Evolutionary Psychology and Adaptive Evolution

Evolutionary Psychology

• Evolutionary psychology is the study of the evolutionary biology of mind, brain, and behavior, combining insights from evolutionary biology, biological anthropology, psychology, and cognitive neuroscience.

Adaptive Evolution

• Adaptive evolution is a special kind of change caused by natural selection.
• It builds adaptations, which are traits that exist because they contributed to reproduction in ancestral populations.
• Natural selection builds adaptations that are good for the gene, not the species, group, or individual.

Infanticide in Animals

• Infanticide, the killing of infants, is an adaptation in some species, including langurs, where it is committed by usurping males in harem species.
• The reason for infanticide is likely reproductive acceleration, as it allows the new male to accelerate the resident females' reproduction.

Evolution by Natural Selection

• Prerequisites for evolution by natural selection include:
  • Variation
  • Heritability
  • A quantitative relationship between the two
• Natural selection builds adaptations that are good for the gene, which can lead to conflicts between individual and group selection.

Replicators and Vehicles

• Genes are replicators, and individuals and groups are vehicles that carry these replicators.
• Natural selection builds adaptations that are good for the gene, which can lead to conflicts between individual and group selection.

Facultative Responses

• Facultative responses are adaptations that are triggered by specific environmental cues.
• Examples of facultative responses include UVb-dependent suntanning, resource-dependent growth, and animacy-dependent attention.

Interaction between Genes and Environment

• In evolutionary psychology, the interaction between genes and environment is conceptualized in terms of facultative responses and susceptibilities.
• Selection favors genes that respond appropriately to their environment, but genes have "expectations" about the kinds of environments they will encounter.

Critique of the Standard Social Science Model (SSSM)

• The SSSM views the human mind as a blank slate, shaped by experience, with minimal biological constraints on human behavior.
• Evolutionary psychology critiques the SSSM, arguing that the mind is not a blank slate, but rather a collection of specialized modules built by selection to address specific challenges faced by our ancestors.

Role of Culture

• In the SSSM view, culture is an independent variable, but in the EP view, culture is both dependent and independent.
• Culture is not an arbitrary set of conventions, but rather a set of patterns of learned and shared behavior and beliefs that are constrained by human nature.

Conclusions

• The human mind is not an amorphous computer, but rather a content-rich system with many domain-specific cognitive, emotional, and behavioral modules designed to meet challenges faced by our ancestors.
• Fitness is not a direct motivator, but rather explains why certain proximate goals are motivators.

Behavioral Genetics

• Behavioral genetics studies the genetic basis of behavioral traits, focusing on heritability, which is the amount of phenotypic variation that is due to genetic differences.
• Heritability provides an estimate of how much of a feature of the phenotype is due to genes, and is essential for understanding the genetic basis of behavior.### Evolutionary Psychology
• One argument against evolutionary psychology is that it naturalizes or excuses oppressive or immoral behaviors, such as rape.
• Genetic explanations for behavior should not be used to justify or excuse bad events.
• Understanding genetic influences on behavior can help us predict and prevent negative outcomes.

Psychological Traits as Adaptations

• Psychological traits are preserved by selection because of their contribution to fitness in ancestral environments.
• They have a specialized, domain-specific function.
• They are formed cumulatively, by the selective retention of favorable mutations.
• They are good for the perpetuation of the underlying genes.

Psychological Adaptations

• Psychological adaptations are costly, like all adaptations.
• They will only be built and maintained when the resulting fitness benefits justify their costs.
• Examples of psychological adaptations include phoneme perception and vision.

Sensation and Perception

• Sensation and perception are "poster children" for domain-specific adaptations.
• Each sense is specialized to handle particular kinds of input.
• Processing is often localized to particular brain areas.
• There are two views of perception: providing information about the environment and guiding action.
• These views are not the same, as the former implies precise, accurate judgments, while the latter allows for evolved, fitness-enhancing biases.

Themes in Sensation and Perception

• Adapted to species-specific risks and opportunities.
• Shaped by sources of relevant data.
• Provide insight into the relevant selection pressures.
• Senses have evolved to exploit different categories of cues.

Examples of Sensory Adaptations

• Cryptochrome proteins in birds allow them to see the earth's magnetic field.
• Hearing uses pressure waves in air to detect movement.
• Chemical senses, such as taste and smell, use specific receptors to detect different molecules.
• Touch is a complex sense that includes pressure, temperature, tickle, itch, and pain.
• Bat sonar is an example of a non-human sensory adaptation, using echolocation to navigate in the dark.

