Social cognition is the name for both a branch of psychology that studies the cognitive processes involved in social interaction, and an umbrella term for the processes themselves.
It uses the tools and assumptions of cognitive psychology to study how people understand themselves and others in society and social situations. For example, it may be concerned with how people select, interpret, remember and act on social information such as language, facial expression, group consensus and prevalent group attitudes or beliefs.
Particularly, social cognition is concerned with how such information is represented and how it interacts with, and is handled by, more fundamental cognitive processes such as memory, attention, perception and problem solving.
Social cognition came to prominence with the rise of cognitive psychology in the late 1960s and early 1970s and is now the dominant model and approach in mainstream social psychology. It is probably true, though, to say that social psychology was always a lot more cognitive than mainstream psychology to begin with, as it traditionally discussed internal mental states such as beliefs and desires when mainstream psychology was dominated by behaviourism and rejected them as illusory.
There has been much recent interest in the links between social cognition and brain function, particularly as neuropsychological studies have shown that brain injury (particularly to the frontal lobes) can adversely affect social judgements and interaction. The case of Phineas Gage was an early and influential example of this finding.
People diagnosed with certain mental illnesses are also known to show differences in how they process social information. There is now a expanding research field examining how such conditions may bias cognitive processes involved in social interaction, or conversely, how such biases may lead to the symptoms associated with the condition.
It is also becoming clear that some aspects of psychological processes that promote social behaviour (such as face recognition) may be innate. Studies have show that newborn babies, younger than one hour old can selectively recognise and respond to faces, whilst people with some developmental disorders such as autism or Williams syndrome may show differences in social interaction and social communication when compared to their unaffected peers.