Role of spatial and temporal coincidence in depth organization

The linking of spatial information is essential for coherent space perception. A study is reported of the contribution of temporal and spatial alignment for the linkage of spatial elements in terms of depth perception. Stereo half-images were generated on the left and right halves of a large-screen video monitor and viewed through a mirror stereoscope. The half-images portrayed a black vertically oriented bar with two brackets immediately flanking this bar and placed in crossed or uncrossed disparity relative to the bar. A pair of thin white 'bridging lines' could appear on the black bar, always at zero disparity. Brackets and bridging lines could be flickered either in phase or out of phase. Observers judged whether the brackets appeared in front of or behind the black bar, with disparity varied. Compared to conditions when the bridging lines were absent, depth judgments were markedly biased toward "in front" when bridging lines and brackets flashed in temporal phase; this bias was much reduced when the bridging lines and brackets flashed out of phase. This biasing effect also depended on spatial offset of lines and brackets. However, perception was uninfluenced by the lateral separation between object and brackets.     

Mothers' adjustment to the birth of a second child: a longitudinal study on use of verbal and nonverbal behaviors toward two children

4 mothers' skillful use of verbal and nonverbal behaviors to their first and second children was examined while each mother was playing with them for about one year after the birth of the second child. Analysis showed that maternal verbal interactions with the firstborn were frequently accompanied by nonverbal interactions toward the secondborn, especially during the first few months postpartum. The concurrent use of verbal and nonverbal behaviors with the two children may be a behavioral strategy for the mother to adjust to the birth of the second child.     

Visually guided facial actions in rhesus monkeys

We trained 2 monkeys to display facial actions in response to corresponding arbitrary visual cues. Each monkey executed the task successfully, and each displayed two different facial actions corresponding to either hand-sign or color cues. More than 90% of the responses were correct for each monkey. These results provide evidence that monkeys can execute facial actions in response to conditioned visual cues in the absence of social context. These data suggest that facial actions of monkeys are flexible enough for use in further laboratory investigations—for example, in studies on the neural mechanisms underlying the execution of actions.     

Acquisition of auditory–visual intermodal matching-to-sample by a chimpanzee (Pan troglodytes): comparison with visual–visual intramodal matching

A chimpanzee acquired an auditory–visual intermodal matching-to-sample (AVMTS) task, in which, following the presentation of a sample sound, the subject had to select from two alternatives a photograph that corresponded to the sample. The acquired AVMTS performance might shed light on chimpanzee intermodal cognition, which is one of the least understood aspects in chimpanzee cognition. The first aim of this paper was to describe the training process of the task. The second aim was to describe through a series of experiments the features of the chimpanzee AVMTS performance in comparison with results obtained in a visual intramodal matching task, in which a visual stimulus alone served as the sample. The results show that the acquisition of AVMTS was facilitated by the alternation of auditory presentation and audio-visual presentation (i.e., the sample sound together with a visual presentation of the object producing the particular sample sound). Once AVMTS performance was established for the limited number of stimulus sets, the subject showed rapid transfer of the performance to novel sets. However, the subject showed a steep decay of matching performance as a function of the delay interval between the sample and the choice alternative presentations when the sound alone, but not the visual stimulus alone, served as the sample. This might suggest a cognitive limitation for the chimpanzee in auditory-related tasks. Accepted after revision: 11 September 2001 Electronic Publication     

Relationship between types of humour and stress response and well‐being among children in Japan

This study examined the relationship between three types of children's humour (aggressive, self‐defeating, and playful) and the children's stress response and well‐being in the Japanese context, where a collectivistic culture is prevalent. To do so, 500 study participants (250 elementary and 250 junior high school students) were recruited. The participants reported the types of humour, stress responses, and level of well‐being that they experienced. After correlation analysis, aggressive humour and playful humour showed a positive correlation with stress responses; in addition, aggressive humour showed a negative correlation with well‐being. Self‐defeating humour showed a negative correlation with stress responses and a positive correlation with well‐being. We also conducted a cluster analysis using the scores for the three types of humour, analysing four groups: “aggressive humourists” (respondents who demonstrated above‐average aggressive humour and scored average for all other humours), “nonhumourists” (below‐average humour in all areas), “self‐deprecating humourists” (above‐average self‐defeating humour, below‐average aggressive humour, and average playful humour), and “multiple humourists” (above‐average humour in all areas). Upon comparing the results of stress responses and well‐being scores among the four groups, we found that self‐deprecating humourists reported the highest level of well‐being. These results show that in collectivistic cultures, self‐defeating humour may be adaptive.     

Short-term memory in the rhesus monkey: A behavioral analysis of delayed-response performance

This study obtained quantitative data on the bodily orientations of rhesus monkeys in a delayed-response task and determined whether such orientations mediate the correct response in a choice trial. The basic task was a two-key chain schedule with the key leading to food signaled in the initial component. During the subsequent delay interval, the signal was removed, but it was necessary that one of the keys be pressed to advance the schedule to the terminal choice component. The position of the key pressed thus indicated orientation during the delay interval. When the monkeys had free access to the left and right keys, they tended to press the key leading to food throughout the chain schedule components and received food on more than 85% of the trials, even when the delay was extended to 20 seconds. However, when orientation toward the food key was disrupted by forcing the monkeys to press an extraneous center key during the delay, choice performance deteriorated. Requiring the center key presses early, rather than late, in the delay component had a strong disruptive effect. The relation of the results to the mediating coding-response hypothesis is discussed.     

Matching vocalizations to vocalizing faces in a chimpanzee (<Emphasis Type="Italic">Pan troglodytes</Emphasis>)

Auditory–visual processing of species-specific vocalizations was investigated in a female chimpanzee named Pan. The basic task was auditory–visual matching-to-sample, where Pan was required to choose the vocalizer from two test movies in response to a chimpanzees vocalization. In experiment 1, movies of vocalizing and silent faces were paired as the test movies. The results revealed that Pan recognized the status of other chimpanzees whether they vocalized or not. In experiment 2, two different types of vocalizing faces of an identical individual were prepared as the test movies. Pan recognized the correspondence between vocalization types and faces. These results suggested that chimpanzees possess crossmodal representations of their vocalizations, as do humans. Together with the ability of vocal individual recognition, this ability might reflect chimpanzees profound understanding of the status of other individuals.