Psychobiology III

Solution

- Consider INDIRECT (genetic) benefits was well as direct benefits • Inclusive fitness: the total fitness that an individual gains, by breeding itself and by helping close relative to breed • Key Point: individuals can increase THEIR OWN FITNESS by helping relative to breed because relative share copies of their genes • Kin selection: the process by which character...

Reciprocal altruism

- Kin selection has the potential to explain altruism if donor and recipient of altruism are related. But sometime unrelated individuals engage in latish • Reciprocal altruism - provided that the benefit of an altruistic acts to the recipient is greater than the cost to the don't, then as long as the help is reciprocated at a later date both participants gain - one of first reported cases: in olive baboons, unrelated males appeared to assist each other in getting matings -- debate now about whether this is RA or mutualism (both benefiting at the same time) • Reciprocal altruism VERY rare in animals - most of reported cases can be explained by other mechanisms (e.g. mutualism, exploitation by dominant ) - lack of conclusive examples

Machiavellian intelligence in primates

Considered by Andrew Whiten and Richard Byrne • Look at social manipulation in primates • Collated anecdotes of 'tactical deception' from primatologists • *Machiavellian Intelligence hypothesis* - acting manipulatively, tactical deception • Tactile deception: short term tactics where elements from an honest counterpart in the individual's repertoire are used in a functionally deceptive act Tactile deception - concealment - hiding behind rock - distraction - pretended there was a predator and then escaped - creating an image - manipulation of target using social tool - deflection of target to a fall guy - concealment of deception • Concealment & distraction were most commonly reported types of deception in primates - baboons and chimpanzees most deceptive • Note - many of these categories are connected with manipulation and monitoring of causal attention • BUT anecdotes are not sufficient to demonstrate intentional deception - i.e. deception that involves manipulations of another individual's mental state --> don't know that they were intentionally trying to deceive

Secondary sexual traits

-Where heritability variation in the factors that cute differences in success in intra-sexual competition and inter-sexual choice generates selection in the competing/chosen sex for increased body size, weaponry, and sexual displays --> variations often occur on the competing sex (often the males) -- leads to the dramatic differences between the appearances of the sexes of the same species = sexual dimorphism

Human evolutionary psychology

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Comparison of facial expressions

Possible to identify emotional faces in chimps • Developed Facial Action Coding System FACS in humans and chimps - originally developed for humans - Action units in human and chimp face • Allowed them to show that there is convergence of action units involved in particular expressions - parallel in anger and submission displays • can objectively compare what muscles are involved - have now expanded this coding to other animals = animals outside of the primate lineage can be seen to produce expressions as well

Social behavior & communication

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Appear to be high level strategies in territorial behavior and co-operative hunting

• *In aggressive interactions* - between different communities elaborate strategies are evident - numerical assessment (experiments by Wilson & Hauser(, silent patrols (males appear to actively search for signs or presence of neighbors by patrolling alongside or within their territories - infiltrations characterized by silent progression) • *Sophisticated 'collective' hunts* - with hunters performing complimentary roles all directed towards the same pray - chasers wo pursue prey pressing them forward and ambushers tho go ahead, apparently anticipating escape direction, and force prey back; a lot of individuals variation in strategy and success rate

Most common mating systems

• *Polygyny* - multiple females per male • Can occur in a number of different forms - in *one-male units* - e.g. Hamadryas baboons - males control tight-knit haram of females - in *multi-male multi-female groups* - e.g. Olive & yellow baboons - males for consorts - lots of competition between males for the sexually receptive females - males try to form consortships with sexually receptive females - males guard the female and exclude other males - duration of the censorship depends on the dominance of the male - in *multimale-multifemale groups* - e.g. parry macaques - mating is highly promiscuous

Language-like abilities in animals

• *Semantics* - animals seem to share semantics with us: animals can attach acoustic labels to objects and events • But little evidence of *Syntax* - high order structure - grammar - certainly nothing equivalent to humans Duality of Patterning (where meaningless phonemes are combined into morphemes and words, and words are combined into sentences • Syntax evolved in the human lineage, while semantics is shared among more species

Sexual selection in humans

• *Sexual dimorphism* (males/females looking dif based on sexual selection) important factor likely to be selection on males for success in contest against other males (intra-sexual competition) - but also remember mate choice - larger body size and greater upper body strength in males than females - more bodily and facial hair in males (note beard confer no obvious survival advantage) - enlarged breasts and buttocks in females ==> evidence that sexual selection is present • Human mating systems are indeed predominately polygamous: - marriage patterns in 849 societies (from ethnographic atlas - primarily pre-industrial societies) -- polygamy leads to more sexual dimorphism in males

Social organization - Mating systems

• *Social organization* - how animals interact with and space themselves in relation to other individuals of the same species (quality as well as the quality of social bonds are important in describing social organization) • *Mating system* - describes the way that individuals obtain and bond the mates (the number of mating partners that individual males and females obtain is a key issue)

MATING SYSTEMS Solitary // Monogamous family units

• *Solitary* - e.g. orangutans - sexes live apart - come together for mating - have overlapping home ranges = may interact = solitary but social • *Monogamous family units* - e.g. gibbons - long term pair bond - male and female (with offspring) jointly defend territory using elaborate song - jointly take care of offspring • *Polyandry (very rare)* - e.g. Tamarins & Marmosets: - several males bonded to one female - male parental care - 2 or more adult males with the female, extra male helps carry the young (they generally have twins = extra male is very useful)

