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.

Grooming-at-a-distance by exchanging calls in non-human primates.

The 'social bonding hypothesis' predicts that, in large social groups, functions of gestural grooming should be partially transferred to vocal interactions. Hence, vocal exchanges would have evolved in primates to play the role of grooming-at-a-distance in order to facilitate the maintenance of social cohesion. However, there are few empirical studies testing this hypothesis. To address this point, we compared the rate of contact call exchanges between females in two captive groups of Japanese macaques as a function of female age, dominance rank, genetic relatedness and social affinity measured by spatial proximity and grooming interactions. We found a significant positive relationship between the time spent on grooming by two females and the frequency with which they exchanged calls. Our results conform to the predictions of the social bonding hypothesis, i.e. vocal exchanges can be interpreted as grooming-at-a-distance.

Is cannabidiol (CBD) effective to ease separation anxiety?

CBD is the primary noneuphorizing and nonaddictive compound of cannabis. It has recently been shown to possess considerable therapeutic potential for treating a wide range of neuropsychiatric disorders in humans, such as anxiety. In addition to humans, domestic cats are provided with such endocannabinoid system with which CBD interacts almost in the same manner researchers think it does in humans. However, little has been known about the clinical implications of CBD in the animals. Here the effects of CBD administration upon separation anxiety were evaluated in ten healthy cats. The animals experienced brief separation from their caregivers twice, once following the administration of CBD 4.0 mg/kg/day over a 2-week-period and once following the administration of sunflower oil alone as placebo. Upon the caregiver's return from a brief absence, response of the animal can be categorized into these three categories: reduced stress one with contact-exploration balance with the caregiver (the Secure Base Effect), remaining stressful and keeping proximity excessively, and avoidance behavior or approach/avoidance conflict (disorganized behavior). When receiving placebo administration, the cats spent more time in physical contact with the caregiver or, in avoidant behavior than when receiving CBD administration whereas they spent more time in proximity to the caregiver when receiving CBD administration than when receiving placebo (ps < 0.01). With the brief separation from their caregivers, the cats became distressed, and signs of such distress was more evident after the placebo administration whereas the Secure Base Effect was more distinct in the results of SBT when receiving CBD administration than when receiving placebo. The results suggest anxiety-reducing effects of CBD in cats.

Possible effects of cannabidiol (CBD) administration on the vocal activity of healthy domestic dogs upon their temporary separation from caregivers.

Recent human clinical studies indicate that cannabidiol (CBD), the primary non-addictive component of cannabis, possesses considerable therapeutic potentials. The purpose of the present study was to explore the possibility of effects of CBD administration on behaviors of healthy domestic dogs. It is well-known that when temporarily separated from their caregivers, they may show an increase in vocalization. Here the effects of CBD administration upon such vocal activity were assessed. Ten 4- to 7-year-old healthy dogs experienced temporary separation from their caregivers twice, once following the administration of CBD at 2.0 mg/kg/day over a 2-week-period, and once following the administration of the same amount of olive oil as placebo over the same length of period. When the behavioral assessment was conducted by computing the total duration of any vocal activity exhibited by the dogs before the separation from their caregivers and after the separation, it was found that all of the 10 participant dogs vocalized more often when being left alone (after the separation) than when being with their caregivers (before the separation), whether they had received the administration of CBD or placebo. Following the CBD administration, however, the degree of such increase was significantly less robust than that following the placebo administration (p < 0.01). As one of the possible explanations for the results. the author hypothesizes anxiolytic effects of CBD in healthy domestic dogs, as has been reported in humans.

[Man meets snake].

The author reviews recent findings of a series of experimental studies on snake detection in visual search which he himself has undertaken. It reveals that this method is quite useful as an experimental paradigm to investigate anxiety levels of humans whether they are adults or children.

Soprano singing in gibbons.