Learning

• Learning is the modification of behavior by experience.
• Innate vs. learned is a false dichotomy, as all behavior depends on some kind of experience.
• Learning mechanisms are evolved facultative adaptations.
• There are different types of learning, including associative learning, classical conditioning, and operant conditioning.

Classical Conditioning

• Classical conditioning is the process of learning to associate events or stimuli that frequently happen together.
• Temporal contiguity is not necessary or sufficient for learning to occur.
• The usual claim is that temporal contiguity is necessary for learning, but this is not the case.

Operant Conditioning

• Operant conditioning is the process by which behaviors are reinforced or punished.
• Behaviors that are followed by consequences that are satisfying to the organism are more likely to be repeated.
• Behaviors that are followed by unpleasant consequences are less likely to be repeated.

Evolutionary Biology of Mind, Brain, and Behavior

• Natural selection causes things to increase in frequency if they are good for the individual.
• Hamilton's rule states that rb>c, where r is the degree of relatedness, b is the benefit, and c is the cost.
• Kin selection is the process by which individuals can spread their genes through their relatives.

Evolutionary Biology of Mind, Brain, and Behavior

Language as an Adaptation

• Language is an adaptation that has evolved to improve reproductive success
• Its function is to transfer complex understandings about the world from one brain to another
• Language abilities evolved via natural selection, not languages themselves
• Examples of how language was used by hunters and gatherers:
  • Communicating about food and resources
  • Passing on knowledge and skills
  • Gossip and social learning
• Features of language:
  • Phonemes: meaningless but meaning-distinguishing sounds
  • Morphemes: meaningful combinations of phonemes
  • Morphophonemic rules: rules for combining phonemes and morphemes
  • Grammar: rules for forming and interpreting sequences of morphemes

Design Features of Language

• One sound per concept (not found in animal communication systems)
• Combination of a small set of distinguishable sounds (phonemes) to form unique strings for each concept
• Syntax: rules for combining words to form messages
• These features allow for infinite expressions of ideas

Evidence for Language as an Adaptation

• Mastery of spoken language is a human universal
• No "simple" languages; all have similar features (phonemes, morphemes, grammar)
• Regular pattern of language development across childhood
• Conversion of pidgins to creoles by children
• Double dissociation with general intelligence
• Evidence of recent selection for genes associated with language ability
• Language abilities are localized to particular parts of the brain

---

The Beginning of Language

• It is difficult to think about the beginning of language because of its complexity
• The process of language evolution must have been cumulative
• Possible first steps:
  • Noun-verb relations
  • Object words
  • Modifiers (adjectives and adverbs)
• Further research strategies:
  • GWAS studies of specific language impairments
  • Ancient-DNA studies comparing modern and ancestral populations

---

Social Learning

• Two kinds of learning:
  • Individual learning: learning from the environment
  • Social learning: learning from conspecifics
• Role of culture:
  • Interpersonally transmitted information essential for human survival
  • Contains behavioral solutions for successful living
• Assumptions:
  • Social learning is cheaper than individual learning
  • But social learning may produce lower fitness benefits
• Argument for Strong Constraints: if culturally acquired behaviors reduce fitness, the capacity for culture would be altered or destroyed by natural selection.### Social Environment and Frequency-Dependent Selection
• Social environment: complex, involving coordination and competition
• Frequency-dependent selection: matching (e.g., language) and divergence (e.g., competitive situations)

Cognition

• Definition: mental processes involved in acquiring, processing, storing, and using information
• Most cognitive processes are unconscious and mentally impenetrable (e.g., phoneme parsing, trajectory calculation, emotion detection)
• Categorization: a fundamental aspect of cognition, simplifies response and uses prior experience to assign to category

Categorical Thinking

• Categorical thinking: fuzzy categories, fade out at the edges (Eleanor Rosch)
• Natural kinds (biological entities) are linked in nested trees, making fuzzy categories a good way to represent them
• Even children use fuzzy categories in the right way, being less willing to assign category-specific properties to more taxonomically peripheral exemplars

Rationality

• Definition: ability to make judgments and choose courses of action under uncertainty
• Heuristics and biases: "heuristics wars" (Tversky and Kahneman vs. Gigerenzer)
• Availability heuristic: neglecting base rates, leading to inaccurate judgments

