Temporal integration in face perception: Evidence of configural processing of temporally separated face parts.

Temporal integration is the process by which temporally separated visual components are combined into a unified representation. Although this process has been studied in object recognition, little is known about temporal integration in face perception and recognition. In the present study, the authors investigated the characteristics and time boundaries of facial temporal integration. Whole faces of nonfamous and famous people were segmented horizontally into 3 parts and presented in sequence, with varying interval lengths between parts. Inversion and misalignment effects were found at short intervals (0-200 ms). Moreover, their magnitude was comparable to those found with whole-face presentations. These effects were eliminated, or substantially reduced, when the delay interval was 700 ms. Order of parts presentation did not influence the pattern of inversion effects obtained within each temporal delay condition. These results demonstrate that temporal integration of faces occurs in a temporary and limited visual buffer. Moreover, they indicate that only integrated faces can undergo configural processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cholecystokinin decreases food intake in rats.

Tested the effects of cholecystokinin (CCK) on a total of 120 adult male Sprague-Dawley rats. Partially purified CCK was injected intraperitoneally into fasted Ss prior to food presentation. The hormone produced a large dose-related suppression of intake of solid and liquid diets. Identical doses of the synthetic terminal octapeptide of cholecystokinin produced identical results. An effective dose of CCK did not suppress drinking after water deprivation. Treated Ss did not appear ill and were not hyperthermic; neither CCK nor the octapeptide produced learning of a taste aversion in bait-shyness tests. The effect of CCK is not a property of all gut hormones, since injections of secretin did not affect feeding. These studies raise the possibility that CCK plays an inhibitory role in the short-term control of feeding behavior. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Demand for food and cocaine in Fischer and Lewis rats.

Fischer and Lewis rat strains often serve as animal vulnerability models for drug abuse and addiction. When these strains respond for drugs of abuse, several measures, including total drug intake, response rate and progressive-ratio breakpoints, have been reported to be strain-dependent, a result suggesting genetic differences in drug reactivity and vulnerability. The present study extends these strain comparisons to a previously untested measure--demand analysis. In Experiment 1, four Fischer and four Lewis rats earned their daily food ration by lever pressing under a fixed-ratio schedule, the size of which was increased every three sessions from 3 to 1,000 in logarithmic steps. Consumption was plotted as a function of ratio size, and modeled by the exponential-demand equation (Hursh & Silberberg, 2008). Experiment 2 replicated Experiment 1 except that different rats were used, and cocaine reinforced lever pressing. A between-experiment comparison showed a commodity-by-strain interaction: Fischer rats defended consumption with greater vigor when cocaine served as the reinforcer than did Lewis rats; for food, this relation was reversed. However, for both strains, defense of consumption of food exceeded that of cocaine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Diazepam-induced eating and lever pressing for food in sated rats.

Found in 8 experiments with male Wistar rats that diazepam (2.5 mg/kg) produced vigorous eating but not drinking in sated Ss. The effect was found with familiar food in both test box and home cage and during both day and night. Ss trained under food deprivation leverpressed for food but not water under diazepam; the rate of response was dose dependent. Diazepam motivated learning of leverpressing for food but not as well as did deprivation. Diazepam-induced eating lasted 25-30 min and was terminated by feedback from eating, rather than by catabolism of the drug. Stomach loads of food but not of water inhibited the eating. These data indicate that diazepam has specific actions on hunger or food-satiety mechanisms. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A natural food aversion in Norway rats.

During a single 1-hr feeding test, adult male Norway rats were offered intact carcasses of adult male rodents, sacrificed by CO? asphyxiation. In Exp I, 79 Ss fed more readily on conspecifics dead 24–220 hrs than on conspecifics dead 10 min or 6 hrs. In Exp II, 22 Ss fed readily on roof rats (Rattus rattus) whether they had been dead 10 min or 24 hrs. In Exp III, 15 Ss rendered anosmic by zinc sulfate treatment fed more readily on conspecifics dead for 10 min than did 17 controls. In Exp IV, 34 Ss consumed more flesh from house mice coated with roof rat urine than from mice coated with Norway rat urine. It is concluded that Norway rats exhibit a natural aversion to feed on the intact carcasses of freshly sacrificed adult conspecifics in the sense that they are more likely to feed on other species of rodent. The aversion diminishes with the dissipation of the chemoreceptive cue(s) identifying the carcass as a conspecific. (64 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal horizons in decision making.

