into perspective for me.  We experience the sensory neurons and motor neurons, and therefore, I think that we only seem to appreciate these neurons.  Yet, these peripheral neurons are less than .1% of all the neurons present in the body.  I think that this speaks volumes to the complexity of the nervous system and the high quality communication that must be taking place at extremely high speeds in order for the brain to properly receive and dictate a response. 

Penn Tong's picture


In response, I believe that the fact that .000001% of our total neurons being made up of sensor and motor neurons is not as surprising as most of us thought during class. So we have about 10,000+ sensory-motor neurons. It may seem just a few compared to interneurons, but 10,000+ is actually a HUGE number. So if each of those nerves can be excited or at rest, then think of all the possible combinations you could have of excited or resting nerves. Technically it is 2^ 10,000 . That is a ridiculous number. 2^10 = 1024 2^11 = 2048 (2^50 > 10^15 !!!!!)

So what I'm saying is managing all these inputs in our environment with 10,000 sensor and motor neurons is actually conceivable.

Leaving us with over 10^11 interneurons, imagine the possibilities the brain can do with that.

So I calculated that an 80 year old person will have lived about 2.5 x 10^12 milliseconds. That is less than 2^50. So if we were to live 80 years it is possible that each millisecond we experience is a different combination of neurons.
So maybe the brain is only made up of neurons turning on and off depending on the input. Maybe the brain really is just a very complex machine. I'm not saying it IS the answer, but it is definetly plausible. Who knows.

Madina G.'s picture

Does the lack of an input render the ability of the output?

The concept that the brain is a system of inputs and outputs in which certain outputs are capable of being generated regardless of the presence of an input  is a notion that well incorporates observations of the brain and behavior and I agree with this model completely. An demonstrative example of this can be seen in Phantom Limb Disorder, a disorder suffered by 50-80% of amputee patients. Upon surviving a serious accident, many people suffering severe pain in one of their limbs undergo amputation of that limb in an effort to alleviate the pain. Often, the pain is not cured and the patient is now left both limbless and suffering the same excruciating pain. Biologically, neurons at the base of the stump that were once in communication with the neurons in the amputated limb begin to send random signals to the brain, and although these signals are nonsense, they are processed in the brain as pain. Treating this as a psychological disorder, one treatment for this that was developed was simply placing a mirror in front of the patient and asking them for example to lift their right arm, if it was their left arm that was amputated. Upon raising their right arm, the patient witnesses their left arm being lifted in the mirror and report that their pain is alleviated. In one situation the patient was even completely cured from ever experiencing pain in their “phantom limb.”


This is a most illustrative example of how the brain works as an input-output system while it is quite possible and actually a regular function of the brain to produce outputs even with the lack of an input at any given time. 

mkhilji's picture

I'm am trying to go back to

I'm am trying to go back to the “Harvard Law of Animal Behavior”, and agree as some mentioned above that this means that it is possible that animals will behave whatever way it please--whether there is a motivation (input) or not. However going back to the example of a baby, it will cry for various reasons---some that we may not know as we probably cannot remember what we may have been thinking when we were young. However generally people who have experiences with babies have found that either the baby cries for milk, or to get changed, or because they may be uncomfortable in a certain position. As the baby matures and becomes a toddler the kid has made an observation that every time he/she cries, they will get attention. It reminds me when I was little and I would cry and sometimes when my dad would ask why my mom would sometimes just claim "for no reason at all but attention"--however my wanting of attention is still an underlying reason/motivation so doesn't that count as a possible input.

I am reading from a lot of people that the term input/output are challenging as we often think about math, computer science or something mechanical--however I would propose that it input could be analogous with the term motivation, and behavior would be analogous with output. The motivation could be physical or mental.

Now going back to the arrangment of each individuals neurons and whether people from the same culture/religion share the same arrangement of neurons--I think this is quite possible depending on the different influences, such as how they came about learning about the certain culture or religion. I would argue that it may be one thing to identify yourself with a culture or religion--but mentality wise you may be on a different page altogether. It is our experiences that influence our different motivations and produce different behaviors--thus the way we may perceive or understand content may vary from someone else.


jwong's picture

I really like this analogy

I really like this analogy that Michelle used to translate input/output. In terms of the brain and behavior, an input can come in the form of physical or mental influence; these influences convince us towards some direction but inevitably it is our own experiences that convince us of the validity of certain ideas and beliefs. I think this is a reason why people have difficulty understanding or being able to believe ideas they have no previous experience with. Without a proper motivation to understand the opposing viewpoint, the input of the idea might perhaps get directed towards the output reaction to disregard the idea. This is stretching the ideas about input and output a bit, but I think it makes sense that the brain, with all its complex input and output connections, also forms familiar connections that are hard to break away from sometimes. People are habitual beings; it often becomes easier to associate familiarity with comfort, and comfort with goodness and wellbeing. In other words, maybe the whole idea of input/output boxes is a good way to demonstrate why it can often be harder to form new ideas or new output reactions to new ideas.

Mahvish Qureshi's picture

Twins and Behavior

I found the class discussion about twins and the simalirity/differences in their behavior to be rather interesting. Afer reading some braod articles about the behavior of twins, and the genetic make up of twins I have put together some thoughts about why identical twins would behave differently to the same input despite their identical genetic make-up.

While the twins may have the same genetic make-up, and have shared manyof the same enviromental influences such as family upbrining, there have still been many different influences in the lives of twins such as their peer groups. So while the genetic make-up may be identical/similar different genes may have developed in one rather than the other.

Behavior is not coded for by one gene in the genetic make-up but is a polygenic trait. So while twins may have the same genetic make-up their behavior will be different based on whcih of the genes are activated etc.

When there is an input from the outside world, the behavior/output of identical twins will differ based on their experiences and the development of certain traits or genes in their identical genetic make-up.

Lyndsey C's picture

Yay Giants! (and neurobiology)

I think the idea that "the brain is a nested set of input/output boxes, and that it is the organization of these boxes that is responsible for behavior," is a pretty accurate assumption. So far, we've been talking a lot about "getting it less wrong," and I think this is the very first step in understanding neurobiology because this fact enables us to open a whole new window of understanding about how the brain works. The spaghetti bowl metaphor we have been talking about is only the beginning of what will eventally lead us to more specific processes that lead to behavior.

