Decision-Making in Autism: An Empirical Protocol

All tasks were delivered online. Participants first signed a written consent form and completed demographic information (e.g., age, education, gender, prior diagnoses). Those in the autism group also uploaded their diagnosis certificate (see details in S1 File). All participants then performed the IGT. In this task participants are presented with four decks of cards labeled A, B, C, and D. They can select a single card from these four decks in each trial. After selecting each card, participants receive token money (the amount is displayed on the screen). Task payoffs are presented in Table 1 and screen illustrations appear in S1 File. Two of the decks are advantageous and produce lower gains but somewhat lower (uncertain) losses; these have positive expected values. The other two decks are disadvantageous and produce higher gains but also higher (uncertain) losses; these have negative expected values. The cumulative payoff is presented at the bottom of the display and is updated at the end of each trial. The display also includes the amount given to participants at the beginning of the task as a “loan”. The initial loan in our study was $3500. The minimum inter-trial interval was set to one second, and the task included 120 trials, which were analyzed by dividing them into four 30-trials blocks. Participants were given verbal instructions identical to those provided in Johnson et al. [4 (link)] (see S1 File). Following the standard version of the IGT there was another block of trials with no payoff feedback. This trial block was administered at the end so that participants first learn the incentive structure of the task. Given the fact that there was no feedback we felt that 30 trials would be sufficient to gage the participants’ responses. Prior to this no-feedback block, participants were instructed that over the next trials they would not receive any payoff feedback. Amounts were converted to actual money at the end of the task at a rate of $1 for each $1500 of token money.
Next, participants completed verbal and non-verbal brief intellectual aptitude tests. The verbal test was the Multidimensional Aptitude Battery (MAB; [26 ]), a modified Similarities subscale from the Wechsler Abbreviated Scale of Intelligence (WASI; [27 ]). The non-verbal test was the Raven Standard Progressive Matrices (RSPM, Set 1; [28 ]).
Finally, in order to validate group differences, we administered additional self-report questionnaires for autism-related symptoms, the Autism Spectrum Quotient (AQ10) [29 (link)] and the Social Responsiveness Scale, 2nd Edition (SRS-2) (adult self-report version [30 ]). The AQ10 is a self-administered ten-item questionnaire used for measuring where adults lie on the autism spectrum or continuum. Though there are some findings questioning the reliability and validity of the AQ10 [31 (link), 32 ], we used it as a brief validation of the documented diagnosis. The SRS-2 is a 65-item questionnaire that assesses difficulties in reciprocal social behavior that lead to interference with everyday social interactions.