Complex social organization

• *dominance hierarchies* are the most prominent - i.e. barbary macaques • Fights are costly - rank helps to know who will win and lose and thus who not to fight - can plot dominance hierarchy according to who wins and loses fights - depending on where they lie on the hierarchy they will or will not engage in fights - try to slowly work their way up

Sexual selection is generated by 2 key processes

• *intra-sexual competition* - competition between members of the same sex over mates • *Inter-sexual choice* - choice by members of one sex for particular mating partners of the opposite sex --> this competition made the secondary sexual traits evolve overtime - larger body and antlers, etc. --> if these are actually reliable indicators of fitness then these will be continued to be used on in evolutionary time

Acoustic cues

• Acoustic cues in the roar are also important in assessment: - Lower vocal tract resonance (more baritone roars) indicated larger stags (Fitch & Reby, 2001; Reby & McComb, 2003; Reby et al. 2005) - here honestly is generated by a physical constraint (exactly how long their vocal tract is) • NB signal reliability generated by two routs: energetic cost and physical constraint

Cognitive bias in animals

• Animals trained that on cue predicts a positive event and another a negative event - Subjects then presented with ambiguous (intermediate) cues - initial evidence that animals in a more negative affective state are more likely to judge these ambiguous cues as of they predict the negative event (pessimistic response) • NB Positive emotions and Animal Welfare: - well-being is not simply the absence of negative emotions, but also (and even predominantly) the presence of positive ones = also important

Sexual displays

• Bring sexes together for mating and influence outcome of: - Intra-sexual competition - Inter-sexual choice • Information is transferred via signals (and more static ties) that may be visual, acoustic or olfactory (chemical/pheromonal)

Evaluate the reliability of studies

Female orgasm & mate choice - Up-suck hypothesis: female organism functions to suck ip sperm during copulation - leads the cervix to gape and dos into the seminal pool • Women with partners that had low fluctuating asymmetry (and their partners) reported significantly more copulatory female organisms than were reported by women with partners that had high fluctuating asymmetry • This sort of study should be treated very cautiously - need to question how reliable such data (based on self report) would be - highlighted that you have to be critical about evidence

Evolution of behavior

Following Lectures: - Evolution of emotion - Social behavior and communication - Sexual behavior and communication - Cognitive abilities in animals - Primate social and mating systems - Human evolutionary psychology

Hare et al. - Theory of Mind

• Chimpanzees could seen through trap door - could see where experimenter walked - couldn't directly seen the food when it was placed down - when opened the trapdoor and let the 2 into the arena the subordinate always let the dominant get the food - In the experimental condition = screen over dominant's door = can't see - when opened, in this condition the subordinate always rushed to get the food because he know that they dominant didn't know there it was • In another, when the dominate saw the placement, but then was switched out with another dominated , subordinate rushed to the food just as before • = know what the other sees, and how the other is that is seeing it

Recent evidence that wild chimpanzees may be aware of knowledge and ignorance in others

• Chimpanzees more likely to alarm call in repose to presentation of a snake (model vapor) in the presence of unaware group members (than aware group members) -- if they had seen the snake, or had heard a previous snake alarm call = less likely to produce the alarm call -- if the chimps were ignorant = more likely to call ==> the have an understanding of the knowledge states of other • ==> *some evidence that chimps have some degree of theory of mind* even if it is not elaborate as ours

Possible assessment cues in human mate choice: Symmetry in morphological characteristics

• College women sniffed and rated the attractive of the scent of 41 shirts worn overnight by different men • Women near the peak of fertility prefer the scent of symmetrical men - this preference is not found during the low fertility parts of cycle • Male symmetry calculated on bail of measures of characteristics such as ear length, ankle width, and finger lengths on the tow sides the body

Sexual selection in humans: Sperm competitions

• Competition between sperm from different ejaculates/males for fertilization of eggs produced by a single female • Human testes size suggests adaptation for multi-male mating system - although indicates not as much sperm competition as in e.g. chimps • Penis is longer, thicker and more flexible in human males than in non-human primate males = there has been a little selection for sperm competition • Baker & Bellis: ejaculates collected in condoms from subjects at Univ. of Manchester • The less time the couple has spent together (i.e. the greater the risk that the female has copulated with another male( the more sperm the male ejaculates (controlling for time since last ejaculation) • But the amount to sperm in masturbatory ejaculates does NOT depend on proportion of time together

Kin selection: Caring of genetic offspring verses stepchildren

• Completely indiscriminate allocations of resources between kin and non-kin would be something of an anomaly in evolutionary terms • Daly and Wilson present evidence that children living with step-parent are more at risk of physical abuse (controlling for other potentially confounding variables such as socioeconomic status) than those living with natural parents • Many families with step-children function extremely well - but these results suggest simply that underlying psychological mechanisms may make investment in non-kin more difficult • Adapted from Daly and Wilson • for pre-school children, risk of bing on child abuse register is 40x greater in homes with one natural and on step-parent • Various criticism can be leveled at these results but the findings are very consistent across studies - the pattern seems to be consistent across culture

Chimps and humans are similar in some ways:

• Complex fission-fusion social system - elaborate strategies in territorial behavior and co-operative hunting (suggesting anticipation and planning); evidence of lethal aggression, mainly by males in inter-community attacks - ability to fashion and use tools in unusually diverse and flexible ways

Characteristics of primate social groups

• Complex social organization - irrespective of mating system • Based of a variety of long-term social relationships • Dispersal of males or females at adolescence - different systems have different impacts -- dispersal happens when adolescents reach sexual maturity - prevent interbreeding - if females remain in the group then they are more closely related - males will come in when they reach sexual maturity - in female dispersing specific (male philopatchy) • Most common is to have the males leave and females stay

