Seeing motion of controlled object improves grip timing in adults with autism spectrum condition: evidence for use of inverse dynamics in motor control.

Previous studies (Haswell et al. in Nat Neurosci 12:970-972, 2009; Marko et al. in Brain J Neurol 138:784-797, 2015) reported that people with autism rely less on vision for learning to reach in a force field. This suggested a possibility that they have difficulties in extracting force information from visual motion signals, a process called inverse dynamics computation. Our recent study (Takamuku et al. in J Int Soc Autism Res 11:1062-1075, 2018) examined the ability of inverse computation with two perceptual tasks and found similar performances in typical and autistic adults. However, this tested the computation only in the context of sensory perception while it was possible that the suspected disability is specific to the motor domain. Here, in order to address the concern, we tested the use of inverse dynamics computation in the context of motor control by measuring changes in grip timing caused by seeing/not seeing a controlled object. The motion of the object was informative of its inertial force and typical participants improved their grip timing based on the visual feedback. Our interest was on whether the autism participants show the same improvement. While some autism participants showed atypical hand slowing when seeing the controlled object, we found no evidence of abnormalities in the inverse computation in our grip timing task or in a replication of the perceptual task. This suggests that the ability of inverse dynamics computation is preserved not only for sensory perception but also for motor control in adults with autism.

The role of anterior prefrontal cortex (area 10) in face-to-face deception measured with fNIRS.

Anterior prefrontal cortex (PFC, Brodmann area 10) activations are often, but not always, found in neuroimaging studies investigating deception, and the precise role of this area remains unclear. To explore the role of the PFC in face-to-face deception, we invited pairs of participants to play a card game involving lying and lie detection while we used functional near infrared spectroscopy (fNIRS) to record brain activity in the PFC. Participants could win points for successfully lying about the value of their cards or for detecting lies. We contrasted patterns of brain activation when the participants either told the truth or lied, when they were either forced into this or did so voluntarily and when they either succeeded or failed to detect a lie. Activation in the anterior PFC was found in both lie production and detection, unrelated to reward. Analysis of cross-brain activation patterns between participants identified areas of the PFC where the lead player's brain activity synchronized their partner's later brain activity. These results suggest that during situations that involve close interpersonal interaction, the anterior PFC supports processing widely involved in deception, possibly relating to the demands of monitoring one's own and other people's behaviour.

The virtual maze: A behavioural tool for measuring trust.

Trusting another person may depend on our level of generalised trust in others, as well as perceptions of that specific person's trustworthiness. However, many studies measuring trust outcomes have not discussed generalised versus specific trust. To measure specific trust in others, we developed a novel behavioural task. Participants navigate a virtual maze and make a series of decisions about how to proceed. Before each decision, they may ask for advice from two virtual characters they have briefly interviewed earlier. We manipulated the virtual characters' trustworthiness during the interview phase and measured how often participants approached and followed advice from each character. We also measured trust through ratings and an investment game. Across three studies, we found participants followed advice from a trustworthy character significantly more than an untrustworthy character, demonstrating the validity of the maze task. Behaviour in the virtual maze reflected specific trust rather than generalised trust, whereas the investment game picked up on generalised trust as well as specific trust. Our data suggest the virtual maze task may provide an alternative behavioural approach to measuring specific trust in future research, and we demonstrate how the task may be used in traditional laboratories.

Brief Report: A Comparison of the Preference for Viewing Social and Non-social Movies in Typical and Autistic Adolescents.

The recently proposed Social Motivation theory (Chevallier et al., Trends in cognitive sciences 16(4):231-239, 2012) suggests that social difficulties in Autism Spectrum Condition (ASC) might be caused by a difference in the motivation to engage with other people. Here we compared adolescents with (N = 31) and without (N = 37) ASC on the Choose-a-Movie paradigm that measures the social seeking. The results showed a preference for viewing objects over smiling faces in ASC, which is in line with the theory of low social motivation. However, typical adolescents did not show any stimuli preferences, raising questions about developmental changes in social motivation. Age was found to play a significant role in moderating the choice behaviour of the participants. We discuss the implications of these findings in detail.

