Biological Approach and Natural Selection

• Natural selection: Charles Darwin’s theory of natural selection argues that individuals with traits better suited to their environment are more likely to survive, reproduce, and pass on those traits to their offspring.
• Adaptation: Over generations, species develop adaptive characteristics that make them more competitive in their environment. This process is known as adaptation.
• Darwin's observations: In the Galapagos Islands, Darwin observed that finches had different beak shapes on different islands, suited to the food sources in their specific habitats.
• The Descent of Man (1871): Darwin noted that humans share certain behaviors with animals, such as mate selection, maternal love, and self-preservation. He also identified facial expressions and emotions that humans share with apes.

Evolutionary Psychology

• Evolutionary psychology: This branch of psychology applies Darwin’s theory to explain how human behaviors have developed over time through natural selection.
• Gene-behavior relationship: Natural selection selects genes that may produce behaviors, but not behaviors themselves. Evolutionary psychologists assume that behaviors are genetic and may be inherited. However, this assumption is still under investigation.

The Social Competition Hypothesis (Price, 1994)

• Depression as a subordinate strategy: Price proposed that depressive behaviors are an involuntary subordinate strategy evolved to signal defeat in social competition and reduce aggression. This behavior helps individuals avoid conflict and injury, increasing their chances of survival.
• Resource holding potential (RHP): An animal’s RHP—its awareness of its fighting capacity—determines whether it adopts a dominant or submissive strategy. This is considered a precursor to self-esteem in humans.
• Submissive behaviors and inclusive fitness: These behaviors restore stability within social groups, allowing them to function successfully, which increases inclusive fitness—the ability to pass genes to the next generation.

Evaluation of Price’s Social Competition Hypothesis

• Strengths:

  • Explains the higher prevalence of depression in females.
  • Supported by animal research (Raleigh et al., 1984).
  • Depressed patients avoid competition more than others (Kupferberg et al., 2016).

• Limitations:

  • Suggests depression can be alleviated by accepting lower social status, which raises concerns for treatment.
  • Does not address cognitive or biochemical origins of depression.
  • Speculative regarding the role of depression in inclusive fitness.

  Evaluation of Price’s Theory

  Strengths	Limitations
  Explains higher prevalence of depression in females due to greater parental investment.	Suggests depression can be alleviated by accepting lower social status, raising concerns about the implications for treatment.
  Supported by animal research (e.g., Raleigh et al., 1984).	Does not address cognitive or biochemical origins of depression, making the theory reductionist.
  Evidence that depressed patients avoid competition more than others (Kupferberg et al., 2016).	The role of depression in inclusive fitness is speculative.

  This table outlines the key elements of Price’s Social Competition Hypothesis and evaluates its strengths and limitations.

Raleigh et al. (1984)

• Aim: Investigate the relationship between social status and serotonin (a neurotransmitter linked to depressive symptoms) in vervet monkeys.
• Procedure:
  • Adult male monkeys were observed in groups and categorized as dominant or subordinate.
  • Changes in dominance hierarchies were observed, and serotonin levels were measured before and after these changes.
• Findings:
  • Serotonin levels increased in monkeys that became dominant and decreased in those that became subordinate.
  • Manipulation of dominance hierarchies led to corresponding changes in serotonin levels.
• Conclusion: The study supports the idea that loss of social status triggers behaviors associated with depression, such as social withdrawal and decreased motivation.