Diversifications in primate vocalization, including human speech, are believed to reflect evolutionary modifications in vocal anatomy and physiology. Gibbon song is acoustically unique, comprising loud, melodious, penetrating pure tone-like calls. In a white-handed gibbon, Hylobates lar, the fundamental frequency (f(0) ) of song sounds is amplified distinctively from the higher harmonics in normal air. In a helium-enriched atmosphere, f(0) does not shift, but it is significantly suppressed and 2f(0) is emphasized. This implies that the source is independent of the resonance filter of the supralaryngeal vocal tract (SVT) in gibbons, in contrast to musical wind instruments, in which the filter primarily determines f(0) . Acoustic simulation further supported that gibbons' singing is produced analogously to professional human soprano singing, in which a precise tuning of the first formant (F(1) ) of the SVT to f(0) amplifies exclusively the f(0) component of the source. Thus, in gibbons, as in humans, dynamic control over the vocal tract configuration, rather than anatomical modifications, has been a dominant factor in determining call structure. The varied dynamic movements were adopted in response to unique social and ecological pressures in gibbons, allowing monogamous gibbons to produce pure-tonal melodious songs in the dense tropical forests with poor visibility.

The origins of language and the evolution of music: A comparative perspective.

According to Darwin [Darwin, CR. The descent of man, and selection in relation to sex. London: John Murray; 1871], the human musical faculty 'must be ranked amongst the most mysterious with which he is endowed'. Music is a human cultural universal that serves no obvious adaptive purpose, making its evolution a puzzle for evolutionary biologists. This review examines Darwin's hypothesis of similarities between language and music indicating a shared evolutionary history. In particular, the fact that both are human universals, have phrase structure, and entail learning and cultural transmission, suggests that any theory of the evolution of language will have implications for the evolution of music, and vice versa. The argument starts by describing variable predispositional musical capabilities and the ontogeny of prosodic communication in human infants and young children, presenting comparative data regarding communication systems commonly present in living nonhuman primate species. Like language, the human music faculty is based on a suite of abilities, some of which are shared with other primates and some of which appear to be uniquely human. Each of these subcomponents may have a different evolutionary history, and should be discussed separately. After briefly considering possible functions of human music for language acquisition, the review ends by discussing the phylogenetic history of music. It concludes that many strands of evidence support Darwin's hypothesis of an intermediate stage of human evolutionary history, characterized by a communication system that resembled music more closely than language, but was identical to neither. This pre-linguistic system, which could probably referred to as "prosodic protolanguage", provided a precursor for both modern language and music.

Anxiolytic Effects of Repeated Cannabidiol Treatment in Teenagers With Social Anxiety Disorders.

Accumulated evidence indicates that cannabidiol (CBD), a nonpsychotomimetic and nonaddictive main component of the Cannabis sativa plant, reverses anxiety-like behavior. The purpose of the present study was to assess the efficacy of CBD treatment for Japanese late teenagers with social anxiety disorder (SAD). Thirty-seven 18-19-year-old Japanese teenagers with SAD and avoidant personality disorder received, in a double-blind study, cannabis oil (n = 17) containing 300 mg CBD or placebo (n = 20) daily for 4 weeks. SAD symptoms were measured at the beginning and end of the treatment period using the Fear of Negative Evaluation Questionnaire and the Liebowitz Social Anxiety Scale. CBD significantly decreased anxiety measured by both scales. The results indicate that CBD could be a useful option to treat social anxiety.

Electrophysiological correlates of the processing of different self-aspects of handwritten names.

Humans recognize the self in various visual domains, such as faces, names, and motions, as well as in products, such as handwritten letters. Previous studies have indicated that these various domains of self are represented differently in the brain, i.e., domain-specific self-representation. However, it remains unclear whether these differences in brain activation are due to the processing of different visual features or to differential self-processing among the domains, because the studies used different types of visual stimuli. The present study evaluated event-related potentials (ERPs) while participants were presented with their own and others' names generated by the participants themselves or someone else. Therefore, the visual stimuli included two domains of self-related information, name and motor agent, but only one type of stimulus (handwritten names). The ERP results show that the amplitudes of the P250 component (250-330 ms) in the posterior regions were smaller for self-generated handwritten names than for non-self-generated handwritten names. The results also show that the amplitudes of the P300 component (350-500 ms) were larger for the self-name than for the non-self-name. These results suggest domain-specific processing of self-related information regarding the name and agent of handwritten stimuli.

