Sociobiology: A Theoretical Framework for Studying Primate Behavior

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SociobiologyA Theoretical Framework for
Studying Primate Behavior

• Inclusive Fitness
• Reproductive/Sex Strategies
• Anthropological Significance
• Critique

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Definition

• Sociobiology the science that examines
  behaviorparticularly social behaviorfrom an
  evolutionary perspective
• 2 main concepts
• (1) Inclusive Fitness
• (2) Reproductive/Sex Strategies

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I. Inclusive Fitness

• A. Key Points
• Your genes are shared by your relatives
• How fit your genes are isnt just about you
  (i.e., the individual)its also about how fit
  (well adapted and successful) your relatives (who
  share your genes) are.
• Relatives are included (hence the name inclusive
  fitness) here because of the idea of shared genes
  (alleles, or versions of a trait or gene).

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I. Inclusive Fitness

• A. Key Points (continued)
• Behaviors you engage in to help your relatives
  survive also help you survive because the genes
  (alleles) you share will survive (whether or not
  you or your relatives pass those alleles on to
  the next generation).
• Animals (e.g., primates) are seen to engage in
  this helpful behavior more so perhaps toward
  relatives than non-relatives.
• This helpful behavior is called altruism

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I. Inclusive Fitness

• B. Altruism
• Definition behavior one engages in that aids
  others (for primates, its mainly relatives)
  without concern for oneself.
• Examples providing food, protection, shelter,
  rescue, etc.
• Sociobiologists say that altruistic behaviors are
  selected for (i.e., by natural selection) because
  they help individuals who are doing the helping
  get their genes (alleles) passed on to the next
  generation even if those helpers perish while
  helping relatives.
• Example a primate mom risks her life to save
  her offspring to ensure its survival to grow and
  reproduce because she may be too old to
  reproduce, so its more beneficial for her
  offspring to survive than for her to survive

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I. Inclusive Fitness

• B. Altruism (continued)
• Altruism is seen as not purely for others
  benefitaltruistic behaviors also help the helper
  by preserving the general family genes (alleles)
• The above means that it doesnt matter whether or
  not the family genes (alleles) are in the helper
  or the ones being helped.

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II. Reproductive Strategies

• A. Discussion
• Definition idea that individual organisms have
  evolved behaviors that maximize reproductive
  success (reproductive strategies are also known
  as sex strategies)

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II. Reproductive Strategies

• A. Discussion (continued)
• Since females and males contribute differently to
  reproduction and rearing of young, sociobiology
  looks at sex differences in behavior as having a
  biological basis
• 1. What behaviors or functions do females
  contribute to reproduction?
• 2. What behaviors or functions do males
  contribute to reproduction?

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Reproductive StrategiesA. Discussion (continued)

• Primate female contributions to reproduction
• Gestation
• Birthing
• Nursing
• Caring for young

• Primate male contributions to reproduction
• Attempts to mate
• Sperm
• Protection of female and males own young

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II. Reproductive Strategies

• A. Discussion (continued)
• Since female and male contributions are
  different, and
• sociobiology says that traits which enhance these
  behaviors are selected for,
• these reproductive/sex behaviors are subject to
  similar forces of natural selection as other
  traits (e.g., physical features).

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II. Reproductive Strategies

• A. Discussion (continued)
• In a sense, reproductive/sex behavioral patterns
  are seen as having a genetic basis.
• Or, certain reproductive/sex behavioral
  tendencies or proclivities may be genetic.

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II. Reproductive Strategies

• B. K-selected and r-selected
• K and r selection refer to different types of
  adaptations in various animals with regard to
  reproduction (getting the genes on to the next
  generation for survival of the species)
• Note that K is always capitalized, and r is
  always lowercase

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Reproductive StrategiesPrimates are
K-selectedLess complex animals tend to be
r-selected

• K-selected
• Fewer offspring
• Longer growth and development period of offspring
  (more to learn to survive)
• Greater parental investment (i.e., more effort to
  feed, protect, teach, etc.)

• r-selected
• Numerous offspring
• Shorter growth and development period of
  offspring
• Less parental investment

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III. Anthropological Significance

• Whats the anthropological significance of
  sociobiology?
• How is sociobiology as a theoretical framework
  important to anthropology?
• Some answers follow

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III. Anthropological Significance

• We can compare closely related species of
  primates such as
• chimpanzees, bonobos, and humans who all may have
  diverged from
• a common ape ancestor roughly 5-6 million years
  ago, to see
• what types of behaviors are the result of biology
  or maybe culture (i.e., environment)

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III. Anthropological Significance

• If there is a biological basis for behaviors, we
  can attempt to
• learn how or why our own human behaviors evolved
  (changed over time) as they did, or
• why they might have even originated in the first
  place

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III. Anthropological Significance

• We can study primate behaviors best through
  ethology.
• Ethology the study of animal behaviors in the
  animals natural environment (not in a lab
  setting, or a caged setting, etc.).

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IV. Critique of Sociobiology

• Remember that sociobiology is a theoretical
  framework for understanding animal behavior
• It is one perspective, not the only perspective
• Therefore, some criticisms exist
• Its good to know the pros/cons of various
  theoretical perspectives so you can develop
  strong critical thinking skills

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IV. Critique of Sociobiology

• Some of the limitations to sociobiological
  studies
• There is the lack of long-term data on the
  demography and
• social behavior of the larger groups to which
  individually known primates belong
• So, are there changes in behavior over time?
  Maybe, maybe not

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IV. Critique of Sociobiology

• Some of the limitations to sociobiological
  studies
• There is the lack of long term information on how
  resources (food, shelter, mates) are distributed
  over time and geographic space
• Does social status change?
• Do environments and the availability of resources
  change significantly enough to alter behaviors?
• Maybe, maybe not

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IV. Critique of Sociobiology

• Some of the limitations to sociobiological
  studies
• There is sometimes an inability to trace the male
  genetic line
• Who is the father of most offspring in a primate
  group?
• Paternity matters as it relates to social status
  and access to resources
• Paternity issues tie in with infanticide events
• see your text for an explanation of why
  infanticide exists and what it is

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IV. Critique of Sociobiology

• Some of the limitations to sociobiological
  studies
• Deciding on the costs and benefits of certain
  primate behaviors (e.g., are they adaptive or
  maladaptive) can be somewhat arbitrary
• Who gets to decide?
• What are the criteria for deciding which
  behaviors are good or bad?

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IV. Critique of Sociobiology

• Some of the limitations to sociobiological
  studies
• More information on the genetics of primate
  social behavior is needed
• This criticism may be true of all behavioral
  studies, and is a somewhat broad criticism

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IV. Critique of Sociobiology

• Some of the limitations to sociobiological
  studies
• Sociobiology models are practically non-testable
• Many hypotheses relating to questions of which
  behaviors are
• more influenced by genetics or which are more
• influenced by environment are non-testable
• Theyre non-testable because for ethical/moral
  reasons we dont force matings

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Concluding remarks

• The basic difficulty in testing behavior is the
• complexity of primate behaviors, human and
  non-human.
• The environmental influence can be just as strong
  in non-human primates as it is on humans
• The End