Thermal homeostasis in pregnant rats during heat stress.

Sprague-Dawley rats exposed to inescapable heat stress maintained a controlled hyperthermia while increasing heat loss by cutaneous vasodilatation and by grooming behavior. In nonpregnant Ss, the evaporation of saliva groomed onto the body surfaces increased exponentially as a function of ambient temperature above 36°C. In contrast, Ss in an advanced stage of pregnancy became dependent on grooming behavior for thermoregulation of ambient temperatures of 30-36°C. This was associated with a decrease in the body temperature threshold for salivary secretion from the submaxillary gland, which then began at approximately the same body temperature as cutaneous vasodilatation. The pregnant Ss maintained a lower level of controlled hyperthermia during heat stress than did nonpregnant Ss. This appeared to result from a decreased production of metabolic heat, reduced insulation on the ventral surface, and an increased motivation to keep cool during heat stress. These changes met the increased need for thermolysis during pregnancy and provided for thermal homeostasis both in the pregnant rat and in the unborn fetuses. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The ontogeny of feeding in rats: V. Influence of texture, home odor, and sibling presence on ingestive behavior.

Determined with Charles River rat pups in 3 experiments that terry-cloth texture, home odor, and the presence of siblings modulated Ss' ingestive behavior. Unlike warmth, which affected ingestion in pups until at least 15 days of age, the relative importance of other cues varied with age. At 3 days, ingestion was dependent on warmth but was not influenced by the other cues. At 6 days, texture and home odor enhanced ingestive behavior (intake, activity, mouthing, and probing), but the presence of siblings had no effect. Home odor or terry-cloth texture did not alter the ingestive behavior of 12-day-olds, but the presence of siblings enhanced milk intake. Thus, during development, the external sensory controls for ingestion became progressively more complex. Warmth served as a primary permissive cue for ingestion, but as Ss grew older, such other cues as odor, texture, or social stimuli also gained significance. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Activation and odor conditioning of suckling behavior in 3-day-old albino rats.

Investigated circumstances under which a novel odor could elicit nipple attachment behavior in 3-day-old Sprague-Dawley rats. In Exp I, Ss suckled washed nipples scented with citral (a lemon odor) only if they either had received tactile stimulation (by stroking with a soft brush) or had been administered amphetamine in the presence of citral prior to the suckling test. Ss stimulated in citral's absence or only exposed to citral without stimulation failed to suckle such nipples. In Exp II, Ss stimulated in a benzaldehyde (an almond odor) ambience suckled washed nipples scented with benzaldehyde but not those with citral scent. The opposite held for those stimulated in a citral-rich environment. The stimulus conditions that supported this conditioning were investigated in Exp III. Simultaneously increasing citral concentration and raising ambient temperature markedly attenuated the phenomenon. Exp IV demonstrated that not all classes of stimulation produced conditioning. Caffeine, in a wide range of doses, did not allow citral to elicit suckling on washed nipples. Findings are discussed within a framework of higher-order conditioning and may provide a mechanism by which naturally occurring stimuli come to elicit the species- and age-typical behavior of suckling. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral thermoregulation in the squirrel monkey: Adaptation processes during prolonged microwave exposure.

Investigated exposure duration at power densities above and below the threshold of 6-8 mW/cm2 with 2 male monkeys. Ss were restrained in the far field of a horn antenna inside an anechoic chamber heated and cooled by forced convection. Ss learned to control the temperature of the circulating chamber air by selecting between cold and warm air sources. Ss were exposed to 12.4-cm (2450-MHz) continuous-wave microwaves for periods from 5 to 150 min. Microwave power densities explored were 4, 10, and 20 mW/cm2. The 4 mW/cm2 microwave exposure did not modify thermoregulatory behavior. The 10 and 20 mW/cm2 exposures stimulated the monkeys to select ambient temperatures 1.5 and 3.0°C cooler than control levels, respectively. Except during the early minutes of an exposure, duration had no significant effect on selection of air temperature or on the body temperatures thereby achieved. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of dopamine-depleting brain lesions on suckling and weaning in rats.

