Effects of element separation on perceptual grouping by humans (Homo sapiens) and chimpanzees (Pan troglodytes): perception of Kanizsa illusory figures

The processing of Kanizsa-square illusory figures was studied in two experiments with four humans and two chimpanzees. Subjects of the two species were initially trained to select a Kanizsa-square illusory figure presented in a computerized two-alternative forced choice task. After training, adding narrow closing segments to the pacman inducers that composed the Kanisza illusory figures lowered performance in both chimpanzees and humans, suggesting that the discrimination could be controlled by the perception of illusory forms. A second experiment assessed transfer of performance with five sets of figures in which the size of the inducers and their separation were manipulated. Only for chimpanzees was performance directly controlled by separation, suggesting that chimpanzees are more sensitive than humans to the separation between visual elements. Accepted after revision: 15 August 2001 Electronic Publication     

Cultural Differences in Visual Search for Geometric Figures

While some studies suggest cultural differences in visual processing, others do not, possibly because the complexity of their tasks draws upon high‐level factors that could obscure such effects. To control for this, we examined cultural differences in visual search for geometric figures, a relatively simple task for which the underlying mechanisms are reasonably well known. We replicated earlier results showing that North Americans had a reliable search asymmetry for line length: Search for long among short lines was faster than vice versa. In contrast, Japanese participants showed no asymmetry. This difference did not appear to be affected by stimulus density. Other kinds of stimuli resulted in other patterns of asymmetry differences, suggesting that these are not due to factors such as analytic/holistic processing but are based instead on the target‐detection process. In particular, our results indicate that at least some cultural differences reflect different ways of processing early‐level features, possibly in response to environmental factors.     

Need for Cognition Promotes Adaptive Style of Self‐Focusing with the Mediation of Effortful Control

Previous studies have indicated that “need for cognition” (NfC), which is the tendency to enjoy effortful cognitive activity, affects various cognitive processes and behaviors. However, the effects of NfC on mental adaptation have not been investigated. According to previous studies, it can be hypothesized that NfC decreases maladaptive self‐focusing, which is called self‐rumination, through increasing effortful control (EC); therefore, we hypothesized that NfC would indirectly inhibit self‐rumination through the mediation of EC. As we expected, the results of a cross‐sectional questionnaire study with 152 undergraduate participants indicated a negative indirect association between NfC and self‐rumination through the mediation of EC. Secondarily, the present results revealed a direct positive association between NfC and adaptive type of self‐focusing, which is called self‐reflection. The present study is the first to propose the possible contribution of NfC to mental health through decreasing self‐rumination and increasing self‐reflection.     

Is perceived emotional support beneficial? Well-being and health in independent and interdependent cultures

Previous studies show there is little or no association between perceived emotional support and well-being in European American culture. The authors hypothesized that this paradoxical absence of any benefit of perceived support is unique to cultural contexts that privilege independence rather than interdependence of the self. Study 1 tested college students and found, as predicted, that among Euro-Americans a positive effect of perceived emotional support on subjective well-being (positive affect) was weak and, moreover, it disappeared entirely once self-esteem was statistically controlled. In contrast, among Asians in Asia (Japanese and Filipinos) perceived emotional support positively predicted subjective well-being even after self-esteem was controlled. Study 2 extended Study 1 by testing both Japanese and American adults in midlife with respect to multiple indicators of well-being and physical health. Overall, the evidence underscores the central significance of culture as a moderator of the effectiveness of perceived emotional support.     

Stream/bounce perception and the effect of depth cues in chimpanzees (Pan troglodytes)

The stream/bounce display represents an ambiguous motion event in which two identical visual objects move toward one another and the objects overlap completely before they pass each another. In our perception, they can be interpreted as either streaming past one another or bouncing off each other. Previous studies have shown that the streaming percept of the display is generic for humans, suggesting the inertial nature of the motion integration process. In this study, chimpanzees took part in behavioral experiments using an object-tracking task to reveal the characteristics of their stream/bounce perception. Chimpanzees did not show a tendency toward a dominant "stream" perception of the stream/bounce stimulus. However, depth cues, such as X-junctions and local motion coherence, did promote the stream percept in chimpanzees. These results suggest both similarities and differences between chimpanzees and humans with respect to motion integration and object individuation processes.     

Origins of a theory of mind

Twenty-two pairs of typically developing toddlers (M = 24.32 months) and their mothers were observed in a play-room solving puzzles during 30 min. The target of the observations was hand-taking gesture. Researchers have thought that this gesture is rare among typically developing children and is more frequent among autistic children. Ten in 22 children showed this gesture in only 30 min. They should know “I can not do it by myself, but my mother can do it.” When we can assume that children know others’ mental mechanism, it might be the origins of a theory of mind.     

Consistent air flow to the face facilitates vection

We examined whether a somatosensory cue suggesting forward self-motion facilitated vection. We provided a consistent air flow to subjects' faces by using an electric fan.Vection strength was increased when the air flow was provided.     

An infant chimpanzee (Pan troglodytes) follows human gaze

The ability of non-human primates to follow the gaze of other individuals has recently received much attention in comparative cognition. The aim of the present study was to investigate the emergence of this ability in a chimpanzee infant. The infant was trained to look at one of two objects, which an experimenter indicated by one of four different cue conditions: (1) tapping on the target object with a finger; (2) pointing to the target object with a finger; (3) gazing at the target object with head orientation; or (4) glancing at the target object without head orientation. The subject was given food rewards independently of its responses under the first three conditions, so that its responses to the objects were not influenced by the rewards. The glancing condition was tested occasionally, without any reinforcement. By the age of 13 months, the subject showed reliable following responses to the object that was indicated by the various cues, including glancing alone. Furthermore, additional tests clearly showed that the subject's performance was controlled by the "social" properties of the experimenter-given cues but not by the non-social, local-enhancing peripheral properties. Electronic Publication