Darwin's theory: evolutionary change thrgouh natural selection

• Continual competition between individuals in a population for resources and some individuals contribute more offspring for the next generation than others • provided that offspring resemble parents (physical, behavioral traits are heritable) the traits of individuals that leave more offspring than average will increase in frequency over time (the contribution of an individual to the gene pool in the next generation is its evolutionary *fitness* This produces evolutionary change • *Key element in determining fitness: individual survival and reproduction

Darwin (1872) The expression of emotion in animals and humans

• Darwin applied remarkably acute observations to study the facial and bodily expression son cates, dogs, and infants - saw lots of parallels • Only recently have people begun to take this up and look at the evolution of emotion across species

Inter-sexual mate choice in animals

• Degree of symmetry in male ornaments indicates fitness and low asymmetry preferred by females • e.g. female choice for low levels of Fluctuating Asymmetry (FA) in length of outermost tail-feathers in barn swallows • Evidence that FA reflects individuals' propensity to withstand stress during development and predicts fitness • Idea is that level of FA is hones because only high quality males can experience significant stress during development (temperature perturbations, etc.) and still end up looking symmetrical

Hoe so animals experience emotions?

• Difficult question to answer • AS well as understanding adaptive significance of emotional expressions - need to understand animal emotions in order to properly protect their welfare

Explaining why animals live in social groups need to explain how it enhances individual survival and reproduction

• Direct benefits - Lower probability of being killed by predators (primarily shared vigilance and dilution effects and co-operative defense) - PREY - Better at finding and capturing food - PREDATORs - must also them share the food - Improved competitive ability - bigger group = can hold more territories and better protect offspring - Improved success at reading own young (for dominant individual - help from delayed breeders or non-reproductives) • Different benefits apply to PREY versus PREDATORS

Key forms of Intra-Sexual competition (usually male-male competition)

• Direct combat - males with large body size and weaponry selected • Sperm competition - males whose sperm successful in fertilizing eggs selected (those that produce more or those that are better st swimming, etc.)

Dominance ranks are key in social groups

• Direct combat is avoided using visual and vocal signals - example of visual signal: threat faces - escalating scare of threat faces: stare, eyebrow flash, open-mouthed/bared teeth - • These communicative signals are another key of primate social groups

Displays and Inter-sexual choice

• Displays also function to attract mating partners of the opposite sex - and specifically to provide a means by which individuals can choose a mate of the right species and also the nest mate out of those available at the time

Factors important in defining emotion Why do we have emotions

• Emotions change rapidly - can be triggered by specific events - related to key cognitive and physiological changes in the body • Emotions are universal - innate - important in helping us make adaptive decisions - approach/withdrawal in positive/negative situations

Relationship between number of vocalization types (vocal repertoire) and social living across primate species

• Evolutionary increases in vocal repertoire size among non-human primates were associated with evolutionary increases in group size and extent of social bonding -- to maintain social group need large vocal repertoire

Splays and Intra-sexual competition

• Evolutionary models • have shown that where fighting is costly, for example the risks of injury are high or fighting has high energetic costs, individuals should monitor the RHP of their opponents and withdraw without fighting if they would be likely to lose the fight • if this is actually happening we should see animals contests often being settled by displays of strength during which individuals ASSESS the RHP of their opponents • this sort of assessment can only be manipulated by election if the display gives a reliable indication of fighting ability; if weak individuals are able to, by bluffing, imitate the display of strong individuals, there would be selection to detect bluffers and use of the bluffable cue for assessment would be abandoned

Psychology: systematic study of behavior and the mind in man and animals

• Evolutionary theory is an important tool for psychologists and can enhance our understanding of human behavior - we have already seen how relevant it is to condor human and animal behavior in the same evolutionary framework

Evidence that females use assessment signals that are honest indicators of fitness - Peacock

• Eyespots in peacocks: Petrie, 1994 • Why honest?: likely that only high quality males can afford the cost of growing and displaying a large train (Simple index vs. Handicap Principle) - Recent research indicates males are more likely to give trail rattling display when females on there "sunny side" - take female perspective into accounts (Dakin & Montgomery 2009) • Males with larger eye-spots on the tail predicted the fitness in the male - led to more healthy offspring

Key function of emotional signaling

• Facilitates social cohesion and reduces uncertainty • Emotion is crucial in decision making - adaptive functions of positive and negative emotions (negative emotions allow us to respond appropriately to aversive stimuli, positive emotions to make adaptive choices) - Note that in tandem with this, established emotional expressions may be employed ritualistically to signal - e.g. difference in dominance

Female choice in masculine faces

• Female preference for masculinized faces are stronger during fertile phase of cycle • similar evidence on preferences for male body shapes, tallness and testosterone related vocal characteristics

Degree of symmetry in male ornaments may also indicate fitness

• Females choice for low levels of Fluctuating Asymmetry (FA) in length of outermost tail-feathers in barn swallows (Moller, 1992-3) •Fluctuating Asymmetry (FA) = absolute deviation form perfect asymmetry on characteristic that are (on average) symmetrical on the two sides of the body • Evidence that FA reflects individual's propensity to withstand stress during development and predicts fitness •Female Japanese scorpion flies prefer pheromones of more symmetrical males: THornhill 1992) • Hones because only high quality males can experience significant stress during development (temperature pertunattions, ets.) and still look symmetrical

