schedules of reinforcement

exam 2

Schedules of Reinforcement

• A rule stating how and when discriminative stimuli and behavioral consequences will be presented

• The arrangement of the environment in terms of discriminative stimuli and behavioral consequences.

• Specifies the requirements for reinforcement.

• a statement of the conditions under which a behavior is reinforced.

• The arrangement of discriminative stimuli, operants, and consequences

Performances on schedules of reinforcement have been found to be very similar across:

• Species

• Types of behavior

• Types of reinforcing consequences

Why are schedules of reinforcement important?

Approximates some of the complex contingencies that operate with humans in everyday environment

Schedules of reinforcement tend to:

produce stereotypical response patterns

Patterns are:

a product of exposure to the contingencies of reinforcement

Contingency

the focus on the relationship between behavior and its consequences

Steady-state performance

the pattern of response that develops after repeated exposure to a contingency of reinforcement

• Example: The fixed-ratio pause-and-run pattern

The Most Common Types of Schedules

• Reinforcement for a particular number of responses

• Reinforcement for a response after a particular interval of time has passed

what does Inter response time (IRT) mean?

time between responses

how many basic schedule types are there?

four

Continuous reinforcement (CRF):

behavior is reinforced for every response — Often used in the early stages of shaping

• Examples include showering, eating, vending machines

Intermittent schedules of reinforcement

behavior reinforced occasionally — Requirements can be based on the number of responses required, time, or both, and are more resistant to extinction

• Examples include checking the mail, checking your phone.

schedules diagram

Ratio Schedules

An organism has to respond a specified number of times for reinforcement

• The rate of responding will influence the rate of reinforcement.

• The faster you respond, the faster you earn reinforcers

• Reinforces shorter interresponse time (IRT) because IRT prior to reinforcement is likely to be short

Fixed Ratio Schedules (FR)

The number of responses required for reinforcement is constant

this schedule is a:

fixed ratio

PRP

post-reinforcement pause

FR 5

5 responses to earn a reinforcer

A fixed ratio schedule on a graph is called a:

break-and-run pattern

• the ‘break’ happens after the response occurs EVERY time

Characteristics of Fixed Ratio Performance:

• break and run

• Post reinforcement pause (PRP)

• Ratio strain

Break-and-run

A typical pattern associated with fixed ratio schedules that has a high response rate until reinforcement is received and then a post-reinforcement pause or PRP

Post reinforcement pause (PRP)

A pause in responding after a reinforcer is delivered (‘break’ in break-and-run)

• This occurs because of the workload ahead

• “Pre-ratio pause”

Ratio strain

Extended pauses after reinforcement or during a run of responses. Occurs when shaping is done too quickly or with too large of steps

• This can be avoided with proper training 

• It happens when the reinforcement have increased too quickly 

• Stops responding when everything increases too quickly

FR

LOWER resistance to extinction , and rapid response, with short pause after reinforcement

Typical FR (fixed ratio) response pattern

Higher ratios generate higher rates of responding and longer pauses

• A real-life example of fixed ratio schedules is piecework…manufacturing an American flag 

Variable Ratio Schedule (VR)

A changing number of responses is required for reinforcement

• Specifies the average number of responses required

• Generally produces the highest rate of responding

• NO BREAKS/pauses

• steep slope

VR3 = an average of 3 responses to earn a reinforcer (ITS AVERAGE…SO IT COULD BE 2, COULD BE 5)

this schedule is a…

Variable ratio

Characteristics of Variable Ratio Performance

• PRPRs do not usually occur in variable ratio schedules

• Ratio strain is possible

• VR has a higher resistance to extinction 

VR

HIGHER resistance to extinction, and high, steady rate without pauses

Interval Schedules

An organism’s behavior is reinforced for the first response after a ‘given time interval’ has passed

• The response MUST occur for reinforcement

• The rate of responding has little influence on the rate of reinforcement

• Both long and short interresponse times are reinforced

• There is a time component

Fixed Interval (FI) Schedule

The first response after the constant time interval has expired is reinforced

• examples include waiting for the bus or checking the mail

• after 10 minutes have passed a response will occur

• scalloped

This graph is …

Fixed interval

• FI 1 min = response after 1 min or longer earns a reinforcement

  • further explanation: You don’t check the oven right after you put the cookies in the oven, you check after 15 minutes to see if the cookies are ready. You have to wait a certain amount of time. so you would have FI 15 min.

Characteristics of Fixed Interval Performance

• PRP is common

• After a pause, behavior may progressively increase (SCALLOPED)

• or, behavior may become rapid and steady (break and run)

As the interval gets closer to timing out, the probability of reinforcement increases, so your response gets faster and faster

• real life example: checking the clock

FI

LOWER resistance to extinction, and long pause after reinforcement yields

Variable interval (VI) schedule

The first response after the variable time interval has expired will be reinforced. States the average interval after which a response will be reinforced.

• Examples include calling someone whose line is busy, or waiting for a letter in the mail.

• On average have to wait about 30 seconds for my response to occur  

• Shallower slope

• Deals with seconds

this graph is a …

variable interval

• VI 30 seconds = response after an average of 30 seconds earns a reinforcer

Characteristics of variable interval performance

• Brief PRPs occur occasionally

• An increase in the size of the interval produces a decrease in the response rate

• Moderate

VI

HIGHER resistance to extinciton, and steady rate without pauses

• real life example: surfing with waves

Response Independent Schedules (also known as time-based schedules)

• fixed time (FT)

• variable time (VT)

May lead to superstitious behavior (through accidental behavior)

Fixed Time (FT)

after a fixed amount of time, a consequence is delivered regardless of the responding

Variable Time (VT)

after an average amount of time, a consequence is delivered regardless of responding

Fixed

every time

variable

average amount of time

The use of Schedules of Reinforcement 

• form a stable baseline

  • The baseline can be used to test IVs such as drug administration

• be used as IVs themselves

  • it teaches us more about basic behavioral process

• to test if your lab is working properly

  • you should be able to get the proper response patterning for each schedule

Advantages of Intermittent Schedule

• FR schedule (e.g. FR 10) generates higher rates of responding than CRF schedules

• Less chance of satiation

• Under some circumstances, behavior is more resistant to EXT (variable schedules)

• Schedules more closely simulate the natural environment

Satiation

fully satisfied