Facial expression responsible for controlling the expression differ in each case. Voluntary facial expressions are often socially conditioned and follow a cortical route in the brain. Conversely, involuntary facial expressions are believed to be innate and follow a subcortical route in the brain. Facial recognition is often an emotional experience for the brain and the amygdala is highly involved in the recognition process. The eyes are often viewed as important features of facial expressions. Aspects such as blinking rate can possibly be used to indicate whether a person is nervous or whether he or she is lying. Also, eye contact is considered
Facial symmetry face is evaluated by human brain via the facial recognition process. This fast and effective detection is difficult with computer programs. For instance, the faces that were considered to possess a strong aesthetic appeal were the ones where the conjunction of similar or corresponding facial features were, to some extent, contrasting. Likewise shared features echoism, proportions and similarity to people the person bonded to early in life (prima copulism) have been suggested as relevant. Research indicates that facial symmetry is linked to the 'big-five' model of personality. The most consistent finding is that facial symmetry is positively correlated with extraversion,