Ch. 6: Nature Nurture Debate

Contact Between Classical Ethologists and Comparative Psychologists

  • Contact between these two fields was marked by tension and a lack of amicability.

Nature/Nurture Controversy

  • Central debate regarding the influence of genetic inheritance versus experiential learning in shaping behavior.

    • Classical Ethologists (Nature)

      • Argument: Behavior is primarily inherited and adaptive, refined through natural selection suited to life circumstances.

    • Comparative Psychologists (Nurture)

      • Argument: Learning forms the basis of behavior, indicating that instinct and innate tendencies are peripheral or irrelevant.

Criticisms of Classical Ethology

  1. Experimental Flaws

    • Lack of rigorous experimental control within field-based observational studies.

  2. Quantification Deficiency

    • Absence of quantifiable data and failure to utilize inferential statistics.

  3. Abstract Models

    • Critics argue that theoretical models did not provide functional insights into real nervous system activities.

Example of Criticism: Lorenz’s Psychohydraulic Model

  • Concepts involved:

    • Action Specific Energy (ASE)

    • Releaser or Sign Stimulus

    • Innate Releasing Mechanism (IRM)

    • - The Psychohydraulic Model, proposed by Konrad Lorenz, is a classic ethological model that attempted to explain the motivation and execution of fixed action patterns (FAPs). - It operates on the premise that behavioral drive accumulates internally until released by an appropriate external stimulus. - This model strongly supported the classical ethologists' "nature" argument by positing that many behaviors are pre-programmed and internally driven, rather than learned. - Concepts involved: - **Action Specific Energy (ASE)**: This refers to the hypothetical motivational energy that continuously accumulates within an animal for a particular fixed action pattern. The longer the FAP is not performed, the more ASE builds up, increasing the animal's urge to perform the behavior. - **Releaser or Sign Stimulus**: An external sensory cue or object that triggers a specific fixed action pattern. This stimulus acts as a key to unlock the accumulated ASE. - **Innate Releasing Mechanism (IRM)**: A hypothetical neural mechanism or filter that is genetically programmed to recognize the specific releaser. When the IRM detects the appropriate releaser, it "releases" the accumulated ASE, leading to the execution of the fixed action pattern. - **Contribution to the "Nature" Debate**: Lorenz's model explicitly emphasizes the internal, inherited components of behavior. It suggests that the drive for certain behaviors (ASE) and the mechanism to recognize their triggers (IRM) are innate, rather than learned. This perspective highlights the genetic predisposition and evolutionary adaptation of behaviors, reinforcing the classical ethological view that behavior is primarily inherited and independent of extensive learning or experience.

The Concept of Tabula Rasa (Blank Slate) (Nurture Debate)

  • Statement by Watson (1930):

    • Claim: "Give me a dozen healthy infants… and I'll guarantee to take any one at random and train him to become any type of specialist… regardless of his talents, peculiarities…"

    • This concept emphasizes nurture over nature, positing that experience shapes individual potential.

Criticisms of Comparative Psychology

  1. Laboratory Context

    • Many studies lack a natural context, rendering it unsuitable for observing adaptive behavior.

  2. Limited Behavior Scope

    • Focus on behaviors like bar pressing and maze learning deemed irrelevant to natural behavioral contexts of rats.

  3. Species Bias

    • Overemphasis on rat behavior suggests that extensive laboratory breeding has removed natural behavioral elements.

Continuous Nature/Nurture Controversy

  • The controversy persisted for many years, with mounting evidence contradicting established beliefs from both sides.

Challenges to Classical Ethology

  • Observations that began to challenge classical ethologists' beliefs:

    • Behaviors initially labeled as innate or characteristic could actually be attributed to experiential learning.

Example: Ichneumonid Wasps

  • Behavior:

    • These wasps usually oviposit eggs into flour moth larvae.

    • Laboratory evidence reveals: when wasp eggs are transferred to a different moth species, the adult females display a preference for ovipositing on their foster species, indicating learned host preference.

Fundamental Points from Challenges to Classical Ethology

  • Stereotypical or species-characteristic behaviors do not inherently imply independence from experience.

  • Even socially isolated animals can be influenced by external stimuli essential to behavior development.

Example: Peking Ducklings

  • Ducklings orient towards their species’ maternal call, previously thought to be an innate preference.

  • Experimental Analysis:

    • Isolated ducklings still respond preferentially despite isolation from the mother and siblings.

  • Findings show this response is not entirely innate, as isolation during prenatal stages influences response, while playback stimuli can restore preference.

Challenges to Comparative Psychologists

  • Breland and Keller's Findings

    • Students of Skinner who trained animals for commercial purposes, their results illustrated innate predispositions disrupting learned behavior.

  • Example: Raccoons conditioned to deposit coins exhibited behaviors resembling their natural habits of cleaning food, indicating instinctive behavior over conditioned responses.

Keller and Marian Breland's 1961 Observations

  • Emphasis on the necessity of broadening species studied within experimental conditions.

    • "The behavior of animals cannot be adequately understood… without knowledge of its instinctive patterns, evolutionary history, and ecological niche." - Breland (1961)

Critique of the Principle of Equivalence of Associability

  • Original assertion that all stimuli possess equal associative potential was found lacking.

  • Example: Garcia & Koelling (1966)

    • Rats conditioned to avoid stimuli associated with electric shock versus X-ray irradiation, showing contextually dependent aversions.

  • Results indicated:

    • Gustatory aversion learned better with X-ray; auditory-visual aversion with shock.

  • This demonstrated the importance of understanding the rats’ natural feeding behaviors, highlighting evolutionary perspectives to behavior.

Conclusions from Late 1960s Findings

  • Emergence by mid-1960s of a consensus that experience influences innate behaviors.

  • Recognition that innate predispositions can and do interfere with learned responses.

  • Resulting acceptance by both camps of the idea that behavior arises from the interplay of genetics and environment.

Misunderstandings and Premises

  • The initial conflict stemmed from fundamentally different inquiries posed by classical ethologists and comparative psychologists.

    • Reference: Tinbergen N (1963) On the aims and methods of Ethology.