Enhanced cognitive processing by viewing snakes in children with autism spectrum disorder. A preliminary study.

BACKGROUND: Prioritization of the processing of threatening stimuli induces deleterious effects on task performance. However, emotion evoked by viewing images of snakes exerts a facilitating effect upon making judgments of their color in neurotypical adults and schoolchildren. We attempted to confirm this in school and preschool children with and without Autism Spectrum Disorder (ASD). METHODS: Forty French children participated and corresponded to two age groups: a group of schoolchildren and a group of preschool children, each group including 10 children with typical development and 10 children with ASD. Each participant was exposed to 120 trials composed of 20 photographs of snakes and 20 photographs of flowers, each of which appeared 3 times (in red, green and blue). Participants were asked to indicate the color of each image as quickly as possible via key-press. A three-way analysis of variance test for reaction time (RT) considering image type (IMAGE), participant group (PARTICIPANT), and age (AGE) as main effects and its interaction terms was performed for each subject. RESULTS: When the reaction time required to respond to presented stimuli was measured, schoolchildren tended to respond faster when stimuli were snake images than when stimuli were flower images whether the children had or did not have ASD. For the 5-to-6-year-old preschool participants, the difference between reaction time for the color-naming of snake images and flower images was ambiguous overall. CONCLUSIONS: There were possible odd color-specific effects in children with ASD when images were presented to the children in green. Implications of the findings are argued with respect to active avoidance or attraction as one of the behavioral characteristics commonly noted in children with ASD.

Traffic symbol recognition modulates bodily actions.

Traffic signals, i.e., iconic symbols conveying traffic rules, generally represent spatial or movement meanings, e.g., "Stop", "Go", "Bend warning", or "No entry", and we visually perceive these symbols and produce appropriate bodily actions. The traffic signals are clearly thought to assist in producing bodily actions such as going forward or stopping, and the combination of symbolic recognition through visual perception and production of bodily actions could be one example of embodied cognition. However, to what extent our bodily actions are associated with the symbolic representations of commonly used traffic signals remains unknown. Here we experimentally investigated how traffic symbol recognition cognitively affects bodily action patterns, by employing a simple stimulus-response task for traffic sign recognition with a response of either sliding or pushing down on a joystick in a gamepad. We found that when operating the joystick, participants' slide reaction in response to the "Go" traffic symbol was significantly faster than their push reaction, while their response time to the "Stop" signal showed no differences between sliding and pushing actions. These results suggested that there was a possible association between certain action patterns and traffic symbol recognition, and in particular the "Go" symbol was congruent with a sliding action as a bodily response. Our findings may thus reveal an example of embodied cognition in visual perception of traffic signals.

Neurodiversity and Artistic Performance Characteristic of Children With Autism Spectrum Disorder.

Neurodiversity refers to the notion that seemingly 'impaired' cognitive as well as emotional features characteristic of developmental disorders such as autism spectrum disorder (ASD) fall into normal human behavioral variations that should enjoy some selective advantages. In the present experiment, the author compared what was depicted in subjects' drawings after they experienced an identical event, e.g., going on a picnic to a garden in the vicinity of their nursery school, between children with ASD and IQ-matched, typically developing (TD) children. When the material was coded according to types of drawn objects, such as human, animal, plant, food, vehicle, building, and others, the overall variability of the objects did not differ between TD children and children with ASD. However, TD children were more likely than children with ASD to depict human images. Conversely, other objects were more likely to be drawn by children with ASD than by TD children. While TD children were more likely to focus on humans than on non-human objects when drawing, children with ASD were more likely to focus on non-human objects than on humans even after both had experienced an identical event. The author argues that such findings are empirical evidence for the claim that there is some selective advantage of enhanced capabilities characteristic of ASD, i.e., neurodiversity, that may represent a balance toward "folk physics" at the expense of "folk psychology."

Preferential attentional engagement drives attentional bias to snakes in Japanese macaques (Macaca fuscata) and humans (Homo sapiens).

