Social memory of the male laboratory rat.

Used duration of social-investigatory behavior by 36 mature male Long-Evans rats as a measure of individual recognition in 5 experiments to assess social memory. In Exp I, the duration of social investigation during a 2nd exposure to the same juvenile (n?=?12) was directly related to the length of the interexposure interval. In Exp II, Ss were exposed to the same or different juvenile 10 min after an initial 5-min exposure to a novel juvenile; reexposure to the same juvenile elicited significantly less social investigation than an exposure to a different juvenile. Exps III and IV demonstrated that following a 5-min introductory exposure, social memory of the juvenile was relatively brief in comparison with that of mature Ss. Exp V revealed a retroactive interference effect on recently acquired memory for an individual: 12 mature Ss exposed to interpolated social experience engaged in significantly longer investigation of a juvenile than those with no interpolated social experience. The combined results suggest that (1) the rat normally engages in spontaneous learning of individual identity and (2) social memory may be a significant aspect of complex social interactions. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within-compound learning with US presentation in taste aversion.

Determined whether the presentation of a LiCl unconditioned stimulus/stimuli (UCS) disrupts within-compound learning in a taste aversion preparation, using 30 male and 32 female rats in 3 experiments. In Exp I, Ss showed stronger associations between 2 solutions presented in a compound when the compound was followed by LiCl. Exp II showed that an immediate LiCl injection produced stronger flavor–flavor association than a delayed injection. Exp III provided a comparison with Ss that did not receive the treatment to enhance consumption of salty solutions. Results indicate that the effects of Exp II depended on the treatment that altered consumption of 1 component. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The low-ball compliance technique: Task or person commitment?

Three experiments with 195 undergraduates examined the mediating process involved in the low-ball procedure for increasing compliance. In Exp I, Ss who agreed to but were not allowed to perform an initial request complied with a more costly version of the same request to a greater extent than did controls only when the 2nd request came from the same person as did the 1st request and not when it came from a different person. In Exp II, Ss who agreed to but were not allowed to carry out an initial low-cost request complied with a larger request from the same person to the same extent, whether the 1st request was related or unrelated to the 2nd. In Exp III, Ss were allowed or not allowed to perform an initial small request after agreeing to do so. Later, these Ss were approached by either the same or a different person with a larger 2nd request. All groups showed increased compliance over a control cell. However, Ss not allowed to perform the initial request who were approached by the same person for the 2nd request showed a higher rate of compliance than Ss in the other experimental conditions. Results suggest that an unfulfilled obligation to the requester, rather than a commitment to the initial target behavior, is responsible for the effectiveness of the low-ball technique. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of prior exposure on conditioned taste aversion in the rat: Androgen- and estrogen-dependent events.

Studied the effects of preexposure and gonadal hormone manipulation on the extinction of a conditioned taste aversion in 198 male Sprague-Dawley rats. In Exp I, Ss were given 1 prior exposure to sucrose at some selected time (Days 4, 2, or 1) before a 2nd exposure (Day 0) to sucrose and a LiCl injection, or they were given only a single exposure (Day 0). Under single exposure, castrated Ss extinguished the aversion faster than either testosterone-treated castrated Ss or sham-operated Ss. In Exp II, estradiol, dihydrotestosterone, and testosterone were studied by using only a Day 1 preexposure condition. The testosterone-treated group maintained the aversion for the longest period, followed by dihydrotestosterone-treated, sham, castrated, and estradiol-treated groups. In Exp III, estradiol was administered alone or in combination with 2 doses of dihydrotestosterone. Findings indicate that the outcome of behavior was dependent on the ratio of estradiol to dihydrotestosterone, with variations in this ratio resulting in fast (estrogen effect) to slow (androgen effect) rates of extinction. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of group consensus and social support on stimulus meaning: Mediation of conformity by cognitive restructuring.

