Brain mechanisms of social signalling in live social interactions with autistic and neurotypical adults

The simple act of watching another person can change a person's behaviour in subtle but important ways; the individual being watched is now capable of signalling to the watcher, and may use this opportunity to communicate to the watcher. Recent data shows that people will spontaneously imitate more when being watched. Here, we examine the neural and cognitive mechanisms of being watched during spontaneous social imitation in autistic and neurotypical adults using fNIRS brain imaging. Participants (n = 44) took part in a block-moving task where they were instructed only to copy the block sequence which people normally do using a straight low action trajectory. Here, the demonstrator sometimes used an atypical 'high' action trajectory, giving participants the opportunity to spontaneously copy the high trajectory even if this slowed their performance. The confederate who demonstrated each block sequence could watch the participant's actions or close her eyes, giving a factorial design with factors of trajectory (high/low) and watched (watched/unwatched). Throughout the task, brain signals were captured from bilateral temporal/parietal/occipital cortex using fNIRS. We found that all participants performed higher actions when being watched by the confederate than when not being watched, with no differences between autistic and neurotypical participants. The unwatched conditions were associated with higher activity of the right inferior parietal lobule in all participants and also engagement of left STS only in autistic participants. These findings are consistent with the claim that people engage different neural mechanisms when watched and unwatched and that participants with autism may engage additional brain mechanisms to match neurotypical behaviour and compensate for social difficulties. However, further studies will be needed to replicate these results in a larger sample of participants

Sense of Self: Evidence from Neurotypical people and people with Autism Spectrum Conditions

