ANT 154B Course notes- Lecture _7

ANT 154B Course notes- Lecture _7 - ANT 154BN Course notes...

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Unformatted text preview: ANT 154BN Course notes Lecture #7: Brains & cognition 25 January 2011 Key terms and concepts are indicated in blue Outline 1. Brains 2. Social and ecological intelligence 3. Tool use and intelligence 4. Tool diffusion and transmission EQ Measuring relative brain size = Encephalization Quotient = observed / expected brain size 1. Brains As usual, we must plot relative size Log (Brain Weight) C O G Correlates of larger brains ‘EBR’= (Neocortex + striatum) / (Brain stem) Log (Body Weight) Behavioral innovation Social learning Tool-use Another method of comparison, on evolutionary time scales: independent contrasts The method of independent contrasts Values of Y 7 8 9 14 17 Y d1 d2 2 6 X 4 10 Values of X 20 20 22 24 30 40 35 10 Contrasts in Y 0 0 d2 d1 d3 d1 d3 d2 15 Contrasts in X ANT 154B Lecture #7 course notes Brains are metabolically costly Humans have large brains page 2 of 7 Humans How can we afford them? Brain size (all primates) The expensive tissue hypothesis Body size The expensive tissue hypothesis Allman et al. 1993 Human have larger brains and smaller guts than predicted based on body size. The expensive tissue hypothesis Human have larger brains and smaller guts than predicted based on body size. Larger brain More energy available Aiello & Wheele Higher quality diet Reduced food bulk, energy rapidly absorbed More energy available Smaller gut requires less energy Aiello & Wheeler 1995 • key point: elements of diet, ecology, and life history are intimately tied together ANT 154B Lecture #7 course notes page 3 of 7 2. Social and ecological intelligence Types of intelligence Social intelligence Alliances Tactical deception/perspective-taking (TOM) Ecological intelligence Spatial memory Tool use The “social brain” hypothesis Social Intelligence Hypothesis: Runaway directional selection for social cognition in primates Conspecifics are competitors Group living aggravates competition Mean social cognitive ability increases selective advantage to individuals successful in inter and intra group competitions Social problem solving abilities (social cognition) predicted as target of selection All wild chimpanzee populations have traditions ALL TRADITIONS 40 35 30 25 20 15 10 5 0 0 5 10 15 20 25 30 35 40 Kibale Budongo Mahale-K Tai Bossou Gombe Tai Mahale-M Bossou Gombe Budongo Mahale-M Kibale Mahale-K still rising ! YEARS OF STUDY ANT 154B Lecture #7 course notes page 4 of 7 3. Tool use and intelligence Differences among taxa Sex differences in tool use: chimpanzee termite fishing Sex differences in tool use: chimpanzee termite fis Sex differences in tool use: chimpanzee termite fishing Female chimps Female chimps • fished 27 months earlier than males • more proficient than males • fished 27 months earlier than males • more proficient than males (more termites (more termites per dip) males did not per dip) whereas Lonsdorf et al. 2004 • used • used mother’s technique, mother’s technique, whereas males did not Lonsdorf ANT 154B Lecture #7 course notes Assessing cognitive ability techniques have lots of limitations aspects Cognitive page 5 of 7 of tool use: Encephalization quotient Comparing brain size Homo EQ = observed brain weight/ expected brain weight (based on body size) Macaca Pan Papio Cebus Cognitive aspects of tool use: Gorilla Pongo Neocortex index Panger 2007 Homo Neocortexobserved= EQ = index brain weight/ expected brain weight size of neocortex relative (based on body to the rest of the brain size) Pan Gorilla Macaca Cebus Other tests Panger 2007 ANT 154B Lecture #7 course notes page 6 of 7 4. Tool diffusion and transmission All populations use tools... … but not all use tools for food 12 Number of tools number of observed tools observed ALL TOOLs (total) 30 Tai Bossou Leaf-grooming Gombe 25 All Customary or customary or Habitual habitual Food-Tools food-tools Tai Bossou Gombe Tai Mahale-K Mahale-M Budongo Kibale 10 8 20 Mahale-M Tai Bossou Gombe Kibale Mahale Budongo Kibale Mahale-K 6 Bossou Gombe Mahale-K 15 4 10 Budongo 2 Budongo Kibale 0 5 10 15 20 5 Mahale-M 25 30 35 40 0 0 0 5 10 15 20 25 30 35 40 years of study Years of Study Years of Study years of study Extant chimpanzee range Mt. Assirik Bossou Tai Lopé Budongo Kibale Gombe Mahale Cultural diffusion Hand-clasp groom Nut-smash Present Absent (but nuts present) Present Absent ANT 154B Lecture #7 course notes page 7 of 7 Support for diffusion: similarity correlated with distance orangutans Population variation in tool use: orangutans chimpanzees chimpanzees Due to opportunities for transmission? van Schaik et al (2003) Science van Schaik et al (2003) Science Take home messages 1. Large brains are associated with increased social learning, behavioral innovation, and tool use. 2. A species’ ability to use tools does not necessarily correspond to other measures of cognitive abilities. 3. Tool use is ubiquitous in chimpanzees, but the number and types of tools differ substantially. 4. Cultural transmission of tools in apes appears to be a function of geographical distance, and perhaps the amount of time spent in contact. Question to ponder FortrstXa of today Central readouthpaperallHerof particular cat ia hetvily has lanteenbaed dset. wC @_ * riimates p class ibrget both eolropical aprirnate pAmenca. which hypothesized that dietary distribution of tropical plant foods served n N you nd S a ecies, svhich nterut pb the the as a key evolutionary stimulus for the evolution of primate intelligence (Milton 1981). DistributionPatternsof Tropical Plant Foodsas an Evolutionary timulusto PrimateMentalDevelopment S KArRl{ARINE. MILTON tJnivers*y J Caltvornia, erkeley o B Pnmatesare notedfor the* mentalabititiesbut thc selectlue a5isor suefitrAtt5 has rebf mainedobscure.It ts hypothesizedhat the elementof predtstablltyassociated iththe t w stntial and temporal isinbutionalterns d p of plangfoodsin tropicalforests as se1vedto h stim1ltate entaldevelopmerlt ptamatesakng muchof theirfoodfromthefirsttrophic m in t leuel.Primates bleto rememberhe locations nd phenological atterns f a widevanety a t a p o of planl foods could moue directb to s7schoods when and wherenwtlable without f wasting ime and energyin rarldomearch.Thiswouldenhanceoverallforaginguccess t s J by loweringproctlrement O5t3 associatedwith a wned and patchtXdutnbutedptant C diet. Membershipn a cohesive50cta lingt,that axtilizedhe sumesupplying l t area aveT many consecUtive generations, wouldalso enhancerc>raging success bysenengto tranamit tmportant nMormation diet ta closekm. Dntaon theforaging behasiorof howter t about and spgder onkeys re presented o te5t certsin 'teple'catt'UnJ m a t of thu hyp?*thesis. .Stmtlur selective ressures} ut appitedtoffioodsTom he secondtrophiclevel, mayhauebeen?r p b J t crttical mportarice the mentaldevelopment f homintds. primates, evolution, intellii m o [ gence, plant foods, Aleles, Alouatta] MOSf'rP^lMArM SItOW A NEMARKAUI, CwAI'^(;IlYfor learllingand retellti{ n. As l)oted hy Eisenberg whatappearto set primatesocietiesapartfromthoseof otherrelatively longwlivedrsdlarge-brained nimalsare particularsets of attributesrelated to the a a storageand retriearal a greatdealof independently cquiredinfoxmation boutthe enof a a arironment. he complex brain of higher primatesfonns the basis for a T (1975)t Discuss the logic of this hypothesis and the main pieces of evidence used to assess its validity. Explain whether and why you find these arguments plausible. How might a) broad comparisons across the primate order and b) consideration of non-primate taxa be used to address this question? ...
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