Human gestures trigger different attentional shifts in chimpanzees (Pan troglodytes) and humans (Homo sapiens)

Brain lateralization has been the matter of extensive research over the last centuries, but it remains an unsolved issue. While hand preferences have been extensively studied, very few studies have investigated laterality of eye use in non-human primates. We examined eye preference in 14 Campbell’s monkeys (Cercopithecus c. campbelli). We assessed eye preference to look at a seed placed inside a tube using monocular vision. Eye use was recorded for 100 independent and non-rewarded trials per individual. All of the 14 monkeys showed very strong preferences in the choice of the eye used to look inside the tube (mean preference: 97.6%). Eight subjects preferred the right eye and six subjects preferred the left eye. The results are discussed in light of previous data on eye preference in primates, and compared to data on hand preference from these subjects. Our findings would support the hypothesis for an early emergence of lateralization for perceptual processes compared to manual motor functions.     

Roots of smile: a preterm neonates' study

Twenty-two preterm neonates were observed 1 h per neonate in the NICU. Ninety-five spontaneous smiles were recorded. Younger and smaller neonates showed more and longer spontaneous smiles than older and larger. The youngest neonate was 200 days from conception on the observational day. She was 511 g. This infant showed spontaneous smiles. The roots of spontaneous smiles are discussed.     

Spontaneous smile and spontaneous laugh: an intensive longitudinal case study

One male infant was observed from the day of his birth to the end of the 6th month. Total observation days were 171 days, and total observation time was 329 h 25 min and 35s. Five hundred and sixty-five spontaneous smiles and 15 spontaneous laughs (smiles accompanied by vocal sounds) were observed. Developmental psychologists have thought that spontaneous smiles integrate at about 3 months, but spontaneous smiles were recorded even in the 6th month. The percentage of bilateral smiles increased from the 2nd month. This is the first intensive longitudinal study on spontaneous smiles and spontaneous laughs.     

Are the windows to the soul the same in the East and West? Cultural differences in using the eyes and mouth as cues to recognize emotions in Japan and the United States

The current research investigated the hypothesis that, depending on an individual’s cultural background, facial cues in different parts of the face are weighted differently when interpreting emotions. Given that the eyes are more difficult to control than the mouth when people express emotions, we predicted that individuals in cultures where emotional subduction is the norm (such as Japan) would focus more strongly on the eyes than the mouth when interpreting others’ emotions. By contrast, we predicted that people in cultures where overt emotional expression is the norm (such as the US) would tend to interpret emotions based on the position of the mouth, because it is the most expressive part of the face. This hypothesis was confirmed in two studies, one using illustrated faces, and one using edited facial expressions from real people, in which emotional expressions in the eyes and mouth were independently manipulated. Implications for our understanding of cross-cultural psychology, as well of the psychology of emotional interpretation, are discussed.     

Cross-cultural differences in relationship- and group-based trust

Two experiments explored differences in depersonalized trust (trust toward a relatively unknown target person) across cultures. Based on a recent theoretical framework that postulates predominantly different bases for group behaviors in Western cultures versus Eastern cultures, it was predicted that Americans would tend to trust people primarily based on whether they shared category memberships; however, trust for Japanese was expected to be based on the likelihood of sharing direct or indirect interpersonal links. Results supported these predictions. In both Study 1 (questionnaire study) and Study 2 (online money allocation game), Americans trusted ingroup members more than outgroup members; however, the existence of a potential indirect relationship link increased trust for outgroup members more for Japanese than for Americans. Implications for understanding group processes across cultures are discussed.     