Rats given large dopamine (DA)-depleting brain lesions as adults exhibit severe impairments in ingestive behavior and sensorimotor function. In contrast to these well-known effects, the present 2 studies showed that virtually complete destruction of central dopaminergic neurons produced no such dysfunctions when it occurred in neonates (Sprague-Dawley). Ss continued to suckle and grow, albeit somewhat more slowly, and they could be weaned readily when they were 27 days old. Although most brain-damaged Ss did not survive weaning when they were 18 days old (controls exhibited no difficulty), this failure appeared to be the consequence of their reduced body weight and related inability to maintain body temperature in a relatively cool environment (22°C). Such premature weaning occurred more successfully when growth was stimulated by rearing brain-damaged pups in small litters or when ambient temperatures were raised to 31°C to minimize heat loss. Results demonstrate that the effects of near-total DA-depleting brain lesions are considerably less severe when they occur in infants than when they occur in adults, and, consequently, they reveal a capacity for neural plasticity during development that is no longer present at maturity. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of children's understanding of the metalinguistic term word..

Designed 3 experiments to assess 24 preschool (mean age 64.63 mo), 24 1st-grade (mean age 76.25 mo), and 24 2nd grade (mean age 88.61 mo) children's understanding of the term word. A modified aural discrimination task was used in which Ss were required to discriminate word from nonword stimuli along only 1 dimension at a time. Exp I tested Ss' discrimination of words and sounds. Exp II examined word–phrase differentiation. Both of these experiments followed previous research in examining children's comprehension of the term word in relation to nouns. Exp III examined Ss' understanding of word with stimuli from a variety of form classes. Results indicate that Ss' word concepts have been underestimated in past research suggesting that young children lack an adequate word concept: although preschool Ss did not understand the term properly, by 1st grade word was understood. These experiments also show that Ss benefited from brief training in which they were taught to attach the metalinguistic label word to their developing concept of the word as a unit of spoken language. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral thermoregulation, core temperature, and motor activity: Simultaneous quantitative assessment in rats after dopamine and prostaglandin E1.

Determined the dose-response autonomic and behavioral thermoregulatory effects and the motor effects of dopamine (DA) and prostaglandin E1 (PGE1) injected into the lateral cerebral ventricles of male Sprague-Dawley rats. The present study was conducted with a computer-controlled thermocline that permitted freely moving Ss to select preferred ambient temperatures (7-39°C). All Ss were studied with the thermocline gradient both on and off to control for nonspecific effects. Results show that PGE1 (0, .1, .2, .5, 1.0 μg) produced a dose-related increase in core temperature and produced a dose-related selection of warmer ambient temperatures. DA (0, 50, 100, 200, 400 μg) produced a dose-related hypothermia and cold-seeking behavior. Without the gradient, DA-injected Ss did not become as hypothermic as in the gradient-on condition. When the gradient was available, Ss showed a significant rebound increase in core temperature 50-80 min after DA, which did not occur when the gradient was off. Overall, DA induced increases in motor activity, but, during the 1st 10 min after injection while the gradient was on, Ss made stable selections of cool ambient temperatures and showed reduced activity. Conversely, the behavioral effect of PGE1 did not facilitate the autonomically mediated heat gain. Findings emphasize the necessity of creating behavioral options for animals to fully evaluate drug effects on thermoregulation. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective recall for personally relevant communications.

Used 2 experiments to test whether people display a recall bias for supportive over refutive information. While previous work has used broad social attitudes, the present research investigated recall for communications relevant to Ss' behavior. In Exp I, 15 smokers, 36 nonsmokers, and 24 ex-smokers read and recalled information related to smoking. In Exp II, 28 seatbelt wearers, 18 occasional wearers, and 15 nonwearers read and recalled pro-seatbelt material. As predicted, in both experiments Ss' behavior significantly affected their recall of information: Nonsmokers recalled more anti-smoking material than smokers, and seatbelt wearers recalled more pro-seatbelt information than nonwearers. There were no significant effects on any measures when Ss in Exp I were divided into seatbelt wearers and nonwearers and when Ss in Exp II were divided into smokers and nonsmokers. Thus, Ss were selective only on the communication relative to their own behavior. (French abstract) (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of out-group cues in determining social identity.

