Effects of obesity and set point on taste responsiveness and ingestion in humans.

Two experiments, with a total of 120 undergraduates, investigated the relationships among degree of obesity, nearness to set point for adipose tissue mass, and responsiveness to taste. In Exp I, Ss rated milkshakes varying in sweetness intensity. Overweight and normal weight Ss did not have significantly different detection thresholds or preference ratings. However, overweight Ss worked longer than normals to obtain their most preferred substance. Exp II varied the ease of tasting the milkshake. Preference and food intake of moderately overweight Ss were significantly more influenced by tastes that they found positive and negative than was the preference of normal weight or obese Ss. The ease of ingesting the taste substance also significantly influenced preference and food intake of the moderately obese only. Nearness to set point, operationally defined as weight stability for 2 yrs, had no significant effects. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing models of delayed sequence discrimination in pigeons: The advance key procedure.

In 2-event delayed sequence discrimination (DSD) training, one arrangement (temporal order) of 2 sample stimuli is the positive sequence and the remaining are the negative sequences for keypecking during a subsequent test stimulus. Three models of the DSD task were tested in 2 experiments with 8 White Carneaux pigeons. In Exp I Ss were allowed to terminate a trial by pecking the "advance key" during the sample stimuli or to let the test stimulus progress to the next trial. In the absence of a peck to the advance key, the trial continued to the completion of the test stimulus. In Exp II, Ss were forced to choose actively between advancing to the next trial and continuing through the current trial. Choice between the advance and continue keys was required with the occurrence of each of the successive sample stimuli and the test stimulus. Although the addition of forced choice resulted in more uniform effects, Ss were able to identify negative sample sequences with the occurrence of the 1st negative sample event in both experiments. Results support the prospective memory model but not the retrospective and hybrid models of temporal sequence recognition in the 2-event DSD task. (French abstract) (15 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)     

The effects of group diffusion of cognitive effort on attitudes: An information-processing view.

232 undergraduates participated in 2 experiments that tested whether persons process a stimulus less extensively when they are part of a group that is responsible for the task than when they are individually responsible. In addition to a group size manipulation, the quality of the stimulus to be evaluated was varied to determine the mediator of the different evaluation of stimuli provided by group (GEs) and individual evaluators (IEs). When evaluating a high quality stimulus, IEs generated more favorable thoughts and evaluated the stimulus more positively than did GEs (Exps I and II); but when evaluating a stimulus of low quality, IEs generated more unfavorable thoughts and evaluated the stimulus more negatively than did GEs (Exp II). This result favors an information-processing view over dissonance, deindividuation, and commodity theory interpretations. Together the studies indicate that Ss will diffuse the responsibility for a cognitive task. The reduction in individual processing that accompanies an increase in the number of persons responsible can thus lead to either enhanced or reduced evaluations, depending on the subjective quality of the stimulus to be evaluated. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of visual imprinting in the emergence of specific filial attachments in ducklings.

Conducted 2 experiments with a total of 36 1-11 day old Khaki Campbell ducklings, to assess the suppression of distress vocalization by 2 distinctive stimuli before and after Ss were imprinted to 1 of the stimuli. In Exp. I, both stimuli strongly suppressed distress calls initially. At 5 days of age, however, only the stimulus involved in imprinting suppressed the calls. Results suggest that the loss of control by the nonimprinted stimulus was age-related and represented the development of fear to insufficiently-familiar stimuli. In Exp. II, 5-11 day old Ss were permitted lengthy exposure to a novel imprinting-type stimulus. Under these circumstances, distress vocalization eventually came under stimulus control. The overall pattern of results suggests that through imprinting, stimuli that innately evoke filial behavior become familiar and thus are prevented from later evoking novelty-induced fear. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual sampling after lesions of the superior colliculus in rats.

