We usually express out feelings and thoughts verbally. But no one ignores the face of a person he's talking to - emotional contact is of no less importance than information transfer. For reflecting their emotions human beings are equipped with facial muscles of expression (only human beings and other apes have such muscles). Evolution has taken care of it. But every one has its own ability to read emotions on the faces. This ability and brain parts responsible for that are subjects for the studies of scientists from Science Centre of Mental Health.
Researchers suggested young men and women to recognize expressions of joy, rage and fear on a photo appearing on a computer monitor only for 40 ms. The testees should have pushed "forward" button, if they thought the face was joyful, "backward" button, if they saw fear and "right" button if they saw rage. Experimentators have measured reaction time and correctness of emotion recognition. In the second series of studies the scientists have recorded electric potentials of various parts of cerebral cortex through electrodes placed on top of a head. These so-called "induced" potentials appear when the brain reacts to visual stimulus.
Joy causes the fastest response and the least number of mistakes, and fear is the most difficult emotion to recognize - testees have had the longest reaction time and maximum mistakes. It is notable that those testees, who had high level of personal anxiety (detected through several tests before the experiment), had the fastest and the most correct reaction to fear. Men, compared to women, have estimated rage and fear emotions more correctly, though their reaction rate was lower. Even mistakes of the testees could be arranged according to gender of a testee: women have made mistakes due to answering too fast, and as for men, they often haven't managed answering and missed the stimulus.
What was going on in the brain during the experiment? Induced potentials can somewhat tell us about it. The scientists have measured the potentials in occipital, temporal and frontal cortex in response to every visual stimulus. In the moment of recognition of any emotion the potentials have changed their amplitude and origin time (latency). The type of emotion most clearly affected certain electric wave ("P150 wave") in the temporal cortex. When one recognized fear, for example, P150 amplitude has been twice as low as for other emotions. The scientists think that temporal cortex is responsible for facial expression recognition. It is where something like structural coding of facial expression takes place - it detects changes in eye, mouth and nose geometry, their relative positions, bending and inclination.
Analysis of electric activity confirmed the idea that those, who are inclined to anxiety and melancholy, recognize fear more accurately than joy. This fact is easily explained, because part of the brain responsible for emotion recognition lies very close to the part, which forms personal emotional ground. So people with melancholic personalities should be more sensitive to the feelings of other people than those with cheerful sanguine type of personality.