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Results 451 - 500 of 650
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Hopkins William D WD Berry College, Georgia, USA. - - 2002
This study examined the influence of experimenter position on hand use in gestural communication in a sample of 127 captive chimpanzees. Hand use in gestural communication was recorded while an experimenter was positioned either left, right, or directly in front of the subject. The type of gesture was also recorded ...
Bartolomucci A - - 2001
This study investigated how male tree shrews (Tupaia belangen) performed in a searching task while in their home cages and assessed whether different food distributions affected their performance. The animals were faced with a holeboard containing 9 food sources arranged in a 3 x 3 matrix or in 3 clusters, ...
Santos L R - - 2001
To survive, organisms must be able to identify edible objects. However, we know relatively little about how humans and other species distinguish food items from non-food items. We tested the abilities of semi-free-ranging rhesus monkeys (Macaca mulatta) to learn rapidly that a novel object was edible, and to generalize their ...
Widholm J J - - 2001
Each of 2 monkeys typically earned their daily food ration by depositing tokens in one of two slots. Tokens deposited in one slot dropped into a bin where they were kept (token kept). Deposits to a second slot dropped into a bin where they could be obtained again (token returned). ...
Lelas S - - 2001
RATIONALE: The discriminative stimulus (DS) effects of chlordiazepoxide (CDP) differ from those of other typical benzodiazepine (BZ) agonists in that CDP does not always occasion full substitution for a BZ agonist DS. OBJECTIVES: The present study tested the hypothesis that the unusual DS effects of CDP may result from its ...
Mathy J W - - 2001
We conducted an experiment on a group of captive rhesus macaques (Macaca mulatta) in which we manipulated both food size and interfood distance independently to examine which factor was more important in causing aggressive competition. For each of 254 trials, the monkeys were offered simultaneously two apple pieces ranging in ...
Anderson J R - - 2001
Three squirrel monkeys (Saimiri sciureus) learned to reach toward a container that covered food if a cooperative trainer rewarded such reaches by giving the food. A competitive trainer kept any food found, but wrong selections by this trainer were also rewarded. The monkeys initially reached toward the baited container indiscriminately, ...
Ryan C A - - 2001
This article reports on lessons learned from using comparison and substitution tasks to assess consumers' ability to apply food guide messages. The study evaluated the usability of the Northeast Regional Food Guide (NERFG), which provides instruction on healthful diets of local foods in season. The tasks showed that the NERFG ...
Mitz A R - - 2001
Neurophysiological and neuropsychological studies in monkeys sometimes require an automated food-pellet dispenser. Commercially available dispensers typically sequester the pellet until delivery and, once delivered, the pellet's availability cannot be controlled. The custom-designed dispenser described here overcomes those two limitations. The device is composed of two separate units: a feeder and ...
Morris J S - - 2001
We used positron emission tomography to measure regional cerebral blood flow (rCBF) in 10 healthy volunteers performing a recognition memory task with food and non-food items. The biological salience of the food stimuli was manipulated by requiring subjects to fast before the experiment and eat to satiation at fixed time ...
Hauser M D - - 2001
When food is launched down a vertically positioned S-shaped opaque tube, cotton-top tamarins (Saguinus oedipus) search for the food in the position directly beneath the release point, even though over several trials it never appears in this position (B. M. Hood et al., 1999). Experiment 1 showed that when the ...
Armus H L HL Department of Psychology, University of Toledo, OH 43606, USA. - - 2001
This study was designed to test whether distinctively flavored food pellets, used as rewards for lever-pressing by rats, would acquire different reward values as a function of the differential effort involved in making the lever pressing response which would be predictable from the concept of cognitive dissonance. Subjects were seven ...
Yanagihara S S Laboratory for Animal Information Biology, Graduate School of Bioagricultural Sciences, Nagoya University, - - 2001
We aimed to reveal what is coded in the basal ganglia of domestic chicks. In the water-reinforced 'go' task, chicks learned to peck selectively at a colored bead in order to obtain a drop of water. Out of 38 units obtained, seven showed excitatory activities specifically during the reward period. ...
