Operant Conditioning & Major Depressive Disorder (DP IB Psychology): Revision Note

Operant conditioning & MDD

• Operant conditioning (OC) is learning through consequences

• Behaviour is shaped by reinforcement (which encourages repetition) and punishment (which discourages repetition)

• Learning is an active process as humans and animals operate on their environment and learn from outcomes (Skinner, 1953)

Types of reinforcement & punishment

• According to Skinner, consequences are learned via three types of direct reinforcement:

  • Positive reinforcement – behaviour repeated to gain pleasant consequences or rewards

    • E.g., doing homework to get praise

  • Negative reinforcement – behaviour repeated to avoid unpleasant consequences

    • E.g., doing homework to avoid detention

  • Punishment decreases behaviour

    • Positive punishment = unpleasant outcome (e.g., being told off)

    • Negative punishment = loss of something pleasant (e.g., not being allowed to go to a party)

Skinner's research (1953)

• B.F. Skinner (1953) conducted experiments to investigate how animals learn from the consequences of their actions

• He used the Skinner Box, placing one rat at a time inside

• The box contained:

  • A lever that released food as a reward

  • An electroplated floor that delivered mild electric shocks as punishment

Key findings

• Positive reinforcement:

  • A hungry rat accidentally pressed the lever – a food pellet was released

  • The consequence was that the rat quickly learned to press the lever repeatedly, as the behaviour was reinforced by the reward

• Negative reinforcement:

  • The rat received an unpleasant electric shock

  • When the rat accidently pressed the lever, the electric shock stopped

  • The consequence was that the rat learned to press the lever immediately when placed in the box to remove the unpleasant stimulus

• Avoidance learning:

  • A light signalled that a shock was about to happen

  • The rat learned to avoid the electric shock by pressing the lever when the light came on

Link to MDD

• Operant conditioning can help explain how depressive behaviours are learned and maintained:

  • Lack of positive reinforcement (reduced social praise/attention) may reduce motivation and lead to withdrawal

  • Negative reinforcement may maintain depressive behaviours (avoiding social situations reduces anxiety but reinforces isolation)

• This shows how environment and consequences can contribute to the onset and persistence of MDD symptoms

Research support for operant conditioning & MDD

 Lewinsohn et al. (2006)

 Aim:

• To compare the amount of positive reinforcement received by patients with MDD and non-depressed participants

 Participants:

• 30 patients with MDD

• A group with another disorder that wasn't depression

• A control group with no MDD

• This was a quasi-experiment

 Procedure: 

• Participants were asked to complete questionnaires daily over a 30 days

  • They rated themselves on a daily mood checklist (e.g., 'I feel happy/miserable/dull')

  • They completed a pleasant activities schedule (320 activities, e.g., sport, meditation, reading, socialising)

• Each activity was rated for enjoyment and repetition on a scale of 0-3

• Positive reinforcement was operationalised in terms of activities that were both enjoyed and repeated

 Results:

• Positive correlations were found between pleasant activities and good mood

• The more pleasant activities a participant was involved in, the higher their mood rating

Conclusion:

• Positive reinforcement from enjoyable activities may help maintain a good mood and protect against MDD

Evaluation of operant conditioning & MDD

Strengths

• The above research uses standardised procedures, which gives it reliability, and it also draws from participants’ daily activities, so it has good ecological validity

• Reinforcement is already successfully applied in token economies (e.g., for schizophrenia), supporting its use in treating mental illness

Limitations

• OC cannot explain why some people continue to engage in harmful behaviours

  • E.g., someone with MDD may persist in self-blame or substance abuse that brings no positive reinforcement

• OC is based on Skinner's animal research, which is environmentally reductionist

  • Humans are much more complex and sophisticated than animals and operate at a higher cognitive level

Link to concepts

Causality

• Operant conditioning uses the mechanisms of scientific inquiry to investigate behaviour (standardised procedures, objectivity, only observable behaviours are measured)

• It strives for a cause-effect solution to explain specific behaviours

  • A problem with this is that human behaviour is more nuanced and difficult to pin down to one discernible cause than, say, a rat pressing a lever for food

Perspective

• Environmental reductionism is the idea that a complex disorder such as MDD can be explained simply by framing it within the context of reward-seeking/punishment-avoiding behaviours

• There is compelling evidence to suggest that MDD may have a biological basis (neurochemical) and/or be the result of faulty schemas (cognitive) so it cannot be viewed in isolation as the result of one environmental influence