Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by social and comm... more Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by social and communication impairments and restricted and repetitive behavior. Although there is currently no established cure for ASD, early interventions for deficits of attention to other individuals are expected to reduce the progression of ASD symptoms in later life. To confirm this hypothesis and improve early therapeutic interventions, it is desirable to develop an animal model of ASD in which social attention is impaired in childhood and ASD-like social behavior is observed in adulthood. However, rodent models of ASD have difficulty in recapitulating the deficit of gaze-based social attention. In this study, we examined the direction of gaze toward other conspecifics during childhood and puberty in a three-chamber test setting using an ASD marmoset model produced by maternal exposure to valproic acid (VPA). We also conducted a reversal learning test in adult VPA-exposed marmosets as an indicator ...
Individuals with autism spectrum disorder (ASD) are exposed to a variety of stressors owing to th... more Individuals with autism spectrum disorder (ASD) are exposed to a variety of stressors owing to their behavioral traits. Cortisol is a hormone typically associated with stress, and its concentration and response to stress are higher in individuals with ASD than in controls. The mechanisms underlying cortisol dysregulation in ASD have been explored in rodents. Although rodent models have successfully replicated the major symptoms of autism (i.e., impaired vocal communication, social interaction deficits, and restricted/repetitive patterns of behavior), evidence suggests that the hypothalamic-pituitary-adrenal (HPA) axis system differs between rodents and primates. We developed an ASD model in the common marmoset (Callithrix jacchus), a New World monkey, utilizing prenatal exposure to valproic acid (VPA). In this study, we collected the salivary cortisol levels in VPA-exposed and unexposed marmosets in the morning and afternoon. Our results revealed that both VPA-exposed and unexposed ...
Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability t... more Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability to detect pictures of snakes more quickly than those of other animals. These findings are consistent with the Snake Detection Theory, which hypothesizes that as predators, snakes were a major source of evolutionary selection that favored expansion of the visual system of primates for rapid snake detection. Many snakes use camouflage to conceal themselves from both prey and their own predators, making it very challenging to detect them. If snakes have acted as a selective pressure on primate visual systems, they should be more easily detected than other animals under difficult visual conditions. Here we tested whether humans discerned images of snakes more accurately than those of non-threatening animals (e.g., birds, cats, or fish) under conditions of less perceptual information by presenting a series of degraded images with the Random Image Structure Evolution technique (interpolation of...
Humans quickly detect the presence of evolutionary threats through visual perception. Many theori... more Humans quickly detect the presence of evolutionary threats through visual perception. Many theorists have considered humans to be predisposed to respond to both snakes and spiders as evolutionarily fear-relevant stimuli. Evidence supports that human adults, children, and snake-naive monkeys all detect pictures of snakes among pictures of flowers more quickly than vice versa, but recent neurophysiological and behavioral studies suggest that spiders may, in fact, be processed similarly to nonthreat animals. The evidence of quick detection and rapid fear learning by primates is limited to snakes, and no such evidence exists for spiders, suggesting qualitative differences between fear of snakes and fear of spiders. Here, we show that snake-naive Japanese monkeys detect a single snake picture among 8 nonthreat animal pictures (koala) more quickly than vice versa; however, no such difference in detection was observed between spiders and pleasant animals. These robust differences between snakes and spiders are the most convincing evidence that the primate visual system is predisposed to pay attention to snakes but not spiders. These findings suggest that attentional bias toward snakes has an evolutionary basis but that bias toward spiders is more due to top-down, conceptually driven effects of emotion on attention capture.
Many non-human primates have been observed to reciprocate and to understand reciprocity in one-to... more Many non-human primates have been observed to reciprocate and to understand reciprocity in one-to-one social exchanges. A recent study demonstrated that capuchin monkeys are sensitive to both third-party reciprocity and violation of reciprocity; however, whether this sensitivity is a function of general intelligence, evidenced by their larger brain size relative to other primates, remains unclear. We hypothesized that highly pro-social primates, even with a relatively smaller brain, would be sensitive to others' reciprocity. Here, we show that common marmosets discriminated between human actors who reciprocated in social exchanges with others and those who did not. Monkeys accepted rewards less frequently from non-reciprocators than they did from reciprocators when the non-reciprocators had retained all food items, but they accepted rewards from both actors equally when they had observed reciprocal exchange between the actors. These results suggest that mechanisms to detect unfa...