I was talking to a friend at dinner about the fact that only 1% of our neurons are sensory and motor neurons, and that really astonished us because we think and act based on our environment, which is perceived through sensory and motor activity. What are all the interneruons doing? Are they specialized? We were also wondering what happens to a brain on LSD since many of the drugs effects are related to heightened sensory experience. I don't know much about brain activity, but obviously something is happening to the neurotransmitters, so Im guessing maybe the sensory neurons fire more raipidly? Or is there decreased inhibition of certain neurons?

llamprou's picture

How can there be output without input?

I have spent most of the weekend thinking about everything I do and why. I only caught myself once doing something that I was not prompted to do and that was drop something, which in my mind was out of my control. Otherwise from cleaning the kitchen to sitting on the couch and watching TV, to changing the channel was all prompted there was always an input before there was an output. I therefore strongly disagree with the final diagram presented in class last Thursday.

I have a dog also, she is an Italian Greyhound and lives inside the house so I am always in really close proximity to her and I spent the weekend observing her also, she ran to the door when there were people walking by it, once she jumped off the bed simply to strech, but I am sure that was prompted by a change in position, maybe she was uncomfertable. As for if she comes when I call her, sometimes she doesn't but that does not mean she parallels the female grasshopper. Just because there is a specific response expected does not mean that it is going to happen all the time, that is why statistics and probability exist. It certainly does not mean however that there is an output without and input.

In my opinion there is not nearly enough evidence to support this claim. I believe it is natural to react to the world around us. Even taking off our sweaters when we get indoors, or turning on the air conditioner when we are hot, or simple cleaning because we feel our enviornment is messy. There is an input for every output.

EB Ver Hoeve's picture

The importance of the Organism

Drawing from observations of my big-eyed rusty red golden retriever, there are clearly times when behavior can not be predicted or explained. Kipling might be sprawled out on the living room floor one moment, and springing up to trot toward the front door the next. Why? Did he perceive a cue that I wasn’t able to perceive or interpret? We have been entertaining the idea that there doesn’t need to be an input for an output to occur. I am not sure. To me, there either was an actual input preceding the output (e.g. a sound of an outside car door) or there was an internal input, perhaps a false alarm that caused neurons to fire and for Kipling’s brain to respond as if the sound had occurred.

The most significant part of the input/output story for me is the role of autonomy within the organism. The input-output system can be thought of as a signal being sent, followed by a direct response. It’s easy to follow a linear system, and this pattern may work at some level for many of our actions and observations. But the reality is that the organism’s attention to, perception of, motivation, and threshold for responding to an output interacts with the strength of the input and the amount of other noise in the surrounding environment and in the system. At the most fundamental level, stimulus-response relationships may help to explain some behavior. But understanding increases exponentially for me when I take all of the imaginary input and output boxes (and all of their associated interactions with one another) and represent them all within a single O (for organism) placed conveniently between the input (stimulus) and output (response). In this way, I redefine input and output so that they no longer represent all external and internal cues, but instead refer only to external cues. I believe that separating the external inputs from the internal inputs is worthwhile not only because it seems like an important distinction but also because it might allow our conversation to expand. Like eambash, I think interneurons must play a significant role in the behavior of the O, but how? I am also intrigued by the concept of the threshold. With so many inputs coming in, is it possible for our brains to interpret them all? Which signals get recognized? Do we have any control over this recognition?
Jessica Krueger's picture

Focusing the lens to find meaning.

A brief perusal of the topics posted thus far lead me back to two concepts I have mulled over on my own for quite some time: predictability and “reason.”

The field of research I would like to enter (which I consequently invest with a great deal of respect), behavior analysis would argue that one of the basic tenants of the behavior of an organism is that it be predictable., This doesn’t mean that we as humans are good at predicting behavior or even articulating it when we were successful at predicting behavior. The idea is that it’s not something or someone inside the head which drives behavior (and I know this idea won’t be popular in this class) but rather that certain aspects of the environment either support or deter certain behaviors. While it’s easy to point at a single immediate scenario and argue that there’s “no way” that anyone could predict a female cricket’s “random” taxis away from a male, we proved in class that if you move the focus away from the imminent sexual pairing to the wider environment of a field, the potential presence of a predator, food source or superior mate can explain her seemingly aberrant behavior. But the scale of analysis need not be limited to the immediate context; a subject’s ontogenetic and phylogenetic history can come into play when trying to explain why certain behaviors are maintained and others extinguished. So whether or not a behavior is “predictable” is less of function of whether or not predictability is an intrinsic characteristic of the behavior itself and more a function of whether or not a certain aspect of the environment has a strong enough influence on the behavior itself (called “stimulus control”) such that it can be detected by the person describing the behavior as predictable.

Following along that line of discussion, the reasonability of a behavior is thought to be determined by an observer’s description of a behavior than a specific aspect of that behavior. Much as the collection of gases over our heads is a “sky” only within our brains, attributes such as “intentional” or “reasonable” have more to do with how the observer describes a behavior. As Professor Paul Neuman says in his paper on intentionality(1), we wouldn’t describe a player dropping the ball during the Superbowl this evening as an intended behavior, but if his hand had just moved a few inches in the correct direction we would say that that catching behavior was intended. Intention doesn’t explain why the behavior occurred in the first place, and thus to a behavior analyst who is interested in understanding the cause of behavior reason and intention are particularly useful distinctions. So instead of describing a behavior as reasonable or predictable, perhaps we should investigate what it is about the behavior that leads us to describing it as reasonable or predictable.