The perception of duration is crucial when we make choices between immediate and delayed rewards. Immediate rewards are valued more than the same rewards if they are delayed. Preferences for earlier rewards become even stronger when the reward can be received within a subjectively proximate time frame. A “rational” decision to wait for a delayed reward may be overruled by an “impulsive” choice when the option for the closer reward falls within this proximate time range. Based on findings on circadian and circannual physiological rhythms, we suggest that there are 2 time units that are both biologically and culturally determined and have an impact on human experience and behavior: the day and the year. We highlight results of a neuroimaging study showing that rewards with delays up to 1 year are discounted differently than reward delays longer than 1 year. This duration-dependent discounting is associated with specific brain activation in the striatum. We present various conceptualizations of subjective time incorporated in parametric models of intertemporal decisions that may lead to a better understanding of human choice behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Salt seeking by food selection in adrenalectomized rats.

Investigated the generality of salt-seeking behavior in 2 experiments with 12 sham-operated and 9 adrenalectomized male albino Dublin strain rats. Under diets which differed in salt content, the adrenalectomized Ss selected salty over plain food. Where the salt concentration was 3% or greater, the adrenalectomized Ss maintained body weight and showed no adverse symptoms. Contrary to previous theories, results demonstrate that when salt is available in food, rats do seek out and can consume NaCl in sufficient quantities to maintain sodium levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social transmission of food preferences: An adaptation for weaning in rats.

Comparison of the extent of social influence on the feeding site selection of 24 adult and 58 weanling domesticated rats revealed that social interaction was a far more potent factor in determining the diet selection of weanlings than of adults. The social transmission of diet preferences is discussed as an adaptation of greatest importance during the weaning period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New horizons in medicine. The attractors

The discovery of the fact that chaotic systems can suddenly coagulate into deterministic systems, and that deterministic systems can precipitate into chaotic systems has, on the one hand, clearly revealed the limits of the Cartesian geometrization of random phenomena, and on the other, has made in possible to identify the attractor as the reference entity when studying the functional dynamics of biological systems. The attractors is identified as the point of equilibrium upon which the behaviour of a dynamic system stabilizes and towards which it is constantly attracted. In some systems the attractor is identified as an "ideal" optimum reference point termed "the point". In other systems, however, the attractor is identified as a closed curve: "the ultimate cycle". Lastly, in other systems the attractor is identified as a surface in which the space of the states delimits a flat doughnut-shaped image constituting a "torus". The recent discovery of the laws governing deterministic chaos has made it possible to identify a new type of attractor termed the "strange attractor". This attractor has a fractal dimension (i.e. one midway between linear and plane), is of finite dimension and depends on the initial condition of the system. In many biological functions it is now possible to demonstrate the presence of attractors that operate starting from different initial conditions or that vary with time or that display both these conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Local time horizons in Pavlovian learning.

Responding to a CS is impaired if the CS is trained in the presence of excitatory local context cues. Four lick suppression experiments with rats explored whether this local context effect arises from the influence of excitatory cues that precede or that follow a reinforced target CS. Pretrained nontarget stimuli served as local context cues that occurred (1) immediately before and after the target CS trial, (2) immediately before or after the target CS trial, or (3) only before or after the target CS trial with varying intervals between the nontarget stimulus and target CS. Results indicated similar control over responding to the target CS by the preceding and following nontarget cues. This outcome implies a symmetrical window of memory integration (local time horizon) for a Pavlovian CS. Possible mechanisms underlying the detrimental effect of embedding a CS in an excitatory local context are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of gastric loads and food deprivation on subsequent food intake in suckling rats.

