PSYB38 - Week 11 Shaping, Stimulus Fading & Behavioural Chaining

Shaping

teaching someone to do something new by rewarding small steps that get closer and closer to the final goal. Guiding them little by little until they can do the whole thing
- method of successive approximations
- uses principles of reinforcement and extinction

Variability and Response class

- variability is a basic feature of operant behaviour, behaviour is rarely repeated in exactly the same form
- reinforcer increases the strength or likelihood of occurrence of other responses that have the same or similar effect on the environment as the reinforced response

Response class

This group of responses - each member or response producing the same or similar effect on its environment (eg. reinforcement) - is called a response class

Shaping dimensions of behaviour

1. Topography of the behaviour
2. Amount of the behaviour
3. Latency of the behaviour
4. Intensity of the behaviour

Topography of behaviour

- what the behaviour looks like
- objective description of the spatial configuration or form of the behaviour (specific movements involved)
- function ignored

Amount of the behaviour

- frequency: number of instances that occur in a given period of time
- duration: length of time that a response lasts

Latency of behaviour

- reaction time
- time between the controlling stimulus and the behaviour

Intensity of the behaviour

physical effect the response has or potentially has on the environment

Keys to effective shaping

- specifying the final target behaviour
- choosing the starting behaviour
- choosing the shaping steps
- choose the reinforcer
- pace of movement through the shaping steps

Techniques of shaping

- shaping can occur even when a subject is unaware of what is going on
- the technique has been used successfully in behaviour therapy to treat a variety of behaviour problems
- teaching social skills to children

Pitfalls of shaping

- inadvertently shaping undesirable or harmful behaviour
- abnormal behaviours may develop from the failure to apply shaping through indiscriminate reinforcement or failure to reinforce (superstitions)

Prompting and transfer of stimulus control

- prompts are cues that are used to increase the likelihood that an individual will engage in the right behaviour at the right time
- prompts are usually temporary; as the client performs the behaviour more frequently, because of reinforcement, the prompt can gradually be withdrawn - a process known as fading

Fading

The gradual removal of prompts as the behavior continues to occur in the presence of the discriminative stimulus.

Errorless discrimination training

a way of teaching someone to tell the difference between two things without making mistakes. Like giving clues to make sure they get it right every time until they've learned it

Guidelines for prompting and transferring stimulus control

- choose the most appropriate prompting strategy
- get the learner's attention
- present the discriminative stimulus
- prompt the correct behaviour
- transfer stimulus control by fading or prompt delay
- continue to reinforce unprompted responses

Dimension

Dimension of a stimulus is any characteristic that can be measured on some continuum

Four types of prompts

verbal, physical, gestural / modelling, environmental

Factors influencing the effectiveness of fading

- final target stimulus
- the starting stimulus: prompt
- the fading steps

Final target stimulus

the final target stimulus should be chosen carefully. It is important to select it so that the occurrence of the response to that particular stimulus is likely to be maintained in the natural environment

Starting stimulus

select a starting stimulus that reliably evokes the desired behaviour

Fading steps

when the desired response is occurring reliably to the prompts given at the onset of the training program, the prompts can then be gradually removed over trials. Steps through which prompts are to be eliminated should be carefully chosen

Fading VS Shaping

Fading involves the gradual change of a stimulus while the response stays about the same; shaping involves the gradual change of a response while the stimulus stays about the same

Behaviour chaining / stimulus response chain

A consistent sequence of stimuli and responses that occur closely to each other in time and in which the last response is typically followed by a reinforcer

Methods for teaching a behaviour chain

- total task presentation method
- backward chaining method
- forward chaining method

Which is the most effective method

All of them, some evidence total-task presentation can be most effective:
- focuses on teaching response topography and response sequence simultaneously
- appears to maximize the learner's independence in early training

Chaining compared with fading and shaping

behaviour chaining, fading and shaping are sometimes called gradual change procedures

each involves progressing gradually through a series of steps to produce a new behaviour, new stimulus control over a behaviour, or a new sequence of stimulus response steps

Unaware-misapplication pitfall

- adventitious chain
- superstitious component
- non functional component that is a part of a behaviour chain that produced the reinforcer