maggie_simon's picture

Predictability and Scales

I would like to focus on another reason that the brain can be unpredictable and touch briefly on the idea of "focusing the lens" or thinking about a situation at different scales.  As I believe Caitlin said in the previous blog session, the brain is an example of emergence: it is made up of grey and white matter, but they interact in such a way as to give rise to thinking, reasoning, and feeling capabilities that we employ everyday.  Systems with emergent properties are unpredictable: you cannot take the building blocks (in this case the grey and white matter) and, using the properties of those blocks alone, predict what the final properties of the system will be.  At the scale of the building blocks, there is a large degree of uncertainty about what will happen when they interact.  However, at the scale of the brain, the uncertainty instead becomes what kind of an output, or type of behavoir, will happen when the brain interacts with its environment.  I would say at this scale, the scale of the organism and its environment, the uncertainty in behavior could still be a result of emergent properties in that the various inputs from the environment, and from internal sources (such as recollected memories or moods/emotions...  what else?), come together to create a complex system in which outputs are not always predictable.  Internal input/output boxes provide another scale at which behavior can be viewed, as well as more nodes to add to the emergent system of the brain.
cheffernan's picture

Too simple for such a complicated system

It seems as though a majority of the class seems to be in agreement that looking at the brain, as a system of input/output boxes is a good way to begin fundamentally understanding the brain. I am in agreement with the rest of the class, but I hesitate to concur completely. The model that was on the website was a box that enclosed other boxes and lines to connect those boxes, which is a perfect way to represent the system as we currently understand it. But my question is: how were the boxes established? How were the connections between these boxes established? And how do you create more boxes and more connections?

The current system that we are commenting on is a stagnant system, which is no way to be looking at the brain. The brain is constantly establishing new connections within itself, which is apart of the learning process. Classical conditioning occurs because the brain is able to connect a sensual input with a physical output, and requires making a connection between neurons that previously never existed. For the current model that we are commenting on, there needs to be the capacity to establish new input/output boxes and connections between the boxes to be a sufficient representation for the brain from which we currently understand it.

While we briefly looked at the “Harvard Law of Animal Behavior”, which states, “under carefully controlled experimental circumstances, an animal behaves as it damned well pleases.” Thinking about this in terms of the input/output system, there doesn’t have to be the expected out come, nor does there have to be an outcome at all. It is important to remember that any input could generate any output, which is not as easily accomplished through the input/output system. It appears to go in a rather linear direction, where some boxes have multiple inputs and/or outputs; there needs to be some kind of connection, be it linearly or more of a web-like connection, from every input to every possible output.

It is impossible to think about the brain as a static system because of the great capabilities that the brain possesses. The process of learning produces so many changes in the brain that no model could ever be capable of recreating; yet I will say that for the relative simplicity of this current model, it does an adequate job of replicating such a complicated system.
Zoe Fuller-Young's picture

Size matter?

Working from eambash and Jean's ideas, I agree with Jean that the question of why the brain works in random ways becomes how does the brain produce accurate, or at least predictable, output? I agree that the input/output box idea is better than stimuli/response. I would not describe input/output boxes as linear as some do above, because it does give room for flexibility and unexplained behavior, rather input/output boxes are restrictive in the sense that Jean explains above about the brain's somewhat limitless capability for randomness. What I mean to say here is that the words input/output are problematic for me, because it gives the idea of something coming from outside going in, and then something from inside going out, but the processes we are discussing seem much more internal, suggesting that the majority of movement occurs possibly without input, and/or without output.

This moves into eambash's discussion of the 99.999% of neurons being interneurons. If neurons are communicating almost exclusivley between themselves, and therefore the input/output boxes are working irrespective of input from the "outside" and output from the "inside," how is it that we behave? Is it the very small percentage of neurons that are working to provide us with visible actions? How can this be?

Also, we were shown the similarity between human/monkey/frog/cat brains, and at the very tiny level of input/output boxes we appeared to be the same, and somewhat agreed that it is the arrangement of the boxes that determines our behavior and therefore our differences of behavior from frogs. What about size? Humans have the largest brain, so are we more "advanced" because of our arrangement or that we simply have more boxes, or is it both?

Margaux Kearney's picture

Brain and Addiction

We know that neurons are tiny input/output boxes and that their arrangement dictates a person's behavior. Will a chemical input (stimulus) with addictive properties such as drugs, addictive substances in food or tobacco 1) "alter" the existing arrangement of neurons? 2) alter the arrangement of neurons for everybody? 3) alter it the same way for everybody? then produce an identical addicted behavior (output) with identical neuron re-arrangement (erasing initial neuronal different arrangerments), or will it react /lock into a specific arrangementt of neurons to produce different behavioral responses (output)? My underlying question is: is there a factor beyond the "system" that plays a role in shaping the output?
jwong's picture


I found an article that got me thinking about the brain as a system ( Scientists were performing tests on monkeys and humans and their abilities to be trained in operating and using complex tools and devices. For example, humans can drive a car or use a computer mouse, and monkeys can be trained to use a rake to gather snacks. The scientists noted the significance of the input-output map and the ability to respond and adjust to “stimuli” from the outside world. Thus again, I think this shows that the brain has this capability because it IS a system and can respond to a different input from one that it might be expecting using a differing output.

jwong's picture

brain brain brain brain

Reading over all the comments, I’d have to say that I agree that the brain is a system, a series of input/output boxes relying on each other to organize and create behavior. It is hard to call our brain a machine, merely because of the image it creates in my mind about something rather inhuman and emotionless/like a metal-box… but in reality what better term is there to use? The idea of organization can be comforting because of its ability to establish stability of thought and the mind’s processes; one example of this deals with human relationships. In order to properly relate and empathize with a fellow human, we would somehow have to be able to share or allude to similar thoughts and actions. Being able to understand ideas that are not our own creation occurs by referencing them to similar or contrasting thoughts in our own minds is exactly what an input and output system defines. This phenomenon is only possible if we all share similar brain mechanisms to allow us to process the same information in parallel manners. Not to say that we all think the same, but as we are all human beings with a common organ like the brain, it seems obvious that this similarity is a connection that relates us all together. If we did not all share that same “system” in our brains, thus sharing similar brain setup and functioning, how would we be able to fully communicate and relate to each other?

Caroline Feldman's picture

neurons and consciousness?