Evolution of Altruism

• Two models: kin selection and reciprocity
• Reciprocity: actors exchange roles as altruist and recipient, with benefits and costs
• Individuals must withhold benefits from non-reciprocators (cheaters)

Logical Problem Solving

• Evolutionary perspective: solving specific fitness-relevant problems, not abstract logical problems
• Wason task: checking rules for violations, with a focus on cheating and social exchange

Moral Intuitions and Ethical Decision-Making

• Evolutionary origins: reciprocity, reputation, and cooperation
• Moral sense: "preplaying" reputation effects, preventing actions that would severely damage reputation

In-Group Bias

• Definition: favoring the in-group and discriminating against the out-group
• Tajfel's experiment: anonymous and trivial distinctions, with resulting negative judgments and allocations
• Coalitional competition: a primitive trait in the chimp-human clade

Group Assignments and Coalitions

• Markers of coalition membership: shared styles, language, preferences, and ancestry
• Cues of group membership: automatically encoded in early childhood (Zoe Liberman)
• Races as social categories: a misperceived marker of coalition membership?

Promoting In-Group Solidarity

• Emphasizing shared identity, language, traditions, and beliefs
• Using solidarity to achieve group-beneficial outcomes in conflicts over resources

The Broader Animal-Behavior Context

• Social behavior: helps in finding and holding onto food patches, detecting and repelling predators
• Solitary behavior: reliance on passive anti-predator strategies, few predators, and small or uniform food patches
• Great apes: solitary due to small food patches, few predators, and passive strategies
• Humans: cooperative foraging for high-variance foods, with resource-sharing limited to a small group of repeatedly interacting individuals

Emotions as Adaptations

• Emotions are not the opposite of rational; they are key inputs to adaptive decision-making, attaching valences to situations and possible outcomes.
• From an evolutionary perspective, each emotion is a distinct adaptation designed to address particular recurrent problems confronted by our ancestors.

Emotions and Survival Machines

• Genes orchestrate developmental programs that build mechanisms (machinery, algorithms) that provide the equivalent of Asimov's laws of robotics.
• Emotions alert the survival machine to fitness-relevant circumstances, helping it make good decisions.

Reciprocity and Altruism

• Reciprocity is a mechanism for the evolution of altruism, with alternating roles and benefits (B) exceeding costs (c).
• Requires discrimination against cheaters (non-reciprocators) and cheater-detection module.

Basic Emotions

• Paul Ekman's six basic emotions:
  • Anger: signals mistreatment by an associate
  • Fear: signals presence of danger
  • Happiness: signals fitness-enhancing situation
  • Sadness: signals fitness-decreasing situation
  • Surprise: signals unexpected event requiring attention
  • Disgust: signals contamination risk
• Emotions can be added, deleted, or elaborated upon through selection, and emotional systems should be sensitive to fitness-relevant circumstances.

Emotional Expressions

• Facial expressions of emotion are facultatively calibrated, not just for communication, but also functional for the self.
• Anger's usefulness is associated with bargaining power, which is based on the ability to inflict costs and confer benefits.

Parent-Offspring Conflict

• Conflict follows from patterns of genetic relatedness within families, with each actor designed by selection to advance their own evolutionary interest.
• Mating system affects parent-offspring conflict, with monogamy reducing conflict and promiscuity intensifying it.

Family and Social Relationships

• Children are a significant evolutionary motivator for marriage, and parental behaviors may not be effectively triggered in non-related individuals.
• Step-parents are statistically more likely to abuse or neglect children, with the biggest risk factor being living with a step-parent.

Cultural Variation and Violence

• "Cultural" variation in violence is facultative, with consequences of winning and losing social-status conflicts.
• Prediction: homicide rates should vary with social inequality, measured by the Gini coefficient.

