Human Mating: Evolutionary Perspectives

Darwinian Aesthetics

Darwinian aesthetics explores why humans perceive certain traits or environments as beautiful, often linking these preferences to evolutionary advantages in our ancestral environment.

• Definition of Beauty: In evolutionary psychology, beauty is often associated with traits or environments that signaled survival or reproductive advantages in the Environment of Evolutionary Adaptedness (EEA).

• Examples: Our preference for plants and natural landscapes may reflect ancestral needs for food, shelter, and navigation.

• Lawns and Nature: Lawns may resemble savannahs, which were resource-rich environments for early humans. Exposure to nature reduces stress and aggression, and promotes health and physical activity.

Human Mating: Sex Differences and Evolutionary Pressures

Human mating behavior is shaped by evolutionary pressures, leading to both intra- and intersexual differences. Evolutionary psychology emphasizes differences between the sexes due to varying parental investment and reproductive strategies.

• Intrasexual Differences: Variations within the same sex (e.g., competition among males for mates).

• Intersexual Differences: Variations between sexes, often emphasized due to differences in parental investment and reproductive potential.

• Reproductive Success: The number of offspring an individual produces.

• Reproductive Potential: The future capacity to produce offspring.

Parental Investment Theory

Trivers' Parental Investment Theory (1972)

This theory explains sex differences in mating behavior based on the relative investment each parent makes in offspring.

• Definition: Parental investment is any effort by a parent that increases the survival of offspring at the cost of the parent's ability to invest in other offspring.

• Gamete Formation: Females produce a small number of large, resource-rich ova (~430 in a lifetime), while males produce a vast number of small sperm.

• Female Investment: Includes gestation, lactation, and post-partum care, leading to greater choosiness in mate selection.

• Male Investment: Typically limited to sperm, resulting in less choosiness and more competition for mates.

Handicap Principle

The handicap principle suggests that some traits are costly to maintain but serve as honest signals of genetic quality.

• Definition: Costly traits (e.g., peacock's train) indicate an individual's ability to survive despite the handicap, signaling good genes to potential mates.

• Purpose: Allows assessment of survival ability and honest signaling of gene quality.

Reproductive Value and Fertility

Reproductive Value

Reproductive value refers to the expected future reproductive output of an individual at a given age and sex.

• Definition: The number of children a person is likely to have in the future.

• Sex Differences: Men tend to prefer younger women due to their higher reproductive value.

• Fertility vs. Reproductive Value: Fertility is the likelihood of producing offspring from a given mating, while reproductive value is the overall future potential.

Concealed Ovulation

• Human Females: Unlike other great apes, human females do not show obvious signs of ovulation (e.g., swelling, scent).

• Implications: Men must maintain close proximity to ensure paternity, and women may be perceived as constantly fertile due to physical traits like breast size.

Paternity Certainty

Challenges and Behavioral Implications

Paternity certainty refers to the degree of confidence a male has that he is the biological father of his mate's offspring.

• Female Certainty: Women are 100% certain of maternity due to gestation and childbirth.

• Male Uncertainty: Men face uncertainty due to concealed ovulation and potential for extra-pair copulations.

• Behavioral Consequences: Men may guard mates and seek signs of sexual exclusivity; women may signal emotional loyalty.

• Paternal Investment: Mothers encourage paternal care, which improves child survival, but men must allocate resources carefully to ensure investment in their own offspring.

Mating Systems

Types of Mating Systems

Mating systems describe the patterns of sexual relationships and parental investment within a species.

• Polygamy: Individuals mate with more than one partner. Two main forms:

  • Polygyny: One male mates with multiple females (most common in mammals).

  • Polyandry: One female mates with multiple males (rare; e.g., some Tibetan societies).

• Monogamy: Individuals mate with one partner. Rare in mammals but considered ideal in humans.

• Sexual Dimorphism: Systematic physical differences between sexes. Greater dimorphism often indicates polygynous systems with intense male-male competition.

Humans are less sexually dimorphic than most mammals, suggesting a tendency toward monogamy or slight polygyny.

Mate Preferences

Universal and Sex-Differentiated Preferences

Research (e.g., Buss, 1989) identifies both universal and sex-differentiated mate preferences across cultures.

• Universal Preferences: Both sexes value intelligence, kindness, honesty, health, and shared values.

• Sex Differences:

  • Women: Place higher importance on financial resources, ambition, and industriousness in mates.

  • Men: Place higher importance on physical attractiveness and youthfulness, which signal reproductive value.

Preferences for Financial Resources

• Women prefer mates with resources, ambition, and industriousness, as these traits enhance offspring survival.

• Men with high occupational status are more likely to marry attractive women.

• Cultural differences exist, influenced by women's opportunities for economic independence.

Preferences for Attractiveness

• Both sexes prefer attractive mates, but men rate it as more important.

• Youthfulness: Features such as large eyes, smooth skin, and small jaw signal high reproductive value (neoteny: retention of juvenile traits in adults).

• Hormonally Mature Traits: Pronounced cheekbones and low waist-to-hip ratio signal high fecundity and health.

Short-Term vs. Long-Term Mating Preferences

Differences in Mate Selection Strategies

• Long-Term Mates: Commitment, shared parenting, emotional bonds, and reduced opportunities for extra-pair mating.

• Short-Term Mates: No commitment, focus on genetic quality, and less knowledge of personality traits.

• Sex Differences: Women are choosier about attractiveness in short-term mates, especially during fertile phases; men are generally less selective in short-term contexts.

• As relationship duration increases, both sexes prioritize personality compatibility.

Major Issues in Mating Research

• Survey Data: Much of the research relies on self-report surveys, which may be influenced by social desirability and cultural norms.

• Mate Value: An individual's own perceived mate value influences their preferences and choices.

Additional info: Where the original notes had blanks, academic context and definitions were logically inferred based on standard evolutionary psychology literature. For example, 'neoteny' was filled in as the retention of juvenile traits, and 'concealed ovulation' was explained as the lack of obvious fertility signals in human females.