Three experiments with a total of 163 undergraduates tested the hypothesis that a person reinterprets the meaning of the stimulus object when facing unpopular responses from a unanimous group and that this change in meaning leads to a shift in response toward the group's position. In Exp I, several opinion items were presented, and either Ss observed unpopular responses, supposedly made earlier by a unanimous group (UG) or by a group having 1 dissenter (social support), or they observed no response at all (control). Ss merely gave their interpretation of the meaning of a key word or phrase in each opinion statement—they did not give their own opinions. Results show that UG Ss gave more uncommon meanings to the stimuli than did Ss in the other 2 conditions. Exp II ruled out the possibility that the shift in meaning was due to Ss' adhering to the interpretation they assumed to be held by the majority. In Exp III, Ss were exposed to scores representing the meanings that were produced by the unanimous group and control conditions in Exp I. Results show that after observing the consensually produced meanings for these items, the Ss shifted their own opinions toward the position held by the UG in Exp I. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sampling of similar and dissimilar comparison persons and objects as a function of the generality of attribution goal.

Conducted an information-search procedure in which Ss were asked to seek information regarding persons and objects in order to validate a given person or object cause. Four hypotheses were tested: When asked to validate a person cause, Ss are more likely to select distinctiveness information than target-object consensus information. When asked to validate an object cause, Ss are more likely to select target-object consensus information than distinctiveness information. As the generality of person inference increases, progressively dissimilar object comparisons are sought. As the generality of object inference increases, progressively dissimilar person comparisons are sought. In Exp I, 26 undergraduates read attitude statements and answered judgment goals or questions about the statement's generality or object inference. 52 undergraduates in Exp II completed a similar task. The first 3 hypotheses were supported in both Exp I and Exp II, whereas the 4th hypothesis received only mixed support in Exp I and was not supported in Exp II. Unlike Exp I, Exp II did not include cues suggesting the relevant type of information to be sought. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fear and affiliation in domesticated male rats.

Male rats actively seek the opportunity to interact with other male rats. Three experiments with 208 Long-Evans males examined the hypothesis that the presence of conspecifics can reduce the behavioral signs of fear and that this capacity provides part of the attraction to conspecifics. In Exp I, the immobility response was measured following exposure to a stressful noise. Ss that were observed in groups exhibited shorter durations of immobility than those observed alone. The "group" effect was sufficiently powerful to nullify different housing conditions and different degrees of familiarity among the Ss. Exp II compared social and nonsocial stimuli and found that only the former effectively reduced the immobility response. In Exp III, stressed Ss were more likely to choose to interact with a conspecific in a T-maze than were nonstressed Ss. Again, rearing conditions made little difference; both individually and group housed Ss were highly attracted to a conspecific. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of contextual change on latent inhibition and on the habituation of an orienting response.

In Exp I, using 20 female hooded Lister rats, the habituation of the orienting response (OR) shown by Ss to a discrete visual stimulus (a 10-sec light) in a given training context (A) was monitored. Dishabituation occurred, in that the OR returned to its initial level, when the light was presented in a different and novel context (B). In Exp II, 24 female rats received 2 sessions/day, one in each of the 2 contexts. For experimental Ss, the light was presented in Context A until the OR habituated. In the test phase, the light was presented in Context B, but the OR was not restored, suggesting that the dishabituation seen in Exp I depended on the absolute novelty of Context B. In Exp III, Ss from Exp II were required to form a light–food association in both contexts. Slow learning was observed in Ss trained with the familiar light in Context A, but learning proceeded normally with the familiar light in Context B. Thus, a context change that failed to produce dishabituation was enough to prevent the occurrence of a latent inhibition effect. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Latent inhibition experiments with goldfish (Carassius auratus).

Examined evidence of latent inhibition in a series of experiments with goldfish. In Exp I, 12 Ss were given nonreinforced preexposure to a color that subsequently predicted shock in an activity conditioning situation; their performance did not differ from that of 12 control Ss preexposed to a markedly different color. In Exp II, 12 Ss given nonreinforced preexposure to a tone and an unstimulated control group of 12 Ss were trained in an appetitive situation, with the tone serving either as a conditioned excitor or as a conditioned inhibitor. Preexposure had significant effect in the conditioned excitation training, but it reduced the level of responding both to the positive stimulus and to the negative compound in the conditioned inhibition training. In Exps III and IV, classical aversive conditioning was studied in the shuttle box. In Exp III, excitatory conditioning to a color was found to be impaired (relative to the performance of nonpreexposed control Ss) as much by nonreinforced preexposure to the training color as by nonreinforced preexposure to a markedly different color; substantial variation in amount of preexposure was without significant effect. In the conditioned inhibition training of Exp IV, 12 Ss with nonreinforced preexposure responded less than did 12 unstimulated control Ss, both to the positive stimulus and to the negative compound. Results demonstrate that the effect of preexposure on goldfish is their reduction of general responsiveness or level of arousal. (47 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-image bias in person perception.