The self has a significant influence on human cognition across different processing domains (memory, perception, attention, action). For example, research often finds self-biases in cognition - the phenomena whereby people show enhanced cognitive processing for information processed in relation to the self, than for information processed in relation to someone else, or in other ways. Given that the self influences cognition, it follows that any individual with an impoverished self-concept should have diminished self-bias capacity/profile. Potentially, this is highly relevant for our understanding of autism spectrum conditions (ASC), which is characterised by atypical development of both the understanding of self (meta-cognition) and of other people (mindreading). One possible reason for this might be that self-other distinction is impaired - e.g., people are processing self-referential information similarly to other-referential information. However, empirical evidence for impaired self-bias in ASC is inconsistent, and importantly, as of yet, no theory or explanation has been put forward that fully accounts for the discrepancy. Therefore, across five experimental chapters (a total of 11 experiments), this thesis investigates typical and atypical self-referential cognition by analysing evidence of self-biases in neurotypical adults and adults with ASC, in the domains of perception, action, and mental states. Chapter 2 (mental-state level) found that whereas neurotypical participants (N = 28) showed a moderate-to-large and statistically significant ownership effect in Experiment 1.2, autistic (N = 28) participants showed a small and statistically non-significant effect (i.e. comparable memory for items encoded in relation to the self and in relation to the experimenter). Importantly however, Chi-squared analysis revealed that there was no categorical difference between groups in the number of people who did/did not display an ownership effect, which suggests that although the size of the ownership effect was smaller in ASC (as shown by our continuous variable analysis), autistic participants were no less likely than neurotypical participants to display an ownership effect, thus suggesting that the ownership effect is not definitively impaired in autism. Furthermore, the ownership effect was unrelated to the number of autistic traits in either the case-control sample (Experiment 1.2: N = 56) or in a larger sample of neurotypical adults (Experiment 1.1: N = 100). Chapter 3 (mental-state level) investigated scene construction - the ability to mentally generate (i.e., imagine) and maintain a coherent spatial scene/event in mind (critical for episodic simulation), and found that scene construction ability was diminished (i.e., lower in quality) in autistic (N = 55) compared to neurotypical (N=62) adults, and was negatively associated with autistic traits. However, the ability to infer others' mental states (i.e. Theory of Mind; ToM) and to recognise emotions in oneself (i.e. alexithymia) were found to be better predictors of scene construction ability than an autism diagnosis. The frequency of descriptions of sensory experiences (which followed the same pattern in both groups: sight > sound > touch = smell > taste) and self-reference did not differ between groups. Chapter 4 (perceptual level) presented two experiments that aimed to test findings of undiminished perceptual self-bias in ASC when using unfamiliar stimuli Both in a case-control sample (pre-registered Experiment 3.2: N = 57), and in a sample of neurotypical adults (Experiment 3.1: N = 59), behavioural results showed that participants experienced both a self-bias and a familiarity effect. Importantly, the number of autistic traits was unrelated to the magnitude of self-bias and familiarity effects on RT or accuracy (in Experiments 3.1 and 3.2) and there was no between-group difference in the speed and accuracy of self-bias and familiarity effects (Experiment 3.2). Analysis of the ERP indices revealed clear evidence of a self-bias in both groups, with self trials eliciting larger N1 and P3 components than familiar ('friend') and unfamiliar ('stranger') other trials. Furthermore, the familiarity effect was largely absent on ERP measures, though the ASC group elicited some modulation of N2 reflecting familiarity conflict. Chapter 5 (mental-state level) investigated the malleability of self and other representations. In two neurotypical adult samples, we found evidence of both simulation induced malleability (Experiment 4.1; N = 163) and self-reflection induced malleability (Experiment 4.2; N = 162). Furthermore, the size of simulation induced malleability was positively associated with the number of autistic traits, but only when the simulated other was considered as the "average person" and not a "similar-other". Furthermore, in two pre-registered case-control experiments, there was greater simulation induced malleability in autistic than neurotypical adults (Experiment 4.3; N = 50) irrespective of similarity of the target, but no self-reflection induced malleability was observed in either diagnosis group (Experiment 4.4; N = 49). Chapter 6 (action level) measured participants' ability to distinguish their own motor repertoire from those displayed by other people of differing levels of similarity - specifically, the self vs. unfamiliar adult (similar-other) vs. unfamiliar child (dissimilar-other). We found a typical imitative compatibility effect in behavioural performance, which was not associated with the number of autistic traits (Experiments 5.1 and 5.2), and did not differ between neurotypical and autistic participants (Experiment 5.2). Furthermore, associated mu/alpha (8-13Hz) and beta (13-35Hz) desynchronisation - which are thought to reflect an index of mirror neuron activity - also did not reveal consistent differences between groups (Experiment 5.2). However, the key manipulation here, the referent effect, did not show any effect in behavioural performance (Experiment 5.1 and 5.2), and the imitative compatibility effect in mu/alpha and beta did not differ between referents (Experiment 5.2). The theoretical and practical implications of these findings for our understanding of self-awareness/self-referential cognition in ASC and in the neurotypical population, are discussed

Indistinguishable behavioural and neural correlates of perceptual self-other distinction in autistic and neurotypical adults

Previous research has suggested that self-bias (i.e., enhanced cognitive processing of self-versus other-relevant information) may be atypical in autism spectrum conditions (ASC), perhaps due to difficulties with self-other distinction. However, empirical evidence for this is inconsistent, and the neural basis of processing differences remains unknown. We present two experiments that aimed to test perceptual self-bias and familiarity effects in ASC using a perceptual-association task. Participants were asked to distinguish face/label associations of the self from those of other people of differing levels of familiarity (i.e., friend vs stranger). Experiment 1 took an individual differences approach by testing whether behavioural self-bias is associated with the number of autistic traits in a neurotypical adult sample (N = 59). Experiment 2 took a case-control approach by testing whether behavioural self-bias and associated ERP responses differ between neurotypical (N = 27) and autistic (N = 30) adults. Across both experiments, behavioural results showed that participants experienced a self-bias (self > friend and stranger) and a familiarity effect (e.g., friend > stranger); neither effect was affected by the number of autistic traits or autism diagnosis. In Experiment 2, analysis of N1, N2, and P3 ERP components revealed a typical self-bias in both groups (self distinct from friend and stranger), and only the autistic group showed evidence of a familiarity effect (N2 more negative-going for stranger than friend). The findings are discussed in relation to self-other distinction ability, and the relevance of other neuropsychological and psychiatric conditions such as anxiety and alexithymia are also considered. [Abstract copyright: Crown Copyright © 2024. Published by Elsevier Ltd. All rights reserved.

