Introduction to Psychology Culture and Identity Prof. Jan Lauwereyns

Lateralization of Brain Function Two hemispheres are not mirror images of each other – left hemisphere controls right side of body – right controls left side – taste and smell input to same side Lateralization is the specialization of labor between the two hemispheres – left hemisphere specialized for language – right specialized for complex visual-spatial tasks and synthetic processing What about language on the left?

Left brain, right brain Why should there be such functional segregation? – Advantages of specialisation? – Of parallel processing? Do monkeys have it too? Or does it originate with language?

Handedness and Language Dominance Right handedness a heritage – 10% of people are left-handed or ambidextrous – 90% of prehistoric drawings show tools in right hand – most chimps and other primates are right handed Left handers – have equal as well as left or right hemisphere dominance for speech if right is dominant, left hemisphere contributes more to spatial perception – Corpus Callosum is thicker for greater communication

Not quite as famous as Sir Edmund Hillary, but…

Where does Corballis get his idea? Corticol control of manual movements Primates acquiring sign language The mirror system in monkeys Left hemisphere for speech and hands Deaf use sign languages with full syntax Nonverbal gestures during speech FOXP2 gene mutated about 200,000 years ago

FOXp2

Corticol control of manual movements Primates acquiring sign language The mirror system in monkeys Left hemisphere for speech and hands Deaf use sign languages with full syntax Nonverbal gestures during speech FOXP2 gene mutated about 200,000 years ago Where does Corballis get his idea?

The mirror system Ventral premotor area – monkey homologue of Area 44 in frontal cortex, that is, Broca’s Area Studied by Rizzolatti and co.

The mirror system Neurons in ventral premotor area …activated both when the subject performs an action and when the subject observes someone else perform the same action Abstract action representation This system likely plays a role both in recognising and planning actions (“thinking about actions”)

Mirror neurons and imitation? (But monkeys don’t imitate much)

Importance of the mirror system? Understanding action? Origins of language? Empathy? Morality?