EXTINCTION OF THE HUMAN EYELID CR AS A FUNCTION OF THE DISCRIMINABILITY OF THE CHANGE FROM ACQUISITION TO EXTINCTION

Retention of Attended and Unattended Auditorily and Visually Presented Material

In the first of two experiments investigating focussed attention, sets of four pairs of digits were dichotically presented to subjects who were instructed to attend to digits arriving in either the left or the right ear. Following presentation, two different report orders were used: attended followed by unattended, and unattended followed by attended. It was found that unattended items did not suffer from being recalled second rather than first. The serial position curve for unattended items was U-shaped. These results were interpreted as evidence that unattended items are not retained in a limited-capacity auditory buffer with a fast rate of loss. The experiment was repeated using visually presented pairs of letters. A similar pattern of results was obtained, consistent with the hypothesis that unattended items are recalled from a store with a large capacity and a very slow rate of loss.

A Bibliography of Experimental Extinction

An alphabetic listing of articles on extinction published from 1935 to 1970 is presented.

Avoidance prone individuals self reporting behavioral inhibition exhibit facilitated acquisition and altered extinction of conditioned eyeblinks with partial reinforcement schedules

Avoidance in the face of novel situations or uncertainty is a prime feature of behavioral inhibition which has been put forth as a risk factor for the development of anxiety disorders. Recent work has found that behaviorally inhibited (BI) individuals acquire conditioned eyeblinks faster than non-inhibited (NI) individuals in omission and yoked paradigms in which the predictive relationship between the conditioned stimulus (CS) and unconditional stimulus (US) is less than optimal as compared to standard training with CS-US paired trials (Holloway et al., 2014). In the current study, we tested explicitly partial schedules in which half the trials were CS alone or US alone trials in addition to the standard CS-US paired trials. One hundred and forty nine college-aged undergraduates participated in the study. All participants completed the Adult Measure of Behavioral Inhibition (i.e., AMBI) which was used to group participants as BI and NI. Eyeblink conditioning consisted of three US alone trials, 60 acquisition trials, and 20 CS-alone extinction trials presented in one session. Conditioning stimuli were a 500 ms tone CS and a 50-ms air puff US. Behaviorally inhibited individuals receiving 50% partial reinforcement with CS alone or US alone trials produced facilitated acquisition as compared to NI individuals. A partial reinforcement extinction effect (PREE) was evident with CS alone trials in BI but not NI individuals. These current findings indicate that avoidance prone individuals self-reporting behavioral inhibition over-learn an association and are slow to extinguish conditioned responses (CRs) when there is some level of uncertainty between paired trials and CS or US alone presentations.

Subjective science: Kenneth Spence's human learning research program

This article examines Kenneth Spence's human learning research from 1949 to 1967. His works show the conditioning field to be in turmoil over basic issues during this time. These issues included whether determinism should be accepted, how to interpret a psychological test score, what psychometric properties a test should have, and how to use theoretical constructs. Turmoil occurred because behaviors and events had different meanings and degrees of importance to different investigators. Thus, what appeared as "objective" scientific change in the conditioning field was really the adaptation of personal preferences in word meanings, research goals, and research methods. These issues also indicate disputes about definitions and purposes of scientific activity during Spence's era.

Use of pseudodesensitization in treatment of an experimentally produced fear

By creating a conditioned fear in the laboratory and using the galvanic skin resistance (GSR) to monitor this fear, it was possible to assess the effectiveness of placebo treatment for reducing a conditioned fear. 10 subjects were classically conditioned to fear a specific signal light. Five of them were treated for the fear with a pseudodesensitization treatment; the others were not. The pseudodesensitization group extinguished the conditioned fear significantly faster than the control group.

Effects of stimulus change and drive level on extinction of the conditioned eyelid response

Rate of extinction of the conditioned eye blink was investigated as a function of maintained drive level in extinction and amount of stimulus change from conditions of acquisition to those of extinction. 50 Ss were given 90 acquisition trials under a partial reinforcement schedule in which the UCS was either delayed or omitted on half the trials. Half of the Ss conditioned under each procedure were given 20 extinction trials with the UCS delayed and half were extinguished with the UCS omitted. There was no evidence for an effect of either drive or amount of stimulus change determining rate of extinction.

Acquisition and extinction of the conditioned eyelid response in the squirrel monkey as functions of the CS-UCS interval

Interstimulus intervals of .5, 1.0, 2.0, and 4.0 sec. were compared for effectiveness in conditioning the blink reaction of the squirrel monkey ( Saimiri sciurea). Control groups receiving unpaired stimulation, CS-only, and UCS-only were run at each level of ISI. Statistically reliable evidence of conditioning was found in the acquisition data only at .5 sec., with the performance of all groups increasing as a function of ISI. Superior resistance to extinction in the paired group was also discernible only at .5 sec. although the combined performance in extinction of the paired and unpaired groups at 2.0 and 4.0 sec. exceeded that of the .5- and 1.0-sec. groups. A replication experiment using a within-subjects design magnified the interval effect in both acquisition and extinction. The results suggest the operation of pseudoconditioning and sensitization of spontaneous blinks in addition to revealing marked differences from human eyelid conditioning data, particularly in extinction.

An apparatus and procedure for conditioning the eye-blink reflex in the squirrel monkey

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