Suppose that consciousness exists in the brain. Clearly, the brain has many other functions, most of which have nothing to do with experience or decision-making. Then why is it that some neurons cause consciousness to appear, while the others are merely pattern recognizers? What is it that decides what I am about to say next? Whatever it is, it is probably inside my neurons, but which ones? Why those ones? There is the problem of deciding which neurons are conscious and which ones are merely information processors. How do these neurons communicate with each other? Perhaps the brain does not simply have a single consciousness. There could be hundreds or thousands of conscious neurons, each one experiencing and interacting with the world independently. Since each of them receive almost identical inputs, they each produce very similar outputs, and it is the amplification achieved through the strength in numbers that is responsible for that which we percieve as a single consciousness.'s picture

The brain is a baller.

I agree with Tara's point above when she mentions that there is no set neuron path that triggers a specific response or action in the human body's behavior. 

Like mentioned in class, all our generalized 'input/output boxes' are constructed with so many different 'input/output boxes' and it is the combination of so many different 'input/output' tracks that determine a different signal.  There are so many (seriously.....sooooooo MANY) combinations and possibilities of variation in behavior.  Thus, to those who question the complete randomness of thought and sudden urges of behavior...these jerks are totally plausible. 

The thing that I find amazing is that despite all of the different combinations and possibilities of behavior being triggered, the brain still is able to group things and have some sort of organization to which thoughts trigger different behavior.  For instance, muscle memory and morality.  We act certain ways because certain actions and thoughts have been embedded in our system since long ago.  Due to so many different combinations, you would think there would be easily an error in the brain's process or a backfire that would disrupt the visible trends completely, however, yet still, the brain triggers relatively accurate responses to different inputs.

 The brain is pretty on-point.

Tara Raju's picture

Mental and Physical Behaviors

Caitlin brings up an important concept- the difference between the "physical" and "mental" behaviors that the brain processes on a daily basis. I view the brain as an input/output system when it comes to more physical behaviors like forcing the heart to beat or breathing, etc. On the other hand, I personally believe that the brain is something else when it comes to the physical behaviors that we all exhibit. There is no set nueron path for any individual when it comes to mental behaviors that are eventually translated into action. The body is constantly subjected to many different types of situations and stimuli so that there is in fact no set behaviors that can be exhibited. Our lives are extremely different from one second to the next, we are all spontaneous individuals who have not conditioned the brain to be constantly just outputting the same behaviors. I believe that the brain has the ability to exhibit both routine behaviors as well as behaviors that we have never exhibited before.
Caitlin Jeschke's picture


The last two posts (by Emily and Sophie) have touched on some of the ideas that I have been considering since Thursday’s lecture.  I too find the idea of internal v. external “inputs” to be very interesting.  The idea that the nervous system was capable of internally generating input was the aspect of our model that I found to be the most intriguing. 

            I wondered whether or not a thought or memory could be considered a type of internal input, because thoughts definitely affect the way a person reacts in any given situation.  A number of thoughts triggered by an external input, for example, could combine with that input and with each other to produce an unexpected output.

            When we talk about how different people react to the same input in different ways, we are necessarily basing this observation on external reactions that are visible.  As others have already mentioned, it is impossible to know an individual’s thought process.  So, different thoughts and memories could explain differences in what is conventionally referred to as “conscious” behavior.   But what about “unconscious” behavior?

            The excerpt that Sophie posted about how some processes are viewed as “physical” whereas others are viewed as “mental” led me to the observation that we do not often consider variation in behavior that is considered “physical.”  I am referring to bodily functions that do not seem to be subject to influence by memory-for example, food digestion or breathing.  These processes are all controlled by the brain, but involve inputs and outputs that are not as readily observable.  I think that it is extremely unlikely that all humans use the exact same neurons and the exact same pathways to maintain these functions.  However, because we do not “consciously” tell ourselves to expand and contract our chest cavity, or to secrete stomach acid, we often assume that these behaviors are identical in all people.  I think that slight differences in these behaviors probably exist, and that the “brain as a machine” model would most easily account for such differences; small variations in neuron connections (or in the construction of the “machine”) could lead to slightly varied outputs.

            So, although I feel that there can be no outputs independent of the brain, there definitely seem to be some inputs that are much more likely to generate thought (and therefore “awareness”) than others. The “conscious”/”unconscious” dichotomy persists.  However, I think the fact that our beliefs and past experiences can affect even some of our actions is very cool.  Some people have expressed discomfort over the idea that there may be no free will.  I say, even if memories and thoughts are just different types of internally-generated input, imagine what our lives would be like if we were not able to generate this input: if every action were as automatic as inhaling. 

            I think that both structural differences (i.e. unique neuron pathways) and internal input in the form of thoughts are responsible for behavioral differences, and that the brain somehow incorporates both of these features. 

Sophie F's picture

Input, Output, just output: what does it mean?

Are not "random" and "without reason" terms we, mere mortals, ascribe to that which we cannot understand? If the brain, in some fashion, receives input, processes it goes through some processes and then outputs, there is some form of categorization or drawing of connections that occurs, sight unseen. If an input is received that does not fall within the realm of that which has been previously learned or experienced then the brain either associates with its closest match, creates a new connection (or perhaps reinforces an old) or rationalizes that it is "random" or "without reason." These are perhaps the "patterns" to which Emily Alspector and Anne Kauth refer above. And, indeed, much of the “work” done in the nervous system is without discernible inputs and thus behavior may it times appear to be “random.”

Some of the discussion, thus far, has called into question the brain as a “system” given that we behave sometimes unpredictably, in ways that seem to defy that which we ascribe to “systems,” such as machines, computers, and even the brain. To my thinking, I tend to agree with eambash, that the fact that we (humans, crickets, etc.) behave unpredictably need not undermine or negate the premise of the brain as a system. After all, a system is a way to organize, synthesize and act upon information. In the case of the brain, as other systems, there are often competing or simultaneous inputs and myriad potential responses. Were it not for the brain’s capacity to perceive, reason, respond, albeit a limited and imperfect capacity, it might not qualify as a system. On the other hand, “system” semantically somehow demystifies the human experience and causes doubt about whether or not our decisions “belong” to us if the brain is at the fore (in all ways). Indeed, the synapses in the brain have the remarkable capacity to form new connections as learning takes place, or to sever connections that are not used or are replaced by others. This means we are all shaped by our experiences, our histories, our cultures, etc. and we are works in progress, as are our brains. We may have different starting materials (gene variation), different exposures (culture, family, etc.), but we have similar potential to learn and modify our behavior as we modify our brains.

