05_CulturalNeuro.pdf

Cultural Neuroscience Social Neuroscience Professor Jon Freeman Columbia University What Makes Humans Different? Is it complex culture(s) and complex social interactions? But modern human culture (e.g. city dwelling) is too recent to have evolved so must depend on other, more basic, mechanisms: – So...

Cultural Neuroscience Social Neuroscience Professor Jon Freeman Columbia University What Makes Humans Different? Is it complex culture(s) and complex social interactions? But modern human culture (e.g. city dwelling) is too recent to have evolved so must depend on other, more basic, mechanisms: – Social learning (imitation, understanding goals, etc.) – Social intelligence (deception, empathy, mindreading, etc.) These can be found, in degrees, in other species Social Intelligence/Brain Hypothesis main evolutionary pressure for human intellectual development is not the ability to be smarter, per se, but rather the ability to understand and predict complex social interactions, work together, and outwit our peers Pressure to be socially smarter drives other changes (e.g. neocortex ratio) and leads to other benefits (e.g. non-social cognition) Seyfarth & Cheney (2002): Primates ‘live in large groups where an individual’s survival and reproductive success depends on its ability to manipulate others within a complex web of kinship and dominance relations’ Brain Size and Social Intelligence Within primate groups, neocortex measured rather than whole brain Dunbar (1992): Correlation between brain size and size of social group – Predicts human group size of 150 Byrne & Corp (2004): Correlation between brain size and observations of tactical deception Reader & Laland (2002): Correlation between brain size and social learning, but also non-social intelligence (innovation, tool use) Joffe (1997): Brain size correlates with length of immaturity (i.e. greater role for social learning, ‘enculturation’). Culture A shared set of values, skills, artifacts, and beliefs amongst a group of individuals Shared among members of a group Differentiated across different groups Learned via a process of social learning from person to person, both within and across generations (not innate) Culture itself may evolve independently from genes (memes) CULTURE-GENE CO-EVOLUTIONARY THEORY Cultural differences in the self Marcus & Kitayama Cultural differences in the self Marcus & Kitayama 5-HTT 5-HTTLPR (serotonin-transporter-linked polymorphic region) Serotonergic uptake transporter gene Two main variants: long (l/l) = more serotonin uptake short (s/s) = less serotonin uptake – More susceptible anxiety, conditioned fear responses, etc. Chiao & Ambady (2007) 5-HTT Hariri et al. (2002) Cultural differences in 5-HTT expression l/l s/s l/l s/s Chiao & Ambady (2007) Cultural differences in 5-HTT expression Chiao & Ambady (2007) Cultural differences in 5-HTT expression IND-COL anxiety 5-HTT mood disorders Chiao & Blizinsky (2009) Cultural differences in 5-HTT expression more collectivism vs. individualism in the region having more s vs. l carriers in a region s se ea cr de s se a re inc increases levels of anxiety/mood disorders in the region s carriers actually have reduced levels of anxiety due to increased collectivism (if it weren’t for collectivism, they’d have increased levels of anxiety) Chiao & Blizinsky (2009) Cultural neuroscience approaches Cultural mapping Mapping function between cultural patterns (perception, cognition, behavior) and neural patterns Source analysis Attempt to discern the sources of observed commonalities and differences Culture, reward, and behavior From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Freeman et al. (2009) Culture, reward, and behavior From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Freeman et al. (2009) Culture, reward, and behavior From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Freeman et al. (2009) Independent vs. interdependent self Trait processing (e.g. brave, childish) of self, mother, and famous person Mother more closely linked to self-concept in Chinese From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Zhu et al. (2007) Self Concepts AnalyticalCross-Cultural vs. holistic perception Hedden et al. (2008) Self Concepts AnalyticalCross-Cultural vs. holistic perception Analytical vs. holistic perception Reading “I” versus “we” narratives affects later global versus local processing (Chinese participants) Lin & Han (2006) Analytical vs. holistic perception Computer mouse-tracking Analytical vs. holistic perception Lin et al. (2008) show ERP differences at 100msec Masuda et al. (2008) Analytical vs. holistic perception Masuda et al. (2008) Computer mouse-tracking Computer mouse-tracking congruent neutral incongruent ASIAN WHITE CONTEXT PROCESSING Computer mouse-tracking Freeman, Ma, Han, & Ambady (2013) Analytical vs. holistic perception Blais et al. (2008) Analytical vs. holistic perception Jack et al. Cultural emotional “dialects” e.g., Ekman, Matsumoto Emotion is universal, but display/decoding rules may exhibit cultural differences e.g., Elfenbein, Ambady Emotion may in part be universal, but there is a culturally specific component as well From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Cultural emotional “dialects” From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Elfeinbein & Ambady Cultural emotional “dialects” From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Chiao et al. (2007) Cultural emotional “dialects” From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Chiao et al. (2007) Reading the mind in the eyes (RME) From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Adams et al. (2009) Reading the mind in the eyes (RME) From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Adams et al. (2009) Reading the mind in