PSYF 212 Principles of Learning - Handout PDF

11/17/24 PSYF 212 Principles of Learning Mehmet Akif GÜZEL, PhD, Assoc Prof, Cognitive Psy, Dep of Psychology, Factory Building, FOA11 2024-2025 Fall Term Mon, 2 hrs (13.00-14.45) Thurs, 3 hrs (...

11/17/24 PSYF 212 Principles of Learning Mehmet Akif GÜZEL, PhD, Assoc Prof, Cognitive Psy, Dep of Psychology, Factory Building, FOA11 2024-2025 Fall Term Mon, 2 hrs (13.00-14.45) Thurs, 3 hrs (13.00-15.45) Chapter6 Schedules of Reinforcement (& Choice Behaviour) Copyright © 2017 Cengage Learning. All Rights Reserved. 1 Introduction Schedule of Reinforcement–program or rule that determines which occurrence is followed by reinforcer Influences how instrumental response learned/maintained by reinforcement In simple schedules, a single factor determines which occurrence of the instrumental response is reinforced. The single factor can be how many responses have occurred or how much time has passed before the target response can be reinforced. Factors can be number of responses occurred or how much time has passed before target response is reinforced 2 1  11/17/24 Introduction Schedule of Reinforcement–program or rule that determines which occurrence is followed by reinforcer Interval Ratio Fixed Variable Fixed Variable FI VI FR VR 3 Introduction 4 2  11/17/24 Ratio Schedules Ratio Schedule–reinforcement depends only on number of responses subject has to perform If the required number is one, every response results in delivery of the reinforcer. Such a schedule is technically called continuous reinforcement (CRF). Continuous Reinforcement (CRF)–every response results in delivery of reinforcer (example = drug treatment, clean urine = vouchers) e.g., FR1 (fixed ratios, for instance, are all continuous reinforcement) Partial/intermittent reinforcement– if responding reinforced only sometimes 5 Fixed Ratio Fixed-Ratio Schedule (FR)–number of responses made and reinforcers it got (example = 10 responses per reinforcer is FR10) Cumulative Record–total number of responses that have occurred up to particular point in time Line slope made by cumulative recorder represents participant’s rate of responding Post-Reinforcement Pause–zero rate of responding that typically occurs just after reinforcement on fixed ratio Ratio Run–high and steady rate of responding that completes each ratio requirement Ratio Strain–if ratio requirement is suddenly increased, animal likely to pause periodically before completion of ratio requirement 6 3  11/17/24 Variable Ratio Variable-Ratio Schedule (VR)–different number of responses required to obtain successive reinforcers VR10 example = Pigeon must make 10 responses to earn first reinforcer, 13 for second, 7 for third, etc. Average = 10 responses per reinforcer VR schedules = fairly steady rate Number of responses required for reinforcement is not predictable; predictable pauses in the rate of responding are less likely with VR than FR schedules (that is, post reinforcement pauses are more prominent in FR than VR). 7 Interval Schedules Reinforced only if it occurs more than set amount of time, last delivery of the reinforcer, or start of trial Fixed-Interval Schedule (FI) Variable Interval Schedule (VI) Amount of time that has to pass before a response is reinforced is constant from one Required to set up reinforcer varies from trial to the next (example = timer) one trial to next Fixed-Interval Scallop–increase in Subject has to respond to obtain the set-up response rate evident as acceleration in reinforcer with unpredictable set-up time cumulative record toward end of each fixed interval VI schedules maintain steady and stable Reflects the participant’s accuracy in rates of responding without regular pauses telling time (as with ratios) Interval determines only when reinforcer becomes available, not when it is delivered (that is, the reinforcer will be available if the instrumental behaviour is performed) 8 4  11/17/24 Typical Pigeon Responses on Simple Reinforcement Schedules 9 Comparison of Ratio and Interval Schedules FR and FI schedules = post-reinforcement pause after each reinforcer FR and FI schedules produce high rates of responding just before next reinforcer delivery VR and VI schedules = steady rates of responding without predictable pauses ???????? schedule motivates most vigorous instrumental behavior due to short inter-response times or relationship between response rates and reinforcement Inter-Response Time (IRT)–interval between successive responses Feedback Function–rates calculated over entire experimental session or an extended period of time; reinforcement is consequence of responding 10 5  11/17/24 Comparison of Ratio and Interval Schedules 11 Choice Behavior: Concurrent Schedules Concurrent Schedule – can have more than one response option/reinforcer Allow for continuous measurement of choice because subject is free to change back and forth between the response alternatives at any time 12 6  11/17/24 Measures of Choice Behavior Example of relative rate of responding to a “left key” BL / (BL + BR) Relative rate of reinforcement earned for each response alternative can be calculated comparable to relative rate of response rL / (rL + rR) 13 7