Operant Conditioning: Skinner's Research (College Board AP® Psychology): Revision Note

Skinner's research

• B.F. Skinner (1938, 1953) built on Thorndike’s Law of Effect by developing operant conditioning and providing a systematic, experimental analysis of how consequences shape behavior

  • To study this, Skinner designed the Skinner box - a controlled environment containing a lever or key, a food dispenser, and sometimes an electrified floor

• Consistent with the behaviorist approach, Skinner focused on observable, measurable behavior, allowing learning to be studied scientifically

Procedure and key findings

• Skinner used the box to demonstrate how different consequences influence behavior

  • Positive reinforcement:

    • A rat received food after pressing a lever. Over time, lever-pressing increased and became the dominant behavior

  • Negative reinforcement:

    • Pressing the lever stopped an electric shock. Rats quickly learned to press the lever to escape or avoid the shock

  • Discrimination:

    • Rats reinforced only when a light was on learned to press the lever only in that condition, showing that behavior depends on specific cues

Shaping

• Complex behaviors are not learned all at once

  • Instead, they are built gradually through shaping

• Shaping involves reinforcing successive approximations

  • These are small steps that move closer to the desired behavior

    • E.g. to train a rat to press a lever:

      • reinforce moving toward the lever

      • then reinforce touching it

      • then reinforce pressing it

  • Each step must be closer to the target than the previous one

Reinforcement schedules

• Once a behavior is learned, the schedule of reinforcement influences the rate, pattern, and persistence of responding

  • Continuous reinforcement: every response is rewarded

    • E.g. a parent praises a child every single time they tidy their toys

      • This leads to rapid learning, but rapid extinction

  • Partial (intermittent) reinforcement: only some responses are rewarded

    • E.g. a parent praises a child for tidying their toys only occasionally

      • This leads to slower learning, but much greater resistance to extinction

• Different reinforcement schedules produce distinct patterns of behavior:

• These differences in response patterns are illustrated in graphs of responding over time:

  • ratio schedules produce higher response rates

  • interval schedules produce slower, more patterned responding

Instinctive drift

• Although operant conditioning explains much behavior, biology can limit what can be learned

  • Instinctive drift is the tendency for conditioned behaviors to revert to innate, instinctive patterns

• Breland and Breland (1961) demonstrated this:

  • A raccoon trained to deposit coins began rubbing them together, resembling natural food-washing behavior

  • A pig trained to deposit coins began rooting them along the ground, an instinctive foraging behavior

• In both cases, instinctive behaviors interfered with the trained response

• This shows that learning is constrained by biology, similar to biological preparedness in classical conditioning

Superstitious behavior

• Sometimes behaviors are strengthened by coincidence rather than real cause-and-effect

• Skinner (1948) showed this by giving pigeons food at fixed intervals regardless of their behavior

• The pigeons developed repetitive actions (e.g. turning or head-bobbing) as if these behaviors caused the food

  • This occurred because whatever behavior happened just before reinforcement was strengthened

• Human examples include:

  • athletes repeating rituals during winning streaks, such as wearing the same socks

  • gamblers using “lucky” behaviors, such as blowing on dice

• These persist because they are reinforced unpredictably, making them resistant to extinction

Learned helplessness

• Not all learning leads to increased responding

  • In some cases, organisms learn that their behavior has no effect

• Learned helplessness occurs when an organism experiences uncontrollable negative events and stops trying to change the outcome

• Seligman et al. (1967) found that:

  • dogs exposed to inescapable shocks later failed to escape, even when escape was possible

  • they had learned that their actions did not matter

  • this effect can transfer to new situations

• Seligman argued that learned helplessness contributes to human depression

  • Repeated uncontrollable experiences may lead to a belief that effort is pointless

• Learned helplessness can also apply to education

  • Students who have repeatedly failed despite effort stop trying even when success becomes possible

Punishment vs. reinforcement

The four consequence types

• To understand consequences, apply two key questions:

  1. Is a stimulus added or removed?

  2. Does the behavior increase or decrease?

• The key difference lies in their effect on behavior:

  • Reinforcement increases the likelihood of a behavior

  • Punishment decreases the likelihood of a behavior

• Both can be positive (adding a stimulus) or negative (removing a stimulus)

Key differences

When is punishment effective?

• Punishment is only effective under specific conditions:

  • Timing: Must be immediate to create a clear link with the unwanted behavior

    • Delayed punishment loses its association with the behavior and becomes less effective

  • Consistency: Must be applied every time, as inconsistency can maintain behavior

  • Paired with reinforcement: Must be combined with reinforcing the desired behavior

Limitations of punishment

• Punishment has several important limitations:

  • Side effects: Harsh punishment can produce fear, aggression, anxiety, and avoidance

  • Suppression, not elimination: Behavior may return when the punisher is absent

  • Does not teach alternatives: It shows what not to do, but not what to do

  • May reinforce avoidance: Unwanted behaviors can be strengthened if they help escape something unpleasant

    • E.g. a child throws a tantrum to avoid eating vegetables. If the parent removes the food, the tantrum is negatively reinforced