Your Goal Is Not Mine: Absence of Mimetic Desire in Autism Spectrum Disorder

Background: The spreading of desires within a group is a form of social contagion that manifests not only in culture and learning, but also in rivalry and mob behaviour. A basic neural mechanism for this phenomenon has recently been demonstrated (Lebreton et al. 2012): adult participants in the general population rated objects as more desirable once perceived as the goals of another agent’s actions. This mimetic desire effectrelies on the modulation of the brain valuation system -a ventral striatoprefrontal network- by the mirror neuron system.

Some behavioural features of autism spectrum disorders (ASD) suggest a lower sensitivity to social influence: persons with ASD tend to develop interests unrelated to those of their peers (American Psychiatric Association, 1994; Kanner, 1943); they have been reported to be less prone to flattery (Chevallier et al, 2011) and hypocrisy (Izuma et al, 2011). On the other hand, social influence in people with ASD may be manifested through the sharing of stereotypes prevalent in their social group (Hamilton & Krendl, 2007; Hirschfeld et al, 2007) or the influence of an observer on motor performance (Izuma et al 2011). Brain basis of mimetic desire effect may be atypical in ASD: disrupted long range connectivity is increasingly believed to be associated with ASD. Although more controversial, an atypical functioning of the Mirror neuron system has also been reported in ASD (Dapretto et al 2006).

Objectives: We assessed whether the mimetic desire effect is reduced in persons with ASD compared to persons without ASD.

Methods: Young adults with ASD and controls without ASD matched for age, IQ and gender took part to the study (current n of 10 per group; data collection still undergoing). Participants in the ASD group met ADOS-G and ADI-R thresholds and DSM-IV criteria for an ASD. All participants had FSIQ>85. Participants with self-reported depression (Beck Depression Inventory score>20) were excluded. Participants attended to a series of videos displaying objects. The objects were either the goals of an action performed by an actor (goal condition) or not (non-goal condition). The participants then rated to what extent they wanted to use the object. We performed an ANOVA to test the interaction between condition (goal vs non-goal) and group (ASD vs non ASD) on desirability rating.

Results: Participants from both groups used the desirability scale similarly (e.g. there was no significant difference in mean ratings and similar variability in scores). Nevertheless, there was a significant group by condition interaction on desirability rating. Participants without ASD gave significantly higher desirability ratings in the goal than non-goal condition (p<0.05), whereas ASD participants gave similar ratings in the goal and non-goal conditions (p=0.45).

Conclusions: Contrary to what was observed in control participants, the desires of persons with ASD were not influenced by others’ actions. We believe that this finding reflects a basic difference in susceptibility to social influence between persons with and without ASD, possibly contributing to the atypical development of interests and learning in ASD. The developmental course and neural underpinning of such difference remains to be explored.