Evolutionary Biology of Mind, Brain, and Behavior

Language as an Adaptation

• Language is an adaptation that has evolved to improve reproductive success
• Its function is to transfer complex understandings about the world from one brain to another
• Language abilities evolved via natural selection, not languages themselves
• Examples of how language was used by hunters and gatherers:
  • Communicating about food and resources
  • Passing on knowledge and skills
  • Gossip and social learning
• Features of language:
  • Phonemes: meaningless but meaning-distinguishing sounds
  • Morphemes: meaningful combinations of phonemes
  • Morphophonemic rules: rules for combining phonemes and morphemes
  • Grammar: rules for forming and interpreting sequences of morphemes

Design Features of Language

• One sound per concept (not found in animal communication systems)
• Combination of a small set of distinguishable sounds (phonemes) to form unique strings for each concept
• Syntax: rules for combining words to form messages
• These features allow for infinite expressions of ideas

Evidence for Language as an Adaptation

• Mastery of spoken language is a human universal
• No "simple" languages; all have similar features (phonemes, morphemes, grammar)
• Regular pattern of language development across childhood
• Conversion of pidgins to creoles by children
• Double dissociation with general intelligence
• Evidence of recent selection for genes associated with language ability
• Language abilities are localized to particular parts of the brain

---

The Beginning of Language

• It is difficult to think about the beginning of language because of its complexity
• The process of language evolution must have been cumulative
• Possible first steps:
  • Noun-verb relations
  • Object words
  • Modifiers (adjectives and adverbs)
• Further research strategies:
  • GWAS studies of specific language impairments
  • Ancient-DNA studies comparing modern and ancestral populations

---

Social Learning

• Two kinds of learning:
  • Individual learning: learning from the environment
  • Social learning: learning from conspecifics
• Role of culture:
  • Interpersonally transmitted information essential for human survival
  • Contains behavioral solutions for successful living
• Assumptions:
  • Social learning is cheaper than individual learning
  • But social learning may produce lower fitness benefits
• Argument for Strong Constraints: if culturally acquired behaviors reduce fitness, the capacity for culture would be altered or destroyed by natural selection.### Social Environment and Frequency-Dependent Selection
• Social environment: complex, involving coordination and competition
• Frequency-dependent selection: matching (e.g., language) and divergence (e.g., competitive situations)

Cognition

• Definition: mental processes involved in acquiring, processing, storing, and using information
• Most cognitive processes are unconscious and mentally impenetrable (e.g., phoneme parsing, trajectory calculation, emotion detection)
• Categorization: a fundamental aspect of cognition, simplifies response and uses prior experience to assign to category

Categorical Thinking

• Categorical thinking: fuzzy categories, fade out at the edges (Eleanor Rosch)
• Natural kinds (biological entities) are linked in nested trees, making fuzzy categories a good way to represent them
• Even children use fuzzy categories in the right way, being less willing to assign category-specific properties to more taxonomically peripheral exemplars

Rationality

• Definition: ability to make judgments and choose courses of action under uncertainty
• Heuristics and biases: "heuristics wars" (Tversky and Kahneman vs. Gigerenzer)
• Availability heuristic: neglecting base rates, leading to inaccurate judgments

Evolution of Altruism

• Two models: kin selection and reciprocity
• Reciprocity: actors exchange roles as altruist and recipient, with benefits and costs
• Individuals must withhold benefits from non-reciprocators (cheaters)

Logical Problem Solving

• Evolutionary perspective: solving specific fitness-relevant problems, not abstract logical problems
• Wason task: checking rules for violations, with a focus on cheating and social exchange

Moral Intuitions and Ethical Decision-Making

• Evolutionary origins: reciprocity, reputation, and cooperation
• Moral sense: "preplaying" reputation effects, preventing actions that would severely damage reputation

In-Group Bias

• Definition: favoring the in-group and discriminating against the out-group
• Tajfel's experiment: anonymous and trivial distinctions, with resulting negative judgments and allocations
• Coalitional competition: a primitive trait in the chimp-human clade

Group Assignments and Coalitions

• Markers of coalition membership: shared styles, language, preferences, and ancestry
• Cues of group membership: automatically encoded in early childhood (Zoe Liberman)
• Races as social categories: a misperceived marker of coalition membership?

Promoting In-Group Solidarity

• Emphasizing shared identity, language, traditions, and beliefs
• Using solidarity to achieve group-beneficial outcomes in conflicts over resources

The Broader Animal-Behavior Context

• Social behavior: helps in finding and holding onto food patches, detecting and repelling predators
• Solitary behavior: reliance on passive anti-predator strategies, few predators, and small or uniform food patches
• Great apes: solitary due to small food patches, few predators, and passive strategies
• Humans: cooperative foraging for high-variance foods, with resource-sharing limited to a small group of repeatedly interacting individuals

Evolution of Human Intelligence

• The primary aim of Cosmides et al. (2010) is to explore the evolutionary origins of human intelligence, particularly focusing on cognitive adaptations for social exchange.

