11.1 Evolutionary perspectives on human behavior

Evolutionary perspectives on human behavior explore how natural selection shapes our actions and thoughts. This approach considers how ancestral challenges influenced the development of traits like mate selection, parental investment, and social cooperation.

Natural selection's impact on human adaptations is examined through sexual selection, adaptive mechanisms, and environmental influences. The theory also delves into inclusive fitness, explaining altruism, kin selection, and cooperation in social interactions.

Evolutionary Theory and Human Behavior

Fundamental Principles of Evolution

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• Natural selection drives evolutionary change through heritable traits enhancing survival and reproduction
• Genetic variation within populations provides raw material for evolutionary change (genetic drift, mutation)
• Adaptation increases an organism's fitness in a specific environment
• Evolutionary mismatch occurs when previously adaptive traits become maladaptive (modern processed foods)
• Phylogenetic analysis traces evolutionary history of behavioral traits across species
  • Compares traits between humans and other primates
  • Provides insights into origins of human behavior (tool use)

Evolutionary Psychology and Human Behavior

• Posits human behaviors and cognitive processes shaped by natural selection
• Applies evolutionary principles to understand various aspects of human behavior
  • Mate selection preferences (physical attractiveness)
  • Parental investment strategies (differential investment in offspring)
  • Social cooperation mechanisms (reciprocal altruism)
• Considers ancestral adaptive problems faced by humans
  • Finding food and shelter
  • Avoiding predators and pathogens
  • Navigating complex social hierarchies

Natural Selection in Human Adaptations

Sexual Selection and Mating Behaviors

• Component of natural selection influencing traits related to mate attraction and competition
• Shapes human mating behaviors and preferences
  • Male traits demonstrating resource acquisition ability (status symbols)
  • Female traits signaling fertility and health (waist-to-hip ratio)
• Evolutionary stable strategies (ESS) represent behavioral patterns resistant to alternative strategies
  • Monogamy as an ESS in certain environmental conditions
• Trade-offs in natural selection explain costs of certain adaptations
  • Energy invested in muscle mass versus immune function

Adaptive Mechanisms and Environmental Influences

• Natural selection shapes human emotional responses as adaptive mechanisms
  • Fear response to potential threats (heights, snakes)
  • Disgust response to contamination risks (spoiled food)
• Frequency-dependent selection maintains behavioral diversity within populations
  • Personality traits like extraversion and introversion
• Environment of evolutionary adaptedness (EEA) refers to ancestral conditions of adaptation
  • Hunter-gatherer lifestyle
  • Small, kin-based social groups
• Considers mismatch between EEA and modern environments
  • Prevalence of chronic diseases related to sedentary lifestyles

Inclusive Fitness and Social Interactions

Kin Selection and Altruism

• Inclusive fitness extends individual fitness to include genetic relatives' reproductive success
• Hamilton's rule predicts evolution of altruistic behavior
  • Benefit to recipient × degree of relatedness > cost to altruist
• Kin selection theory explains apparently altruistic behaviors benefiting genetic relatives
  • Parental care
  • Helping behavior among siblings
• Patterns of cooperation and conflict within families explained by inclusive fitness
  • Parent-offspring conflict over resource allocation
  • Sibling rivalry for parental investment

Cooperation and Social Behavior

• Reciprocal altruism between unrelated individuals understood through long-term genetic benefits
  • Food sharing in hunter-gatherer societies
  • Mutual defense against predators or rival groups
• Inclusive fitness provides insights into evolution of social behaviors
  • Alliance formation in primate societies
  • In-group favoritism in human cultures
  • Ethnocentrism and intergroup conflict
• Application to human behavior considers cultural influences and potential maladaptive outcomes
  • Nepotism in modern organizations
  • Extreme self-sacrifice in warfare

Evolutionary Basis of Cognition and Decision-Making

Cognitive Adaptations and Social Intelligence

• Human brain evolved to process environmental information promoting survival and reproduction
• Cognitive adaptations facilitate social interactions and cooperation
  • Theory of mind allows understanding others' mental states
  • Language capacity enables complex communication and knowledge transfer
• Modular mind hypothesis suggests specialized cognitive mechanisms for specific adaptive problems
  • Face recognition module
  • Cheater detection module
• Sexual selection influenced cognitive abilities related to mate choice
  • Capacity for assessing partner quality (intelligence, creativity)
  • Detecting infidelity (jealousy, suspicion)

Decision-Making Processes and Problem-Solving

• Evolutionary approaches emphasize heuristics and biases as adaptive cognitive shortcuts
  • Availability heuristic for quick risk assessment
  • Confirmation bias for maintaining group cohesion
• Ecological rationality posits decision-making adapted to specific environmental structures
  • Foraging strategies optimized for patchy resource distribution
  • Social exchange rules adapted for reciprocal relationships
• Human intelligence and problem-solving abilities evolved in context of social competition
  • Machiavellian intelligence hypothesis
  • Cultural innovation and transmission of complex skills
• Evolution of human cognition shaped by demands of living in complex social groups
  • Coalition formation and maintenance
  • Tracking social obligations and detecting free-riders