CHAPTER 2 CONTINUED SOCIAL BRAIN THE ORY ( DUNBAR , 1998 ) most species of PRIMATES live in complex social groups with conflicts , power hierarchies & struggles etc . to function well in a highly social community, one must be able to OUTMANEUVER Others within it which requires attending to a highly complex series of relationships: the great cognitive demands of this is what lead our brains to increase in size. primates that were more successful at navigating the intricate & elaborate webs of social, weather relationships had gr chance at survival , mates , and access to secure sources . SUPPORT FOR THE SBH ... comparison across primate species of the NEOCORTEX RATIO - the volume of the neocortar relative to the volume of the rest of the brain. NEOCORTEX is the outermost layer of the brain that govern . higher functions such as SENSORY PERCEPTION , MOTOR CONTROL & CONSCIOUS THOUGHT 1 used as a proxy measure for intellegence. as our neocortex is the largest amongst primates . > CULTURAL ACCUMULATION is NOT limited to physical tools - in addition to the physical characteristics of the environment , humans are a species CUMULATIVE CULTURAL EVOLUTION THE RATCHET EFFECT INITIAL IDEA > modification time > improvement > time time NEW IDEA CULTURAL WORLDS · Cultural information grows in complexity AND in usefulves over time. Like a ratchet , cultural information can continue to build without losing the earlier information . · modified practise is learned by others, who then add their own modifications and these modifications accumulate over time . · Cumulative cultural evidence requires CREATIVE INVENTION: The tool/ practise needs to be repeated accurately enough that others have a solid foundation upon which to build any future innovations . This would require precise imitative learning and sophisticated communication. · In non-human species, animals learn through emulative learning , but don't build on their technique , as humans do . Humans uniquely have cumulative cultures - in addition to the physical world that we live in, We also exist within CULTURAL WORLDS - worlds that contain cultural ideas that have accumul - ated over time. We are constantly being influenced and learning from shared ideas that make-up our culture. cultural complexity of people living in isdated environment POPULATION SIZE & INTER CONNECTION IMPORTANT FACTORS OF ACCULTURATION How CAN I MAKE IMPROVE - MENTS IN THIS TOOL ? G Reason behind cultural accumulation is that the population has been increasing at a progressively rapid pace & people have been becoming more & more inter connected. how inter- connected the members of the people among the group one. internet also accelerates the race of cultural change. BETTER PERSPECTIVES IDEAS MORE PEOPLE = MORE NEW 1 more innovations come from cities where like minded people are Clustered Cumitowns, industrial Wales . ) The bigger the group, the greater the likelihood of having a successful model to copy and build on in a larger group than i. a smaller group . THE