Utility of habituation-dishabituation procedure for comparative cognitive studies of Callithrix jacchus and Aotus spp.: preliminary assessments

The utility of the habituation-dishabituation procedure was examined in the common marmosets (Callithrix jacchus) and the owl monkeys (Aotus spp.). The same movies were repeatedly shown to monkeys during an habituation phase, followed by a test phase during which monkeys were presented with a different movie. The time monkeys spent looking at the movie gradually decreased during the habituation phase and then significantly increased when they were presented the new movie. The limited findings indicate that these monkeys were sensitive to the habituation-dishabituation paradigm, suggesting that this procedure might be used to assess cognition and perception.     

Swimming-induced taste aversion and its prevention by a prior history of swimming

In two experiments, the evidence showed that 20 min of forced swimming by rats caused aversion to a taste solution consumed before swimming. When one of two taste solutions (sodium saccharin or sodium chloride, counterbalanced across rats) was paired with swimming and the other was not, the rats’ intakes of these two solutions showed less consumption of the former than the latter solution. Furthermore, a post-training two-bottle choice test clearly demonstrated long-lasting avoidance of the swimming-paired solution. These results imply that forced swimming acts as an unconditioned stimulus for establishing taste aversion. Preexposure to swimming opportunities before conditioning disrupts such conditioned taste aversion induced by forced swimming.     

Similarity attraction and actually selecting similar others: How cross-societal differences in relational mobility affect interpersonal similarity in Japan and the USA

Several studies have demonstrated that similarity between friendship partners is higher in the West than in East Asian countries. We hypothesized that these differences could be explained by relational mobility, or the number of opportunities to form new relationships in a given society. Through two studies, we confirmed that whereas the preference for similarity did not differ, similarity between friendship partners was higher in the USA than in Japan. Furthermore, a measure of relational mobility mediated the cultural difference in similarity, supporting our hypothesis. The effectiveness of considering socio-ecological factors when interpreting cultural differences in behaviour is discussed.     

Group differences in the mutual gaze of chimpanzees (Pan troglodytes)

A comparative developmental framework was used to determine whether mutual gaze is unique to humans and, if not, whether common mechanisms support the development of mutual gaze in chimpanzees and humans. Mother-infant chimpanzees engaged in approximately 17 instances of mutual gaze per hour. Mutual gaze occurred in positive, nonagonistic contexts. Mother-infant chimpanzees at a Japanese center exhibited significantly more mutual gaze than those at a center in the United States. Cradling and motor stimulation varied across groups. Time spent cradling infants was inversely related to mutual gaze. It is suggested that in primates, mutual engagement is supported via an interchangeability of tactile and visual modalities. The importance of mutual gaze is best understood within a perspective that embraces both cross-species and cross-cultural data.     

Orthography and phonology in reading Japanese kanji words: Evidence from the semantic decision task with homophones

Correspondences between spelling and sound for Japanese kanji are complex and deep. The meaning of kanji words has generally been assumed to be accessed directly from orthography without phonological mediation. Experiment 1, however, replicated the findings of Van Orden (1987) that subjects made more false-positive errors on homophone foils than they did on nonhomophone controls in a semantic decision task, although they did so only when the foils were orthographically similar to the correct exemplars, which indicates both orthographic and phonological activations of meaning. Experiment 2 showed the same results when subjects were not required to pronounce the target words after semantic decisions, which indicates automatic phonological activation of kanji words. In Experiment 3, under pattern-masking conditions, this homophony effect was reduced but remained on errors, and the orthographic-similarity effect remained strong on both homophone and nonhomophone foils. These results suggest that both orthography and phonology play an important role in the comprehension of kanji words.     

Perception of emergent configurations in humans (Homo sapiens) and chimpanzees (Pan troglodytes)

We examined the perceptions of emergent configurations in humans and chimpanzees using a target-localization task. The stimulus display consisted of a target placed among multiple identical distractors. The target and distractors were presented either solely, within congruent contexts in which salient configurations emerge, or within incongruent contexts in which salient configurations do not emerge. We found that congruent contexts had similar facilitative effects on target localization by humans and chimpanzees, whereas similar disruptive effects emerged when the stimuli were presented within incongruent contexts. When display size was manipulated, targets under the congruent-context condition were localized in a parallel manner, but those under the no-context and incongruent-context conditions were localized in a serial manner by both species. These results suggest that both humans and chimpanzees perceive emergent configurations when targets and distractors are presented within certain congruent contexts and that they process such emergent configurations preattentively.     

Visibility pattern of Bose–Fermi mixtures in one-dimensional incommensurate lattices

Abstract

We performed numerical simulations to demonstrate localization phenomena of Bose–Fermi mixture systems on incommensurate optical lattices by changing Bose–Bose and Bose–Fermi interactions. Visibility patterns of the bosons were measured to observe bosonic coherence in various selections of the interaction parameters. We found that the coherence was enhanced with repulsive Bose–Fermi interactions. It was also enhanced with attractive Bose–Fermi interactions but only in certain conditions. The enhancement by repulsive interactions and that by attractive interactions occurred with different mechanisms.     

The effect of swimming experience on acquisition and retention of swimming-based taste aversion learning in rats

Swimming endows rats with an aversion to a taste solution consumed before swimming. The present study explored whether the experience of swimming before or after the taste-swimming trials interferes with swimming-based taste aversion learning. Experiment 1 demonstrated that a single preexposure to 20 min of swimming was as effective as four or eight preexposures in causing the interference effect. Experiment 2 found that a single 5-min preexposure was enough to cause the interference effect. Experiment 3 showed that preexposure to swimming interfered with but did not completely thwart the acquisition of swimming-based taste aversion learning. Experiment 4 failed to demonstrate a reliable retroactive interference effect by swimming postexposures. With a modified procedure, however, Experiment 5 successfully demonstrated a reliable effect by four postexposures. The associative and habituation accounts of these results are discussed.     

Relative numerosity discrimination by chimpanzees (Pan troglodytes): evidence for approximate numerical representations

Two adult chimpanzees were trained on a relative “numerosity” discrimination task. In each trial, two arrays containing different numbers of red dots were presented on a CRT monitor. The subjects were required to choose the array containing the larger number of dots. In Experiment 1, using numerosities between 1 and 8, 28 different pairs were presented repeatedly, and accuracy scores were analyzed to explore which cues the chimpanzee subjects utilized to perform the task. Multiple regression analyses revealed that the subjects’ performance was (1) not simply controlled by the “numerical” difference between arrays, but that it was (2) best described by Fechner’s Law–that is accuracy increased linearly with the logarithmic value of the numerical difference between arrays divided by the number in the larger of the two arrays. This relationship was maintained when using much larger numerosities (Experiment 3). In Experiment 2, the chimpanzees were tested on the effects of total area and density by manipulating dot size and presentation area. The results revealed that these factors clearly affected the subjects’ performance but that they could not alone explain the results, suggesting that the chimpanzees did use relative numerosity difference as a discriminative cue.