1. Schedules and more Schedules

2. Schedule of Reinforcement -- Terminology
Contingency
Causal Relationship between a response and the reinforcer
(R) - (O) doing (R) produces (O)
Schedule of Reinforcement: Rule determining the response reinforcer relationship, the contingency
Sometimes contingency is not 1:1, sometimes doing(R) does not produce (O)
Pressing remote control button to turn on the TV
Schedule Effects: Refers to the pattern and rate of performance produced by a particular reinforcement schedule
The pattern of buttons pushing
Particular kind of reinforcement schedule tends to produce a particular pattern and rate of performance
Rate of Responding
How fast the responses are made
Slope of the line on a Cumulative Recorder
Mechanical recording equipment use by Skinner to study schedules
See Figure 6.1

3. Figure 6.1 – The construction of a cumulative record by a cumulative recorder for the continuous recording of behavior.
The Principles of Learning and Behavior, 7e by Michael Domjan
Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

4. Schedules of Reinforcement
Continuous Reinforcement (CRF)
Behavior is reinforced every time it occurs 1:1
Examples:
Rat gets food pellet every time it presses lever
Children praised each time they hang up their coats
Leads to rapid increases in the rate of behavior
Not very common in natural environments (including humans)
Intermittent Schedules
Behavior that is reinforced on some occasions but not others
2 main categories
Ratio – reinforcement depend on number of responses
Fixed: number of responses to get reinforcer stays the same
Variable: number of responses to get reinforcer varies
Interval – reinforcement depend on responses and amount of time passed
Fixed: amount of time is fixed
Variable: amount of time varies
See Figure 6.2

5. The Principles of Learning and Behavior, 7e by Michael Domjan
Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

6. Fixed Ratio (FR) Schedule
A fixed number of responses to get reinforced
Indicated by letters FR followed by number of required responses
FR4 requires four response
FR10 requires ten responses
CRF is technically an FR 1
Type of behavior pattern produced see Figure 6.2
CRF produces a mostly steady moderate rate of responding
Higher FR schedules produce a pause after the reinforcer is delivered
Post-Reinforcement Pauses (PRP)
Pause occurs after the reinforcer is delivered
Occurs in anticipation of making the next set of responses
Examples
“Piecework” Paid by number of items produced
Mowing lawns, washing cars, writing a research paper

7. Post-Reinforcement Pauses (PRP)
Average size of PRP increases as size of ratio increases
Example: FR 40 may have PRP of 3 seconds, but FR 130 = PRP 6 seconds
most noticeable at high FR
Ratio Run is the burst of responding to get the next reinforcer
Rate of responding once responding starts
stays fairly constant regardless of ratio size
Run Rate for FR5 same as FR10
Ratio strain:
With a large increase in the ratio requirement
can produce pauses during the ratio run
or stop responding altogether
Procrastination related pause before starting a task

8. Variable Ratio (VR) Schedule
A variable number of responses to get reinforced
Indicated by letters VR followed by average number of required responses
VR4 requires four response on average
2 , 5, 3, 6, 4 responses requires but average rate is 4
VR10 requires ten responses on average
Type of behavior produced: see Figure 6.2
Steady rates of performance at rates similar to comparable FR schedules
Absence of long post-reinforcement pauses (PRP)
Some small PRPs do occur
Examples
Salesperson working on commission
Games of chance

9. Fixed Interval (FI) Schedules
Fixed amount of time before the reinforcer is available “setup time”
Indicated by FI followed by time interval
FI 2min: reinforcer is available after 2 minutes
2 minutes starts counting down after delivery of the reinforcer
After 2 minutes the next response will produce the reinforcer
Type of behavior produced: see Figure 6.2
Pattern referred to as fixed-interval scallop
Like FR, there is a PRP
Unlike FR start responding slowly and as time passes, rate of responding increases hence the scallop pattern
Because of keeping track of the fixed interval
Rate of responding increases in anticipation of the interval ending
Examples
behavior of students studying for a scheduled exam
going to the bus stop to catch a bus