STORMy Interactions: Gaze and the Modulation of Mimicry in Adults on the Autism Spectrum.

Mimicry involves unconsciously imitating the actions of others and is a powerful and ubiquitous behavior in social interactions. There has been a long debate over whether mimicry is abnormal in people with autism spectrum conditions (ASC) and what the causes of any differences might be. Wang and Hamilton's (2012) social top-down response modulation (STORM) model proposed that people with ASC can and do mimic but, unlike neurotypical participants, fail to modulate their mimicry according to the social context. This study used an established mimicry paradigm to test this hypothesis. In neurotypical participants, direct gaze specifically enhanced congruent hand actions as previously found; in the ASC sample, direct gaze led to faster reaction times in both congruent and incongruent movements. This result shows that mimicry is intact in ASC, but is not socially modulated by gaze, as predicted by STORM.

Reduced Mimicry to Virtual Reality Avatars in Autism Spectrum Disorder.

Mimicry involves unconsciously copying the actions of others. Increasing evidence suggests that autistic people can copy the goal of an observed action but show differences in their mimicry. We investigated mimicry in autism spectrum disorder (ASD) within a two-dimensional virtual reality environment. Participants played an imitation game with a socially engaged avatar and socially disengaged avatar. Despite being told only to copy the goal of the observed action, autistic participants and matched neurotypical participants mimicked the kinematics of the avatars' movements. However, autistic participants mimicked less. Social engagement did not modulate mimicry in either group. The results demonstrate the feasibility of using virtual reality to induce mimicry and suggest mimicry differences in ASD may also occur when interacting with avatars.

The shaping of social perception by stimulus and knowledge cues to human animacy.

Although robots are becoming an ever-growing presence in society, we do not hold the same expectations for robots as we do for humans, nor do we treat them the same. As such, the ability to recognize cues to human animacy is fundamental for guiding social interactions. We review literature that demonstrates cortical networks associated with person perception, action observation and mentalizing are sensitive to human animacy information. In addition, we show that most prior research has explored stimulus properties of artificial agents (humanness of appearance or motion), with less investigation into knowledge cues (whether an agent is believed to have human or artificial origins). Therefore, currently little is known about the relationship between stimulus and knowledge cues to human animacy in terms of cognitive and brain mechanisms. Using fMRI, an elaborate belief manipulation, and human and robot avatars, we found that knowledge cues to human animacy modulate engagement of person perception and mentalizing networks, while stimulus cues to human animacy had less impact on social brain networks. These findings demonstrate that self-other similarities are not only grounded in physical features but are also shaped by prior knowledge. More broadly, as artificial agents fulfil increasingly social roles, a challenge for roboticists will be to manage the impact of pre-conceived beliefs while optimizing human-like design.

Gazing at me: the importance of social meaning in understanding direct-gaze cues.

Direct gaze is an engaging and important social cue, but the meaning of direct gaze depends heavily on the surrounding context. This paper reviews some recent studies of direct gaze, to understand more about what neural and cognitive systems are engaged by this social cue and why. The data show that gaze can act as an arousal cue and can modulate actions, and can activate brain regions linked to theory of mind and self-related processing. However, all these results are strongly modulated by the social meaning of a gaze cue and by whether participants believe that another person is really watching them. The implications of these contextual effects and audience effects for our theories of gaze are considered.

A review of visual perspective taking in autism spectrum disorder.

Impairments in social cognition are a key symptom of autism spectrum disorder (ASD). People with autism have great difficulty with understanding the beliefs and desires of other people. In recent years literature has begun to examine the link between impairments in social cognition and abilities which demand the use of spatial and social skills, such as visual perspective taking (VPT). Flavell (1977) defined two levels of perspective taking: VPT level 1 is the ability to understand that other people have a different line of sight to ourselves, whereas VPT level 2 is the understanding that two people viewing the same item from different points in space may see different things. So far, literature on whether either level of VPT is impaired or intact in autism is inconsistent. Here we review studies which have examined VPT levels 1 and 2 in people with autism with a focus on their methods. We conclude the review with an evaluation of the findings into VPT in autism and give recommendations for future research which may give a clearer insight into whether perspective taking is truly impaired in autism.