Conducted 3 experiments using a total of 283 male and female high school students. Exp I demonstrated that the more desirable the self-rating on a personality characteristic, the more central that characteristic is in perceiving others. This self-image bias in person perception was hypothesized to reflect the defense mechanism protecting high self-evaluation. In Exp II it appeared that, consistent with this defense interpretation, there was lower self-image bias among Ss in a condition that reduced defensiveness by using objective self-awareness techniques. Exp II also suggested an alternative to this defense explanation: a purely cognitive process whereby self-image mediates external evaluative stimuli and centrality of characteristics. Exp III attempted to test this alternative explanation; results support a cognitive interpretation of self-image bias in person perception. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects and aftereffects of stressor expectations.

Examined whether it is possible to obtain "stress responses" during and after the period in which stressor exposure is being anticipated. In Exp I, with 33 undergraduates, Ss' expectation of submerging their hands in ice water resulted in decreased frustration tolerance and increased blood pressure when compared with control groups not expecting this stressor. Exp II, with 91 undergraduates, replicated and extended these results to show that the expectation of control over the stressor ameliorated the negative impact of stressor expectation. It was also found that despite being relieved of the expectation that they would immerse their hands in ice water, Ss who had expected stressor exposure had decreased frustration tolerance when compared with Ss who had expected a nonstressful procedure or those who had expected to have control over stressor termination. Exp III, which involved 55 undergraduates and used noise as the expected stressor, replicated both the aftereffect of the anticipation period and the moderation of the effect by perceived control. Implications for understanding why aftereffects occur are discussed. It is proposed that previously observed stressor exposure effects may in fact be postexpectation effects. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of negation and task complexity on illusory correlation.

In 3 experiments with a total of 463 undergraduates, signs, disorders, or both signs and disorders were negated. Exp I negated the disorder but resulted in no reduction in illusory correlation, measured several ways. Exp II replicated Exp I but informed Ss that some of them would be in a zero-relationship condition. Again, no reduction in illusory correlation was found. Exp III included conditions negating not only the disorder but also the sign and the sign and the disorder, and again no reduction due to negation was obtained. An additional experiment (153 Ss) manipulated the number of disorders per sign and resulted in significant effects due to complexity. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Escape learning in houseflies ( Musca domestica ).

Performed 4 experiments to examine instrumental escape learning in the housefly ( N = 244). Each experiment allowed Ss to move from a hot, brightly illuminated half of a Plexiglas tube to the other half, which was relatively cool and dark. In Exp I, Ss were able to move freely throughout the tube at all times. The amount of time spent in the lighted half decreased significantly over the course of 20 1-min trials. In Exps II, III, and IV, a gate separating the 2 halves of the tube was used to create a typical shuttle box. In Exp II, escape latency decreased significantly over trials, and the effect was maintained over a 24-hr intersession interval. However, the effect was reversed when heat-absorbing filters were inserted. Exp III and IV showed that repeated exposure to either heat or light was not sufficient to produce the effect. Escape latency decreased only when there was a contingency between the response and escape from heat. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of sensory limitations on hemispheric processing.

How the brain processes information is partly determined by the characteristics of the input. To examine whether the 2 cerebral hemispheres are equally affected by manipulations of quality of incoming information, 3 experiments using M. I. Posner and R. F. Mitchell's (1967) paradigm (matching pairs of letters of same or different case or name) were conducted under 8 viewing conditions, consisting of manipulations of exposure duration, retinal eccentricity, and stimulus size. The same procedure but different designs were used in the 3 studies: a between-S design in Exp I; a within-S design with viewing conditions blocked in Exp II; and a within-S design with viewing conditions mixed in Exp III. In all experiments, which used 88 18–30 yr old right-handed Ss, exposure duration and retinal eccentricity each interacted with visual fields, whereas the interaction of letter size and visual field was significant only in Exp II. Results are interpreted with respect to the properties of the visual system and its capacity to extract information in terms of the spatial-frequency spectral components of a stimulus. Methodological implications are discussed. (French abstract) (2? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual discrimination and detection of configurational invariance in 3-month infants.

