1、150607080901002What environmental events?Very remote (in time) events PAST Natural selection Semi-remote events PAST Contingencies (respondent and operant) Current events PRESENT Presentation of stimuli (US, CS, SD, SD) Motivational & emotional operations3Chapter 20Behavioral Chains4Behavioral C

2、hain A sequence of stimuli and responses. Each response produces a change in the environment that acts as a discriminative stimulus (SD) for the next response.5“.behavior does not occur as random strings of unrelated responses but in organized sequences, called chains, in which each successive respo

3、nse produces the stimuli, internal or external, that determine what comes next. And when the time arrives to initiate a new sequence of behavior, that, too, is signaled by a change in stimulus conditions.”(Dinsmoor, 1995)6Task AnalysisA task analysis is an analysis of complex behavior and sequences

4、(chains) of behavior into component responses.7Eating PotatoesTASK ANALYSIS?Pick up forkSpear potatoLift fork to mouthOpen mouthPlace fork in mouthClose mouth1. Pull fork from mouth8TASK ANALYSISPick up forkSpear potatoLift fork to mouthOpen mouthPlace fork in mouthClose mouth1.Pull fork from mouth9

5、Dual Functioning Chained Stimuli A stimulus in a behavior chain reinforces the response that precedes it. That stimulus also acts as an SD or operandum for the response that follows it.10BehPick up forkSr Oper.Fork in handBehaviorPut fork in potatoSr/SDFork in potatoDual-Functioning Chained StimuliB

6、ehaviorRaise forkSr/SDFork raisedSDSight of potatoesBehaviorPut potato in mouth11Dual Functioning Chained Stimuli A stimulus in a behavior chain reinforces the response that precedes it. That stimulus also acts as an SD or operandum for the response that follows it.12Sr/SDLight onBehaviorPull chainB

7、ehaviorPress leverSr/SDDipper clickBehaviorApproaches dipperSrWater13After/Sr/SDLight onBehaviorBehaviorAfter/Sr/SDBehaviorAfter/SrWaterSDBeforeBeforeBefore14Forward Chain The establishment of the first link in a behavioral chain, with the addition of successive links, until the final link in acquir

8、ed.15BehPick up forkSr Oper.Fork in handBehaviorPut fork in potatoSr/SDFork in potatoBehaviorRaise forkSr/SDFork raisedSDSight of potatoesBehaviorPut potato in mouthTrain this link firstTrain this link secondFORWARD CHAINING1617Total Task The simultaneous training of all links in a behavioral chain.18Total TaskEach one of the hand washing stepsPhysical guidanceVerbal InstructionPraiseModelingEach one of the hand washing stepsTraining LinksTraining ToolsResults19Backward Chaining The establishment of the final link in a behavioral chain, w