Creation of a Novel Measure to Assess Social Motivation in Youth with Autism Spectrum Disorder

Background: Diminished social motivation in ASD has been conceptualized as a trait marker that influences the emergence and maintenance of ASD symptomology. Measurement of social motivation to date has largely relied on indices of overt social behavior with little regard for the cognitive processes that can influence goal-directed tasks involved in social interaction. Understanding internalized cognitive processes may distinguish underlying motivations which influence engagement in social behavior. This study aims to assess how beliefs, mindsets, and attitudes can influence one’s motivation to engage in social interaction.

Objectives: The primary aim of the present study was to create and evaluate a novel measure of social motivation for youth aged 8-17 with ASD.

Methods: A two-phase study design was adopted. Phase 1 created and refined an interview item pool based on expert consultation. The content validity index (I-CVI) was used to quantify expert feedback and establish construct integrity. Phase 2 conducted pilot testing and established psychometric properties of the measure from an item response theory (IRT) framework.

Results: The Social Motivation Interview (SMI) is a theoretically-informed, clinician-administered interview designed to assess interest or desire to engage in social situations. To establish content validity, each item of the SMI was evaluated by a panel of 5 experts (M_{years of experience} = 20.33, SD = 10.89, Range = 7-40). I-CVI ratings < 0.667 were revised or deleted. After external review, twenty-three items were retained for the final iteration of the SMI, with items loading on two distinct subscales. Clinicians assigned a rating for each item on a latent continuum.

Eighteen individuals with ASD (M_age = 12.84, SD = 2.61, Range = 8-17, 4 female) and their caregivers jointly participated in the pilot psychometric evaluation of the SMI. Participants were communicative (M_IQ = 100.12, SD = 18.0, Range = 63-127) and had a clinical diagnosis of ASD, confirmed by a research-reliable administration of the ADOS (M_{Comparison Score} = 7.44, SD = 1.98). SMI administration was brief (M_mins = 45, Range = 21-60) and the scale had strong internal consistency (α = 0.96). The spread of scores was adequate, M = 19.889 (SD = 13.634, Range = 4-53). Discriminant validity was demonstrated as the total score was not significantly correlated with age, r (17) = 0.020, p = 9.83. Convergent validity was satisfactory as measured by the correlation with the ADIS- ASD Social Motivation Subscale, r (17) = 0.49, p = 0.04. The Standard Error of Measurement (SEM) was 2.98. Participant acceptability ratings were high (M = 4.50, out of 5).

Conclusions: The development of the SMI followed stringent criteria to create a unified measure that was methodologically sound and theoretically-informed. SMI development followed guidelines to ensure item pool development was consistent with the proposed construct. Pilot testing suggests feasibility of administration, user satisfaction, and promising psychometric properties. Future examination of the SMI in large-scale field testing is warranted.