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Chapter 2, Part 1: Elicited Behavior and Habituation

Elicited Behavior or Unconditioned Behavior

  • Elicited behavior often occurs without any past experience for the individual upon the first presentation of a stimulus.
  • It is inherited through the process of Darwinian natural selection.
  • Elicited behavior may change with further experience or vary depending on current circumstances.
  • Examples:
    • Example 1: Unconditioned behavior elicited by a weak intensity stimulus may decline in magnitude or probability over repeated presentations, a phenomenon known as habituation.
    • Example 2: Unconditioned behavior elicited while the animal is “wary” may elicit a larger than normal response, a phenomenon known as sensitization.

Elicited Behavior: Facial Display

  • Mothers’ responses to their own infants are invariant across cultures.
  • This suggests it is not a learned response; it is elicited by a baby stimulus.

Some Features of Elicited Behaviour

  • 1. Simple Reflexes
    • Can be just frac{2}{3} neurons: afferent (sensory), interneuron, efferent (motor).
    • All human reflexes involve 3 neurons.
  • 2. Orienting Reflexes
    • Pay attention to a triggering stimulus.
  • 3. Taxis (taxes)
    • A directional change; we approach appetitive (positive) stimuli and withdraw from aversive (negative) stimuli.
  • 4. Kinesis (kineses)
    • Change the vigor (increase or decrease) of ongoing behaviour.

Jumpscare and Immediate Elicited Reactions

  • Jumpscare involves eye wince, scream, arms-up – a simple reflex.
  • Gross body movements correspond to kinesis (vigorous movements).
  • Move away corresponds to negative taxis (withdraw from potential danger).
  • Look back toward whatever scared you corresponds to an orienting response.

Elicited Behaviour: Startle

  • Startle is a defensive reaction to a potential threat.
  • When a loud sound causes startle reactions, this is called the acoustic startle response.

MAPs (Modal Action Patterns)

  • MAPs are:
    • A sequence of behaviors initiated in the presence of an appropriate stimulus.
    • The eliciting stimulus for a MAP is usually called a sign stimulus.
  • Sign stimuli can be social (another animal); when this happens, interactions are more species-specific.
  • Repetition: often the behavioural sequence becomes more efficiently executed over repeated occurrences.
  • Sometimes the behaviour requires an underlying drive to be present (e.g., seasonal mating in many species).

Sign Stimuli for a Highly Territorial Male Stickleback Fish

  • Appetitive (leads to courting behavior).
  • Aversive (leads to attack of intruder).

Terminology in Learning and Biology

  • In learning theory:
    • Appetitive describes situations where a potentially valuable commodity is available (e.g., food, sex) and the approach system is activated.
    • Aversive describes situations with a potential threat (e.g., predator, poison) and the avoidance system is activated.
    • The missing noun being modified is “motivation.”
  • In biology:
    • Appetitive behavior refers to early components of foraging behavior, while later components are called consummatory behavior.
    • The missing noun for biologists is “foraging.”

MAPs in Foraging and Caregiving

  • Herring gulls example:
    • Hungry baby pecks to open beak; mother drops food into open beak.
    • This MAP requires underlying drive: hunger and attachment (to the chick) in the mother.

What’s the “Effective” Stimulus?

  • Most stimuli are complex mishmashes of sensory features.
  • Question: which of these many features triggers the response?
  • Supernormal stimuli are exaggerated sign stimuli that release more than natural levels of responding (e.g., moving red stripes on a stick).

Habituation

  • A simple type of learning shown by a change in elicited behaviour over trials.
  • Defined as a reduction in responsiveness (frequency, magnitude) over successive trials.
  • Cardinal feature: stimulus specificity. Habituation is not caused by fatigue; if you change the stimulus, habituation goes away.

Stimulus Specificity (Evidence)

  • Group 1: Infants habituated to the face forward of Person X, tested with profiles of Persons X and Y. They looked more at the new face (Y) than the habituated face.
  • Group 2: Infants habituated to the face profile of Person X, tested with faces forward of Persons X and Y. They looked more at the new face (Y) than the habituated face.

Stimulus Specificity in Salivation and Liking

  • Salivation and liking decrease over a meal but return to original levels when a new food is introduced (stimulus specificity).
  • New Food indicates stimulus novelty can reset responsiveness.

Forms of Habituation

  • Short-Term Habituation
    • May last only a few minutes or hours.
    • Shows stimulus-specificity.
  • Long-Term Habituation
    • May last weeks, months, years, or a lifetime.
    • Also shows stimulus-specificity.

Hi-Lo Response Vigor, Presentations, and Spontaneous Recovery

  • Hi/Lo response vigor: the amplitude of the elicited response changes across presentations.
  • Number of presentations: how many times the stimulus has been presented.
  • Spontaneous recovery: the return of the response after a rest period.
  • Short-Term Habituation (definitions):
    • Defined by the presence of spontaneous recovery after a short time and the reoccurrence of the identical stimulus.
  • Long-Term Habituation (definitions):
    • Lack of spontaneous recovery; the response remains reduced for longer periods.

Intertrial Interval Effects

  • Short intertrial intervals (e.g., 2 ext{ sec}) cause startle to habituate to a much lower level within a single session, compared to longer intervals.
  • Longer intertrial intervals (e.g., 16 ext{ sec}) lead to less habituation in the short run, but any habituation that occurs is not lost if interval spacing is varied.
  • What is learned depends on training conditions.

Practical Note on Training Schedules

  • Short-term habituation can be rapid with tight intertrial spacing.
  • To promote durable habituation, longer exposure across days (e.g., once a day for many days) helps make habituation stick.