Even if the input is not discernible or cannot be pinpointed, what triggers behavioral outputs? Learning? Neurotransmitters? Is nothing we do random or is everything we do random, such that an input cannot be identified? Even if the mind and brain are one, is there necessarily some dualism to account for the many dichotomies of existence? Or is it as John Dewey suggests, ..."we shall not regard the difference as other than one of degree and emphasis…” ?

I found the following to be very interesting, of which I am posting a somewhat lengthy excerpt: a talk given by John Dewey, entitled “Preoccupation with the Disconnected,” given to the New York Academy of Medicine in 1928. It can be found in its entirety here:


“The very problem of mind and body suggests division; I do not know of anything so disastrously affected by the habit of division as this particular theme. In its discussion are reflected the splitting off from each other of religion, morals and science; the divorce of philosophy from science and of both from the arts of conduct… The division in question is so deep-seated that it has affected even our language. We have no word by which to name mind-body in a unified wholeness of operation. For if we said ‘human life’ few would recognize that it is precisely the unity of mind and body in action to which we were referring. Consequently, when we endeavor to establish this unity in human conduct, we still speak of body and mind and thus unconsciously perpetuate the very division we are striving to deny. I have used, in passing, the phrases "wholeness of operation’, ‘unity in action.’ What is implied in them gives the key to the discussion. In just the degree in which action, behavior is made central, the traditional barriers between mind and body break down and dissolve. When we take the standpoint of action we may still treat some functions as primarily physical and others as primarily mental. Thus we think of, say, digestion, reproduction and locomotion as conspicuously physical, while thinking, desiring, hoping, loving, fearing are distinctively mental. Yet if we are wise we shall not regard the difference as other than one of degree and emphasis…”

eambash's picture

Input/output within the body vs. outside the body

Our latest class discussion was rather comforting to me in terms of dealing with the input/output question. It's confusing (and seems to be for lots of others, too, judging by this thread) to think that things can happen with absolutely no discernible cause or that clear-cut causes can have no effects. But I think it makes a lot more sense when considering what we talked about in class: the idea that what happens inside the nervous system interacts less than 1% of the time with what happens outside the nervous system.

If 99.999% of neurons are interneurons, then it's going to be insanely difficult, and possibly pointless, to match up behaviors, or arrangements of neurons, with inputs and outputs -- at least if we think of inputs and outputs as being things that come into or go out from the large-scale nervous system (and thus the body). In the case of sensory and motor neurons, we can see things happening as a result of things coming into the nervous system or things being sent out from the nervous system. But, when it comes to interneurons, we don't necessarily see any big interaction happening with the BIG box.

I wonder what that says about the little boxes, though. If each little motor neuron has its own input/output box, and other types of neurons send inputs to that box or receive outputs from it . . . does that not still mean that we can have inputs and outputs for every change in behavior? Or can each little box, or each little neuron, do things completely of its own accord, without really connecting itself to any other neuron? It's easy for me to accept that the nervous system as a whole needs no inputs or outputs to do something -- just because so much happens WITHIN the box, without interaction with other things -- but does that mean each little input/output box can also send or receive without interacting with other input/output boxes?

Anna G.'s picture

While I agree that the

While I agree that the brain can be thought of as an input/output box, I think that Jackie raises some very good points. The idea of input "dying" in the brain doesn't seem to be 100% accurate to me. Input may not result in outward output, what we are measuring I guess, but it can result in changes in other processes in the brain. It can stored in memory, to be used later or it can be used to make a conscious decision not to do anything outward. In addition, the idea of output being generated from no input is understandable if you are talking in terms of seeing a response, and finding the stimulus. However, if you have an output generated by the brain, at some point, there must have been some input that changed that area of the brain that generated that output, reducing this to input --> output.


I also liked Angel's comment on how, there are lots of ways in which we can see that neuronal patterns would differ, but in the cases where people are the same, do they really have the same shared arrangements? This reminds me of something I read, where the author mentioned something like this, and asked, "Do you think that if you asked an American kid and a Chinese kid about Mao Zhe Dong, they would have the same thought processes?" Each person learns about different concepts with an internal bias as well as an external one, only reinforced through time. Therefore, people think about the same things, but fire different neurons in their brain. I'll look for the actual quote because it was said much more powerfully, but that’s a summary of the idea.


            Also I ran across a website I think was interesting and applicable, and I’ll post the url here: It discusses the possibility and issues people find when thinking about the creation of a robot that is conscious. Since consciousness and machinelike properties of the brain are being called into question in our discussions, I thought this was applicable. For, if it is (and while I admit it would be incredibly difficult, I believe ultimately it is) possible to create a conscious robot, then we really would have shown the lack of need for a mind or anything of the sort in humans.

eambash's picture


I find your post very intriguing. That "How do you reach the thought of Mao Zhe Dong?" question seems like a good way of balancing the problem of the arrangement of neurons with the problem of finding inputs/outputs. It makes sense to me that even if two people have the same behavior -- and therefore the same arrangement of neurons -- at one particular moment, there is no reason to think they got to that arrangement through the same processes or that they looked at all the same the moment before. One ramification of that might be that if you give several people the same input they might all have different outputs. I wonder what it says about outputs, though. If a bunch of people perform the same behavior, and therefore their neurons probably look similar when they do so, does that say anything about how their neurons were arranged a minute before they did that? Should we even care about how arrangements came to be formed? (I think we should, if we're interested in whether or not outputs need inputs.)