Resource defense polygamy

• Females mating with males who have the ability to defend resources • Number of wives related to resources of Kipsigis Borgerhoff-Mulder • Bridewealth in Maasai: Groom and his family donate resources - cattle ==> in certain societies there are still traces of a mating system that is very common in animals and is governed by the same sorts of principles

Female choice and male voices: evidence for meal choice on the basis of acoustic cues

• Females prefer low voice pitch in males - associated with dominance, masculinity and health • Testosterone levels affect voice pitch • In Hadza hunter-gatherers - men with low pitched voices produce more children (probably through access to more fertile women) • Some evidence that women view men with low pitched voices as between at acquiring resources • Also evidence that both fundamental frequency and formants (vocal tract resonances) affect the dominance ratings that listeners give to voices

Maternal rank and dominance

• Fighting isn't the only way that dominance is established - In males dispersing primate species: females inherit the dominance rank immediately below their mother, in reverse age order e.g. Rhesus macaques - most common system - In Chimpanzees (where males stay in natal group) dominant mothers have dominant sons

Chimps: unusually complex social systems

• Fission-Fusion society: requires great flexibility • Live in communities (average ~ 60 individuals) • Group members gather in unstable temporary groups ('parties') that usually include only a small subset of the while community: mixed sex • Adult males form coalitions • High association rates between particular adult females ('friendships') --> must know a lot - highly complex socially, this type of Fission-Fusion society - also in other 'intelligent species'

Birds ToM - Western Scrub-jays

• Food caching western scrub-jays keep track of who was watching when • Birds preferentially stored food (eat worms) in distant site when watched by another jay, but used near and distant equally when observer's view was blocked by a screen • Items that were stored in view of the observer where moved multiple times • When two different birds saw them cache different food items, they tailor re-caching to whichever competitor reappears - re-cache just the food items that competitor saw

Social behaviors in humans kin selection: resource sharing

• Genetic relatedness is major factor determining pattern of alliances, resources sharing and inheritance • - analysis of Canadian wills shows that (with exception of bequests to spouses) 95% estates goes to relatives (most to offspring and siblings) compared to 5% to non-relatives

Roaring in red deer

• Glutton-Brock and Albon (1979) found that fights were more frequently preceded by roaring contests where the approacher roared more frequently than approached than other would round • Also played back recorded roars to simulate the presence of a rival stage • Stages would increase their roaring rate to match that of playback - unless the challenger simulated by the playback was roaring so fast that they couldn't match him • Roaring rate is an hones indicator of fitness probably because it is energetically costly • Second Stage of Assessment in red deer: parallel walking - gauge each others physical size - As a result of these two processes of assessment only 50% of challenges end in fight

Knowing what others can and cannot hear

• Grapes placed in both boxes - one box had a ringer when you opened it • When human competitors looked at them, the monkey was equally likely to steal from the noisy or the silent box • When the competitor wasn't looking, the monkey preferentially stole from the silent box ==> Monkeys understand what information you can get when you can and cannot hear things

Allow individuals of different ranks to interact without getting into fights

• Grunts in vert monkeys: different grunts used for interactions with dominant vs subordinates - know where they are in the group • Appease opponents after agonistic disputes • Olive baboons: grunting by a dominant to a subordinate after an aggressive interaction allows them to relax

The mathematics of altruism

• Hamilton's rule: - Defines the conditions under which we would expect genes causing an increase in altruistic behavior to read as: -- B/C > 1/r - B = benefits to there recipient - C = costs to the donor - r = coefficient of relatedness (probability that gene in one individual is an identical copy, by descent, of a gene in another individual) - probability that genes will by copied into another generation -- Values of r in diploid organisms (0.5) - mother-offspring: .5, full-siblings .5, niece/nephews: .25 • NOTE: recent evidence in some animals suggests that helpers may have little change of establishing own breeding groups - so maximize fitness by helping related dominants to breed

Human facial expression

• Have common evolutionary origin - largely innate • Darwin recognized that human facial expression had a common evolutionary origin with non-human primates and were largely innate • Paul Ekman identified the basic emotions in human facial expressions using photographs to study understanding of emotions in different communities - anger, fear, disgust, surprise, happiness, sadness • Universality in human facial expressions first proposed by Darwin - and later demonstrated by Paul Edman and colleagues. - see associations made with different expressions except fear and surprise not well defined in New Guinea

Lateralization in processing of emotions

• Have different responses/functions in different sides of the brain • When presented with different chimeras or emotional expressions - overall right hemisphere advantage, but shift back to left when processing pro- as opposed to anti-social expressions - they suggest a pro-social/approach/left hemisphere versus anti-social/withdraw/fight hemisphere dichotomy

How social behavior is achieved

• Have looked at WHY social behavior occurs, but in behavioral terms HOW it is achieved in practice • Communication is at the basis of social behavior: animals exchange specially adapted signals (vocal, visual, olfactory, etc. to mediate their relationship with others - this sort of interaction facilitate sand undermines social behavior • *Communication* is therefore a MECHANISM that allow social behavior to occur

Cultural variation in a range of behaviors

• High level of mental abilities - have observed deception, teaching and empathy - may recognize intelligence o others - limited theory of mind

Potentially huge functional benefits if deceptive performed with understanding of outcome - particularly metal state understanding

• However - though bubble isn't necessary necessary to explain this behavior - may be he result of LEARNING • Key use is distinguishing understanding another's BEHAVIOR from understanding another's MIND

Cognitive abilities in animals

• Huge implications for behavior • Cognition: the mental processes concerned with acquiring and using knowledge, including perception and thinking • How animals perceive, represent and process the world around them • Interesting questions: -- What functional uses do animal cognition abilities have? (why have these abilities evolved?) -- How do animals cognitive abilities compare with our own?

