Orienting-reflex behavior and clinical psychopathology

The effects of diagnosis, sex, age and medication on the orienting-reflex behavior of 263 psychiatric patients and 58 normal subjects were studied. Significant differences between the normal and patient groups and within the patient groups in different diagnostic categories were found. In the patient populations, further variations by types of medication received were found, whereas sex and age did not affect the orienting reflex. On the basis of frequency of response only normal subjects and patients could be distinguished, whereas amplitude analysis revealed a continuum in which the highest responses were given by normal subjects and the lowest by patients with chronic organic brain damage. In all subgroups the amplitudes of the responses of patients receiving antidepressant medication were higher than those of patients receiving antipsychotic medication.     

Taï chimpanzees anticipate revisiting high-valued fruit trees from further distances

The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Taï National Park, Côte d’Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females’ approach distance was measured from their last significant change in travel direction until the moment they entered the tree’s maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the possibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees.     

Taï chimpanzees use botanical skills to discover fruit: what we can learn from their mistakes

Fruit foragers are known to use spatial memory to relocate fruit, yet it is unclear how they manage to find fruit in the first place. In this study, we investigated whether chimpanzees (Pan troglodytes verus) in the Taï National Park make use of fruiting synchrony, the simultaneous emergence of fruit in trees of the same species, which can be used together with sensory cues, such as sight and smell, to discover fruit. We conducted observations of inspections, the visual checking of fruit availability in trees, and focused our analyses on inspections of empty trees, so to say “mistakes”. Learning from their “mistakes”, we found that chimpanzees had expectations of finding fruit days before feeding on it and significantly increased inspection activity after tasting the first fruit. Neither the duration of feeding nor density of fruit-bearing trees in the territory could account for the variation in inspection activity, which suggests chimpanzees did not simply develop a taste for specific fruit on which they had fed frequently. Instead, inspection activity was predicted by a botanical feature—the level of synchrony in fruit production of encountered trees. We conclude that chimpanzees make use of the synchronous emergence of rainforest fruits during daily foraging and base their expectations of finding fruit on a combination of botanical knowledge founded on the success rates of fruit discovery, and a categorization of fruit species. Our results provide new insights into the variety of food-finding strategies employed by primates and the adaptive value of categorization capacities.     

The Japanese Multidimensional Attitudes Scale Toward Persons With Autism Spectrum Disorders1

This study aimed to develop a Japanese Multidimensional Attitudes Scale (J-MAS) as a useful instrument to assess negative attitudes toward persons with autism spectrum disorder among typical Japanese persons. Five hundred and fifty-two Japanese participants completed the Japanese translation of the original version of the MAS, which was derived via the translation/back-translation method. An exploratory factor analysis revealed four factors (Cognitions, Negative Affects, Behaviors, and Calm) that corresponded to the factor model of the original version of the MAS. Nine items were statistically negligible, accordingly. A confirmatory factor analysis revealed that the factor model of the J-MAS is fairly good, and preferable to the factor models of the English, Spanish, French, Korean, and German versions for a sample of typical Japanese persons. These results indicate that the J-MAS provides a valid assessment of attitudes toward persons with autism spectrum disorder among typical Japanese persons.