Angel Desai's picture

More inputting and outputting

The idea of inputs and outputs in some respects, certainly gels with my own understanding of the brain thus far, especially in comparison to the other models presented to us in class last week. Reading over some of the other posts it appears that there are a few others who agree! However, I do wonder about a few elements of this overall concept. For example, we emphasized the idea of different arrangement of neurons effectively "equaling" behavior, but I wonder if this is really the case. While this idea does explain the existence of different ideology, personality, and flat-out belief, what about shared concepts among different individuals? Millions of people all over the world believe in certain, shared things despite their differing environments (an example would be religious faith)-does this mean that they have shared arrangements of neurons in certain cases, but not in others (since these people also differ in a million different other ways) And I also wonder how these "arrangements" are related to inputting and outputting-although certain individuals exhibit the same behavior or beliefs, often times it is actually the result of completely different motivations. How does this fit into the neuron arrangement/input-output theory?
mcrepeau's picture

Plasticity and the brain

I'm not sure if I can state that all people who share similar thoughts on important soical subjects, such as religion and politics, have the same arrangement of neurons per say, but I can suggest that if they do have similar neuronal arrangments that it is due, not so much, to the phenomenon that they happened to be born with similar neuronal arrangments (although some genetic predisposition towards certain things could play its part as well), but that similarities in believes and behaviors that revolve, especially around an institution which usually has its own solidified dogma, can be learned and that we can actively (although perhaps unconsciously) re-arrange those input/out box arrangments, and more importantly the connections between those input/output box and how they interact with each other, the potential dialogues they share, etc. After all the brain is an enormously plastic enity and undergoes some pretty profound physical and intrinsic changes as we develop throughout ourlives. Although, the brain is always plastic (we are always capable of learning new things and thus changing the arrangment and connections of neurons) there are several particular times in our development where our brains are particularly plastic. For example, an infant's brain is not the same as an adults brain. An infant's brain generally tends to be more "plastic" and can absorb enormous amounts of inputs and produce a wide range of outputs, feeling out and testing the world around it, finding what can be predictable and patterned (language for instance, a particulalry interesting development interms of plasticity--the window for our word/language lexicon, for example, that we can incorporate and internalize intrinsically and fluently is pretty small, some have suggested only up to the age of three, after which (while we can add words in our own language) attempts of learning other languages outside of out established lexicon is a system of substitution) and what can seemingly not be predictable or patterned. Also, the teenaged brain is not the same as an adult's or an infant's brain, and enters into its own cycle of growth and significant plasticity. It is during these times of particulalr plasticity that we really establish clear patterns about who we are and how we behave through trial and error and through the absorption of enironmental and social cues that seem to influence the arrangement of our neuronal connections, behavior and thought. Maybe it is because brains are plastic, that they are always rearranging and make new combinations, and potentially new qualities etc. that we are able to come to similar conclusions, etc. from different places , i.e. it may not be that people who share similar beliefs, etc. all have neruon 3 in cortical layer 4 adjacent to neuron 5 in layer 3, but that other arrangements else where could have the same effect. Brains change and we learn to act the same.
anonstudent01's picture

Predicatable Behavior

During our discussion yesterday I was distracted for about twenty minutes by the thought of how much we determine due to percieved "patterns of behavior." Parents will change disciplinary measures with their children if they perceive that behavior has improved sufficiently. In a relationship people read behavior as an indication of feelings and can even decide to communicate feelings based on perceptions of their significant other's feelings. Prison inmates are offered parole if their behavior has shown improvement..... their are so many examples even smaller than these in our everyday lives as well.

How then can we make these judgements and decisions if the brain is not in fact predictable? If one input does not have a fairly predictable output? Brain informs behavior, thus if our decided stipulations are correct then everything that we judge to be behavior and respond to ourselves (another form of behavior) is most likely misinformed and incorrect. My summaries of observations are in direct conflict with the idea that behavior is anything but predicatable and I will make an effort to rethink my judgements and choices that I base on perceived behavior.

Jackie Marano's picture

Everything happens for a reason

After some additional thinking about our discussion in class this past week I can state that I agree with our transition from 'stimulus' and 'response' to 'input' and 'output,' repectively. With respect to the relationship between inputs and outputs, I thought a very interesting question was raised in class: is there really a such thing as having NO input...and JUST an output? I have always firmly believed that everything happens for a reason, but as humans we lack the ability to consistently identify the reason. So, even when we say or do something that we would consider to be 'random' or 'without reason,' I am still convinced that biologically something occurred to make us act in that way (whether on the molecular, cellular, or organismal level) to produce an output.

Another related question that comes to mind is: "Is there a such a thing as having JUST an input and NO output?" If the female cricket chooses to be what we might call 'unresponsive' to the male cricket's call, do we or do we not consider that to be an output? If the female decides that she prefers to sleep or to search for food instead of seeking the male, we could consider her movement away from him and towards the location of these activities as an 'output.' And if she stays completely still, appearing to ignore his call (as if she was deaf), I think we could also consider that to be an output. I think it is cricitcal to associate output with both 'action' AND 'inaction.'

On I found some definitions of the word ACTION: "the state or process of acting or doing," "behavior or conduct," "a function or the performance of a function of the body or of one of its parts." So I think that whether the female is active or inactive, she is still acting, behaving, conducting herself in a specific manner, responding, and "outputting." If we claim to observe JUST and input or JUST an output, I think we would be oversimplifying what is really occuring at some biological level. I think there is always an input and always an output (whether it is active or not). I think we are in the right place in our class discussion though with our focus not just on the existence of an input/output structure, but also on the relationship between the two.

Paul Grobstein's picture

"Everything happens for a reason"?

Glad you and Mahvish like the substitution of "input" and "output" for "stimulus" and "response", and agree that there are yet some issues to clarify along these lines. Among them is the meaning of "random" or "without a reason". Perhaps relevant along these lines: Evolution/Science: Inverting the Relationship Between Randomness and Meaning. Maybe also relevant to Emily Alspector's thinking about whether "systems" are "supposed to be reliable and predictable"?

Emily Alspector's picture

Mind Doesn't = Brain to me...