10. Variable Interval (VI) Schedules
Variable amount of time before the reinforcer is available
Indicated by VI followed by the average time interval
VI 4min: reinforcer is available on average after 4 minutes
Series of 2 min, 5min, 3min, 6min, 4min intervals that average to 4min
After the time interval the next response will produce the reinforcer
Type of behavior produced: see Figure 6.2
Steady, moderate rate of responding
Examples:
Sales clerk waiting for customers
Predators waiting for prey
Limited Hold
With interval schedules usually reinforcer remains available forever
Under limited hold conditions the reinforcer is available for a set time and then disappears
For example food service at the cafeteria

11. Comparing VR and VI response rates
VR schedules produce higher response rates than VI schedules.
One possibility: Response rate higher when reinforcement rate (reinforcer per min) is higher.
Will VR still produce higher response rate if rate of reinforcement is equated on both schedules?

12. Comparing VR and VI response rates
Reynold’s (1975) Experiment See Figure 6.3
Compared responses on a VI schedule yoked to a VR schedule
One pigeon reinforced on VR schedule
One pigeon on VI yoked to a pigeon on VR
when the pigeon on VR was one response short of the VR requirement, the next response by both birds produced food.
food availability depended on the time it took the VR bird to complete its response requirement.
this time interval varied from one reinforcer to the next (dependent on # of responses the VR bird had to make and how long it took the VR bird to make them).
Both birds received food at approximately the same time, and therefore the rate of reinforcement (i.e., reinforcers per min) was the same for both birds.
Despite the effort to equate rate of reinforcement, the VR bird pecked much more rapidly than the VI bird.
Thus, differences in reinforcement rate do not account for the differences in response rate
Replicated using students playing a video game (Raia 2000)

13. The Principles of Learning and Behavior, 7e by Michael Domjan
Copyright © 2015 Wadsworth Publishing, a division of Cengage Learning. All rights reserved.

14. Comparing VR and VI response rates
Interresponse Time (IRT) Reinforcement Theory
A better way to explain the difference in response rates between ratio and interval schedules is based on the Inter-response time (IRT) – the interval, or pause, between responses
On variable interval schedules
the probability of reward increases with slow responding which is a longer IRTs
On a VI schedule, long IRTs are more likely to be reinforced, thus less rapid responding is reinforced.
On variable ratio schedules
A low response rate increases duration to the next reward
On a VR schedule, short (IRTs) are more likely to be reinforced, thus rapid responding is reinforced.
So interval schedules reinforce slower responding while ratio schedules reinforce faster responding

15. Comparing VR and VI response rates
Feedback Functions
Feedback function takes into account the consequence of making responses over a long period of time
Ratio schedules have a direct relationship between responses and reinforcement
if on a VR 20 schedule responding twice as fast produces twice as many reinforcers
for example with "piece work" you can increase income by working faster
Interval schedule have an indirect relationship between responses and reinforcement
if on a VI 30 second schedule responding twice as fast does not change rate of getting reinforcers
for example salaried (hourly) employees can not increase their income by working faster

16. Procrastination
To voluntarily delay an intended course of action despite expecting to be worse-off for the delay
Major causes of procrastination
Personal Traits: Self-Efficacy, Energy, Impulsiveness & Self-Discipline, Achievement Motivation
Task Characteristics: Aversiveness
We seek to avoid aversive stimuli, and consequently, the more aversive the situation, the more likely we are to avoid it (e.g., procrastinate).
People who find tasks aversive, tend to be procrastinators
Explanations for procrastinating writing a term paper is simple, “Really dislike writing term papers.”
Task Characteristics: Delay
The further away an event is temporally, the less impact it has upon our decisions
Students indicate that they are less likely to procrastinate as a deadline approaches

17. Procrastination Management
Break a big task into smaller series of tasks
Reduces PRP
Set rewards for completing a task
Set consequences for not completing the task
can be effective as long as they are attached to a deadline.
personal contract with a penalty pay $100 for missing the deadline