It is well known that adult humans detect snakes as targets more quickly than flowers as the targ... more It is well known that adult humans detect snakes as targets more quickly than flowers as the targets and that how rapidly they detect a snake picture does not differ whether the images are in color or gray-scale, whereas they find a flower picture more rapidly when the images are in color than when the images are gray-scale. In the present study, a total of 111 children were presented with 3-by-3 matrices of images of snakes and flowers in either color or gray-scale displays. Unlike the adults reported on previously, the present participants responded to the target faster when it was in color than when it was gray-scale, whether the target was a snake or a flower, regardless of their age. When detecting snakes, human children appear to selectively attend to their color, which would contribute to the detection being more rapidly at the expense of its precision.
4th IEEE/RAS International Conference on Humanoid Robots, 2004.
We describe how normal and autistic children interacted with a humanoid, Infanoid, focusing espec... more We describe how normal and autistic children interacted with a humanoid, Infanoid, focusing especially on the effect of the robot's attentiveness and emotiveness on the children's understanding of what the robot can do and how to interact with it. Infanoid is an upper-torso humanoid robot, which is capable of attentional and emotional interaction with humans through gaze, voice, facial expressions, and bodily/manual gestures. We observed 14 normal children (ranging from 6 months old to 9 years old) and one autistic child (6 years old) interact with Infanoid. Each of the children sat in front of Infanoid with his/her caregiver and gradually got into the loop of interaction, where he/she spontaneously played with the robot, gradually deepening the level of interaction, in a playful mood. We assume the relatively high predictability of Infanoid's behavior enabled the autistic child, as well as the normal children, to get into the relaxed interaction with the robot, from which the children explore higher communicability of the robot. This study suggests potential applicability of humanoids to remedial services as well as psychological investigation of social interaction.
柴崎全弘 2, 3 川合伸幸 名古屋大学 The e亜 ects of response cost and time on choosing a stimulus Masahiro Shibas... more 柴崎全弘 2, 3 川合伸幸 名古屋大学 The e亜 ects of response cost and time on choosing a stimulus Masahiro Shibasaki and Nobuyuki Kawai Nagoya University We investigated how people develop preferences for stimuli, as a function of di唖 erent levels of response cost. In Experiment 1, participants learned to discriminate between stimuli that followed high-cost versus low-cost responses. Contrary to previous studies of pigeons, participants chose the stimulus that appeared after a single response. In Experiment 2, three kinds of discriminations low-cost, high-cost, and delay conditions followed a single response, 20 responses or a ve-s delay period, in order to examine how temporal factors a唖 ect choice. Participants with fast reaction times chose the stimuli in the low-cost condition, over those in the high-cost and delay conditions. Participants with slow reaction times chose the stimuli in the high-cost condition over those in the low-cost condition. These results suggest that temporal factors may become critical when choosing a stimulus that is presented after the response. These results are discussed in terms of the di唖 erence between expected and actual values of the reward, which determined stimulus preference either by virtue of contrast or assimilation.
Although studies have emphasized the multiple components of anger, little is known about the phys... more Although studies have emphasized the multiple components of anger, little is known about the physiological and psychological mechanisms of the approach motivational component and the negative emotional component of anger. In the present study, participants wrote brief opinions about social problems (e.g., tuition hikes) and received a handwritten, insulting comment about their composition from the experimenter. Half of the participants (apology group) received a simple apologetic sentence at the end of the insulting comment. Half of the participants (no apology group) did not receive one. The physiological responses of the participants were recorded prior to, and after they read the comments. Increases in heart rate and asymmetric frontal brain activity were suppressed only in the apology group. Both groups showed an increase in skin conductance response. Our psychological scales showed that the apology suppressed self reported state anger from an approach-motivational standpoint but not from a negative emotional standpoint. The results suggest that anger is not a unitary process but has multiple components. The apology did provide a different physiological profile but did not dampen down the subjective experience of anger. Thus, providing an apology may not always be effective for alleviating the experience of anger to an insult.
Humans as well as some nonhuman primates have an evolved predisposition to associate snakes with ... more Humans as well as some nonhuman primates have an evolved predisposition to associate snakes with fear by detecting their presence as fear-relevant stimuli more rapidly than fear-irrelevant ones. In the present experiment, a total of 74 of 3-to 4-year-old children and adults were asked to find a single target black-and-white photo of a snake among an array of eight black-and-white photos of flowers as distracters. As target stimuli, we prepared two groups of snake photos, one in which a typical striking posture was displayed by a snake and the other in which a resting snake was shown. When reaction time to find the snake photo was compared between these two types of the stimuli, its mean value was found to be significantly smaller for the photos of snakes displaying striking posture than for the photos of resting snakes in both the adults and children. These findings suggest the possibility that the human perceptual bias for snakes per se could be differentiated according to the difference of the degree to which their presence acts as a fear-relevant stimulus.