I'm not sure I would equate "random" to "without a reason". It seems like if there is a higher force, everything has meaning and nothing is random, and the opposite is true if one doesn't believe in a greater force. But when it comes to an entity like our nervous system, I would argue that nothing is random, and that every action that occurs within it is the outcome of another action, from either within or without itself.

Also, what is the difference between having meaning and being predictable? I'm not sure I can think of these in the same terms. To me, meaning is associated to the "mind" part of us and predictability is associated with the "brain" part of us. I can't say that a neurotransmitter crossing a synapse has meaning, but it's action is predictable. Similarly, deciding to give up your seat on the subway or not return someone's wallet has meaning, and probably not as much, if any, predictability.

Jen Benson's picture

I really like how you have

I really like how you have equated the mind with unpredictability and the brain with predictability. I do think that believing in the mind certainly can make one feel as if ones life has “meaning,” or something above and beyond what could be explained by neurobiology, genetics, or environmental stimuli or input. Believing in the existence of the mind might eliminate the need for a neurobiological account of unpredictable behavior and instead provide a more parsimonious and attractive account for such actions. I found Professor Grobstein’s reminder that believing in a mind or soul is a more appealing explanation quite important. Perhaps people have evolved psychologically to have this proclivity for believing in a greater un-seeable power (residing within or without individuals). Perhaps an fmri could track the parts of the brain involved in nurturing such a belief.
I certainly find it appealing to consider the possibility that risky behavior and the experience of imagination (as opposed to more rational behavior and reality-focused thought) could be attributable to something unexplainable by biology or the environment. Stories of heroes and artists who have been culturally idealized often emphasize their ability to overcome great odds against them as presented by their biological makeup (like disabilities) or by their backgrounds/cultures/environments (like being really poor or marginalized). I think people prefer to believe that their behaviors and identities are greater than the physical reality of their brains and world. Such movies as Gattaca and Dark City have explored this concept and I provide examples of this desire to believe in the existence of something greater than genetics and experience (environmental input) in explaining identity and behavior.
Paul Grobstein's picture

Dualisms and the brain

Thanks, all, for a rich set of thoughts in last week's forum and in class Tuesday. No, we didn't of course settle the question of whether Descartes or Dickinson was "right". But I came away with a clearer understanding of the issues that need to be addressed by any effort to make sense of human behavior and experience in terms of an organized array of matter with no appeal to an additional something.

Basically, an alternative to a dualist approach can't simply do away with dualisms, but must instead provide a description of a material system that displays dualisms. In particular, my experience (and I think most peoples') is that there is indeed SOME kind of a distinction between behavior that is affected by one's thinking and behavior that isn't, and between being conscious and not being conscious. If that isn't in fact a distinction between mind and brain, then it is going to have to be accounted for by some dualism within the brain.

Similarly, the distinctions between "material" and "spiritual", between "biology" and "psychology", between "rational" and "irrational", between "reality" and "imagination", between "innate" and 'learned", and between "safe" and "risky" are not going to disappear. The question therefore is whether the architecture and function of the brain provides a way to make sense of these and related distinctions that is somehow better than the sense made of them by dualist stories.

We'll see ?

Mahvish Qureshi's picture


After reading over the above posts, I understand and agree with the concept that using the terms input/output make the brain seem like a machine or a computer. Despite the ability of these terms to take away the human-quality of the brain, I feel that they are a better description of the brain's function.

The use of the word response seems to convey a non-passive action. Such as when the doctors test for reflex's and the response is the kicking out of the leg. When a student zones-out or day dreams in class that is not considered a response but more so a lack of a response. However the input of the environment or the lecture is still present but hte response is not an active one, which is why I feel the word output better suits the behavior.

The word stimulus also seems to convey the idea of a direct action, such as poking someone. Input seems to better describe not just actions, but also an environment. Such as the colors and the sounds of the surrondings are inputs rather than stimulus's.

Because of the previous connotations presented by words such as stimulus and response, it seems to me that the terms input/output are better used to describe the way the brain acts and links to the behavioral result of inputs.

Nelly Khaselev's picture

that actually cleared things

that actually cleared things up for me!
mkhilji's picture

Reading over comments and

Reading over comments and after class on Tuesday I think that the idea of our brain functioning off of simply inputs and outputs is plausible, however it makes the brain seem linear and as mentioned by Emily it seems very limiting for other possible behaviors. Going back to the female cricket example, if it decided not to move either in the direction of the male or away from the male can also be interpreted as a possible output. However this concept of inputs and outputs makes me think our brain is like a computer, which is a concept that I am not ready to accept because that would mean that we would have to be programmed differently in order for us to react differently.
Jordan's picture

I know what photographic memory is but whats the mem. with words

Photo graphic memory is a visaul pic in ur head but WHAT IS THE MEMORY WITH WORDS

Nelly Khaselev's picture

Well, we are programmed

Well, we are programmed differently. Every time we experience something new or learn something different, the arrangement of our input/output boxes differ slightly. At least that’s what I gathered from discussion in class. I unlike many people previously stated have no problem with calling the brain a machine. It is an amazing machine! Of which we do not know everything about, yet if ever. And to assume that because we cannot explain certain situations with the brain- input/output box theory, it does not mean we should automatically "fill in the gap" with a soul or spirit. I also would not say to eliminate it as a possibility (even though I personally do not think a mind outside the brain exists). I think that even with the brain being some what like a machine, it sounds harsh but what is the problem with saying I made this choice based on previous experiences my brain has stored, chemical signaling, hormone level, and more not so clear biological "stuff". In class we talked about how many neurons a person has.... A LOT!! The lst thing I picture is a linear system. Now imagine the endless possibilities of combinations and arrangement. I almost have trouble seeing how any behavior could be predicted at all, according to the Harvard Animal Behavior theory it cannot be.

eambash's picture

Duality as an ingrained part of the brain and its external ties

To address both of the above comments, the reason I am okay with the idea of the brain as a system is because I think the word "system" can be defined as a concept much broader than its common-knowledge associations. A system can be by nature imperfect and surprising. That's why the input/output description is more convincing than the stimuli/response one. I think what characterizes this particular system - the brain - is the fact that it IS so odd, so seemingly random, so spontaneous. I see the sporadic nature of the brain as a trait that stands out more than any regularity we see in it.

