Social transmission of food preferences in Japanese monkeys (Macaca fuscata) after mere exposure or aversion training

In Experiment 1, 3 mother-child pairs of Japanese monkeys (Macaca fuscata) were given simultaneous choice tests between raisins and popcorn. The mothers and offspring showed different choice patterns. Cofeeding opportunities were then alternated with individual choice tests. In Experiment 2,2 other pairs were added. Each animal was again offered simultaneous choice tests between marshmallows and almonds. Food aversion conditioning was used to create different choice patterns for mothers and offspring. After cofeeding and choice tests, the differences in choice patterns disappeared in both experiments. The changes after contact with the other's eating pattern during cofeeding was as follows: foods consumed by either came to be eaten by both; foods consumed by both continued to be eaten by both; and foods consumed by neither continued to be ignored. The results provide evidence for social transmission of food preferences in this species.     

Auditory-visual intermodal matching of small numerosities in 6-month-old infants

Recent studies have reported that preverbal infants are able to discriminate between numerosities of sets presented within a particular modality. There is still debate, however, over whether they are able to perform intermodal numerosity matching, i.e. to relate numerosities of sets presented with different sensory modalities. The present study investigated auditory-visual intermodal matching of small numerosities in infancy by using a violation-of-expectation paradigm. After being familiarized with events of a few objects impacting a surface successively, 6-month-old infants were alternatively presented with two and three tones while the movement of each object remained hidden behind an opaque screen. The screen was then removed to reveal either two or three objects. Results showed that the infants looked significantly longer at the numerically nonequivalent events (the three-tone/two-object and the two-tone/three-object events) than at the numerically equivalent events (the two-tone/two-object and the three-tone/three-object events) irrespective of the rate or duration of auditory tones presented. These findings suggest that infants are capable of performing intermodal matching of small numerosities and that they might possess abstract representations of numerosity beyond sensory modalities.     

Baby arithmetic: one object plus one tone

Recent studies using a violation-of-expectation task suggest that preverbal infants are capable of recognizing basic arithmetical operations involving visual objects. There is still debate, however, over whether their performance is based on any expectation of the arithmetical operations, or on a general perceptual tendency to prefer visually familiar and complex displays. Here we provide new evidence that 5-month-old infants recognize basic arithmetic operations across sensory modalities. Using a violation-of-expectation task that eliminated the possibility of the familiarity and complexity preference, 5-month-old infants were presented alternatively with two types of arithmetical events: the expected, correct outcomes of operations (1 object+1 tone=2 objects and 1 object+2 tones=3 objects) and the unexpected, incorrect ones (1 object+2 tones=2 objects and 1 object+1 tone=3 objects). Results showed that subjects looked significantly longer at the unexpected events than at the expected events, suggesting that infants are able to recognize basic arithmetic operations across sensory modalities.     

Do the upright eyes have it?

Eye contact is crucial for social communication. A perceived direct gaze facilitates detection, whereas face inversion diminishes this facilitative effect (Senju, Hasegawa, & Tojo, 2005). In the present study, we adopted a visual search paradigm to investigate why a direct gaze facilitates detection in an upright face, but not in an upside-down face. Upright eyes were found to facilitate detection even when other parts of the face were inverted or absent, whereas inverted eyes had no effect on search performance. A critical role for the morphological information of upright eyes, which can be distorted by “eye inversion,” in direct gaze processing is suggested.     

Advantage of dichromats over trichromats in discrimination of color-camouflaged stimuli in humans

This study investigated whether 12 participants with color-vision deficiency had superior visual discrimination of color-camouflaged stimuli shown on a computer screen compared with 12 participants with normal trichromatic vision. Participants were asked to distinguish a circular pattern from other patterns in which textural elements differed from the background in orientation and thickness. In one condition, stimuli were single-colored, green or red; in the other condition, stimuli were color camouflaged with a green and red mosaic overlaid onto the pattern. Color-vision deficient participants selected the correct stimuli in the color-camouflaged condition as quickly as they did in the single-colored condition. However, normal color-vision participants took longer to select the correct choice in the color-camouflaged condition than in the single-colored condition. These results suggest that participants with color-vision deficiency may have a superior visual ability to discriminate the color-camouflaged stimuli.     

Age-Related Changes in Distance From Center of Mass to Center of Pressure During One-Leg Standing

ABSTRACT. The purpose of this study was to clarify the age-related effects of distances from the center of pressure (COP) to the center of mass (COM) (COP-COM distances) during one-leg standing (OLS) task. Healthy old and young adults (n = 11 each) participated in this study. The authors divided the task into 3 phases (accelerated, decelerated, and steady) based on the relationship between COM and COP. COP-COM distances in the older group were significantly reduced during the accelerated phase, then significantly increased during the decelerated and steady phases. Furthermore, distances during these phases correlated inversely with OLS time. The authors conclude that OLS time is shortened by the larger braking response to COM shifts just after leg-lifting, and the production of larger inertial forces to maintain COM position during the OLS in older individuals.     

Is anyone looking at me? Direct gaze detection in children with and without autism

Atypical processing of eye contact is one of the significant characteristics of individuals with autism, but the mechanism underlying atypical direct gaze processing is still unclear. This study used a visual search paradigm to examine whether the facial context would affect direct gaze detection in children with autism. Participants were asked to detect target gazes presented among distracters with different gaze directions. The target gazes were either direct gaze or averted gaze, which were either presented alone (Experiment 1) or within facial context (Experiment 2). As with the typically developing children, the children with autism, were faster and more efficient to detect direct gaze than averted gaze, whether or not the eyes were presented alone or within faces. In addition, face inversion distorted efficient direct gaze detection in typically developing children, but not in children with autism. These results suggest that children with autism use featural information to detect direct gaze, whereas typically developing children use configural information to detect direct gaze.     

Stability and strain of decagonal Al-Ni-Co quasicrystal under high pressure up to 70GPa

The stability of high-quality decagonal Al72Ni20Co8 single quasicrystals has been investigated under high pressure up to 67 GPa by means of an in situ angular-dispersive X-ray powder diffraction method using synchrotron radiation and a diamond anvil cell. It is found that the compression behaviour is almost isotropic. On the other hand, the strain behaviour on compression is found to be fairly anisotropic. This means that the quasiperiodic structure in the decagonal Al72Ni20Co8 quasicrystal is much more easily distorted than is the periodic structure.