Cognitive Specializations for Social Exchange

• Humans have evolved specialized cognitive mechanisms for engaging in social exchanges, including the ability to detect cheaters, remember social contracts, and understand the intentions and motivations of others.
• These mechanisms are robust and appear to be universal across different cultures, suggesting a common evolutionary origin.

Cheater Detection

• Humans have an ability to detect cheaters in social exchanges, which is crucial because cooperation can be exploited by individuals who take benefits without reciprocating.
• Experiments demonstrate that people are particularly adept at identifying violations of social contracts, more so than detecting other logical inconsistencies.

Evolved Algorithms

• Human intelligence includes evolved algorithms specifically designed to manage social interactions, processing information about trustworthiness, reputation, and fairness.
• These cognitive tools enable humans to navigate the complexities of social life, form alliances, and maintain long-term cooperative relationships.

Cross-Cultural Evidence

• The study presents evidence from diverse cultural contexts, showing that the cognitive mechanisms for social exchange are present in various societies.
• This cross-cultural consistency supports the idea that these mechanisms are evolutionary adaptations rather than learned behaviors.

Role of Intelligence in Social Contexts

• Human intelligence, as shaped by evolution, is not just about abstract reasoning or problem-solving in isolation, but is deeply social, geared towards understanding and predicting the behavior of others, managing relationships, and fostering cooperation.

Human Intelligence and Social Evolution

• The findings underscore the idea that a significant portion of human intelligence evolved to solve problems related to social living, including managing relationships, detecting cheaters, and maintaining cooperation within groups.
• Intelligence is seen as a set of specialized cognitive tools tailored to navigate the social environment effectively.

Social Exchange as a Driving Force

• Social exchange is identified as a crucial driving force in the evolution of human cognitive abilities, with the need to cooperate and form alliances placing strong selective pressures on our ancestors, leading to the development of sophisticated social cognition.

Evolutionary Psychology (EP)

• EP is the evolutionary biology of mind, brain, and behavior, synthesizing evolutionary biology, biological anthropology, psychology, and cognitive neuroscience.

Adaptive Evolution

• Adaptive evolution is a special kind of change caused by natural selection.
• It builds adaptations, constrained by heritability, and cannot build things that are not heritable or do not contribute to reproduction.

Infanticide in Langurs

• In langurs, infanticide is committed by usurping males to accelerate the reproduction of resident females.
• This behavior is likely an adaptation that has evolved repeatedly in similar environments.

Natural Selection

• Natural selection is the differential reproduction of heritable elements due to better or worse fit with the environment.
• It builds adaptations that are good for the replication of genes.

Prerequisites for Evolution by Natural Selection

• There must be variation, which is sufficiently heritable and affects its own rate of replication.
• There must be a quantitative relationship between the variants and their replication rates.

Adaptations and Gene-Centered View

• Adaptations are traits that exist because they contributed to reproduction in ancestral populations.
• Genes are replicators that build vehicles (individuals) with adaptations to propagate themselves.

Proximate vs. Ultimate Explanations

• Proximate explanations focus on mechanisms and ontogeny (how a trait develops).
• Ultimate explanations focus on adaptation, function, and phylogeny (why a trait exists).

Difference between EP and Traditional Psychology

• EP focuses on ultimate explanations, while traditional psychology focuses on proximate explanations.
• EP considers the role of experience and culture in shaping human behavior, while traditional psychology emphasizes the SSSM (Standard Social Science Model).

Critique of SSSM

• SSSM views the human mind as a blank slate, shaped by experience, with minimal biological constraints.
• EP argues that the mind is not a blank slate, but rather a collection of specialized modules built by natural selection.

Human Nature and Culture

• EP views human nature as a collection of psychological adaptations built by natural selection.
• Culture is not an independent variable, but rather a dependent variable shaped by human nature.

Behavioral Genetics

• Behavioral genetics studies the genetic basis of behavioral traits.
• Heritability is the proportion of phenotypic variation due to genetic differences.

Evolutionary Psychology and Adaptations

• Evolutionary psychology is a field of study that examines how human behavior and cognition have evolved to solve adaptive problems.
• Psychological traits are adaptations that have been preserved by selection because of their contribution to fitness in ancestral environments.
• These traits are specialized, domain-specific, and have been formed cumulatively through the selective retention of favorable mutations.

