What is Unique and What is Typical of Human Mind?

“High" vs “low status", “top of the heap", “bottom of the barrel": Similar expressions are widely observed across languages. The cross-modal correspondence between the visuospatial domain (e.g. high or low) and an abstract domain (e.g. rank) has been described as a conceptual metaphor, which is believed to be a linguistic construction, and therefore uniquely in human. A conceptual metaphor takes one concept and connects that to another concept to better understand that concept. The question remains if conceptual metaphorical mapping is indeed uniquely human or if it appears in other primates and thus describes a conceptual metaphorical mapping that predates language. To address this question, we examined if non-human primates (chimpanzees and rhesus monkeys) have space-order correspondences as we humans do. The subjects had been trained to perform a number sequence task in which they touched a sequence of “small" to “large" Arabic numerals presented in random locations. This task was presented in sessions that also included test trials consisting of two numerals horizontally arranged. On half of the trials the smaller number was located to the left of the larger one, whereas on the other half the arrangement is reversed. Their performance was influenced by the spatial arrangement of the stimuli; specifically, they responded quicker when the smaller number was on the left to the larger one compared to the other way around. This result suggests that chimpanzees, like humans, spontaneously map a sequence onto space.

Humans often show rhythmic coordination. When we walk with others, we tend to change our walking stride length and speed to match with those of others, either spontaneously or automatically. When did and when do humans acquire the ability for rhythmic coordination? My research investigates the evolutionary and developmental origins of the ability for rhythmic coordination in humans. In a comparative study, I examined chimpanzees and humans producing rhythmic tapping movements with a conspecific partner in close proximity. My results show that chimpanzees and humans share the ability to adapt the tempo of rhythmic movements in response to a partner, whereas the ability for quick and accurate adjustment was observed in humans but not in chimpanzees. In a developmental study, I examined human children, aged 1.5, 2.5 and 3.5 years, while they performed spontaneous drumming behavior with a partner. Based on these findings from comparative and developmental studies, I will discuss how the uniquely human ability for rhythmic coordination emerged.

There are large differences between individuals in their ability to recognize faces. Investigating the factors that are responsible for these differences can help us to identify the cognitive and neural mechanisms that contribute to successful face recognition. Our research in this area has focused on individuals with developmental prosopagnosia (DP), who show severe face recognition deficits that typically emerge in early childhood, without any apparent neurological damage. It is not yet known which face processing mechanisms are impaired in DPs, and in particular whether their face recognition problems are caused by early perceptual or later memory-related deficits. It is often assumed that the core problem for DPs is their failure to process faces holistically, but there is little support for this hypothesis. Our recent work suggests that the face recognition problems in DP may already arise at an earlier level of visual processing where facial features are analysed. I will discuss some of our recent studies where face perception and recognition in DPs and age-matched control participants were assessed behaviourally and with EEG-based measures. These studies suggest that face processing in DP is poorly tuned to perceptual features that are critical for determining facial identity, and in particular to signals from the eye region. I will discuss possible reasons why DPs would show atypical face perception, and also more general implications for neuropsychological and neurodevelopmental perspectives on prosopagnosia and on individual differences in face recognition skills.

Impaired joint attention represents the core clinical feature of autism spectrum disorder (ASD). However, previous psychological studies reported intact gaze-triggered attentional shift in ASD. We hypothesized that individuals with ASD may be impaired not in conscious but in unconscious gaze-triggered attentional shift. First, we tested this hypothesis in ASD and typically developing (TD) individuals. We used a cueing paradigm with supraliminal and subliminal presentation of gaze cues. Under the supraliminal condition, the gaze cueing effect was evident in both groups. Under the subliminal condition, the ASD group, unlike the TD group, did not show the gaze cueing effect. Next, we investigated the neural mechanisms underlying these behavioral patterns. We acquired functional magnetic resonance imaging data while ASD and TD individuals viewed supraliminally or subliminally presented gaze cues of averted or straight direction. The temporo–parieto–frontal regions showed stronger activation in response to averted vs. straight gaze in both groups under the supraliminal condition. The amygdala was more activated while viewing averted vs. straight gaze in the TD group than in the ASD group under the subliminal condition. These findings provide an explanation for the psychological and neural mechanisms underlying the impairment in unconscious but not conscious joint attention in individuals with ASD.

