Primary and Secondary Reinforcement
A delayed primary reward does not have to be the only influence operating during the delay.
The Delay Problem
In instrumental conditioning, an action and its reward do not always occur together. When the interval between them becomes longer, it can become more difficult for the reward to influence learning across the entire interval. Hull's account addresses this problem by proposing that the delayed primary reward does not have to be the only influence operating during the delay.
Primary and Secondary Influences
Secondary reinforcement is a reinforcing influence that develops from stimuli regularly occurring during the delay between an action and a delayed primary reward. It provides a more immediate influence during the interval, rather than requiring learning to depend only on the primary reward at the end.
| Primary reward | Secondary reinforcement |
|---|---|
| The reward delivered after the delay | A more immediate reinforcing influence occurring during the delay |
| Directly follows the delayed sequence at its endpoint | Develops from stimuli that regularly occur during the delay |
| May have difficulty influencing learning across a long interval by itself | Can help maintain the connection across part of that interval |
Tracing the Bridge
Following One Delayed Sequence
Trace how learning may be supported when an action is followed by a delay containing regularly occurring stimuli and then by a primary reward.
Action: The learner performs the instrumental action.
Delay: The primary reward does not arrive immediately, so the action and reward are separated by an interval.
Regular stimuli: Stimuli appear regularly during the interval. These conditions can favor the development of secondary reinforcement.
More immediate influence: Secondary reinforcement supplies a reinforcing influence during the delay instead of leaving the primary reward as the only influence.
Primary reward: The delayed primary reward still occurs at the end of the sequence and works together with the secondary influence.
The action-to-reward relation can be supported across more of the delay because a reinforcing influence operates before the primary reward arrives.
The important point is not that every event during a delay automatically becomes reinforcing. The source states that regularly occurring stimuli can favor secondary reinforcement. Under conditions that support this development, those stimuli provide a more immediate influence during the interval.
Stimulus Traces and Goal Gradients
Hull's theory uses molar stimulus traces to refer to the lingering presence of a stimulus. The source presents these traces as part of the explanation for how a goal gradient can span time. Hull's proposal is that secondary reinforcement works together with these traces, allowing the resulting gradient to extend beyond the period that stimulus traces alone would cover.
Secondary reinforcement does not replace the delayed primary reward. Its role is to add a more immediate reinforcing influence during the delay and, together with stimulus traces, help the goal gradient extend across a longer interval.
When the Bridge Is Obstructed
The effect of a delay depends partly on whether conditions support or obstruct secondary reinforcement. A delay with accessible, regularly occurring stimuli is therefore not equivalent to a delay in which those conditions are obstructed.
| Delay with secondary reinforcement supported | Delay with secondary reinforcement obstructed |
|---|---|
| Regularly occurring stimuli can favor secondary reinforcement during the delay | The conditions do not provide the same opportunity for secondary reinforcement during the delay |
| A more immediate reinforcing influence can operate before the primary reward | Learning relies more heavily on the delayed primary reward across the interval |
| Learning decreases with increased delay less than when secondary reinforcement is obstructed | Learning decreases with increased delay more than when secondary reinforcement is supported |
Common Reasoning Errors
Treating the primary reward as the only influence during the delay
Hull's account proposes that secondary reinforcement can provide a more immediate reinforcing influence during the interval.
Fix:
Inspect the delay for regularly occurring stimuli that can favor the development of secondary reinforcement.Assuming that every stimulus during a delay is automatically secondary reinforcement
The source says that regularly occurring stimuli can favor the development of secondary reinforcement; occurrence alone does not establish that development.
Fix:
Describe the stimulus as a condition that can support secondary reinforcement, unless the learning arrangement establishes the secondary reinforcing influence.Comparing only a delayed condition with an immediate condition
The source emphasizes comparing delays with different opportunities for secondary reinforcement.
Fix:
Ask whether the delay supported or obstructed secondary reinforcement.Leaving stimulus traces out of the goal-gradient explanation
Hull's proposal places secondary reinforcement in conjunction with molar stimulus traces.
Fix:
Explain that secondary reinforcement works with stimulus traces, allowing the resulting gradient to extend beyond the period traces alone would cover.
Apply the Distinction
A learner performs an action, experiences a delay, and then receives a primary reward. In one condition, regularly occurring stimuli are available during the delay. In another condition, the conditions obstruct secondary reinforcement. Explain why the two conditions should not be treated as equivalent, and identify which condition should show the smaller decrease in learning as the delay increases.
Hints
- Look for the more immediate reinforcing influence during the delay.
- Compare opportunities for secondary reinforcement rather than comparing delay with no delay.
- Use the source's prediction about learning as increased delay is introduced.
What do you think happens?
Which condition should show learning that decreases less as the delay increases?
Reveal answer
Answer: The condition with regularly occurring stimuli that favor secondary reinforcement
The source reports that when conditions favor secondary reinforcement during a delay, learning decreases with increased delay less than when those conditions obstruct secondary reinforcement.
Key Takeaways
- A delayed primary reward does not have to be the only influence operating during the delay.
- Regularly occurring stimuli during the delay can favor the development of secondary reinforcement.
- Secondary reinforcement provides a more immediate reinforcing influence and can extend the goal gradient when it works with molar stimulus traces.
- The effect of delay depends partly on whether conditions support or obstruct secondary reinforcement.
- Learning decreases with increased delay less when secondary reinforcement is supported than when it is obstructed.
Key Takeaways
- Secondary reinforcement helps bridge the interval between an action and a delayed primary reward.
- Regularly occurring stimuli during the delay can favor this secondary reinforcing influence.
- Secondary reinforcement works with molar stimulus traces to extend a goal gradient across time.
- Delays that support secondary reinforcement produce less decline in learning as delay increases than delays that obstruct it.