Evolutionary Psychology

How do recent novel environmental phenomena affect human evolutionary psychology?

1. Mismatches between modern and ancestral environments may negate the adaptive utility of some evolved psychological mechanisms. 2. Novel environmental stimuli, such as media images or pornography, may trigger, hijack, or exploit our evolved psychological mechanisms.

Four kinds of questions that ethologists ask about animal behaviour:

1. Ontogeny questions; questions about developmental influences on behaviour. 2. Mechanistic questions about the immediate influence on behaviour. 3. Phylogenetic questions about the phylogenetic origins of behaviour. 4. Functional/Adaptational questions about the adaptive function of behaviour.

Five basic principles underlying research in ev. psych:

1. The brain is a physical system which functions as a computer. Its circuits are designed to generate behaviour that is appropriate to one's environmental circumstances. 2. Our neural circuits were designed by natural selection to solve problems that our ancestors faced during our species evolutionary history. 3. Consciousness is just the tip of the iceberg; most of what goes on in your mind is hidden from you. As a result, your conscious experience can mislead you into thinking that our circuitry is simpler than it really is. Most problems that you experience as easy to solve are very difficult to solve - they require very complicated neural circuitry. 4. Different neural circuits are specialized for solving different adaptive problems. 5.Our modern skulls house a stone age mind.

Evolutionary Psychology assumes two elementary principles of genetic evolution:

1. The genes that define contemporary human populations are products of a long history of evolution by natural selection. 2. The human nervous system develops according to a recipe encoded in those genes.

The Five Principles of Evo. Psych. encourage us to ask what four questions?

1. Where in the brain are the relevant circuits and how, physically, do they work? 2. What kind of information is being processed by these circuits? 3. What information-processing programs do these circuits embody? 4. What were these circuits designed to accomplish (in a hunter-gatherer context)?

Ontogeny (development)

Asks, how does x develop over the course of an organisms life span?

The Social Brain Hypothesis

Based on the observation that humans have very large brains, and that human brain development has exploded in a relatively recent chunk of evolutionary time. States that social groups, and their expansion, is primarily responsible for human brain development: ie, in order to be able to make decisions about how to act, animals need to be able to manipulate large and constantly changing social environments.

The limitations of evolutionary psychology

Evolutionary psychology struggles to explain phenomena that appear to reduce an individual's reproductive success, and cannot be explained by mismatches with, or hijacking of, our psychological mechanisms by modern-day novel environmental inputs (such as homosexuality, suicide). 2. Other limitations include the lack of detailed knowledge of many selection pressures that humans faced over the millions of years of their evolution; however there is a surprisingly abundant amount of historical information which we do know to a reasonable degree of certainty. 3. Relative deficiency in explaining cultural and individual differences; ev. psych. has been far more successful in predicting and explaining species-typical and sex-differentiated psychological adaptations than explaining variation within species or within the sexes; it does not account well, thus far, for variability.

Adaptive flexibility

Flexibility in cognitive/behavioural outputs. The two ways in which genes build organisms to be flexibly responsive to the environment are: 1. Developmental Process (Phenotype Plasticity) - in response to input from the developmental environment, genotype produces phenotypic features that historically facilitated reproductive success within that kind of environment (ie. extroversion is lower where rates of disease are higher (r=-.51)) 2. Neurocognitive Process (Functional flexibility) - evolved brain mechanisms are adaptively designed in such a way that, in response to input from immediate circumstances, these mechanisms temporarily produce cognitive, affective, and behavioural responses that historically facilitated reproductive success within those circumstances (ie. when risk of infection is temporarily higher, people are temporarily less extroverted).

Nairne & Pandeirada memory studies:

Found that people were more likely to recall items from a list after being told they were touched by a sick person; found that survival related words were recalled much more often than even self-references and other memory beneficial things.

The time-lag problem

Genes cannot determine behaviour in real time; in order to adapt they require the successive mutations over multiple generations. To solve this problem, some organisms father huge numbers of offspring while other organisms build in for individual adaptability through the use of larger and more complex brains.

Genetic determinism vs. Interactionism

Genetic determinism is the view that genes determine phenotypes such as morphology, psychology, or behaviour, with little or no environmental influence. Ev. Psych. forcefully rejects this view, preferring instead an interactionist perspective which invokes the role of the environment at every step of the causal process, including; a) the selection pressures that give rise to psychological adaptations, b) the environments needed for the proper development of these mechanisms in individual humans, and c) immediate proximate inputs necessary for their activation. Adaptations exist in their current form precisely because they historically solved adaptive problems posed by various environmental contingencies.