Sensation and Perception

• Sensation and perception are "poster children" for domain-specific adaptations, as each sense is specialized to handle particular kinds of input.
• The senses have evolved to exploit different categories of cues in the environment.

Learning and Adaptation

• Learning is a modification of behavior by experience, and is not necessarily a direct reflection of the environment.
• There are different types of learning, including associative learning and operant conditioning.
• Learning is an adaptation that has evolved to facilitate adaptive behavioral adjustments.

Language as an Adaptation

• Language is an adaptation that has evolved to communicate propositional information (who did what to whom, what is true of what, when, where, and why).
• The function of language is to transfer complex understandings about the world from one brain to another.

Features of Language

• Phonemes are meaningless but meaning-distinguishing sounds that can be combined to express infinite ideas.
• Morphemes are meaningful combinations of phonemes.
• Morphophonemic rules govern the combination of phonemes and morphemes.

Design Features of Language

• One sound per concept is not feasible in human language, as it would lead to confusion and crowding in the sound space.
• The solution is to combine a small set of distinguishable sounds (phonemes) to form unique strings for each concept (morphemes).

Evolutionary Side Effects

• An evolutionary side effect is a feature that is incidental to the evolved function of an adaptation.
• Examples of side effects include the color of bone, which is a result of the fact that selection built internal skeletons out of calcium.

Language and the Brain

• Language function is generally localized around the sylvian fissure.
• Damage to Broca's area usually creates problems related to producing speech, grammar, and syntax.

Language Deficits

• Damage to Wernicke's area usually causes problems in recognizing familiar words and using words correctly.
• Damage to certain other areas in the perisylvian region is associated with other specific language deficits.

Evidence for Language as an Adaptation

• Mastery of spoken language is a human universal, unlike other (simpler) kinds of mastery.
• There are no "simple" languages; all have phonemes, morphemes, morphophonemic rules, morphology, and syntax, interacting in similar ways.

The Origin of Language

• The process of language evolution must have been cumulative, with each step being beneficial; otherwise, selection would have gotten rid of it.
• Suggestive steps in language evolution include noun-verb relations, then objects, then modifiers (adjectives and adverbs).

Future Research Directions

• Combining GWAS studies of specific language impairments with ancient-DNA studies comparing modern and ancestral populations could provide further insight into the relationship between genetic factors, selective pressures, and the emergence of language in human evolution.

Social Learning

• Culture is interpersonally transmitted information essential for human survival, containing behavioral solutions for successful living.
• There are two kinds of learning that can evolve via natural selection:
  • Individual learning: learning from the environment
  • Social learning: learning from conspecifics who learned from the environment

Role of Culture

• In the EP view, culture is both dependent on and independent of human nature.
• Two opposing views on culture:
  • Argument for Weak Constraints (SSSM): biological constraints on culture are too weak to be significant.
  • Argument from Natural Origins: culturally acquired behaviors tend to enhance fitness, or else natural selection would have altered or destroyed the capacity for culture.

Evolution of Social Learning

• Social learning is cheaper than individual learning.
• If social learning is rare, social learners will acquire recent information about the environment, giving them a fitness advantage.
• When all learning is social, information acquired is many generations old, and social learning will have lower fitness than individual learning.

Cognition

• Thinking involves mental processes of acquiring, processing, storing, and using information, most of which are cognitively impenetrable.
• Categorical thinking simplifies response and action by using prior experience to assign to categories and deduce properties from category membership.
• Cognitive categories are fuzzy and centered on taxonomically dense parts of the cladogram.

Rationality and Heuristics

• Rationality is the ability to make judgments and choose courses of action under uncertainty.
• Heuristics are mental shortcuts that can lead to biases.
• Examples of heuristics:
  • Base-rate neglect
  • Availability heuristic
  • Gambler's fallacy
• Formats matter: presenting information in a frequency format can help avoid base-rate neglect.

Evolution of Altruism

• There are two models for the evolution of altruism:
  • Kin selection
  • Reciprocity
• Reciprocity involves exchanging roles as altruist and recipient, with b > c, where b is the benefit and c is the cost.

Cheater Detection and Cooperation

• Individual must withhold benefits from non-reciprocators (cheaters).
• Logical problem solving is important for spotting cheaters.
• The Wason task measures people's ability to detect cheaters, which is influenced by the possibility of cheating.