Examined the role of out-group cues in determining social identity and guiding behavior in 2 experiments with 131 undergraduates. In Exp I, Ss were exposed to a cue either of an in-group (Ss' college), a relevant out-group (a rival college), or an irrelevant out-group (a baseball team). Ss examined a list of words and were later asked to recognize those they had seen from a larger list in which words related to the 3 groups were embedded. Results indicate that Ss made more false recognitions of in-group related words when a relevant out-group was salient than when an irrelevant out-group was salient. Exp II tested a behavioral implication of Exp I: Out-group salience increases adherence to an in-group norm. In the 1st phase of Exp II, Ss were divided into 2 groups and deliberated 2 civil suits. Ss' in-group favored the plaintiffs for both cases. Ss were divided into new groups for the 2nd phase, and the same procedure was followed. This time, however, the in-group favored the defendants. In the 3rd phase, Ss were exposed to a cue either of the out-group in Phase 1 or Phase 2. Ss' judgments for 2 new cases were biased in the direction of the norm of the in-group that was associated with the salient out-group. Ss favored the plaintiff (or defendant) when the 1st (or 2nd) out-group was salient. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Copying and reproducing pictures in relation to subjects' operative levels.

Past Piagetian memory research has established that Ss' operative levels influence their recall of operatively derived stimuli. To determine the locus of operative influence, children from Grades 1–5 with immature, transitional, or mature concepts of verticality were asked to copy and/or to reproduce verticality stimuli. Stimuli were either operatively advanced (a vertical tree on a hillside) or primitive (a tipped tree). Memory was tested immediately (Exp I, 96 Ss), 1 wk (Exp II, 168 Ss), or 5 mo (Exp III, 46 Ss) after the initial viewing. In each study there was a significant relationship between operative level and performance on the operatively advanced stimulus only. For the tipped stimulus, more distortion was evident in memory than in copy drawings. Contrary to predictions, however, there was no difference between distortion in copy and memory drawings for the straight stimulus regardless of Ss' operative levels. Results suggest that progressive distortion increases over time but that regressive distortion occurs before the stimulus is removed from sight. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Three experiments using an algorithm for empathic responses.

Each of 3 experiments tested an algorithm (a set of specified procedures) for directing novice counselors (university counseling students) in making empathic responses. The independent variable was assessed using CLIENT 1, a computer simulation of an initial client interview. Exp I (26 Ss) showed that an algorithm could control Ss' behavior and revealed ways to improve the algorithm, which was then rewritten and used in the subsequent studies. Exp II (28 Ss) employed a completely randomized design, and a significant difference in favor of the experimental group was found. In Exp III (32 Ss), the algorithm was modified and a randomized block design employed. The experimental group again performed significantly better. It is concluded that algorithms can affect Ss' ability to create empathic responses. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Referencing and bias in social interaction.

Examined the consequences of schematic referencing for social behavior. In Exp I, 23 female and 21 male undergraduates worked in pairs on a word association task. In the self-referencing condition, Ss were told that their partner would judge their personality; in the other-referencing condition, Ss were asked to judge their partner's personality. Results show biased recall of Ss' own behavior over another person's behavior in a dyadic interaction. Exp II employed an alternative, more realistic manipulation of self-referencing using situational cues. 16 pairs of undergraduate Ss performed the same word association task either in front of judges or by themselves. The biased recall effect was replicated. Moreover, corresponding biases in Ss' attributions about the quality of their performance were found. Results confirm that self-referencing cues can cause the sort of egocentric reactions that have been observed in previous studies in which members of an interaction remember more of their own contributions and attribute more responsibility for joint tasks to themselves. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of posterior hypothalamic lesions on swimming movements in different water temperatures by the rat.

38 male hooded rats were subjected either to posterior hypothalamic cathodal lesions or sham operations. Postoperatively, lesioned Ss were somnolent for 3-5 days. Ss could groom, scratch, or facewash but did not engage in spontaneous locomotor behavior. The Ss recovered from somnolence but remained akinetic, lacking spontaneous movement throughout testing. In swimming tests at different water temperatures, lesioned Ss sank in 37. C water, but as water temperature deviated from body temperature, swimming improved, as measured by time the S's nose remained above water and appearance of mature swimming patterns. Similar results were obtained in both hypothermic (27. C) and hyperthermic (41.5. C) Ss. Results suggest that the lesions damage a system responsible for linking and integrating motor and sensory systems and for triggering voluntary movement. (French summary) (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recruiter and job influences on candidates for employment.