Adaptationist logic dictates that _________ is not the opposite of learned. For EPs, learning is not an explanation but _________________.

Innate; the question is never learning vs. innateness. The brain must have innate abilities to learn, or "innate learning mechanisms'. a phenomenon that requires explanation.

Domain-specific learning mechanisms (learning adaptations)

Mechanisms for learning which are specialized to certain tasks that, throughout evolutionary history, were beneficial to the survival and propagation of the human organism.

The use of our memory for survival relevant things typically requires some level of _____________; this implies that memory is an evolved system used for: We can then expect that people will be better at recalling memories which are associated with:

Planning; planning future actions; proactive, planning behaviour (memory is enhanced when used in service of this planning-for-the-future function).

Proximate vs. Ultimate Explanations

Proximate; explanations which describe events closest to, or immediately responsible for, causing some observed result (ie. Ontogeny and mechanistic approaches). Ultimate; explanations which describe a higher order cause, thought of as the 'real' reason something occurred (Phylogeny and Function/Adaptation approaches).

Good genes and attractiveness:

Psychological mechanisms that are sensitive to, and respond positively to, evidence that a potential mate has "good genes" would have led to more reproductive success, therefore, we can expect to find these mechanisms in people. "Sexually attractive", in these terms, refers to evidence that a potential mate has "good genes".

Inferences about adaptations in the absences of knowledge of molecular-genetic substrate

Reliably developing, universal, and complex design features provide ample evidence of adaptations, even though the specific genes/ gene interactions involved in such adaptations are not yet known.

Ovulatory shift hypothesis

Sexual attraction sensitivity should be greater in women, especially when they are the most fertile; this is the case when women are in the ovulatory phase of the menstrual cycle. The study on this particular hypothesis used body odor as a measure of gene fitness, and its correlation to another measure; body symmetry. Women in specific stages of the menstrual cycle were asked to smell men's t-shirts who had already had their symmetry measured; the results found that women were statistically more likely to find more symmetrical men's body odors more attractive; especially when they were ovulating.

Shortcomings of explanations based on domain-general mechanisms

The failure-to-predict problem; domain-general rational thought has not been used to predict or discover new empirical findings, only to give a post hoc account. The problem of combinatorial explosion; domain-general theories of rationality implies a deliberate calculation of ends which, in the real world, there is no time for when making critical decisions. Predictable and rapid reactions to threats, etc. points to a specialized psychological circuit rather than a response caused by a deliberative domain general rational system. The poverty of the stimulus problem; there is often a lack of past statistical information required for a person to make a predictable rational judgment. Selection can favor specialized adaptations that exploit statistical regularities that are not detectable ontogenetically. The context-specific rationality problem; because what is 'rational' differs across adaptive problems, sexes, ages, and life circumstances, there exists no single domain-general criterion of rationality.

Dunbar's model/ number

The model which describes frontal cortex growth in humans and primates as correlated to social group size; the r itself is called dunbar's number

Phylogenetic versus adaptationist explanations:

The phylogenetic approach; how has x changed over the course of human evolutionary history? The adaptationist approach; what, if any, selective advantage was conferred by x over the course of human evolutionary history?

Differences between evolutionary psychology and the standard social science model:

The standard social science model includes the assumption that all human knowledge is based on experience; the evolutionary psychological perspective instead posits that all normal human minds reliably develop a functionally specified and domain specific collection of reasoning and regulatory circuitry.

Mechanism

What are the structures and processes that, at any particular moment in time, exert an influence on x?

EEA (Environment of Evolutionary Adaptedness)

a statistical composite of selection pressures that caused the design of an adaptation; not a space or time specifically.

Evolutionary Psychology is not defined by any specific topics of inquiry but:

a systematic way of viewing the field of psychology.

An organisms phenotype can be partitioned into __________________, which are present because they were selected for, _________________, which are present because they are causally connected to the former, and _____________, which was injected by the stochastic components of evolution.

adaptations; by-products, noise

Three complementary levels of explanation in evolutionary psychology:

adaptive problem; cognitive program; neurophysiological basis; inferences can be made from one level to another

Some have misrepresented the well-supported claim that selection creates functional organization as the obviously false claim that:

all traits of organisms are functional.

Design features

attributes or component parts of an adaptation that have been forged or "designed" by a past history of natural selection; no forward looking or intentional process is implied by this phrase.

Inclusive fitness

combines the notions of 1. direct fitness- behaviours that enhance an organism's own reproductive success 2. indirect fitness- behaviours that enhance reproductive success of other organisms carrying those same genes. Genes that promote inclusive fitness are more likely to become common within a population. Implication: genetic relatedness really matters!