Moral Intuitions and Ethical Decision-Making

• Having a moral sense allows us to "preplay" the reputation effects of a particular action and prevent damaging our reputations.
• In-group bias is a phenomenon where people favor their own group and disparage the out-group, even when there is no instrumental link between the criteria for intergroup categorization and the nature of the responses requested.

Coalitional Psychology

• Humans form coalitions to gain fitness, and reputation matters in these coalitions.
• In-group bias is a result of coalitional psychology, where people treat decisions as zero-sum, as if there is a finite resource supply.

Human Development and Social Behavior

• Humans begin to attend to cues of group membership in their second year of life, attending to shared preferences, language, styles of dress, and behaviors.
• Infants automatically categorize people by race, age, and other characteristics, which may be misperceived as a marker of coalition membership.

Promoting In-Group Solidarity

• Emphasizing shared language, traditions, beliefs, religion, ancestry, and identity can promote in-group solidarity.
• This solidarity can be used to achieve group-beneficial outcomes in conflicts over resources with out-groups.

The Broader Animal-Behavior Context

• Being social can provide benefits, such as help in finding and holding onto food patches and detecting and repelling predators.
• However, being solitary can also be beneficial in certain circumstances, such as when feeding on small food patches or relying on passive anti-predator strategies.### Language as an Adaptation
• Language is a human universal with complexity, including phonemes, morphemes, morphophonemic rules, morphology, and syntax.
• Universality is evident in the regular pattern of language development in children.
• Evidence for language as an adaptation includes pidgins turning into creoles, dissociation with general intelligence, genetic evidence, and localization in the brain.

Animal Communication vs. Human Language

• Animal communication lacks complex structure, whereas human language allows for infinite expression through phonemes and morphemes combination.

Evolution of Language

• Language likely evolved cumulatively, starting with simple noun-verb relations, then incorporating objects and modifiers.
• Each step in language evolution had to be beneficial for natural selection to favor its development.

Evolutionary Psychology and Personality

• Big Five Personality Traits are more differentiated in complex societies, showing lower inter-factor correlation.

Social Learning and Culture

• Culture is interpersonally transmitted information essential for human survival.
• Types of learning include individual learning from the environment and social learning from conspecifics.
• Models of cultural transmission include Weak Constraints (SSSM) and Natural Origins (Strong Constraints).

Efficiency of Learning

• Social learning is cheaper than individual learning but may result in lower fitness benefits due to outdated information.

Adaptation and Behavior

• Social learning efficiency depends on environmental stability and the efficiency of individual versus social learning.
• Domain-specific learning has different parameters for learning about the natural world versus social environments.

Conclusions on Social Learning

• Culture is essential for solving survival problems that cannot be discovered individually.
• Both human nature and culture shape human behavior, with social learning being context-dependent.

Cognition

• Cognition involves mental processes for acquiring, processing, storing, and using information.
• Much of cognition is unconscious, such as phoneme parsing and emotion detection.
• Humans categorize to simplify responses and deduce properties from prior experiences.

Heuristics and Rationality

• Rationality involves making judgments under uncertainty, influenced by heuristics (mental shortcuts).
• Base rate neglect is a tendency to ignore base rates in favor of vivid or available information.
• Heuristics evolved to solve problems quickly and reliably in ancestral environments.

Evolution of Moral Intuitions

• Moral intuitions evolved to navigate social interactions, influenced by reciprocity and reputation.
• In-group bias is a tendency to favor one's group, influenced by minimal distinctions.
• Evolutionary functions of moral intuitions include reputation management, cooperation, and conflict resolution.

Family Dynamics and Evolution

• Kin selection provides an evolutionary perspective on family conflicts and cooperation.
• Parent-offspring conflict arises due to differing genetic relatedness and resource allocation.
• Impact of mating systems and parental investment also play a role in family dynamics.

Evolution, Selection, and Adaptations

• Williams (1966) presented a gene-centered view of evolution, emphasizing that natural selection operates on individual genes rather than organisms or species.
• Evolutionary adaptations are best understood at the level of genes, which drive the development of traits that enhance fitness.

Biology and Social Sciences

• Nettle (2018) explored the intersection of biology and social sciences, focusing on cultural universals.
• Cultural universals highlight the influence of biological evolution on human behavior, suggesting that certain social behaviors are rooted in our evolutionary past.

