The genes we inherit from our parents influence our psychological characteristics – things like our intelligence and memory ability – and our chances of developing conditions that affect the way we think, such as autism and schizophrenia. In that sense, identical twins – who share all the same genes – do think more alike than unrelated people or even non-identical twins and other siblings. Brain-imaging research has shown that during mental tasks, such as memorising numbers, the patterns of brain activity (which can be considered a physical correlate of thought) are more similar among identical twins than non-identical twins.
