Related Experiment Videos
Blocking and unconditioned response diminution in human classical autonomic conditioning.
1Dept. of Psychology, University of South Florida, Tampa 33620.
Summary
Blocking in human conditioning is complex. While unconditioned response diminution occurred, blocking effects were delayed and design-dependent, challenging theories of reduced unconditioned stimulus processing.
Area of Science:
- Psychology
- Cognitive Science
- Behavioral Science
Background:
- Recent conditioning theories link reduced unconditioned stimulus (UCS) processing to unconditioned response (UCR) diminution and blocking.
- Blocking occurs when a previously conditioned stimulus (CS) overshadows a new CS in compound conditioning.
- UCR diminution suggests reduced UCS processing, potentially explaining blocking.
Purpose of the Study:
- To investigate blocking and UCR diminution in human electrodermal conditioning (SCR).
- To test the hypothesis that reduced UCS processing underlies both UCR diminution and blocking.
- To examine the influence of experimental design on blocking and UCR diminution.
Main Methods:
- Three experiments involving human participants undergoing SCR conditioning.
- Utilized within-subject and between-subject designs.
- Included extinction trials for both blocked and non-blocked stimuli.
Main Results:
- Consistent evidence of UCR diminution across all three experiments.
- Blocking was observed only in the third experiment, which used a within-subject design.
- Blocking in the third experiment was delayed, appearing after extinction trials, irrespective of testing order.
Conclusions:
- The findings provide clear evidence for UCR diminution in human SCR conditioning.
- Blocking effects are not consistently observed and appear dependent on specific experimental designs (within-subject) and procedures (post-extinction).
- Results challenge the proposed link between UCR diminution and blocking, suggesting reduced UCS processing is not the sole or primary mechanism for blocking.