In humans, attentional biases have been shown to negative (dangerous animals, physical threat) and positive (high caloric food, alcohol) stimuli. However, it is not clear whether these attentional biases reflect on stimulus driven, bottom up, or goal driven, top down, attentional processes. Here we show that, like humans, Japanese macaques show an attentional bias to snakes in a dot probe task (Experiment 1). Moreover, this attentional bias reflects on bottom up driven, preferential engagement of attention by snake images (Experiment 2a), a finding that was replicated in a study that used the same methodology in humans (Experiment 2b). These results are consistent with the notion that attentional bias to snakes reflects on an evolutionarily old, stimulus driven threat detection mechanism which is found in both species.

The effects of eye and face inversion on the early stages of gaze direction perception--an ERP study.

Eye direction perception is highly important for social cognition. However, the neural mechanism underlying gaze direction perception has not been well elucidated. The present study aimed to examine the specific neural mechanism of gaze direction perception by investigating how the event related potential components, which presumably reflect the early stages of face processing, are affected by inverting eye region and face context, i.e., facial parts other than eye region. The results showed that eye region inversion significantly delayed the peak latency of the N170 component. At the same time, N170 latency was also delayed by inverting face context alone. Moreover, we observed that the P100 latency was delayed by inverting the eye region in an upright face context, but not in an inverted face context. We suggest that N170 reflects the eye-sensitive cortical response, but also the processing of other facial regions, and that the processing of eye region begins at an early stage of face processing, around 100 ms after stimulus onset.

Neural correlates for learning to read Roman numerals.

This study examined the neuronal correlates of reading Roman numerals and the changes that occur with extensive practice. Subjects were scanned by functional Magnetic Resonance Imaging (fMRI) three times the first day of the experiment and once following two to three months of practice. This allowed comparison of brain activations with varying levels of practice on the same day and across the two to three months of training. The results revealed that upon learning that the alphabetical symbols had numeric meaning subjects immediately activated a network of brain areas, many of which have been previously implicated in numerical processing. Subsequent practice led to a change in the pattern of neuronal activity in only a single region of the mid-dorsolateral prefrontal cortex in the left hemisphere. Implications of these findings are argued with regard to the prevalent neuronal model for the implementation of elementary numerical abilities.

Neurodiversity, Giftedness, and Aesthetic Perceptual Judgment of Music in Children with Autism.

The author investigated the capability of aesthetic perceptual judgment of music in male children diagnosed with autism spectrum disorder (ASD) when compared to age-matched typically developing (TD) male children. Nineteen boys between 4 and 7 years of age with ASD were compared to 28 TD boys while listening to musical stimuli of different aesthetic levels. The results from two musical experiments using the above participants, are described here. In the first study, responses to a Mozart minuet and a dissonant altered version of the same Mozart minuet were compared. In this first study, the results indicated that both ASD and TD males preferred listening to the original consonant version of the minuet over the altered dissonant version. With the same participants, the second experiment included musical stimuli from four renowned composers: Mozart and Bach's musical works, both considered consonant in their harmonic structure, were compared with music from Schoenberg and Albinoni, two composers who wrote musical works considered exceedingly harmonically dissonant. In the second study, when the stimuli included consonant or dissonant musical stimuli from different composers, the children with ASD showed greater preference for the aesthetic quality of the highly dissonant music compared to the TD children. While children in both of the groups listened to the consonant stimuli of Mozart and Bach music for the same amount of time, the children with ASD listened to the dissonant music of Schoenberg and Albinoni longer than the TD children. As preferring dissonant music is more aesthetically demanding perceptually, these results suggest that ASD male children demonstrate an enhanced capability of aesthetic judgment of music. Subsidiary data collected after the completion of the experiment revealed that absolute pitch ability was prevalent only in the children with ASD, some of whom also possessed extraordinary musical memory. The implications of these results are discussed with reference to the broader notion of neurodiversity, a term coined to capture potentially gifted qualities in individuals diagnosed with ASD.

Negative emotion evoked by viewing snakes has a motivating effect on cognitive processing in human children with or without intellectual disability.