Investigated 40 3-mo-old infants' discrimination of simple visual arrangements of discrete elements, using an operant high-amplitude sucking technique in a stimulus familiarization–novelty paradigm. In Exp I, response recovery was found following changes in the arrangement of 3-dot patterns. To rule out contour density and position as possible cues, Ss were familiarized in Exp II with sets of stimuli varying in size and position but of constant arrangements. Response recovery was found following new arrangements of similar size and position, but Ss failed to recover to the familiarized arrangement presented in novel sizes and positions. Results of Exp III indicate the ability of infants to discriminate changes in size and position similar to the variations received during familiarization in Exp II. Results suggest sensitivity to pattern configuration and the ability to detect pattern invariance. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The opioid/nonopioid nature of stress-induced analgesia and learned helplessness.

Investigated whether the same factors that activate the processes that produce escape interference might also activate processes leading to opioid stress-induced analgesia (SIA). Exposure to a variety of stressors produces a subsequent analgesic reaction that is sometimes opioid in nature (reversed by opiate antagonists and cross-tolerant with morphine) and sometimes nonopioid. In Exp I, 40 male albino rats were subjected to 20 min of intermittent footshock, 3 min of continuous footshock, tailshock on a VI schedule, or confinement only. Ss were given escape/avoidance training 24 hrs later. In Exp II, 36 Ss received SIA with a tail-flick apparatus. In Exp III, 40 Ss received inescapable tailshocks or confinement only. In Exp IV, 24 Ss received 2 sessions of footshock before tail-flick was assessed. Both of the opioids SIA procedures produced a learned helplessness effect as assessed by shuttlebox escape acquisition and an analgesia that was reinstatable 24 hrs later. The nonopioid procedures produced neither a learned helplessness effect nor a reinstatable analgesia. These data implicate the learning of uncontrollability in the activation of opioid systems. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sensory preconditioning in rats following early visual deprivation.

Conducted 3 experiments in which a total of 131 light- and dark-reared (LR and DR) male hooded rats were given sensory preconditioning (SPC). In each experiment, Ss were presented with 2 stimuli either paired or unpaired, followed by conditioning to 1 and extinction on the other. 2 auditory stimuli were used in Exp. I. SPC was found for both LR and DR Ss, with no significant difference due to rearing condition either in acquisition or in the SPC test. In Exp. II, light and tone were employed; SPC was demonstrated and was more effective for LR than DR Ss. In Exp. III, rectangle stimuli were employed. The effect of SPC was evidenced in LR Ss; however, performance of DR Ss was not significantly different from that of controls. Results are discussed in terms of the effect of early visual deprivation on information-processing mechanisms. (27 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction of Pavlovian conditioning with a zero operant contingency: Chronic exposure to signaled inescapable shock maintains learned helplessness effects.

Four studies, with 372 male Holtzman rats, examined the effect of Pavlovian contingencies and a zero operant contingency (i.e., uncontrollability) on subsequent shock-escape acquisition in the shuttle box using triads consisting of escapable-shock (ES), yoked inescapable-shock (IS), and no-shock (NS) rats. After exposure to 50 signals and shocks per session for 9 sessions, interference with shuttlebox escape acquisition for IS Ss was a monotonically increasing function of the percentage of signal–shock pairings during training (Exp I), with 50% pairings producing little or no impairment. Without regard to signaling, ES Ss performed as well as NS Ss. Exp II demonstrated that training and test conditions led to substantial and equal impairment in IS Ss preexposed for 1 session to 100 or 50% signal–shock pairings or to unsignaled shocks. In Exp III, chronic exposure to 100% signaled ISs resulted in impairment only if the signal (light) was present during the shuttlebox test. The continuous presence of the signal during the test contrasted with its discrete (5-sec) presentation during training and suggested that an antagonistic physiological reaction rather than a specific competing motor response had been conditioned. Exp IV provided evidence for possible conditioned opioid mediation. Findings suggest that chronic exposure to uncontrollable shocks maintains the impairment produced by acute exposure only if the shocks are adequately signaled. (63 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)