Crucial to appreciate

• Human behavior per se was not designed by selection, instead most human behavior is the production of the interaction of multiple psychological mechanisms - and, over the course of our evolutionary history, these mechanisms would have been shaped by selection • As out environment has changed, psychological traits originally selected for may be of little or no adaptive value new (could even be detrimental - i.e. attraction to sugar - originally was adaptive in some sense) • Human behavior is influenced by biological predispositions AND and social environment (cultural influences/social learning crucial) - ignoring social environment would be a logical error, but so would ignoring the influence of genetics and evolutionary history • Human behavior is uniquely flexible and very many aspects of it are under conscious control - not automatically determined by the environment

Evolutionary approaches to studying human behavior

• Human behavioral ecology - focuses on the reproductive consequences of human behavior - e.g. Borgerhoff-Mulder - often involves study of tribal (non-westernized) peoples with assumption that they are close to our ancestors -- kind of outdated today • *Evolutionary psychology* - looks at more than there reproductive consequences - focuses on the adaptiveness of *psychological the mechanisms that underlie human behavior*; human behavior is the product of the interactions of a myriad of psychological mechanisms and these mechanisms came about through natural selection e.g. Barlow, Cosmoses, Tooby -- mechanisms are influenced by natural and sexual selection, so they should be present at least somewhat today - *potentially much more useful*

Contrasting ideas of why humans are social

• Humans primarily selfish, solitary and aggressive, but enter into a social contract to curb their naturally selfish instincts • Group living benefits individuals, so that behaviors which facilitate group living are favored -- Evolutionary explanation

Need to be extremely cautious when applying evolutionary principles of human behavior

• Hunter-gatherers for 95% of our history • Humans no longer live in the environment in which most of our evolution would have taken place - in very recent history (particularly last 10,000 years) we have made huge changes in many aspects of our lives (agricultural, industry)

A key function of signaling is to transmit information on the identity of a signaler

• Important for staying in contact with companions and advertising ownership of resources - mother-offspring recognition (norther fur seals) - females roar to defend territories and recruit companions (lions)

Conflict in dominance hierarchies

• Important to be able to achieve appeasement and reconciliation after fights in primates - achieved through: *social grooming* - very much a method of active bonding -- Dunbar's idea that grooming is like gossip - a mechanism by which friendship is formed and maintained - *Vocal signals*: (NB the importance of vocalizations in facilitating social living generally) - used to reinstate friendships

Social /moral emotion

• In addition to the 6 basic emotions, also social or moral emotions such as jealousy, guilt, embarrassment • Jaak Panksepp proposes a more neurobiologically inspired classification of emotions - 4 basic emotional systems each associated with a particular set of neural structures and neurotransmitters - fear, seeking, panic, rage • Could be quite useful for applying to animals

emotions

• In humans emotional intelligence affects social success, e.g. emotional intelligence of group leader affects performance of team • What about animals? Interesting topic of future studies - although there is an expanding new field of "affective neuroscience" relatively few studies have systematically investigated behavioral phenomena related to emotions in non-human animals or tried to directly relation emotional sensitivity to social behavior • Other questions: humans have the capacity to vicariously experience the emotional of there - what about animals?

Allows individuals and groups to assess rivals

• In individuals contests: assessment of fighting ability/resources holding potential of opponent

Choice for best mate

• In sedge warblers (work by Catchpole & colleagues) - females prefer males who sing more sing types (larger song repertoire). - These males: -- get mates first -- are more stimulating to females in the lab • Evidence that males with larger repertoire provide good genes, may also sire more attractive sons

Benefits have to outweigh COSTS of social living - Costs

• Increased changes of being detected by predators • Higher risk of parasitism • Resources have to be shared with other group members • Increased risk of reproductive suppression (for subordinates) • --> Where benefits outweigh costs there can be direct selection on individual to live in groups -- so bereifst don't always outweigh the costs

Social behavior and communication

• Interesting questions about social behavior - why does social behavior occur? - clear benefits to living in social groups, but also costs as well, so a little hard to explain in evolutionary terms - how is it achieved - mechanisms - communication amongst individuals which allows us to function in groups

Primate social and mating systems

• Interesting questions: - what sort of mating and social systems do non-human primates have in the wild? - What particular similarities (and differences) are there between chimps (our closest relatives) and humans?

Human evolutionary psychology

• Interesting questions: - what is evolutionary psychology? - What insights can it provide into human sexual and social behavior? • Outdated view: animals are rigidly controlled by their biology, human behavior is determined by culture • Challenged by what we know about animal behavior • Ignores our shared evolutionary history - small genetic variation • Ignores the biological basis of many human traits and the cultural basis of some animal traits

Contingent cooperation

• Interesting recent evidence for a form of reciprocity: contingent co-operation in baboons • Previously receiving grooming renders them more likely to respond when hear recruitment call = - Interesting to also note evidence for food-sharing with non-relatives in chimpanzees and rates - benefits is unclear

Elephants

• Investigate fresh using from elephants that are walking behind them - when relatives smelled pee from a family member that was walking ahead - didn't care because it could logically be there - when smelled relatives pee that was walking behind them = violated their expectations - they were much more interested • = elephants are keeping tract of where elephants are in the social group