Study of a cognitive effects model in Dohsa‐hou for the elderly

This study investigates the primary factors responsible for cognitive performance improvements as a result of dohsa‐hou (Japanese body‐oriented psychotherapy) for the elderly. The study divided participants into two homogeneous groups: an experimental group that attempted to improve upright balance by performing dohsa‐hou, and a control group to establish the drop‐off period for the effect of performing the given activities. The task processing time of Stroop Test and body sway and the situational anxiety during task processing of Stroop Tests were measured before and after the dohsa‐hou and drop‐off period. The results confirm that only the experimental group improved in body sway, had a shorter Stroop Color Test processing time and lower situational anxiety. From this study, it has been identified that: (a) information‐processing capacities spared for posture control are affected by distribution of processing resources towards solving other cognitive tasks; and (b) the effect of the release of attention from threat‐related information due to a decrease in attentional bias, which accompanied the decrease in situational anxiety, are primary factors in improving cognitive task performance.     

Differential reliance of chimpanzees and humans on automatic and deliberate control of motor actions

Humans are often unaware of how they control their limb motor movements. People pay attention to their own motor movements only when their usual motor routines encounter errors. Yet little is known about the extent to which voluntary actions rely on automatic control and when automatic control shifts to deliberate control in nonhuman primates. In this study, we demonstrate that chimpanzees and humans showed similar limb motor adjustment in response to feedback error during reaching actions, whereas attentional allocation inferred from gaze behavior differed. We found that humans shifted attention to their own motor kinematics as errors were induced in motor trajectory feedback regardless of whether the errors actually disrupted their reaching their action goals. In contrast, chimpanzees shifted attention to motor execution only when errors actually interfered with their achieving a planned action goal. These results indicate that the species differed in their criteria for shifting from automatic to deliberate control of motor actions. It is widely accepted that sophisticated motor repertoires have evolved in humans. Our results suggest that the deliberate monitoring of one’s own motor kinematics may have evolved in the human lineage.     

Perceptual mechanism underlying gaze guidance in chimpanzees and humans

Previous studies comparing eye movements between humans and their closest relatives, chimpanzees, have revealed similarities and differences between the species in terms of where individuals fixate their gaze during free viewing of a naturalistic scene, including social stimuli (e.g. body and face). However, those results were somewhat confounded by the fact that gaze behavior is influenced by low-level stimulus properties (e.g., color and form) and by high-level processes such as social sensitivity and knowledge about the scene. Given the known perceptual and cognitive similarities between chimpanzees and humans, it is expected that such low-level effects do not play a critical role in explaining the high-level similarities and differences between the species. However, there is no quantitative evidence to support this assumption. To estimate the effect of local stimulus saliency on such eye-movement patterns, this study used a well-established bottom-up saliency model. In addition, to elucidate the cues that the viewers use to guide their gaze, we presented scenes in which we had manipulated various stimulus properties. As expected, the saliency model did not fully predict the fixation patterns actually observed in chimpanzees and humans. In addition, both species used multiple cues to fixate socially significant areas such as the face. There was no evidence suggesting any differences between chimpanzees and humans in their responses to low-level saliency. Therefore, this study found a substantial amount of similarity in the perceptual mechanisms underlying gaze guidance in chimpanzees and humans and thereby offers a foundation for direct comparisons between them.     

Parents Don’t (Always) Know Their Children Have Been Bullied: Child‐Parent Discrepancy on Bullying and Family‐Level Profile of Communication Standards

Discrepancy between bullied victims’ experience and their parents’ understanding indicates underutilization of family support system, and thus presents an important risk factor. An online survey (N = 300 child‐father‐mother triads) was conducted to establish a framework that helps distinguish families with different child‐parent discrepancy levels. This family‐level variability was modeled by profiling child‐father‐mother triad’s family communication standard (FCS) orientations. This “FCS profile” indeed distinguished families with different levels of discrepancies. Further, SEM analyses revealed that those discrepancies presented a distinct risk factor vis‐à‐vis effects of bullying reports per se. Finally, FCS profile had an indirect association with victims’ well‐being via mediation by child‐parent discrepancy. These findings are discussed with regard to the role of family communication in bullied individuals’ coping processes.     

Slowly walking down to the more food: relative quantity discrimination in African spurred tortoises (Centrochelys sulcata)

Animal Cognition - Quantity discrimination, is thought to be highly adaptive as it allows an organism to select greater amounts of food or larger social groups. In contrast to mammals, the...