In 2 experiments with 20 male black-hooded rats, Ss with bilateral lesions of the superior colliculus showed significantly poorer relearning of a horizontal/vertical stripe discrimination than control Ss. In Exp I, all Ss showed disruption of performance when a stimulus–response (S–R) separation was introduced by raising the stimuli above the site of responding. However, colliculectomized Ss were much more disturbed by the S–R separation than were control Ss. In Exp II, all Ss showed lower performance levels when conflicting patterns were introduced into the upper portion of the stimulus doors, but this time Ss with collicular lesions were less disturbed than controls. It is suggested (a) that when the stimulus and response sites are discontinuous, rats must make an appropriate orienting response to effectively sample the visual stimuli and (b) that lesions of the superior colliculus alter performance by interfering with this orienting behavior. The impairment in relearning is attributed to the absence of preoperative overtraining on the discrimination task. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personal adjustment and the free recall of materials with affectively positive or negative meaningfulness.

Conducted 2 experiments on the role of affective assessment in human verbal learning. In Exp I, 40 high school students grouped according to Tennessee Self-Concept Scale scores were given consonant-vowel-consonant trigrams as learnable items. Ss with high self-concepts learned the trigrams they liked more rapidly than disliked trigrams. Ss with low self-concepts reversed this customary pattern and learned disliked trigrams more rapidly than liked trigrams. In Exp II, 64 undergraduates who had completed the Barron Ego-Strength scale were given real words as learnable materials. Results showed that it was possible for the same S to learn certain words along a negative and other words along a positive reinforcement-value sequence. This depended upon whether the word meanings involved reflected a problem area or an area of competence for the Ss being studied. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motivational biases in causal attributions of arousal.

Two studies hypothesized that the desire to seek ambiguity as to the cause of a particular state of arousal will increase if either that arousal state or its source is potentially threatening to self-esteem. In Exp I, 22 high- and 21 low-sex-guilt male undergraduates (as determined by the Mosher Forced Choice Sex Guilt Inventory) were shown either an arousing erotic movie or a nonarousing movie; in Exp II, 28 high- and 28 low-guilt females were led to believe that they were very aroused by pictures of nude men. Ambiguity was introduced into both situations by means of a bogus, nonthreatening, alternative arousal source (a placebo). Results indicate that high-guilt Ss were actively involved in the process of determining which source was arousing them. More importantly, this involvement appeared to be motivated by ego-defensiveness. In both experiments, when high-guilt Ss were confronted by an erotic stimulus, they chose to attribute arousal to the bogus source—and thus create ambiguity as to the actual cause and nature of their arousal—more than did low-guilt Ss. (23 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)     

Evaluative judgments of aspects of life as a function of vicarious exposure to hedonic extremes.

In 2 experiments with 156 female undergraduates, the hypothesis was corroborated that vicarious exposure to hedonic extremes—especially the hedonically negative—results in contrast regarding evaluative judgments of aspects of life that have evolved or been acquired in the course of life beyond the laboratory. In Exp I, Ss who wrote about hedonically negative events occurring at the turn of the century expressed greater satisfaction on a composite index of present life quality than Ss who wrote about hedonically positive events. In Exp II, Ss who wrote about hedonically negative events (personal tragedies) scored higher on a composite index of satisfaction with life, health, and physical appearance than Ss who wrote about hedonically positive events. The findings for the composites corroborate a comparison level model of evaluative judgment. The findings for individual items, however, suggest that aspects of life are not evaluated in terms of a single utility scale and standard—the comparison level. Other findings are discussed that appear to contradict a simple affective model of evaluation in which the positivity of evaluations is postulated to increase with the positivity of affective states. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Olfactory discrimination, reversal learning, and stimulus control in rats.

Conducted 3 experiments with a total of 21 Wistar rats. In Exp I Ss were trained to discriminate lights, tones, or odors and then given a series of discrimination reversals. Only Ss trained with odors showed positive transfer on the first reversal and acquisition of a reversal set. Other experiments demonstrated that (a) Ss preferentially attended to odors when presented in compound with lights or tones; (b) odors exerted more discriminative control than tones in tests using compound stimuli of competing sign; and (c) after pretraining on the positive stimulus, acquisition of an odor but not a light discrimination occurred with virtually no errors. These results demonstrate the importance of stimulus modality in the establishment of stimulus control and the need for more careful analysis of stimulus factors in cross-species comparisons of learning ability. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feeling more than we can know: Exposure effects without learning.

