The effect of CS-US contingency variation on GSR and on subjective CS-US relational awareness

Ninety subjects were tested in a single-cue Pavlovian conditioning paradigm involving three groups which differed with regard to the contingency relationship between CS and US (negative contingency, zero contingency, positive contingency). To examine the relationship between conditioned GSR performance and subject’s cognitive beliefs regarding the CS-US relationship, both GSR and CS-US relational learning were constantly measured on a continuous scale over the entire experimental session. The data suggest the independence of autonomic and cognitive responding in the single-cue Pavlovian paradigm.     

Object memory and change detection: dissociation as a function of visual and conceptual similarity

People often fail to detect a change between two visual scenes, a phenomenon referred to as change blindness. This study investigates how a post-change object's similarity to the pre-change object influences memory of the pre-change object and affects change detection. The results of Experiment 1 showed that similarity lowered detection sensitivity but did not affect the speed of identifying the pre-change object, suggesting that similarity between the pre- and post-change objects does not degrade the pre-change representation. Identification speed for the pre-change object was faster than naming the new object regardless of detection accuracy. Similarity also decreased detection sensitivity in Experiment 2 but improved the recognition of the pre-change object under both correct detection and detection failure. The similarity effect on recognition was greatly reduced when 20% of each pre-change stimulus was masked by random dots in Experiment 3. Together the results suggest that the level of pre-change representation under detection failure is equivalent to the level under correct detection and that the pre-change representation is almost complete. Similarity lowers detection sensitivity but improves explicit access in recognition. Dissociation arises between recognition and change detection as the two judgments rely on the match-to-mismatch signal and mismatch-to-match signal, respectively.     

Punishment shock intensity and basal skin resistance

The relationship between punishment shock intensity and basal skin resistance (BSR) was investigated in two sessions with human females selected for their ability to maintain a fairly substantial operant rate under a wide range of shock intensities. In both sessions each button-pressing response was reinforced with a counter tally. Subjects were paid one cent for each 20 counts. In session 1, punishment followed each response during alternate 4-min periods; in session 2 punishment was programmed in all 4-min periods. Shock intensities were presented randomly among the 4-min shock periods, with the restriction that the first three presentations occurred in ascending order. Operant responding showed some suppression at higher shock intensities in session 1, with substantial recovery in most subjects during session 2. Respondent behavior was characterized by greater activity at successively higher intensities, with recovery at all shock levels, especially the lowest levels, apparent during the second session.     

Effect of CS-US pairings on shock-elicited aggression as a function of US intensity

In two experiments with paired rats, the effect of superimposing CS-US pairings on a baseline of shock-elicited aggression was studied. Baseline shocks (3.0 mA, 0.125-sec duration) occurred at a rate of 20 shocks per min throughout each session. In Experiment I, each independent group of two pairs of subjects received (in addition to baseline shocks) US shocks of 1.0, 3.0, or 5.0 mA and 5-sec duration, each shock signalled by a 1-min CS. At all three US intensities, aggression increased during the CS. In Experiment II, pairs of subjects received each unconditioned stimulus intensity in a within-subjects design. This procedure revealed a direct relationship between rate of responding and unconditioned shock intensity.     

Size contrast as a function of figural similarity

Size contrast occurs in numerous configurations where a test figure appears apparently larger when surrounded by small elements and apparently smaller when surrounded by large elements. Using the Ebbinghaus illusion, the magnitude of this effect is shown to vary as a function of apparent similarity between test and inducing element.     

Favouritism as a function of assumed similarity and anticipated interaction

Discussions of intergroup behavior (e.g., Rabbie and Wilkens, 1971; Tajfel, Flament, Billig and Bundy, 1971) have drawn attention to the influence of both assumed similarity and anticipated future interaction between an individual and other members of his group on his tendency to assign more favourable outcomes to members of his own group than to members of another group. This note examines whether similar processes may also affect an individual's tendency to make intragroup discriminations between different members of a group to which he himself does not belong, in a situation where the variables of similarity and anticipated interaction may be treated as independent factors.