In 4 experiments, a total of 478 suckling Charles River rats were subjected to deprivation periods of 6-8 hrs. Intake following deprivation was greater in deprived than in nondeprived Ss but did not increase with increasing deprivation. Gastric loads of NaCl solutions depressed subsequent intake; 3% NaCl was more effective than .9% NaCl. Other gastric loads of varying osmotic and caloric values also depressed subsequent intake. In order of increasing effectiveness in depressing intake, the gastric loads were protein hydrolystate, heavy cream, water, milk, lactose, glucose, and corn oil. Effectiveness was unrelated to osmotic or caloric value of the load. Gastric fill and, possibly, some property of carbohydrate appeared to be important determinants of satiety in the S. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Beyond symbolic processing: Expanding horizons for educational psychology.

R. E. Mayer (1992) believes that fractionation in educational research is giving way to a unified cognitive approach based on subject-matter psychologies, study of learning strategies, and the learning-as-knowledge construction metaphor. Yet, the paradigm described by Mayer is now being strongly challenged by a number of educational research communities, as different forms of the knowledge construction metaphor vie with one another for dominance. Challengers argue that schools must focus on preparing students for participation in complex multidisciplinary thinking activities that characterize life outside of school and that the dominant US cognitive paradigm has been inadequate for examining those kinds of processes. Important entrants into this dialog are racial constructivism and the situated cognition movement. Therefore, this is not a period of unification for educational research but a period of great argumentation and change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comprehending narratives containing flashbacks: Evidence for temporally organized representations.

This study investigated the representations that readers construct for narratives describing a sequence of events. Participants read narratives describing 4 successive events in chronological order (Event 1, Event 2, Event 3, Event 4 [E1, E2, E3, E4] Experiment 1) or in nonchronological order with E1 being mentioned in a flashback (E2, E3, E1, E4; Experiments 2-4). The information about the duration of E2 was manipulated, and the mental accessibility of E1 was tested at the end of a passage. All 4 experiments showed that E1 was less accessible if the text implied that it occurred a relatively long time ago in the described world compared with when it occurred a shorter time ago. This result suggests that readers construct a temporally organized representation even if the text structure does not suggest such an organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Somatostatin decreases food intake of rats and baboons.

Somatostatin is a peptide hormone found in the CNS and the gastrointestinal tract. It has the ability to modify a number of metabolic factors associated with food intake. The purpose of the 7 experiments reported here was to determine the effect of somatostatin on the intake of individual meals of 2 species, the rat (131 female Wistar, 20 male Wistar and Long Evans) and the baboon (4 male Papio cynocephalus). In one set of experiments, Ss received somatostatin (10 ng–2 μg/kg) or a control solution ip. There was a dose-dependent decrease of food intake relative to vehicle-injected controls. In subsequent experiments, these doses had no effect on water intake and did not cause a conditioned taste aversion. Findings suggest that somatostatin acts relatively selectively on food intake and probably does not induce nausea or illness. The administration of somatostatin into cerebrospinal fluid had no effect on food intake. Therefore, somatostatin apparently works peripherally to reduce food intake in both rats and baboons. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Some determinants of a natural food aversion in Norway rats.

Adult male Long-Evans rats were permitted to feed on the carcasses of adult male rodents, freshly sacrificed by CO? asphyxiation. In a 2-choice preference test (Exp I), hungry Ss were offered 1 conspecific and 1 house mouse, the pair of carcasses being either intact or skinned. 18 Ss offered intact carcasses fed on the mouse or on neither carcass, but 18 Ss offered skinned carcasses fed indiscriminately, usually on both carcasses. In Exp II, 10 hungry Ss that earlier had observed a cagemate feeding on intact conspecific carcasses fed more readily on a similar carcass during a single-choice test than did 8 controls. In Exp II, 20 food-deprived Ss (96 hrs) fed more readily and consumed more tissue from an intact conspecific carcass than did 20 nondeprived Ss. It is concluded that the aversion to feeding on the intact carcass of a freshly sacrificed adult conspecific is deprivation dependent and is mediated by chemoreceptive stimuli from the skin and/or fur. The aversion is diminished by social facilitation. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