BACKGROUND: It is well known that prioritization of the processing of threatening stimuli generally induces deleterious effects on task performance. However, a study recently reported that emotion (possibly fear) evoked by viewing images of snakes exerts a facilitating effect upon making judgments of the images' color in neurotypical adults and schoolchildren. Here, the author has attempted to confirm the relevance of this notion in children with and without intellectual disability. METHODS: The author here compared the reaction time required to name the colors of snake and flower images between children with Down syndrome (DS) and mental age matched, typically-developing (TD) children. RESULTS: Snake images were responded to faster than flower images in both the groups, while the children with DS tended to respond more slowly overall. CONCLUSIONS: As in TD children, negative emotion can have a motivating effect on cognitive processing in children with DS. Some implications of the findings are pointed out with respect to the lower-level task persistence as a characteristic motivational orientation in children with DS.

Implications of the idea of neurodiversity for understanding the origins of developmental disorders.

Neurodiversity, a term initially used mostly by civil and human rights movements since the 1990s, refers to the notion that cognitive as well as emotional properties characteristic of developmental disorders such as autism spectrum disorders (ASD) are not necessarily deficits, but fall within normal behavioural variations exhibited by humans. The purpose of the present article is to examine the relevance of this notion to scientific research on ASD. On the assumption that one crucial survival advantage of intelligent activity is vigilance toward dangers in the external world, and such vigilance must work in the social domain as well as in the non-social domain, the author argues that the pattern of operation of an individual person's mind can be categorized according to the domain toward which that individual is more oriented. Individuals with ASD, overall, do not rely upon their social relationships but rather are predisposed to process perceived non-social objects in more depth, which manifests itself as hyper-sensation and hyper-attention to detail. It can be assumed that underconnectivity among cortical areas and subcortical areas underlies such mental operation neurologically. One of the main predictions based on this assumption is that all facets of psychological function are susceptible to disruption in ASD. Indeed, it has traditionally been thought that there are such general deficits in this disorder. However, contrary to the prevalent belief that people with ASD lack empathy, in fact people with ASD are capable of empathizing with the minds of others if those others are people with ASD. Thus, the neurological underconnectivity in ASD certainly leads some processing of information in the mind to work with less coordination, but has in fact contributed to providing Homo sapiens with behavioural variants. Finally, the clinical implications of the advantages of viewing ASD as a variation in neurodiversity are discussed.

Goal attribution to inanimate moving objects by Japanese macaques (Macaca fuscata).

Humans interpret others' goals based on motion information, and this capacity contributes to our mental reasoning. The present study sought to determine whether Japanese macaques (Macaca fuscata) perceive goal-directedness in chasing events depicted by two geometric particles. In Experiment 1, two monkeys and adult humans were trained to discriminate between Chasing and Random sequences. We then introduced probe stimuli with various levels of correlation between the particle trajectories to examine whether participants performed the task using higher correlation. Participants chose stimuli with the highest correlations by chance, suggesting that correlations were not the discriminative cue. Experiment 2 examined whether participants focused on particle proximity. Participants differentiated between Chasing and Control sequences; the distance between two particles was identical in both. Results indicated that, like humans, the Japanese macaques did not use physical cues alone to perform the discrimination task and integrated the cues spontaneously. This suggests that goal attribution resulting from motion information is a widespread cognitive phenotype in primate species.

Atypical Color Preference in Children with Autism Spectrum Disorder.

So far, virtually no study has ever investigated color preference in children with autism spectrum disorder (ASD). In order to address this issue, 29 boys with ASD varying in age between 4 and 17 years, and 38 age-matched typically developing (TD) boys were studied regarding their preference among six colors: red, pink, yellow, brown, green, and blue, in clinical settings. When mean rank of preference was computed in each of the ASD and TD groups with regard to each color, it was found that boys with ASD were significantly less likely than TD boys to prefer yellow and more likely than TD boys to prefer green and brown colors. These results appear to be caused by hyper-sensation characteristic of ASD, due to which boys with this disorder perceive yellow as being sensory-overloading.