Sulkowski G M - - 2001
Animals, including pigeons, parrots, raccoons, ferrets, rats, New and Old World monkeys, and apes are capable of numerical computations. Much of the evidence for such capacities is based on the use of techniques that require training. Recently, however, several studies conducted under both laboratory and field conditions have employed methods ...
Wallis J D - - 2001
To gain insight into the nature and neural specificity of the relationship between simple problem solving, inhibitory control and prefrontal cortex, comparison of the effects of excitotoxic lesions of the orbitofrontal and lateral prefrontal cortex were examined on the performance of common marmosets on a detour reaching task. Monkeys were ...
Laska M - - 2001
I assessed the occurrence of food preferences in captive squirrel monkeys and pigtail macaques and analyzed whether their preferences correlate with nutrient composition. Using a two-alternative choice test, I repeatedly presented six Saimiri sciureus and six Macaca nemestrina with all possible binary combinations of 12 types of food that are ...
LaBar K S - - 2001
Functional magnetic resonance imaging (fMRI) was used to determine whether visual responses to food in the human amygdala and related corticolimbic structures would be selectively altered by changes in states of hunger. Participants viewed images of motivationally relevant (food) and motivationally irrelevant (tool) objects while undergoing fMRI in alternately hungry ...
Gharib A A Department of Psychology, University of California, Berkeley 94720-1650, - - 2001
Two rat experiments shed light on how variation in behavior is regulated. Experiment 1 used the peak procedure. On most trials, the 1st bar press more than 40 s after signal onset ended the signal and produced food. Other trials lasted much longer and ended without food. On those trials, ...
Fernandez-Duque E - - 2001
Owl monkeys are small monogamous primates ranging over a wide area extending from Panama to the Chaco region of northern Argentina. The Chaco, an alluvial plain covering over one million km2 of Argentina, Bolivia, Brazil, and Paraguay, consists of a mosaic of grasslands, savannas, xeric thorn forests, and gallery forests. ...
Hare Brian - - 2001
We conducted three experiments on social problem solving by chimpanzees, Pan troglodytes. In each experiment a subordinate and a dominant individual competed for food, which was placed in various ways on the subordinate's side of two opaque barriers. In some conditions dominants had not seen the food hidden, or food ...
Lyons D M DM Department of Psychiatry and Behavioral Science, Stanford University School of Medicine, MSLS Room P111, Stanford, CA 94305-5485, USA. - - 2000
Little is known about frustration-induced changes in stress physiology in humans and nonhuman primates. Here we assess in two experiments with squirrel monkeys plasma levels of pituitary-adrenal stress hormones in conditions designed to provoke frustrative nonreward. In the first experiment 18 prepubertal monkeys were trained to feed from one of ...
Morgan D - - 2000
The present study used a concurrent schedule of food and drug delivery in socially housed male cynomolgus monkeys (Macacafascicularis; N = 15) to study variables that influence cocaine acquisition. Each monkey was implanted with subcutaneous vascular access ports, and responding was maintained under a concurrent food, saline schedule with the ...
Ishibashi H - - 2000
Four Japanese macaques were trained in the use of a T-shaped rake. Use the tool and development of the level of the skill of tool-use took place in three distinct stages. During stage 1, two of the monkeys seemed to use insight for initial solution, while fortuitous experiences led the ...
Westlund K - - 2000
Post-conflict (PC) affiliation has been demonstrated in a number of Old World monkeys and apes, but very little is known about the occurrence of the phenomenon in New World monkeys. This study examined 282 PC interactions after spontaneous conflicts around feeding time in two family groups (N = 12) of ...
Valsecchi P - - 2000
Search abilities of mice (Mus musculus domesticus) were evaluated using an arena closed by a ceiling in which 9 food sources (which mice could reach standing on their hind legs) could be arranged according to 2 configurations: a 3 x 3 square matrix and 3 clusters each containing 3 food ...
de Waal - - 2000
Capuchin monkeys (Cebus apella) share food even if separated by a mesh restraint. Pairs of capuchins were moved into a test chamber in which one of them received apple pieces for 20 min, and the other received carrot pieces for the next 20 min. Previous research had shown a correlation ...