It is generally assumed that some form of learning, such as recognition, both precedes and mediates the affective response. The present study questioned that assumption by seeking to obtain positive exposure effects in the absence of stimulus recognition. To unconfound affect and learning effects, 2 experiments with 48 undergraduate females employed a dichotic-listening procedure for stimulus exposure, in which the critical stimuli were exposed on the unattended channel. Reliable attitudinal enhancement toward objectively familiar stimuli was obtained in both experiments, even though recognition levels were low (Exp I) or at chance levels (Exp II). Subjective stimulus familiarity was not a significant predictor of affect in either experiment. It is concluded that positive feelings toward a previously encountered object are not dependent on consciously knowing or perceiving that the object is familiar. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit learning and generalization of the "mere exposure" effect.

Reports 2 experiments that examined the generalization of the "mere exposure" effect. Both experiments demonstrated that positive affect, produced by repeated viewing of a set of stimuli, generalizes to previously unseen stimuli that are similar to the exposed stimuli along certain abstract dimensions. Exp I, with 82 Ss, used letter strings constructed according to a complex rule system. Positive affect attributable to exposure generalized to novel letter strings that obeyed the rule system. Affective generalization was related to Ss' judgments of whether the novel strings obeyed the rule system. Exp II (40 Ss), in which the stimuli were complex visual patterns created by distorting standard forms, yielded an orderly gradient of affective generalization to novel patterns at varying levels of distortion. Results indicate that the exposure effect behaves in a manner similar to "implicit" concept learning and rule induction. The generalization techniques developed here provide a novel method for studying the affective processing of stimuli. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unsolicited interpretation and recall of interpersonal events.

Conducted 4 experiments with a total of 246 undergraduates to examine the variables that influence interpretations and cued recall of interpersonal events. In Exp I, Ss were given a set to empathize with or to be detached from a couple who were shown having an intimate discussion on videotape. The discussion culminated in either a seriously or a moderately negative outcome (SO or MO). A greater amount of attribution (AT) and more accurate recall were found for the empathy set vs the detached set. Greater AT was also found for SO vs MO conditions. In Exp II with a different videotaped event, an SO version and a set to remember the event led to more AT than did an MO version or no set, respectively. Memory-set Ss showed greater recall than no-memory set Ss. In Exp III, Ss given a set to anticipate interaction with 1 of the stimulus persons showed more AT and more accurate recall (R) than did Ss given no such set and an SO led to more AT than did an MO. In Exp IV, Ss given a set about the emotional condition of a stimulus person before observing the event exhibited greater AT and more accurate recall than did Ss given the same set after observing the event or Ss given no set at all. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus selection and irrelevant stimuli in discrimination learning by pigeons.

Studied discrimination learning in 2 experiments with 32 and 16 White Carneaux pigeons. Exp. I confirmed that Ss trained in a free-operant situation produce a sharper gradient of generalization around a specific irrelevant stimulus if they are given true discrimination (TD) training than if given pseudodiscrimination (PD) training. An additional pair of groups, however, showed that this difference could be eliminated if, after initial training but before the test for generalization, both TD and PD Ss were given TD training on an entirely independent set of stimuli. This suggests that the normally flat PD gradient may represent a test effect: control by the specific irrelevant stimulus is masked by other more powerful irrelevant stimuli that are only suppressed by TD training. Exp. II demonstrated that in a discrete-trial situation, PD training results in a sharper gradient than does TD training, suggesting that the other unidentified irrelevant stimuli are present only in free-operant situations. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overt and covert attention and vibrotactile reaction times: Gaze direction, spatial compatibility and hemispatial asymmetry.

