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For this lab we focused on the question of whether or not the origin of a stimulus affected reaction time. After fixing electrodes to the participant's dominant thumb, we poked the participant in the calf, knee cap, and stomach. We recorded the time that elapsed between the poking stimulus and the button-pressing reaction, as well as the time between the poking stimulus and muscle action. Using these two values we were able to calculate the time elapsed between muscle action and the instant of button-pressing. Each participant was subjected to two trials (two calf, knee, and stomach pokes, respectively). We took the average time elapsed between (t1) poking stimulus and button-press, (t2) poking stimulus and muscle action, and (t3) muscle action and button-press.

Our results are as follows:

David:

Calf: t1=.1325 s, t2=.192 s, t3=.0595 s

Kneecap: t1=.149 s, t2=.214 s, t3=.065 s

Stomach: t1=.155 s, t2=.219 s, t3=.064 s

Julia

Calf: t1=.1775 s, t2=.2205 s, t3=.043 s

Kneecap: t1=.188 s, t2=.2395 s, t3=.0515 s

Stomach: t1=.174 s, t2=.214 s, t3=.040 s

We standardized stimulus on the same side (if the participant was right handed, we poked their right calf, their right knee cap, and the right side of their stomach) and we made sure the participant kept his/her eyes closed. This was meant to control for the variable of anticipation. The participant did not know when he/she was going to be poked and thus could not "prepare" for a more swift reaction.

Initially our hypothesis was that the distance between the origin of stimulus and the brain would increase the reaction time, but our data proved inconclusive on this point. On the whole, it was hard to isolate a trend between the two sets of data. One thing we did notice is that Julia's t3 (the time elapsed between muscle activity and button-press) was consistently lower than David's t3. We hypothesize that this is a result of David having a larger thumb muscle; because the muscle is composed of more cells the orchestration required to press the button would take longer.

Further testing would, of course, be necessary, due to the nature of experimenting on complex organisms such as humans.

Also, it is worth noting that Julia actually had the fastest reaction time recorded, with a t1 time of .098. Do not be fooled by our title.