Facial Recognition: A Phenomenon of Our Emotions

The ability to recognize faces is an innate feature that develops extensively throughout early stages of childhood development. Recently developed research has proposed theories for the mode of development of facial recognition, one of which emphasizes human proficiency of recognizing faces which has evolved as a survival technique (1). According to research, the reliance on facial recognition is so high that results show a drastic change of comparison when a human face is inverted; contrastingly, upon the inversion of regular objects such as houses, the recognition of the object remains intact (1). Supplementary to the brain’s inherent tendency to recognize the appearance of a face, there is almost an immediate response of emotional memory that is coupled with the recognition process. The association between a person stored in memory and the face in view allows the identification of another person based on the observation of the face alone. Given this mechanism, there appears to be a hierarchical relationship between facial recognition and a subsequent identification process that follows as a result of information relayed from the region that the face has been processed. While this holds true, even in the absence of recognition of an image of a face, the brain is able to depend almost completely on its system of emotional memory to identify a person; this suggests that the facial recognition relies most heavily on the aspect of the brain that functions to retrieve emotional memory accounts.

Experimental studies have brought forth evidence supporting the hypothesis that stages of facial recognition occur within the fusiform face area (FFA), a site of the fusiform gyrus within the temporal lobe of the brain. Specifically, properties of the FFA include a most highly activated state upon observing human and cat faces versus schematic faces and objects; upright human and cartoon faces as opposed to inverted cartoon faces; complete faces with and without eyes versus eyes alone; and front and profile views versus plain back views of the head (2). The results of the studies revealed an intrinsic tendency of the FFA region to respond to a wide range of faces rather than specifically to a sole feature such as eyes or heads in general (2).

Apart from facial recognition, the ability to recall the identity of a face based on the retinal image processed within the temporal lobe appears to be a separate process that occurs within the limbic system, the site responsible for functions such as emotions and memory (3). In particular, the amygdala is the region associated with emotional memory and can account for the ability to identify a particular face (3). Pathway disjunctions between these bilateral regions of the brain would consequently result in malfunctions of facial recognition processing.

Prosopagnosia, also known as face blindness, is one example of such a disruption in communication between the FFA and the amygdala in which patients suffer an inability to recognize faces, while maintaining the ability to recognize facial features as distinct entities (4). In one of the earliest studied cases of Prosopagnosia, a patient who suffered head injury lost the ability to recognize the faces of friends, family and even his own. On the other hand, he was able to recall these same individuals and identify them through alternative sensory mechanisms such as auditory and tactile senses and intriguingly, other visual stimuli that did not involve viewing the face (4). Evidently, the ability to recall characteristic features of individuals remains intact for Prosopagnosia patients, yet damage to the FFA prevents a concrete linkage between both regions that facilitate the recognition and identification processes. An emotional response is almost always prepared to respond, yet without the presence of face recognition by the FFA, identification of even one’s own face can be destabilized.

Further supportive evidence for an emotional sanction over face identification was provided through a study completed on patients of Propagnosia who demonstrated unconscious recognition of faces. Upon viewing faces that they had seen before, yet could not recognize, the patients demonstrated an emotional response measured through Galvanic skin responses (5). Palpably, there is an unconscious sector to face recognition that remains intact with Propagnosia and is always active in healthy individuals as well; in addition, conscious recognition is a manifestation of the face recognizing areas of the temporal lobe only.

A reverse syndrome of Prosopagnosia is Capgras syndrome, in which patients are fully able to recognize faces, however they believe that the faces belong to imposters of the individuals whom they would normally identify them as (6). This is a situation in which there is a clear presence of face recognition as well as emotional memory, however a lack of interplay between both facilitators hinders the ability to make the connection (6). Nonetheless, the emotional aspect of the processing and identification of the face seems to govern the overall recognition, since a person can fully recognize the physical face yet is emotionally driven to believe that the identity of the individual does not match the face.

The significance of the role of emotions of memory is best exposed in instances in which there is a deficiency of facial recognition due to an abnormality on the part of the facial recognition areas of the temporal lobe. The studies performed on patients who suffer from Prosopagnosia revealed not only the ability to recognize a person on the basis of a present auditory or tactile stimulus rather than face perception, but also a trend of emotional responses from the patient when they saw a face that they had encountered before, regardless of whether or not they claimed to be familiar with the person. This is supportive evidence for the proposal that the prevailing factor of recognition is manifested not in the actual face recognition but rather in the emotions of the memory that is retrievable once stimulated.

References:

1.       Is the Brain Wired For Faces?

2.       Response Properties of the Human Fusiform Face Area

3.       Limbic System

4.       Prosopagnosia

5.       Autonomic recognition of names and faces in Prosopagnosia

6.       Capgras Syndrome