How Well Do You Know Yourself? Measuring Brain Activity During Self-Recognition

What is the self? This question has been fundamental for many centuries, from Aristotle to Freud. Currently, neuroscientists are interested to know how self-related information, such as our own face and name, is processed in our cognitive system to determine the neural representation of the self in the brain.

Thanks to modern neuroimaging techniques, we are beginning to understand how we recognize ourselves. Several studies have shown that the dorsolateral prefrontal cortex and posterior superior temporal sulcus, brain areas associated with attentional control, as well as the fusiform gyrus, a region engaged to face perception, are especially active during self-face recognition. Psychological studies, more focused on behavioral data, also have shown interesting results about the singularity of the self; we are faster and more accurate when recognizing our own face compared to other faces in a broad range of contexts.

This effect, called self-face advantage or self-bias, has been attributed to attentional mechanisms involved during self-processing. Under this view, seeing one’s own face would cause a similar attentional effect as listening to one’s own name, although self-face has some particularities, such as it cannot be shared with anyone else (except for twins), which makes it a more interesting stimulus to investigate the self. However, it should be taken into consideration that our own face is not only the quintessential representation of our identity but is also the most familiar face to each of us. Therefore, it is unknown whether this advantage in recognition is boosted by attention or due to face familiarity, which leads us to the critical question: Is our own face more than a highly familiar face?

Our study addresses this question investigating the temporal dynamics of self-face recognition. Our hypothesis was that self-face involves distinctive neural processing beginning from an early stage, which would indicate that cognitive mechanisms involved during self-face recognition are linked to the idiosyncratic brain response of the self, not to visual familiarity. To test this idea, we designed an experimental task where 25 healthy participants had to identify facial images of three different identities (one’s own face, a friend’s face, and a stranger’s face) while their brain activity was recorded using a 128 electrode EEG system. We also expected to find the same advantage in self-recognition previously seen in other studies, so we additionally collected participants’ response times.

Our results showed that participants recognized their own face faster than other faces, corroborating the self-face advantage phenomenon. Even more interestingly, self-face had a distinctive neural response as early as 200 milliseconds. At this early stage in face processing, self-face is characterized by a lower neural activity compared to other faces. The dissociation between self-face processing and the processing of other faces (either familiar or unknown) happened before reaching facial identity by our cognitive system, which indicates that self-face advantage is not due to familiarity. Rather, the early distinctive processing of the self indicates that self-face perception benefits from bottom-up processing, which is faster than general facial processing, to access to personal information stored in our memory and then achieve recognition. In other words, our own face needs less attentional resources to be processed, which might facilitate its recognition.

Similar to our own name, our own face seems to possess priority in our cognitive system, possibly by its social and personal relevance. Therefore, our own face should be considered more than a highly familiar face, since it leads to information related to us, that is, to the neural representation of the self, in a unique manner.