Evolutionary origins of the smile

• John Ohala - acoustic origins of the smile - threatening vocalizations in dominance displays typically involve bringing the corners o the mouth forward to lengthen the vocal tract and lower the vocal tract resonance (or formants) - with the effect of making an animal sound larger - whereas non-threatening vocalizations used in displays of submission involve drawing the lips back - smile face - makes animals sound smaller = we are responsive to vocalization cues

Other evidence that animals can attach acoustic or visual labels to external objects and events

• Kanzi: bonobo uses lexigram keyboard to communicate • Captive dolphins taught to attach labels to objects - use whistle • Alex: African gray parrot • Rico the corder collie ==> referential signaling seems to be something that animals are readily able to do

The evolution of emotion

• Key question: what are emotions and why have they evolved? - relatively new field in terms of animal behavior

Chimpanzees

• Key studies of chimps - essential to have long-term studies of the behavior of INDIVIDUAL chimps - track their lives over time - gives picture into the complexity of their lives

Knowledge of their party relationships

• Knowledge of dominance relationships between other individuals could confer fitness benefits - allows individuals to assess which potential allies are likely to be effective in coalitions against opponents • Playback studies suggest baboons know what vocal interactions to expect between dominants and subordinates - surprised when subordinate challenges dominate • There is evidence that male bonnet macaques use information about third party relationships when they recruit support from other males, consistently choosing allies that outrank then AND their opponents (Silk, 1999) • ==> understand relationships between other individuals - know what they know and expect of their world

Differences

• Lack language ability - allow for information transmission in all areas and topics

Similarities in laughter expression

• Laughter in great apes and humans - very similar characteristics • Tickle baby chimps, humans, and bonobos = saw strong parallels in they way they expressed laughter and happiness • When rats play they emit trains of high frequency chirps - also induced when tickled by humans Panksepp = rats also laugh

Horses - complex representations about others in the social groups

• Lead horse based test-horse, and them take it behind barrier, and then play whinny - in congruent condition = play the whinny of the horse that was led behind the barrier - Incongruent - whinny doesn't match the horse they saw --> horses looked quicker and longer (surprised) by the incongruent trials • = horses have multimodal representations about the horses on their group

Amphibians

• Male-male assessment based on croak pitch in common toads • Larger males have larger vocal folds and therefore lower pitch croaks • Introduced male much more likely to attack when played the high pitch croak than when played the low pitched croak • Visual cues and tactile cues were also important • Honest because of relationship between larynx (voice box) and body size - larger male, more massive vocal folds

Definition of emotion

• Many proposed, but few are comprehensive / can usefully be applied to both humans and animals • Basic def: An intense but short-lived addictive response to an event which is associated with specific body changes - -doesn't talk about function • Evolutionary def: The emotions are specialized modes of operation shaped by natural selection to adjust the physiological, psychological and behavioral parameters of the organism in ways that increase its capacity and tendency to respond adaptively to the threats and opportunities characteristic of specific kinds of situations

• Relation social systems to matin and sexual selection

• Mating systems • Sexual selection - how this is done depends on social behavior

Weight scaled or height (BMI)

• Men prefer women with intermediate BMI • BMI is strongly linked to health and reproductive potential

Animal minds

• Mental states and representations are inaccessible - animals can't talk to explain their thinking • So look at responses animals give to external objects and events • Use experiments to address questions about animals minds - use surprise to see that the expect -- shows what information thei represent in their minds • E.g. Cheney & Seyfarth use playback to explore animal communication

Choice for mate of right species

• NOTE: choosing the right species to mate with is crucial (hybrids often infertile) and female preferences have clearly also been shaped with respect to this: - e.g. work by Gerhardt on gray tree frogs -- females pay attention to the different pulse rates of the calls of the males - they are very tuned into it • In general H. Chrysoscelis have calls with higher pulse rates BUT pulse rate varies with temperature. Gerhardt found that female H versicolor avoid males with higher pulse rates, particularly at low temperature, female H Chrysoscelis avoid males with lower use rates, particularly at high temps

Machiavellian intelligence

• Niccolo Machiavelli - chancellor in the Florentine republic in 15th century • He provided cunning advice for social interactions based on mind-reading and deception, described in his book - e.g. ".." so it follow that a prudent ruler cannot, and must not, honor his word when it places him at a disadvantage.." -social manipulation

Non-referential alarms = response urgency alarms

• Not all alarms are referential • Vervet monkey alarm calls denote predators in a referential way - but note that simpler alarm calling systems are also common • *Response urgency signaling* in California ground squirrels demonstrated by Owings & Hennessy • Whistle for high urgency predator threat, chitter-chat call for low urgency • NOTE: some animals have alarm calling systems that contain both referential and response urgency information - e.g. meerkats

Key forms of intra-sexual competition (usually) male-male competition in animals

• Not always direct competition • Direct combat: males with larger body size/ weaponry and impressive displays selected • Sperm competition: males whose sperm successful in fertilizing egg selection -- those with more sperm production will be selected for

Tool making and tool use

• Not just in humans - known to be common in all studies population of wild chimps; in Tai forest chimps more than 2 tools used everyday - chimps tool use is very varied and flexible: used mainly in feeding contexts, but also in social interactions and to improve personal comfort - tool making is very coming: moreover, in Tai forest chimps, 46% of all tools are manufactured by chimps before use - in anticipation - change length and shape • Ex. nut-cracking in Tai chimps - use special rocks for different types of nuts - have been using the same tools for hundreds of years - learn from parents and others