In Exp I, videotapes of mock interviews, constructed so that recruiter affect and recruiter knowledge of the job were varied, were shown to 133 undergraduates. In Exp II with 178 Ss, recruiter affect and job attractiveness were varied. Reliable effects of recruiter behavior and job attributes on Ss' propensities to pursue the job were obtained. Results indicate that recruiter behavior was consistently interpreted by Ss as a signal regarding their chances of getting a job offer, whereas job attributes exerted clear influence on perceived desirability of the job. Results from Exp I indicate that recruiters may also influence the perceived desirability of the job. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal thresholds of the rhesus monkey (Macaca mulatta).

Measured thresholds to warming and cooling stimuli presented on the shaved skin of the inner thigh of 2 young male rhesus monkeys by the conditioned suppression method after the skin had been preadapted to 28, 30, 32, 34, 36, 38, and 40. C temperatures. Thresholds to warming stimuli decreased from .14 to .02. C, while thresholds to cooling stimuli increased from .05 to .28. C as the adapting temperature was increased from 28 to 40. C. In comparison to human thresholds, the Ss were more sensitive to changes in stimulator temperature at all adapting temperatures except to cooling at a 40. C adapting temperature. Data suggest that the Ss were able to discriminate between warming and cooling stimuli and that they responded to a change in sensation at the extreme adapting temperatures rather than to the quality of the sensation-warm or cool. (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)     

The direction and range of ambient temperature change influences yawning in budgerigars (melopsittacus undulatus).

Comparative research suggests that yawning is a thermoregulatory behavior in homeotherms. Our previous experiments revealed that yawning increased in budgerigars (Melopsittacus undulatus) as ambient temperature was raised toward body temperature (22→34 °C). In this study, we identify the range of temperatures that triggers yawning to rule out the possible effect of changing temperature in any range. To corroborate its thermoregulatory function, we also related the incidence of yawning to other avian thermoregulatory behaviors in budgerigars (e.g., panting, wing venting). In a repeated measures design, 16 budgerigars were exposed to 4 separate 10-min periods of changing temperatures: (a) low-increasing (23→27 °C), (b) high-increasing (27→33 °C), (c) high-decreasing (34→28 °C), and (d) low-decreasing (28→24 °C). Birds yawned significantly more during the high-increasing temperature range, and yawning was positively correlated with ambient temperature across trials. Yawning was also positively correlated with other thermoregulatory behaviors. This research clarifies the previously demonstrated relationship between yawning rate and temperature by providing evidence that the physiological trigger for yawning is related to increasing body temperatures rather than the detection of changing external temperatures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affect and stereotyping: The effect of induced mood on distinctiveness-based illusory correlations.

In 2 studies, the effects of mood on the formation of distinctiveness-based illusory correlations were examined. After exposure to stimuli inducing positive, neutral, or negative mood, Ss read information about behaviors performed by members of 2 groups in an illusory correlation paradigm. In both experiments, only Ss in a neutral mood formed illusory correlations. In addition, Exp 2 assessed Ss' processing latencies as a means of investigating differential attention to distinctive behaviors. Only Ss in a neutral mood differentially attended to the minority group's infrequent behaviors. Induced mood apparently interfered with the processing necessary to differentially encode distinctive stimuli, undermining the illusory correlation effect. (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)     

Role of avoidance in aggressive responses to attack and no attack.

In 2 experiments male Ss interacted with a presumed opponent in a task that permitted the 2 participants to exchange various intensities of shock, including a zero intensity. The Ss' responses were considered separately following attack (receipt of shock) and no attack (no receipt of shock). For responses following no attack, the Ss' aggressive behavior varied with their ability to avoid further shock. Relative to controls, Ss who could avoid further shock by nonaggression (Exp I, 40 college students) were less aggressive. Those who could avoid shock by being very aggressive (Exp II, 20 college students) were more aggressive than controls. Aggressive responses following attack, however, were not influenced by avoidance contingencies. The ability to avoid further shocks apparently influenced males' aggressive responses in the absence of attack but failed to influence males' aggressive responses to attack. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)