Behavioral Genetics

• Plomin et al. (2016) reviewed key findings in behavioral genetics, highlighting the significant role of genetics in individual differences in behavior and cognitive abilities.
• Genetic factors substantially contribute to social behaviors and cultural patterns, indicating a strong biological basis for these phenomena.

Sensation and Perception

• New et al. (2007) found that humans have a heightened attention to animals compared to inanimate objects, which reflects ancestral priorities.
• New and German (2015) demonstrated that humans are more likely to notice spiders, an ancestral threat, even when attention is divided.

Learning

• Petrinovich and Boles (1954) showed that deprivation states, such as hunger, significantly influence learning and behavior.
• Sznycer et al. (2016) found that cues of maternal investment influence sibling altruism across different cultures.

Language

• Pinker (2003) argued that language is an adaptation shaped by natural selection for specific functions in evolution.

Social Learning

• Rogers (1988) suggested that biological factors can limit the extent and manner in which cultural traits are adopted and transmitted.
• Wertz and Wynn (2014) found that infants selectively learn about plant edibility by observing adults, suggesting an evolved mechanism for acquiring knowledge about safe foods.

Cognition

• Cosmides et al. (2010) identified cognitive specializations for social exchange and cooperation, suggesting that human intelligence evolved to handle complex social interactions.
• Kurzban et al. (2001) found that racial categorization is not a fixed social construct but can be overridden by coalition-based categorization.

Emotions

• Sell et al. (2009) found that anger serves as a bargaining tool in social interactions, signaling strength and deterring others from exploiting the individual.
• Sell et al. (2014) showed that the human anger face enhances cues of strength, making individuals appear more formidable to others.

Social "Pathology"

• Daly et al. (2001) found that higher income inequality correlates with higher homicide rates in Canada and the United States.
• Daly and Wilson (2001) found that stepchildren are more likely to suffer from neglect and abuse than biological children, consistent with evolutionary predictions of nepotism.

Adaptations and Evolution

• Adaptations have two types of costs: developmental costs and maintenance costs.

Evolutionary Psychology

• Evolutionary psychology differs from traditional psychology in its approaches and assumptions, particularly in the idea that an underlying human nature is required to explain human behavior.
• Evolutionary psychologists believe that "nurture" (experiences and upbringing) has a significant influence on human behavior, and reject the "blank slate" view of the human mind.

Environment of Evolutionary Adaptedness (EEA)

• The EEA is the environment in which an adaptation was designed by natural selection.

Genetic Reproduction

• Individuals are better vehicles for genes than species because when individuals reproduce, all their genes have an equal chance of being passed to the next generation.

Natural Selection

• Natural selection is a statistical bias in the rate of replication of alternatives caused by their fit with the prevailing environment.

Evolved Adaptations

• The most useful criterion to decide if something is an evolved adaptation is its efficient design for a hypothesized function.

Facultative Adaptations and Susceptibilities

• Facultative adaptations are phenotypic changes induced by environmental change that augment fitness, while susceptibilities are those that reduce fitness.

Learning Mechanisms

• Evolutionary psychologists think there should be many distinct and specialized learning mechanisms because organisms need to learn many different regularities in their world that have different natural "ecologies" and thus present different cognitive demands.

Heritability

• Heritability is higher when the phenotypic difference between identical and fraternal twins is larger.

Psychological Mechanisms

• Psychological mechanisms convert environmental input into responses that have been favored by past selection.

Infanticide in Langurs

• Langurs sometimes commit infanticide, killing young members of their own species, as a male strategy to accelerate female reproduction.

Adaptation and Evolutionary Forces

• Adaptation can only be produced by natural selection, not by other evolutionary forces.

Evolutionary Perspective

• An evolutionary perspective can provide functional explanations of psychological traits, and there are two established methods for deducing the function of such traits.

Development and Evolution

• "Development" and "evolution" are two different biological processes.

Natural Selection and Mutations

• Natural selection could not occur if there were no mutations, despite most mutations being harmful to fitness.

Structure of Science

• Psychology should be considered a branch of biology, similar to how chemistry is a branch of physics.

Facultative Adaptation Example

• People whose ancestors evolved near the equator tend to be born with more melanin in their skin than those whose ancestors evolved in polar latitudes, an example of a facultative adaptation.