Breastfeeding is a highly conserved element of maternal care in mammal, and the first turn-taking interaction between mother and infant which required reciprocal cooperation. As one mechanism for lactation, a neurohormone oxytocin is necessary for milk let down. Not only oxytocin have a role in these female reproductive system, but over the last two decades, it has been revealed that oxytocin plays a critical role in social behaviors including emotion perception and recognition. In our study, we investigated whether tonic and phasic breastfeeding behaviors and/or accompanying oxytocin level could enhance several types of emotional processing (i.e., attention regulation in detecting emotion signals, recognition of motion category, and arousal rating for emotional facial expressions). We showed that both tonic and phasic breastfeeding behaviors elicit an effect on emotion perception (i.e., attention regulation) although there were no relationships between breastfeeding and oxytocin level. As tonic effect of breastfeeding, accumulated breastfeeding and higher oxytocin level moderated the sensitivity to detecting negative emotion signals. As for phasic effect of breastfeeding, it enhanced the sensitivity for detecting both positive and negative emotional signals. We will discuss that how nurturing experience could change mother's perception by focusing the possible mechanism of endogenous oxytocin function.

Using a novel eye-tracking test, we recently showed that great apes anticipate that other individuals will act according to false beliefs. This finding suggests that, like humans, great apes understand others' false beliefs, at least in an implicit way. One key question raised by our study is why apes have passed our tests but not previous ones. In this article, we consider this question by detailing the development of our task. We considered 3 major differences in our task compared with the previous ones. First, we monitored apes' eye movements, and specifically their anticipatory looks, to measure their predictions about how agents will behave. Second, we adapted our design from an anticipatory-looking false belief test originally developed for human infants. Third, we developed novel test scenarios that were specifically designed to capture the attention of our ape participants. We then discuss how each difference may help explain differences in performance on our task and previous ones, and finally propose some directions for future studies.

Cumulative cultural evolution is the accumulation of beneficial modification thorough social transmission. Cumulative culture is unique to humans due to our capacity for high-fidelity transmission without informational loss (e.g. over-imitation). However, in a series of computer simulations, we demonstrate a case where a certain amount of information loss is beneficial to cumulative cultural evolution. The simulation was based on the adaptive decision framework where individual agents repeatedly make choices from two alternatives with different values (e.g. identify locations with greater resources) with multiple relevant cues. After each decision, agents learn and update their preference for particular cues based on trial-and-error learning. After a considerable numbers of decisions, we implemented generational changes with vertical cultural transmission. Two types of intergenerational transmissions are considered – ‘complete' transmission, or ‘incomplete' transmission. In complete transmission, a cultural parent transmits all the information to a cultural child. In incomplete transmission, a certain amount of information lost during the transmission. After transmission, cultural children make decision and update preference until the next intergenerational transmission event. Our simulation revealed that agents under conditions of perfect transmission increase their performance within a few generations but quickly reach a local optima. In contrast, agents' performance under imperfect transmission conditions begins relatively low but reach a greater local optima than agents under perfect conditions. These results suggest that a certain amount of information loss is beneficial to cumulative cultural evolution when the fitness landscape is multi-modal.

Many philosophers, psychologists and neuroscientists believe that the capacity to 'read minds' or 'mentalise' depends on dedicated cognitive processes, and in the course of human evolution natural selection has produced a highly specific, genetically inherited predisposition to develop these dedicated mindreading processes. This has been described as the nativist or modular view of mindreading and contrasted with more developmental or constructivist accounts, which emphasise the importance of the individual's experience, and especially their social experience, in the development of mindreading. Nativist views tend to be representationalist and built on laboratory-based experimental methods, whereas constructive views tend to resist representationalism and to draw on more naturalistic empirical methods. My recent work has crossed these traditions by assuming that mindreading is representational; proposing that these representations are products of cultural evolution; and challenging what are normally regarded as the more rigorous empirical methods on their own ground. This talk will compare mindreading with print (or script) reading, a capacity that emerged too recently in human history to be dependent on genetically evolved cognitive processes. This comparison helps to clear the ground for close examination of recent experiments that have fortified nativist views by seeming to show that nonhuman primates, infants, and adults are capable of automatic or implicit mindreading. It also introduces the 'softer' but compelling evidence that the development of mindreading is crucially dependent on linguistic communication between adults and children.