"Good genes"

defined as genes that have an effect such that the body they have 'designed' is a little bit more likely to live and reproduce than it would have been otherwise (ie. how well it built that body, and the eventual reproductive success of that body).

Genes promoting behaviour will spread within a population if _______ costs associated with altruism are outweighed by the _______ benefits of altruism.

direct; indirect; This notion is mathematically supported by Hamilton's Rule

Prepared learning

evolved predispositions to easily learn specific kinds of stimulus response associations. Ex) Taste aversions/Garcia conditioning

Cognition as a solution to the time-lag problem:

genes are the primary policy-makers; brains are the executives. But as brains develop, they take on more decisions.

Genes underlying adaptation

genes do not code directly for particular phenotypic traits; rather they code for specific proteins. Most characteristics are phylogenic, meaning they are regulated by complex interactions of many genes in conjunction with specific forms of environmental inputs. All adaptations, by definition, have a genetic basis; if they did not, they could not have evolved by the process of natural selection.

Hamilton's Rule

genes promoting kin-directed altruism will spread within a population if r x b > c. r=relatedness b=indirect reproductive benefits c=direct reproductive costs This informs conceptions of the human capacity for altruism.

Natural selection is a feedback process that "chooses" among alternative designs on the basis of:

how well they function in their environments.

Analyses of primate as well as human social interactions show that throughout history, an organism was likely to have ___________ interactions with within group members and ___________ interactions with outgroup members. Observed reactions show that we have a similar reaction to outgroup members as we do to ____________.

many, mainly cooperative; few, much more hostile/dangerous; predatory creatures

Evolutionary perspectives on learning include:

modularity/functional specificity and prepared learning

What roles do genes play in the framework of evolutionary psychology?

must be analyzed in terms of genetic determinism vs. interactionism, genes underlying adaptations, and inferences about adaptations in the absence of knowledge of molecular-genetic substrate.

The environment of evolutionary adaptedness necessarily included:

other people; humanity's interactions with itself had a major hand in shaping its own evolution.

Studies regarding human interactions with within group members vs. outgroup members found that: This implies the existence of an:

participants were able to learn to fear members of either group, but retained fear of outgroup members much longer; this was especially true of male members of outgroups; adaptive learning mechanism designed to learn fear of male outgroup members.

Studies regarding human recognition of angry faces found that: This implies that:

participants were much more likely to accurately recognize an angry face than a non-angry face; this effect was observed throughout racial ingroups and outgroups; anger has had deciding evolutionary consequences regardless of group.

The brain is a _____________________ designed to:

physical system; generate behaviour that is appropriate to one's environmental circumstances.

kin selection theory

predicts that the degree of altruism depends on the number of genes shared by individuals

Evolutionary Psychology focuses on _________________ and ______________:

specific selection pressures on ancestral populations; cognition, affect, and behaviour in the here and now; ev. psych. links specific selection pressures of the long past with behaviour, cognition, etc. of the contemporary behaviour.

Genetic Relatedness

the amount/percentage of genes shared between members of a species.

Nature vs. Nurture Fallacy

the assumption that we can neatly partition genetic from environmental effects; assumes a false dichotomy of nature vs. nurture. Nurture, in actuality, requires nature; nature determines capacity to learn from environment. Similarly, nature interacts with nurture; both interact to determine behaviour.

Determinism Fallacy

the mistaken assumption that genes control or determine behaviour in a manner independent of environmental influences.

degree of relatedness

the probability that 2 people have a specific gene in common, above and beyond the average number of genes that all humans share.

Naturalistic Fallacy

the tendency to believe that what is natural is good; that what is, ought to be.

Evolutionary psychology inquires into the _______________ that we all share by virtue of being human.

universal, evolved architecture; This is sometimes referred to as the psychic unity of humankind.

Evolutionary psych. implications on memory:

we can expect humans to have an enhanced memory for things which were especially relevant for survival/reproduction within ancestral ecologies. ex)enhanced memory for things which contain risks of infection.

Evolutionary Psych. implications on selective attention:

we can expect humans to have enhanced attention to things that were especially relevant to survival/reproduction within ancestral ecologies. ex) enhanced visual attention to snake, enhanced visual attention to animals, especially humans.

Hamilton's rule predicts that:

when kinship is greater, people will be more likely to help one another; this is especially the case in life-or-death situations: this has been supported by psychological studies. Additionally, it would predict that, keeping r constant, individuals would be more likely to help those with higher reproductive potential; this effect, too, would occur primarily in life-or-death situations: studies on this issue showed this to be the case in life-or-death situations, but that in normal day-to-day circumstances, individuals were more likely to help those with less reproductive potential.