Background: A Noh mask worn by expert actors when performing on a Japanese traditional Noh drama ... more Background: A Noh mask worn by expert actors when performing on a Japanese traditional Noh drama is suggested to convey countless different facial expressions according to different angles of head/body orientation. The present study addressed the question of how different facial parts of a Noh mask, including the eyebrows, the eyes, and the mouth, may contribute to different emotional expressions. Both experimental situations of active creation and passive recognition of emotional facial expressions were introduced. Methodology/Principal Findings: In Experiment 1, participants either created happy or sad facial expressions, or imitated a face that looked up or down, by actively changing each facial part of a Noh mask image presented on a computer screen. For an upward tilted mask, the eyebrows and the mouth shared common features with sad expressions, whereas the eyes with happy expressions. This contingency tended to be reversed for a downward tilted mask. Experiment 2 further examined which facial parts of a Noh mask are crucial in determining emotional expressions. Participants were exposed to the synthesized Noh mask images with different facial parts expressing different emotions. Results clearly revealed that participants primarily used the shape of the mouth in judging emotions. The facial images having the mouth of an upward/ downward tilted Noh mask strongly tended to be evaluated as sad/happy, respectively. Conclusions/Significance: The results suggest that Noh masks express chimeric emotional patterns, with different facial parts conveying different emotions This appears consistent with the principles of Noh which highly appreciate subtle and composite emotional expressions, as well as with the mysterious facial expressions observed in Western art. It was further demonstrated that the mouth serves as a diagnostic feature in characterizing the emotional expressions. This indicates the superiority of biologically-driven factors over the traditionally formulated performing styles when evaluating the emotions of the Noh masks.
Background: A Noh mask, worn by expert actors during performance on the Japanese traditional Noh ... more Background: A Noh mask, worn by expert actors during performance on the Japanese traditional Noh drama, conveys various emotional expressions despite its fixed physical properties. How does the mask change its expressions? Shadows change subtly during the actual Noh drama, which plays a key role in creating elusive artistic enchantment. We here describe evidence from two experiments regarding how attached shadows of the Noh masks influence the observers' recognition of the emotional expressions. Methodology/Principal Findings: In Experiment 1, neutral-faced Noh masks having the attached shadows of the happy/sad masks were recognized as bearing happy/sad expressions, respectively. This was true for all four types of masks each of which represented a character differing in sex and age, even though the original characteristics of the masks also greatly influenced the evaluation of emotions. Experiment 2 further revealed that frontal Noh mask images having shadows of upward/downward tilted masks were evaluated as sad/happy, respectively. This was consistent with outcomes from preceding studies using actually tilted Noh mask images. Conclusions/Significance: Results from the two experiments concur that purely manipulating attached shadows of the different types of Noh masks significantly alters the emotion recognition. These findings go in line with the mysterious facial expressions observed in Western paintings, such as the elusive qualities of Mona Lisa's smile. They also agree with the aesthetic principle of Japanese traditional art ''yugen (profound grace and subtlety)'', which highly appreciates subtle emotional expressions in the darkness.
The development of visual interaction between mother and infant has received much attention in de... more 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 motherinfant 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.
We investigated chimpanzees' color classification using a matching-to-sample procedure. One of th... more We investigated chimpanzees' color classification using a matching-to-sample procedure. One of the two subjects had learned symbolic color names through long-term training, while the other had received less training and had a limited understanding of color names. The results showed similar distributions of classified colors in a color space, irrespective of the subjects' differential color-naming experience. However, the chimpanzee with little color-naming experience showed less stable classifications. These results suggest common features of color classification in chimpanzees, as well as the influence of color experience and/or the learning of color names on the stability of classification of colors.
One of our recent studies has revealed that a numerically trained chimpanzee can memorize a corre... more One of our recent studies has revealed that a numerically trained chimpanzee can memorize a correct sequence of five numbers shown on a monitor. Comparative investigations with humans show very similar patterns of errors in the two species, suggesting humans and chimpanzee share homologous memory processes. Whether or not 5 is a pure capacity limit for the chimpanzee remains an empirical question.
A. Ueno, and the other members of the Language and Intelligence Section for their support of the ... more A. Ueno, and the other members of the Language and Intelligence Section for their support of the research project. Especially we thank N.
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Papers by Nobuyuki Kawai