Schedules of Reinforcement

A schedule of reinforcement refers to a rule that describes a contingency of reinforcement.
- The extremes of reinforcement are:
- Extinction (referred to as "Nothing")
- Continuous Reinforcement (referred to as "All")
Intermittent reinforcement is positioned between these two extremes.

Maintenance refers to a lasting change in behavior.
- A major goal of most behavior change programs is to develop naturally occurring activities, stimuli, or events that function as reinforcement.
- It is noted that intermittent reinforcement is usually necessary to achieve effective maintenance of behavior change.

There are two main classifications for intermittent reinforcement schedules:
1. Ratio schedules: Require a number of responses before reinforcement is delivered.
2. Interval schedules: Require an elapse of time before a response produces reinforcement.

Fixed schedules: The response ratio or the time requirement remains constant.
Variable schedules: The response ratio or the time requirement can change from one reinforced response to another.

Fixed Ratio (FR): Requires the completion of a fixed number of responses for delivery of a reinforcer.
- Example: (FR5) A participant earns reinforcement after reading 5 pages.
Fixed Interval (FI): Provides reinforcement for the first response following a fixed duration of time.
- Example: (FI5) The first question answered in class after a 5-minute interval produces reinforcement.
Variable Ratio (VR): Requires the completion of a variable number of responses for delivery of a reinforcer.
- Example: (VR5) A participant earns reinforcement on average after reading five pages; the specific responses vary (e.g., after 3 pages, then after 10 pages).
Variable Interval (VI): Provides reinforcement for the first response after a variable duration of time.
- Example: (VI5) The first question answered in class after an average of 5 minutes produces reinforcement; variations in response times occur.

Fixed Ratios (FR): Reinforcement is delivered following a set number of responses.
- Effects include:
- Participants tend to complete the required responses with little hesitation between responses.
- FR schedules often produce high rates of response.
- Quick responding maximizes the delivery of reinforcement.
- A larger ratio requirement leads to a higher rate of response.
- Typically followed by a post-reinforcement pause.

Variable Ratios (VR): Reinforcement is delivered following a variable number of responses.
- Effects include:
- Produces quick, consistent, steady rates of response without a post-reinforcement pause.
- Larger ratio requirements correlate with higher rates of response.
- Gradual thinning of the ratio leads to high response levels.

Fixed Interval (FI): The first response after a predetermined, fixed amount of time produces reinforcement.
- Effects include:
- Slow to moderate rates of response with a post-reinforcement pause.
- An initially slow but accelerating rate of response, known as the FI scallop, is evident toward the end of the time interval.

Variable Interval (VI): The first response after a predetermined, fixed amount of time produces reinforcement.
- Effects include:
- Constant and stable low to moderate rates of responses.
- Typically few hesitations between responses.
- A larger average interval correlates with lower overall rates of response.

In a standard interval schedule, the first response after the end of an interval receives reinforcement that is available until the first response.
With a limited hold, there is a restriction in place wherein reinforcement is only available for a set amount of time following the interval.
If responses do not occur during this limited hold period, the interval is reset.

Two procedures for thinning schedules:
1. Gradually increase the response ratio or duration of the time interval of an existing schedule.
2. Use clear instructions to communicate the schedule of reinforcement during the thinning process.
Ratio strain can occur due to abrupt increases in ratio requirements, which may lead to:
- A situation where the ratio becomes too large for the reinforcement to maintain response levels.
- Requirements exceeding physiological capabilities of the participant.

Differential reinforcement of specific rates of responding includes variations such as:
- Differential Reinforcement of High Rates (DRH): Reinforcement is contingent upon responses that exceed a predetermined criterion, producing a higher rate of responding.
- Differential Reinforcement of Low Rates (DRL): Responses are only reinforced when they meet or are below a set criterion.
- Differential Reinforcement of Diminishing Rates (DRD): Reinforcement is provided after a predetermined interval for responses that are consistently lower than the gradually decreasing criterion.
- Example: Reinforcement contingent upon fewer than 5 responses in 5 minutes, then fewer than 4 in 5 minutes, and so on.

A lag schedule reinforces responses that differ in a predetermined way from previous behaviors.
- Examples:
- A Lag 1 schedule rewards any response differing from the prior response.
- A Lag 2 schedule rewards responses differing from the previous two responses.

These schedules systematically thin each reinforcement opportunity within a session, independent of participant behavior.
Ratios are increased until reaching the breaking point where the participant stops responding or until a predetermined duration is met.
- Example: A student is reinforced on a FR1 schedule, and response requirements gradually increase, leading to a decline in response rates on an FR5 schedule.

Concurrent Schedules: Involve two or more reinforcement schedules operating independently and simultaneously.
- An SD (discriminative stimulus) signals each component schedule.
- Example: (Conc FR10/FR3) - A student can choose between two chores with different reinforcement requirements.

Multiple Schedule: Composed of two or more basic schedules presented successively, usually in a random sequence.
- Each schedule has an SD that is correlated with it.
Mixed Schedule: Composed of two or more basic schedules presented in sequence without an SD.
- Example: (Mix FR10/FI5) Reinforcement varies without specific signals for each component schedule.

Two or more basic schedules operate in sequence, possibly requiring the same or different behaviors with an SD correlated with each component schedule.
- Example: (Chain VR3/FR10) Reinforcement occurs after completing several steps of behaviors in sequence.

Similar to the chained schedule, but without an SD signal for each component schedule.
- Example: (Tand FR12/FI4) necessitates completion of specified jobs in sequence with a timed interval for reinforcement.