Stimulus Control & Generalization SPRADLIN & SIMON (2011) CH 5 FISHER ET AL 2011 Stimulus Control u When a given response occurs reliably after the presentation of a specific stimulus and not in its absence, we say that antecedent event or stimulus has over that response. We call that stimulus a ( Ess Dee S D, or S+ ) for that response. u A stimulus in the presence of which a given response occurs is also a annotated as S delta ( S ). 1
Generalization: Several meanings u Primarily which is responding to stimuli to a given stimulus that has been brought under stimulus control for that responding through differential reinforcement. u (E.G., conditioned to respond to a 1000CPS tone, responding will also occur to 900cps or even 600cps ) Generalization: Several meanings u is said to have occurred when responding that is different from the topography ( form, force, duration, etc.) of responding that was established originally through reinforcement, is seen to occur. u ( E.G., naming the correct choice in place of pointing to it ) u Any responding that occurs outside of the training environment u Learning to learn ie more rapid acquisition of new responding u Maintenance over time of responding after training 2
Factors involved in stimulus discrimination for responding 1. The of the stimulus from its background 2. must occur for responding to the stimulus to continue to be discriminated. 3. The response must be organism s Establishing Control by a Single Stimulus 1. SR+ follows emitted in the of the stimulus 2. SR+ does after responses by the stimulus 3. There are correlated with reinforcement and non reinforcement. The stimulus should be presented over so as to not be associated with time If responding occurs before the presentation of the stimulus, reinforcement should be delivered 3
Establishing Control by Successively Presented Stimuli u Spradlin describes a Terrace errorless procedure where the eventual S+ (RED) is presented strongly and for longer periods followed by the eventual S- (GREEN) presented weakly and briefly. Once responding occurs reliably to the Red stimulus. The presentation times and brightness of the 2 stimuli are made equal. u The example results in subjects responding to an E and not responding to a black square. The Square is then gradually formed into a reversed E Establishing Control by Two or More Simultaneously Presented Stimuli u Two or more stimuli presented at the same time u Spradlin describes a study by Sidman & Stoddard(1971) in teaching discrimination between circles and elipses u These types of discrimination between simultaneously presented stimuli are used in procedures that are designed to teach concepts involving Conditional discriminations 4
Conditional Stimulus Control u Reinforcement for responding in the presence of a specific stimulus depends on the u E.G., Pass the Salt vs Bread Conditional Stimulus Control u u A sample stimulus (E.G., 2 ) is presented and the learner is required to touch it (to attend to it). u Once attended to, two or more comparison stimuli are then added to the display ( E.G., a 3 a 2 and a 1 ). u The learner is then required to point to, or touch the comparison 2 in order to gain reinforcement ( IE. The stimulus that is identical to the original sample ) u The sample stimulus changes and comparison stimuli both change and alter positions on each training trial. u Once several stimuli are learned as identical, learning of new stimuli happens on the first trial. This is referred to as. 5
Variations on Matching u In the simple identity matching procedure the sample stimulus remains present when the comparisons are added. If it is removed when the comparisons are added that procedure is called and can use delays of 0 sec to whatever. The longer the delay the harder the task. Similarly these procedures in order to be effective should provide immediate SR+ for correct responding. I most educational applications this is not trues as SR+ is delayed Variations on Matching u : The opposite of identity matching but still a conditional discrimination u A sample stimulus is presented and attended to, then comparison stimuli are presented all of which except one are identical to the sample. SR+ is delivered for choosing the odd stimulus. u : u The correct comparison stimulus is not completely physically identical to the sample u : u The basis for one of the comparison stimuli to be the correct one and receive Sr+ is based on some relation or function or stimulus class rule and not physical similarity u E.G., Given brush as sample choose comb not Car or hammer u NOTE: All matching that is cross sensory modalities is arbitrary or symbolic u E.g., choosing visual stimuli given an auditory (spoken) comand 6
Equivalence Classes u Sidman (1971) the first report of equivalence. Later this was made popular in 1982 (Sidman & Tailby, 1982) u The Concepts ( the way the phenomena are described) are from logic and mathematics and are 1., 2, and 3. u is identity ; A=B therefore is reflexivity ; A=B and B=C Therefore is Transitivity) Equivalence is defined by u bidrectionality is another term for reflexivity and primarily demonstrated by human populations! u Transitivity with derived reflexivity is prmarily seen in language able organisms Equivalence Classes: Research Findings 1. New members can be added readily to the class 2. Equivalence Classes are Durable 3. Performances that indicate equivalence are resistant to change as a function of changes in in baseline reinforcement conditions 4. Conditioning an operant response in the presence of a member of the class, results in generalization to other members of the class. 5. If one or more members of an equivalence class are conditioned to elicit an emotional response, other members of that class will elicit that response 7
Recombination of Stimulus-Response Components u The theme here is how many response possibilities can come for training only a few u Spradlin describes research on in which stimulusresponse combinations are taught and combinations of then appear. u E.G. drop Ball and push Glass teaching results in Dropping glasses and pushing Balls. u This is a relatively new area that has been strongly prompted by equivalence and Relation Frame Theory developments 8