Granted, in some ways the regular patterns help establish consistency, continuity, credibility, concreteness. If each of our individual systems (or brain-to-body relationships) didn't have a high degree of reliability and predicability, then how could we function from day to day? Similarly, the traits and activities our brains all share enable us to relate to one another and our world with an at-least-acceptable level of comfort, expectation, and self-consciousness.

Still, I think the imperfections serve to ground the "system" concept in a real-world context. If the brain were less sophisticated - or more sophisticated, for that matter - it would be too hard (or too easy) to describe. If everything were random, based ONLY on inclinations or thoughts or morals, I'm not sure how anyone could function in the world. On the other hand, if we could sum up the brain in simple, well-established, extremely logical stimuli/response categories, well, why would we even need to study it? I think the brain is somewhere in between.

Free will and systematization are not mutually exclusive. If crickets' brains were not organized in some way, in some system, then why would males continue to chirp and females continue to move toward them? Their expectations do work, at least sometimes, at least in some way. By that same token, though, the fact that females do not always respond predictably (or at all!) to males' chirps means that uncertainty, randomness, and agency are all a PART of the system - not necessarily built into it or accounted for in any systematic way, but nonetheless things that describe it, complicate it, and result from it.

Humans work in a similar way. It seems as if humans across all cultures, when they can, use available tools and materials to build shelter for themselves and use that shelter in inclement weather. But we all build different types of shelters, and lots of us enjoy being outdoors during bad weather. Some people perform rain dances or ski in the snow; others hide inside as soon as it gets too warm or too cold. How can we account for those differences? By saying that we have free will? By saying that we've grown up in different places and become accustomed to different behaviors? Can't we account for the similarities the same way, by saying we've affected and been affected by each other? Where, then, do pictures of the hypothalamus and readings of hormone levels fit into the description? Can't they show us DOING free will, growing up, becoming accustomed? Can't they let us observe the same things, just by different means, through different lenses?

Both similarities and differences seem to be backed up both by biology and by behavior. Just as we can see, at play in fMRIs, the commonalities and oddities of our internal and external features, we witness the same things by thinking, perceiving, and interacting with other people and things in the world. I think the only way of accounting for both differences and similarities, or at least the only way that both confuses and satisfies me, is to say that we all have agency but ALSO that we're all influenced by systems both inside us and external to us.

Zoe Fuller-Young's picture

Why not?

I am not sure why the idea persists that the brain is a machine. Although we also use the word system, it is still assumed to be some sort of machine that makes sense. Speaking to the idea that science does not provide truth, but rather observations, there are many observations that the brain works as a machine, a system with patterns. However, the brain also makes mistakes. Why do we keep questioning the duality of the brain/mind as the soul/free will as the challenge? What about schizophrenia? Is this a system mistake? I do not think that all systems are reliable and predictable, but rather a set of patterns that sometimes work similarly but often differently, and the brain is an extremely complex system that allows us to think about our input and decide what, and if we will produce, our output. And sometimes, even when we know we shouldn't behave in a certain way, we do... why do we do that?
Emily Alspector's picture

What is a system?

Well, since I am still not entirely convinced that brain=behavior, this model does not account for the mind/soul/self/person, whatever you want to call it. There is no free will? No higher plane? Even with the switch from stimulus to input and response to output, the nervous system is still just that, a system. Even if it is capable of
  • different outputs for the same input
  • taking in inputs with no output
  • generating outputs with no input
  • a "semi-autonomous" input/output box consisting of input/output boxes
then what exactly is the point of the system? Aren't systems supposed to be reliable and predictable? This makes me think that there is more to us than this "system" because inexplicable things occur within it. Pointing out these inexplicable things does not justify the existence of a system, it only causes me to question its existence, or at least, to question its independence of something else.
evanstiegel's picture

Couldn't these inexplicable

Couldn't these inexplicable things still be part of this "system"? In my opinion, us not having an explanation for many of these inexplicable things, is no grounds to dismiss it from being a function of the nervous system.  You say that systems are supposed to be reliable and predictable, but I am not sure if that is entirely true.  There are many other systems in our body that have functions that we have explanation for.  I believe that a scientific understanding of the brain/nervous sytem is in its youth, and perhaps in several years from now these inexplicable things may no longer be inexplicable. 

nasabere's picture

The brain and order in the disorderly

While I'm also inclined to believe that something exists beyond the nervous system which is responsible for the mediation of "behavior," I think it is a bit problematic to associate "inexplicable things" with randomness--or disorder. Perhaps an order, unobservable to the human eye, exists. If this is the case, I find this rather simplistic model to be quite profound.

More on order and disorder (and I apologize in advance for the circularity of my discussion): Is not our notion of order and disorder but a mere human construct? It seems to me that order is inexorably tied to the language with which we speak about these phenomena. That is, as science evolves, so will our understanding of "orderliness"; orders and complexities can thus be created.So, if we are to associate "randomness," in terms of response, (and thus disorder) with the uniqueness of each human experience, then perhaps you are right--some other element may mediate these differences, because a "linear" system can not account for such discrepencies. On the other hand suppose that the so called "randomness" associated with nervous system response is in fact quite orderly--as I am inclined to believe. Then this model would truly be "more right." I think our inability to understand the "orderliness" of the nervous system stems from the fact that modern science has yet to equip us with the skills to understand the mode of its governance. As you see, our modern understandings of "order," "disorder" and even "randomness" are quite subjective and perhaps we might benefit from creating a working definition of all the aforementioned terms before we can address the predictability of the "system" and its endeavors.

I am becoming more confident in this notion of "inputs" and "outputs." If this is "more right," it can be inferred that the brain and its associates are are in  fact very predictable and nothing more or less than a series of input/output boxes. A bit unrelated to this--I am intrigued by the idea of "no inputs" and "no outputs." I've always thought of the nervous system as being in a perpetual state of information exchange. I don't know if I buy that there are moments of pure nonexistent input...