Cross-cultural variability of component processes in autobiographical remembering: Japan,Turkey, and the USA

Although the underlying mechanics of autobiographical memory may be identical across cultures, the processing of information differs. Undergraduates from Japan, Turkey, and the USA rated 30 autobiographical memories on 15 phenomenological and cognitive properties. Mean values were similar across cultures, with means from the Japanese sample being lower on most measures but higher on belief in the accuracy of their memories. Correlations within individuals were also similar across cultures, with correlations from the Turkish sample being higher between measures of language and measures of recollection and belief. For all three cultures, in multiple regression analyses, measures of recollection were predicted by visual imagery, auditory imagery, and emotions, whereas measures of belief were predicted by knowledge of the setting. These results show subtle cultural differences in the experience of remembering.     

Dissociating congruence effects in letters versus shapes: Kanji and kana

In order to consolidate the dissociation in feature integration found in earlier studies between letters of the Roman alphabet and corresponding pseudo-letters, the present study used kanji and kana and corresponding pseudo-letters, presented visually, either in isolation or surrounded by congruent or incongruent shape, as targets in a choice-response task with three different response criteria. When the criterion was shape, congruence effects were obtained for both real and pseudo-letters. With the second and third response criteria this result was found for pseudo-letters, but not for letters. These criteria either involved distinguishing between letters and visually similar pseudo-letters or distinguishing between visually similar letters. The dissociation of congruence effects between letters and pseudo-letters was therefore shown to depend on visual similarity between targets, independent of their category. This effect was found to be robust for kanji but not for kana, which is related to distinctions between these two writing systems.     

A Common Force-Sharing Pattern in Joint Action That Consists of Four People

The authors examined the force-sharing patterns in a joint action performed by a group of two, three, or four people compared with a solo action. In the joint actions, 28 participants produced periodic isometric forces such that the sum of forces they produced cycled between 5% and 10% maximum voluntary contraction with the right hand at 1 Hz. In both the three- and four-person tasks, the correlation between forces produced by two of the three or four participants was negative, and the remaining one or two participants produced intermediate forces. The errors of force and interval and force variabilities were smaller in four- and three-people groups than individuals. Four- and three-people groups thus performed better than individuals.     

Conserved evolutionary history for quick detection of threatening faces

Humans quickly recognize threats such as snakes and threatening faces, suggesting that human ancestors evolved specialized visual systems to detect biologically relevant threat stimuli. Although non-human primates also detect snakes quickly, it is unclear whether primates share the efficient visual systems to process the threatening faces of their conspecifics. Primates may not necessarily process conspecific threats by facial expressions, because threats from conspecifics in natural situations are often accompanied by other cues such as threatening actions (or attacks) and vocal calls. Here, we show a similar threat superiority effect in both humans and macaque Japanese monkeys. In visual search tasks, monkeys and humans both responded to pictures of a threatening face of an unfamiliar adult male monkey among neutral faces faster than to pictures of a neutral face among threatening faces. However, the monkeys’ response times to detect deviant pictures of a non-face stimulus were not slower when it was shown among threat faces than when it was shown among neutral faces. These results provide the first evidence that monkeys have an attentional bias toward the threatening faces of conspecifics and suggest that threatening faces are evolutionarily relevant fear stimuli. The subcortical visual systems in primates likely process not only snakes, but also more general biological threat-relevant stimuli, including threatening conspecific faces.     

Interference effects by spatial proximity and age-related declines in spatial memory by Japanese monkeys (Macaca fuscata): deficits in the combined use of multiple spatial cues

Spatial information processing was assessed in 3 young (4-10 years old) and 4 aged (24-25 years old) Japanese monkeys (Macaca fuscata) on 3 delayed nonmatching-to-position (DNMP) tests with relatively short delays of 5 s. Each test had 3 conditions of different horizontal distances between sample and to-be-nonmatched positions. Experiment 1 demonstrated that the performance on the DNMP test in both age groups was impaired when 2 stimulus positions were located next to each other; however, it was fairly accurate when they were located farther apart, suggesting that interference is introduced by spatial proximity. Experiment 2 revealed age-related differences in the situation in which an additional spatial cue, depth information, was available by extending the stimulus array of the DNMP test to a 4 x 2 matrix. In this test, young monkeys performed accurately irrespective of position distance between stimuli, whereas the aged monkeys' performance remained the same as before. Experiment 3 confirmed that the recognition ability in aged monkeys was well preserved on DNMP tests with different objects. These patterns of results indicate that the ability to use information from multiple spatial cues is not accessible to the aged monkeys.     

Looking compensates for the distance between mother and infant chimpanzee

The development of visual interaction between mother and infant has received much attention in developmental psychology, not only in humans, but also in non-human primates. Recently, comparative developmental approaches have investigated whether the mechanisms that underlie these behaviors are common in primates. In the present study, we focused on the question of whether chimpanzee mother and infant replace physical contact with visual contact. To test this hypothesis, we measured non-synchronous looking ('looking') between mother and infant. A unique setting, in which the mother chimpanzee stayed in one location and the infant chimpanzee moved freely, allowed us to analyze the relation between the visual interaction and the distance of a mother-infant pair during the first year of life. Our results showed that 'looking' increased when body contact decreased or when the distance between mother and infant increased. We also show a behavioral sequence of typical 'secure base' behavior, a behavior characterized by the infant regularly returning to its mother when exploring the environment. These findings imply that attachment between mother and infant chimpanzee appears to develop in a similar fashion as in humans.     

“Granny dumping”: Acceptability of sacrificing the elderly in a simulated moral dilemma

In a simulated moral dilemma, most people would be willing to endorse killing a single individual to save five others, but do people show the same degree of resistance to sacrificing people of different ages? In the present study, participants were asked to choose how acceptable it was to sacrifice one individual from a number of different age groups in order to save five others in a trolley problem. The sacrificial targets were a 70‐year‐old male stranger, a 20‐year‐old male stranger, a 5‐year‐old male stranger, or a 20‐year‐old male disabled stranger. Our results indicated that more participants accepted sacrificing the elderly stranger than the other three targets; sacrificing the child was the least accepted option. These results indicate that the decision‐making process in a moral dilemma involves weighing others' lives according to their age and implicitly predicting their life span.     

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     

Bilateral lesions of the insular cortex or of the prefrontal cortex block the association between taste and odor in the rat

The neural basis for the association between taste and odor was investigated in the rat. First, behavioral procedures to study the mechanisms underlying the association between qualitative aspects of the odor and taste in rats were developed. Rats were presented with several pairings of the 0.3 mol/L NaCl solution and a flavor, and pairings of distilled water and another flavor. Then the rats received an IP injection of a furosemide to develop sodium deficiency. On the next day, the rats were presented with either of two types of odor-flavored water: water in which the flavor had been paired with NaCl, or water in which the flavor (grape or coffee) had been paired with distilled water. Normal rats avoided ingesting the water flavored with the odor previously paired with NaCl. Sodium-deprived rats, however, ingested the water flavored with that odor. Rats with lesions in either the insular cortex or in the prefrontal cortex neither preferred nor avoided the water flavored with the odor paired with NaCl. It was concluded that rats acquire association between taste and odor, and that the insular and the prefrontal cortices of the rats were involved in this association.