Kirshenbaum AP - - 2000
The literature on risk-sensitive foraging theory provides several accounts of species that fluctuate between risk-averse and risk-prone strategies. The daily energy budget rule suggests that shifts in foraging strategy are precipitated by changes in the forager's energy budget. Researchers have attempted to alter the organism's energy budget using a variety ...
Kieu N T NT Department of Gastroenterology, Research Institute, International Medical Center of Japan, 1-21-1, Toyama, Shinjuku-Ku, Tokyo 162-8655, - - 2000
This study was conducted to investigate the concentrations of serum fatty acids, lipoprotein(a) and apolipoprotein of three populations in North Vietnam: rural area with low income (n = 101), suburban with average income (n = 97), and urban with high income (n = 95). The results showed the suburban and ...
Olthof A A Department of Psychology, University of Western Ontario, London, - - 2000
In each of 3 experiments, different sets of 4 pigeons (Columba livia) were trained to discriminate between 2 visual symbols that covered wells containing food items that varied in number, mass, or both. In Experiment 1, the symbols were associated with 0, 1, 3, 5, 7, or 9 pieces of ...
Dickinson A A Department of Experimental Psychology, University of Cambridge, United Kingdom. - - 2000
The administration of the dopamine antagonists, pimozide and alpha-flupenthixol, to rats reduced Pavlovian-instrumental transfer when a conditioned stimulus (CS) that had been paired with a noncontingent food reward was tested on instrumental performance. The administration of the antagonists during Pavlovian conditioning and/or testing abolished the enhancement of instrumental performance by ...
Hare B - - 2000
We report a series of experiments on social problem solving in chimpanzees, Pan troglodytes. In each experiment a subordinate and a dominant individual were put into competition over two pieces of food. In all experiments dominants obtained virtually all of the foods to which they had good visual and physical ...
Schieber M H MH Department of Neurology, University of Rochester Medical Center, NY 14642, USA. - - 2000
The visual, tactile, and motor properties of neurons in the ventral premotor cortex (PMv) suggest that the PMv plays an important role in the interaction of the face and upper extremities with visual objects, a function that might be disrupted by inactivation of the PMv. The behavior of three rhesus ...
Visalberghi E - - 2000
Palatability of plant foods may change over time in relation to the concentration of toxic secondary metabolites. We investigated the behavioural response of capuchin monkeys to this type of change and assessed the influence of social conditions. Twenty-seven tufted capuchin monkeys were presented in Social or Individual conditions with a ...
Johnson E - - 2000
This study characterizes food neophobia in semi-free ranging rhesus macaques. In experiment one, monkeys received novel and familiar foods during periods of normal provisioning and when provisioning was suspended. The monkeys did discriminate between novel and familiar foods and continued to exhibit neophobia when provisioning was suspended. In experiment two, ...
Roush RS - - 1999
We examined the effects of social environment on food-asociated calling of cotton-top tamarins, Saguinus oedipus, in two experiments. In experiment 1, we compared the food-associated calling behaviour of six juvenile tamarins living in their natal groups with their calling behaviour 9 months after being removed from family groups and paired. ...
Nakagawa N - - 1999
In order to obtain reliable evidence for differences in habitat preferences between two closely related savanna-dwelling primate species, namely, patas monkeys (Erythrocebus patas) and tantalus monkeys (Cercopithecus aethiops tantalus), I collected data on vegetation and patterns of range use concurrently at a single study site, Kala Maloue, Cameroon, in a ...
Hauser MD - - 1999
In any problem-solving situation, there are features associated with the problem that are relevant from a functional perspective and other features that are irrelevant. To determine whether animals are sensitive to the distinction between functionally relevant and irrelvant features of a problem, we conducted two main experiments with a New ...