New horizons in medicine. Chaos and its laws

We have synthesized the fundamentals that modern technology offers in all areas of research, especially in the field of biomedicine. The theory of systems, cybernetics, synergetics, boolean algebra, communication science (according to modern laws of signal transmission and translation), the solution of non-linear equations by computer science, applied principles of reduction in biological survey, fractal analysis as a representation of dynamic, chaotic, non-linear systems, defined attractors as conditioning elements of biologic function, are just a few of the many instruments that modern science offers as a revolutionary approach to research programming. Borrowing the laws of mathematics, we have defined the fundamental characteristics of linear and non-linear homeostatic systems along with the concept of predictable behavior of a system as a function of its complex structure. Lastly, we have documented, based on personal research and recent findings in biomathematics, and despite current and strong opposition, how the functional death of any dynamic system is identified by the system's absolute state of equilibrium. The operative errors at times caused by different stimuli acting on specific organs and apparatus, are interpreted not as an index of altered function but as an expression of a chaotic response of the deterministic type and therefore an indication of the system's adaptability to the specific functional requirements in that precise moment.     

Novel food and novel running wheels: Conditions for inhibition of sucrose intake in rats.

In 3 experiments with ARS/Sprague-Dawley albino rats it was found that both males (n = 16) and females (n = 40), when first given free access to running wheels, showed a marked reduction in sucrose intake relative to stock diet intake when the sucrose was novel. Further tests showed that both the novelty of the sucrose and the novelty of the running wheel were necessary for the inhibition of sucrose intake. The selective inhibition of sucrose intake is considered to be an example of neophobia in the domestic rat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Androgenic control of food intake and body weight in male rats.

Conducted 2 experiments with 118 adult Sprague-Dawley rats to compare the effects of androgens with those of estrogens and examine the role of target-tissue metabolism in actions of testosterone on body weight. Castration of adult males produced a delayed (by 1 mo), permanent hypophagia and reduction in weight gain. This contrasted with the rapid, transient hyperphagia and increased weight gain caused by ovariectomy in females. Injections of testosterone propionate (TP) stimulated food intake and weight gain in castrated males. Neither 5alpha-reduction nor aromatization of the testosterone molecule played an important role in the stimulation of these measures by TP. The 5alpha-reduced metabolite of TP, 5alpha-dihydrotestosterone propionate (DHTP), was less effective in increasing eating and weight gain than was TP. Very high doses of TP actually reduced weight gain with prolonged treatment (2-6 wks). It is suggested that this reduced weight gain was due to aromatization of TP to an estrogen. The nonaromatizable androgen, DHTP, did not reduce weight gain even in very high doses, and concurrent progesterone injections reversed the weight-reducing actions of high TP doses. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discretionary task interleaving: Heuristics for time allocation in cognitive foraging.

When participants allocated time across 2 tasks (in which they generated as many words as possible from a fixed set of letters), they made frequent switches. This allowed them to allocate more time to the more productive task (i.e., the set of letters from which more words could be generated) even though times between the last word and the switch decision ("giving-up times") were higher in the less productive task. These findings were reliable across 2 experiments using Scrabble tasks and 1 experiment using word-search puzzles. Switch decisions appeared relatively unaffected by the ease of the competing task or by explicit information about tasks' potential gain. The authors propose that switch decisions reflected a dual orientation to the experimental tasks. First, there was a sensitivity to continuous rate of return--an information-foraging orientation that produced a tendency to switch in keeping with R. F. Green's (1984) rule and a tendency to stay longer in more rewarding tasks. Second, there was a tendency to switch tasks after subgoal completion. A model combining these tendencies predicted all the reliable effects in the experimental data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proximity of food, sex, and access to running wheels: Effects on food intake in rats.

To test the hypothesis that the addition and withdrawal of a running wheel affects food intake because of a manipulation of the proximity of the rat to the food dish, a 2nd source of food was made available to the rat when in the running wheel. Ss were 24 male and 24 female ARS/Sprague-Dawley albino rats. Results fail to support the hypothesis. Additional findings were that both sexes showed the reduction in food intake when given access to running wheels, but only the males showed an increase in food intake when deprived of access to running wheels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)