Performed 2 vibrotactile reaction time (RT) experiments, using 32 strongly dextral undergraduates to determine if (1) Ss attention toward/away from the operating hand effected RT and (2) there was an interaction with hand-hemispace and spatial compatibility. In Exp I, 16 Ss were administered a 250 Hz vibratory stimulus to the forefinger of a hand and were required to depress a switch as soon as the stimulus was felt. Hemispace of the stimulated hand was varied and head turns were recorded. In Exp II, 16 Ss were presented with stimuli to the left and the right hand and Ss looked at 1 hand for a block of trials. Results suggest that vibrotactile asymmetries may stem from differences in ability to hold covert attention in a number of spatial locations. It is suggested that overt and covert attention play different mediating roles in performance asymmetries, both at the hemispatial level and in classical anatomical connectivity paradigms of visual field and ear of entry. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Frequency effects in lexical decisions: A test of the verification model.

Lexical decisions about high-frequency words are faster than about low-frequency words. It has been suggested that the locus of this effect is in a verification stage in which a frequency-ordered comparison takes place that requires the continuous availability of a sensory representation of the stimulus. This proposal was tested in 4 lexical-decision experiments, using 64 undergraduates. In Exp I, high- and low-frequency words and nonword stimuli remained visible until Ss responded. The stimuli in Exp II were illuminated for only 1 retrace on a video monitor (16.7 msec), and in Exp III, the single retrace was followed by a pattern mask 50 msec later. The latter 2 conditions have been suggested as manipulations that would eliminate the verification stage of recognition. Nevertheless, the effect of word frequency on decision latencies was comparable in all 3 experiments. Data from Exp IV eliminated orthographic regularity as a factor contributing to the obtained frequency effect. It is suggested that frequency has its effects prior to verification and that the notion of verification as the sole basis for frequency effects needs to be revised. (18 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)     

Attitudes and cognitive response: An electrophysiological approach.

Two experiments employed electrophysiological procedures to assess the covert information-processing activity of message recipients. In Exp I, 24 undergraduates expected to hear discrepant communications and were requested to "collect their thoughts" following each forewarning. As discrepancy increased, anticipatory counterargumentation increased, whereas production of favorable thoughts and agreement decreased. Following forewarnings, oral muscle, cardiac, and respiratory activity increased, whereas nonoral muscle activity remained constant and quiescent. In Exp II, 60 undergraduates anticipated and heard a proattitudinal (P), a counterattitudinal (C), or a neutral (N) communication. Ss evaluated more positively and generated more favorable thoughts and fewer counterarguments to the P than the C advocacy but rated similarly the N and P advocacies. As in Exp I, incipient oral muscle activity increased following the forewarning of an involving C advocacy; it also increased for all conditions during the message. Patterns of subtle facial muscle changes reflected the affective nature of the cognitive responding before and during the message. (3 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sexual responsiveness of college students to rape depictions: Inhibitory and disinhibitory effects.

Conducted 2 experiments with a total of 436 undergraduates to identify the specific dimensions in portrayals of sexual violence that inhibit or disinhibit the sexual responsiveness of male and female college students. Exp I replicated earlier findings that normals are less sexually aroused by portrayals of sexual assault than by depictions of mutually consenting sex. In Exp II, it was shown that portraying the rape victim as experiencing an involuntary orgasm disinhibited Ss' sexual responsiveness and resulted in levels of arousal comparable to those elicited by depictions of mutually consenting sex. Surprisingly, however, it was found that although female Ss were most aroused when the rape victim was portrayed as experiencing an orgasm and no pain, males were most aroused when the victim experienced an orgasm and pain. The relevance of these data to pornography and to the common belief among rapists that their victims derive pleasure from being assaulted is discussed. Misattribution, identification, and power explanations of the findings are also discussed. Finally, it is suggested that arousing stimuli that fuse sexuality and violence may have antisocial effects. (37 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)