Some backdrop on chimps

• Note: in chimps, females disperse as adolescents while males stay in natal communities throughout life (this is unusual among non-human predates where males end to be the dispersing sex) - so female friendships between non-relatives - long lived - large brains (large relative brain size and neocortex) - very fluid social organization - hunt for meat

Vocal signaling in koalas

• Novel vocal production in koalas: Charlton et al. 2013 • Velum (soft plate) is more massive than vocal folds and acts as an alternative source for the vocalization - enables very low fundamental frequency (27Hz) - use pitch

Patterns of mate choices

• Original work by Buss providing evidence of consistency in mating preferences across different cultures (37 samples from 33 countries) • Females found to values cues to resources acquisition in potential mates more highly than males • Males found to value characteristics signaling reproductive potential in potential mates more than females (looks, age, etc.) • E.g. Advertisements from lonely hearts selection of newspapers - males = look for good looks while females females values looks and resources - men advertise looks and resources (more resources) - women advertise looks more

Work with animals cognition in non-primates

• Other animals have interesting cognitive abilities • Recent work on Domestic dogs: - dogs perform better than primates at using human social cues (gaze direction and pointing) to find hidden puppies (originally thought not in wolves by recent evidence that hand reared wolves do respond to such cues) • Dogs are also highly sensitive to attentional states in humans •Associated learning or mental state understanding? -- must determine this

Environment of Evolutionary Adaptiveness (EEA)

• Pleistocene (c. 2 million years ago to 10,000 years ago) taken to represent our ancestral environment - early humans living as hunter-gatherers in a savannah habitat • Likely features of EEA: - hunter-gatherer/scavenger subsistence - low population density small kin-based groups - nomadic or semi-nomadic - high infant mortality and low life expectancy - vulnerability (e.g. predators, disease)

Sexual selection

• Process by which secondary sexual traits become elaborated because they increase the owners ability to gain mates (antlers, peacock tail, etc.) • First coined by Darwin to explain the evolution of apparent extravagant characteristics that didn't enhance survival • *Arises not from struggle for existence but from struggle for possession of mates* • *Genetic* life or death is the key element of evolutionary theory = worth possible death, not just worth surviving, but surviving genetically

Social behavior humans: Reciprocal altruism

• Rare in animals - even examples in olive baboons and vampire bats new disputed • Common in humans - recognition of alliance partners - governed by well-defined roles - defection /punishment of alliance partner cheats - status affected by reputation

Social orgamization

• Refers to show animals interact with and space themselves in relation to other individuals o the same species • Variation: - solitary to social - just to mate or all the time - loose aggregations to close-knit, highly organized groups --> some animals though they live in groups don't actually interact while others do heavily (much more stable social groups - have roles within the group) • We will examine *evolutionary* explanations for society

Rank and friends

• Relations are important for dominance - also alliance • Rank may be dependent on forming alliances with other individuals •Alliance & male rank - gorillas form alliances with relatives - chimps form alliances with relative and non-relatives

Kin selection: Genetic relatedness predicts pattern of adoption in traditional societies

• Reviewed by Silk • Adoption in modern industrial nations by non-relatives - deep desire to raise children - altruistic endeavor (although a relatively small fraction of adaptive parents produce children of their own)

Signals also provide crucial information on intentions

• Ritualized way of signaling submission

Perception of facial expressions in animals -what is their function regarding social signaling

• Sheep discern emotions in other sheep and humans - when given free choice of 2 pictures, sheep show more than 80% preference for the calm sheep face or the smiling human one • Horses also discriminate between happy and sad photos of other horses - almost exclusively to towards the happy one = they are using these expressions in relevant ways - approach/avoid

Parallels in lateralization in animals

• Sheep, dogs and horses, like humans an chimps use left-visual field cues more than right visual -field ones for detecting negative emotion cues on faces • Horses are better at matching owner's voice to sight of owner when owner is in RVF (left hemisphere) - pro-focal task • Many species preferentially view predators with the left eye (right hemisphere) - anti-social/threatening stimulus

Theory of mind

• The ability to attribute mental states (e.g. desires, intentions, knowledge, or beliefs) to others • Currently no conclusive evidence that non-human primates have a fully developed Theory of Mind (ToM) - but some evidence that chimpanzees can attribute visual perspectives to others -- nothing like as elaborate as our abilities

Some interesting things about emotions:

• The key emotions are largely universal across cultures = largely innate and biological • There are parallels between emotional expressions in humans and animals • Recent research indicated that emotions are central to decision making (emotions and cognition interact) • Responses to emotional expressions are lateralized in the brain both in humans and animals - processed in different areas of the brain - see threats with the left eye so that it is processed in the right side of the brain which is more responsive • Emotional intelligence is likely to have important effects on social success - i.e. considerable adaptive value - help us respond appropriately in different situations - not much consideration giver regarding animal behavior

Results of Sexual Dimorphism - How to they decide who competes for who

• The sex with the higher potential reproductive rate (usually males because sperm are cheap to produce and males investment often ends at conception) competes for the sex with the lower potential reproductive rate • Males are usually larger, with more highly developed weaponry and exaggerated displays - by bot always: - e.g spotted sandpiper where males incubate the eggs of severe females and females compete for them --> not always the sex what cares for the eggs that has the lower reproductive rate - i.e seahorses - males compete and do infant care