Beran M J MJ Language Research Center, Georgia State University Decatur 30034, - - 1999
Delay of gratification in 3 chimpanzees (Pan troglodytes) was examined by using a paradigm based on research with children. The chimpanzees either pressed a door-bell button during a trial and received one reward (the immediate reward) or did not press the doorbell and received another reward (the delayed reward). Two ...
Bassareo V V Department of Toxicology and CNR, Center for Neuropharmacology, University of Cagliari, - - 1999
The nucleus accumbens septi is the major target of mesolimbic dopamine neurons originating in the ventral tegmental area of the mesencephalon. Studies involving experimental manipulation of dopamine transmission by drugs and by lesions, as well as in vivo monitoring of extracellular dopamine concentrations, have provided evidence that the dopamine transmission ...
Pakarinen E D - - 1999
The present study assessed the liability of ethanol to be established as an oral reinforcer in 24 juvenile rhesus monkeys. All of the monkeys had a prior oral self-administration history with concurrently available methadone and water. To determine if food restriction and sex differences would contribute to ethanol preference, the ...
Estrada A - - 1999
In Neotropical rain forests, fresh mammal dung, especially that of howler monkeys, constitutes an important resource used by dung beetles as food and for oviposition and further feeding by their larvae. Tropical rain forest destruction, fragmentation, and subsequent isolation causing reductions in numbers of and the disappearance of howler monkeys ...
Laska M - - 1999
The purpose of this study was to determine taste difference thresholds for sucrose in frugivorous spider monkeys and omnivorous baboons. Using a two-bottle preference test of brief duration, we presented four Ateles geoffroyi and four Papio hamdryas anubis with six different reference concentrations (RCs) of 25, 50, 100, 200, 300, ...
Miyazaki K K Laboratory of Brain-operative expression, Brain Science Institute, RIKEN, Wako, Saitama, - - 1998
Single unit recording in rat nucleus accumbens (NAcc) was used to ascertain NAcc neuronal activity in mediating of reward including its anticipation. Of the 103 neurons investigated, 63% showed some response in connection with the task activity. Of these, 20 units responded during delivery of the primary reward (food and/or ...
Tomie A A Department of Psychology, Center of Alcohol Studies, Rutgers University, Piscataway, NJ 08855, - - 1998
Autoshaping conditioned responses (CRs) are reflexive and targeted motor responses expressed as a result of experience with reward. To evaluate the hypothesis that autoshaping may be a form of impulsive responding, within-subjects correlations between performance on autoshaping and impulsivity tasks were assessed in 15 Long-Evans hooded rats. Autoshaping procedures [insertion ...
Parker A - - 1998
Three Cynomolgus monkeys (Macaca fascicularis) learned a flavour-visual conditional discrimination problem, in which one of two possible food items was presented at the beginning of each trial, and acted as an instruction cue to signal which of two visually distinct stimulus objects the animal must displace on that trial in ...
Silberberg A - - 1998
In 5 experiments, 4 monkeys and 1 ape chose between 2 food sources, each held in 1 of the experimenter's hands while he stood in front of a cage. When choosing between 2 sources of the same food that differed in amount, preference for the larger amount decreased as the ...
Hopkins W D WD Division of Psychobiology, Yerkes Regional Primate Research Center, Emory University, Georgia, - - 1998
Hand use in gestural communication was examined in 115 captive chimpanzees (Pan troglodytes). Hand use was measured in subjects while they gestured to food placed out of their reach. The distribution of hand use was examined in relation to sex, age, rearing history, gesture type, and whether the subjects vocalized ...
Novak M A - - 1998
Self-injurious behavior (SIB) occurs in about 10% of individually housed monkeys. Monkeys with SIB bite their own bodies frequently, occasionally inflicting wounds as a result. At present, there is no standard treatment for this phenomenon. We examined the effectiveness of puzzle feeders in alleviating SIB in monkeys with a veterinary ...
Visalberghi E - - 1998
Visalberghi and Fragaszy [Animal Behaviour 49:1089-1095, 1995] have shown that social influences affect acceptance of novel foods. However, little is known about the temporal course on which such influences act (e.g., for how long they persist and for how many encounters they are effective). To explore this issue, 11 adult ...
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