Scene construction ability in neurotypical and autistic adults.

Peer reviewed: TruePeople with autism spectrum conditions (ASC) have difficulties imagining events, which might result from difficulty mentally generating and maintaining a coherent spatial scene. This study compared this scene construction ability between autistic (N = 55) and neurotypical (N = 63) adults. Results showed that scene construction was diminished in autistic compared to neurotypical participants, and participants with fewer autistic traits had better scene construction ability. ASC diagnosis did not influence the frequency of mentions of the self or of sensory experiences. Exploratory analysis suggests that scene construction ability is associated with the ability to understand our own and other people's mental states, and that these individual-level preferences/cognitive styles can overrule typical group-level characteristics

Scene Construction Ability in Neurotypical and Autistic Adults

People with autism spectrum conditions (ASC) have difficulties mentally simulating events, perhaps due to a difficulty mentally generating and maintaining a coherent spatial scene– i.e., “scene construction”. The current study compared scene construction ability between autistic adults (N=55) and age-, gender-, and Intelligence Quotient-matched neurotypical adults (N=63), using a task in which participants were asked to vividly imagine and describe fictitious scenes. Results showed that scene construction was diminished in autistic compared to neurotypical participants, and was negatively associated with autistic traits. ASC diagnosis did not influence the frequency of self-reference or sensory experiences, which followed the same pattern in both groups: sight was referenced more than sound, sound was referenced more than both touch and smell, which were both referenced more than taste. Exploratory analysis of some of the cognitive predictors revealed that scene construction ability was associated with individual differences in Theory of Mind and alexithymia

Revisiting the Ownership Effect in Adults with and without Autism

Self-owned items are better remembered than other-owned items; this ownership effect reflects privileged processing of self-related information. The size of this ownership effect has been shown to decrease in neurotypical adults as the number of autistic traits increases, and is reduced in autistic adults. However, emerging evidence has questioned the reliability of these findings. This paper aimed to replicate previous work using well-powered, pre-registered designs, and Bayesian analyses. Experiment 1 (N=100) found a significant ownership effect in neurotypical adults; however, the size of this was unrelated to individual differences in autistic traits. Experiment 2 (N=56) found an ownership effect in neurotypical but not autistic adults. The findings suggest that individual differences in autistic traits in the neurotypical population do not impact the ownership effect, but a clinical diagnosis of autism might. We discuss how these findings can be explained by differences in psychological self-awareness in autism

Brain mechanisms of social signalling in live social interactions with autistic and neurotypical adults

Abstract The simple act of watching another person can change a person’s behaviour in subtle but important ways; the individual being watched is now capable of signalling to the watcher, and may use this opportunity to communicate to the watcher. Recent data shows that people will spontaneously imitate more when being watched. Here, we examine the neural and cognitive mechanisms of being watched during spontaneous social imitation in autistic and neurotypical adults using fNIRS brain imaging. Participants (n = 44) took part in a block-moving task where they were instructed only to copy the block sequence which people normally do using a straight low action trajectory. Here, the demonstrator sometimes used an atypical ‘high’ action trajectory, giving participants the opportunity to spontaneously copy the high trajectory even if this slowed their performance. The confederate who demonstrated each block sequence could watch the participant’s actions or close her eyes, giving a factorial design with factors of trajectory (high/low) and watched (watched/unwatched). Throughout the task, brain signals were captured from bilateral temporal/parietal/occipital cortex using fNIRS. We found that all participants performed higher actions when being watched by the confederate than when not being watched, with no differences between autistic and neurotypical participants. The unwatched conditions were associated with higher activity of the right inferior parietal lobule in all participants and also engagement of left STS only in autistic participants. These findings are consistent with the claim that people engage different neural mechanisms when watched and unwatched and that participants with autism may engage additional brain mechanisms to match neurotypical behaviour and compensate for social difficulties. However, further studies will be needed to replicate these results in a larger sample of participants