Overall

• The study of human evolutionary psychology is still really in its infancy - but hopefully you can see how applying an evolutionary framework to studying human behavior and cognition, in the way we have examined animal behavior and cognition, can provide important insights. And out evolutionary predispositions are things that we can by usefully aware of, just as it is useful to be aware of how part experiences have conditioned use - all parts of understanding ourselves and being in better positions to change our behavior as a results

Approaches to studying social behavior

• Tinbergen's 4 questions: - *Mechanistic* - understanding mechanisms by which trait achieved - *Ontogenetic* - factors influencing development of trait - *Functional* - understanding fitness consequences of trait - *Evolutionary* - unravelling evolutionary history of traits - why are some social and some solitary • Previously looked largely at physiological mechanisms examples of who they are produced -- eg. w.r.t social behavior in voles how hormone oxytocin regulates pairing bond • Now going to take a *functional* approach to studying social behavior, examining it in relation to its *evolutionary fitness consequences* in animals and subsequently humans

Culture in chimpanzees

• Tool use occurs in all studies population of chimps, but crucially the size and nature of the tool repertoire varies between populations, as does the toolkit - *this is cultural variation* • In *cultural evolution inter-generation transmission of behavior occurs through social learning* (rather than genetically) - in the biological sciences cultural transmutation is recognized as one of the two processes that can generate evolutionary change • Chimps are unusual in that they *show cultural variation in a range of behavior patterns* (not just a single on as is case in many animals) - cultural variation evidence in context of tool-use, grooming, courtship • Patterns observed resemble those in human societies in which differences between cultures characterized by multiplicity of variations in technology and social customs

Understanding of emotions in animals

• Understanding of emotions in animals may be quite sophisticated • Trained chimps in matching task - Chimps can match emotional expression based on image - And have ability to match emotional meaning (inferred for video with positive or negative context)

Referential signaling

• Using signals to functionally denote external objects and events • E.g. vervet monkey alarm calls denot predator types --> different for leopard (bark), eagle (cough) and snake (shutter • Both when they are given naturally and when they are played back to the monkeys in the absence of the predator, these different calls elicit categorically different responses relevant to the predator's hunting style ==> call alone was enough to generate the appropriate escape response - these calls act as the label for the different predators

Parallels in emotional expression across species

• Very basic parallels in emotional expression in animals and humans • Facial expression of disgust - palatable = tongue protrusion - Disguise - non-palatable = gaping open mouth - eyes wide open • = similar across animals

Case study: Chimpanzees

• We are apes - share most of our genetic • Opens a window on differences and similarities humans and animals - chimps share 98.8% of our genes (or 96% of our entire genome) • Chimps are our closest relative and we are theirs - we had a common ancestor

Sexual selection and communication

• What is selection? • Why are sexual signals often hones indicators of fitness? --> sexual behavior is at the core of being able to pass on genes to the next generation

Primate social and mating systems

• What life is like for primates - Broad overview of the ways the non-human primates live their lives

Displays and Intra-Sexual Competition

• When individuals compete for mates opponents are rarely equally matched • In particular differ in abbot to acquire or defend the resource *resource holding potential (RHP)*

Why did semantics evolve

• Why might these labelling abilities evolved? • Evidence some species can *label social relationships* • Maybe this is one of the contexts in which labelling may have been selected for - in response to playback of infant's scream, group members look towards the infant's mother - in vervet, macaques and baboons - Macaque monkeys also recognize mother-infant pairs from photos (Dasser 1998) • ==> Understand general labels both from vocal and visual information

Calls can also refer to the social environment

• e.g. specific grunts in vervet monkeys - social grunt - have subordinate and dominant grunt to which the monkeys respond differently -- also respond to the grunts of rival groups = can detect differences in social grunts and respond appropriately = *have referential calls for social groups as well as predators*

Group contest

• probability of approach closely predicted by ratio of number of defenders

Components of emotion

• triggered by event of some significance/relevance • encompasses a coordinated set of changes in brain and body • appear adaptive in that directed towards coping with challenge posed by triggering event • have onset, dynamic course and offset - transient - (in contrast with moods) *Relevant dimensions* • level of arousal - how excited or relaxed is the individual when they are having the emotion • Valence (positive or negative = excited = positive and high arousal

Adaptive problems faced bu our hunter-gatherer ancestors:

- eating the right food - avoiding predators - *obtaining mates* - *caring for offspring* - *forming alliances* - *reading other people's minds* • How well an individual solved these problems would have affected their success in passing on genes - mental mechanisms for solving these problems should therefore have been selected for - be present today

Direct benefits

- immediate effect on survival and reproduction of individuals are not generally sufficient to explain the most sophisticated forms of group living involving high levels of altruism • *Altruism* = behavior which increase the fitness of the recipient at some costs to the donor • Reproductive altruism is the most extreme form - only one female gets to reproduce

Key parameters in inter-sexual choice (usually female choice)

- theories to what cues they use: • *Good Genes theory*: females choose males with characteristics that indicate high genetic quality and as a result obtain genes for their offspring that confer high viability (offspring grow and survive better); for this to be evolutionarily stable, chosen characteristics must be honest indicators of male genetic quality • *Attractive sons theory* (through a process of Fisherian selection): females choose males who are highly attractive (rather than more viable) and as a result have more attractive sons who are chosen by females in the next generation --> more evidence of the Good Genes theory, but the two likely go together • ALSO NOTE: possibility of *sensory exploitation*: females choosing males that exploit their innate sensory biases - nervous systems are hardwired to attend to certain things over others, and males pick up and exploit these biases --> little evidence that this is one its own, likely goes along with Good gene theory