the eyes (RME) From Zhu et al. (2007). Copyright © 2007 Elsevier. Reproduced with permission. Adams et al. (2009) Cultural neuroscience Culture-gene co-evolution Genetic selection of serotonin transporter and cultural selection of collectivism/individualism co-evolved (Chiao et al.) Cross-cultural differences in individualism/collectivism Reward responses in striatum and related behavioral tendencies Self representation in the vmPFC Differences in visual and attentional processing Facial emotion processing in the amygdala Reading complex social cues in STS ORIGINS OF CULTURE The ‘Culture Pyramid’ An Experimental Example Whiten et al. (2005) Social learning of a ‘tradition’ Social conformity once learned From Whiten et al. (2005). Copyright © 2005 Nature Publishing Group. Reproduced with permission. Non-Human Cultures and Traditions Information transfer in mammals, birds, fish, and some invertebrates, such as bees Traditions in birds (e.g. song learning) and possible culture in New Caledonian crows (multiple types of ‘tool use’) Non-Human Cultures and Traditions Culture in monkeys and apes – E.g. Perry (2003): Different distributions of lots of social games (e.g. hand-sniff-game, toy-game) amongst capuchins Cumulative culture present in humans (alone?) Mechanisms of Social Learning Imitation – reproducing the goals of another person Copying the action without understanding the goal of the action (also called mimicking); an example would be ‘talking’ parrots Stimulus enhancement or local enhancement – drawing attention to an object or location may facilitate self-discovery. Contagion – repetition of behaviors that are innate rather than learned, such as yawning and laughing Imitation by Human Infants Imitation in Non-Human Primates? Remains controversial: – Potato washing and using sticks to get food could arise from stimulus/location enhancement. Some leading researchers (e.g. Tomasello) have changed their position and come out in favor of true imitation in chimpanzees. Imitation in Non-Human Primates? Evidence Chimps (but not macaques) capable of learning a do-as-I-do game (e.g. put thumb in fist); requires training, but flexible thereafter (Custance et al., 1995) Understanding of goals: using tool to get rewards, chimps omit irrelevant stages (Horner & Whiten 2005) Imitation in Non-Human Primates? Evidence for goal-based imitation in chimps but: – Why is evidence for cumulative culture scarce? (lack of innovation?) – Imitation not prevalent in wild, often requires some form of training in labs – Imitation may serve a more social function in humans (we like being imitated, and we imitate people we like) whereas imitation in chimps may be used to obtain personal rewards (e.g. food) Tools, Symbols, and ‘Extended Cognition’ Neural recycling = neural resources, set aside for other functions in the evolutionary past, can be recruited by cultural innovations – E.g. Reading and number recognition recruit similar resources in different brains and different cultures (despite being a cultural invention) Extended cognition = the material world and cultural symbols can expand the cognitive capacities of humans Tools, Symbols, and ‘Extended Cognition’ E.g. Different cultural systems for representing numbers leads to differences in cognitive performance Tool-Use Modifies Neural Representations Receptive fields identified by: (a)= tactile stimulation of hand, (b)-(d) = visual stimulation near hand/tool Mirror Neurons and Imitation Respond to observed (by other) and executed (by self) actions From Rizzolatti et al., 2006. Reproduced with permission from Lucy Reading-Ikkanda for Scientific American Magazine. Characteristics of Mirror Neurons Respond to implied actions Overall, evidence suggests an abstract coding of action related to intentions, and common to self and other Characteristics of Mirror Neurons Respond to same goal with different actions (Umilta et al., 2008) A Potential Problem to Mirror Neurons across Species Monkeys, chimpanzees, and humans all possess mirror neurons However, different species differ dramatically in their spontaneous use of imitation and tool use Macaque monkeys require 10–14 days of extensive training using a special regime to use the rake tool; tool use in the wild by this species is limited to bending branches in order to get fruit from trees Infant macaques can imitate tongue protrusion, etc. (Ferrari et al., 2006) but is this imitation or contagion? Why don’t they imitate tool use after a single exposure, like humans? Conclusion – there is more to imitation and tool use than mirror neurons A Potential Solution to Mirror Neurons across Species Examine what is different in the brains of macaques that have mastered tool use (after extensive training) relative to novices (Iriki & Sakura, 2008). Changes in gene expression in intra-parietal region induced by tool use, plus: – Extra connections between intraparietal sulcus (containing multisensory neurons and mirror neurons) and the temporal-parietal junction in those that have learned tools – Perhaps such pathways are innately present in humans (and chimpanzees?) but are only present in monkeys as a result of deliberate training Summary Multiple mechanisms of social learning across species (imitation, stimulus enhancement, contagion, mimicking) Other species socially learn and have traditions, but most researchers believe only cumulative culture present in humans Tool use facilitated by multisensory neurons found in nonhuman primates Controversial if imitation exists in other primates, but certainly exists in humans including human infants What makes complex culture unique to humans? – Can’t just be existence of mirror neurons – But maybe it’s the gene expression of those neurons and their pathways to other regions (e.g., theory of mind regions, TPJ)