Treatment group used GuessWhat during the 4 week intervention period.

Participants in control group received standard treatment as usual.

The GuessWhat app is a charades style game and app that engages parent and child in fluid social interaction where the parent must guess what the child is acting out based on the prompt shown on the phone screen. Participants will use their own personal phone to download the study app. Parent and child will be encouraged to play using the emojis and emotion game mode at least 3 individual game sessions per week. Parents are asked to play GuessWhat with their child 3-4 times per week for 4 weeks.

The Social Responsiveness Scale-2 is a 65-item measure where parents rate their child selecting responses on a Likert Scale. This measure will be used to measure and identify social impairment associated with Autism Spectrum Disorder (ASD) and to quantify its severitySocial Responsiveness Scale (SRS) raw scores measure social abilities with lower scores indicating better social skills. (Raw Score Range: 0 - 195 and T-Score Range: 37- above 90).

Vineland Adaptive Behavior Scales, 2nd edition (VABS-II) Socialization subscale of the Parent/Caregiver Comprehensive form will be administered online to the parents. Scores from the socialization domain of the VABS-III reflects one's functioning in social situations. The socialization subscale is 32 items, where raw scores are converted to IQ-type standard scores--v-scale scores (M=15, SD=3) where scores range from 1 to 24, and factor in age equivalents, growth scale values, and higher scores indicate better adaptive functioning.

App usage data comprised of game decks selected, number of game sessions started, ended, and shared.

Qualitative survey delivered to parent participants at Week 4 to understand preferred games, overall feedback including likes and dislikes, any technical issues they experienced or challenges in using the app.

The Social Communication Questionnaire (SCQ) screens for autism in children over 4:0 years in age. Parents are asked 40 Yes/No questions and the resulting score is out of 39 (the first question is not associated with a numerical value). The SCQ assesses a child's communication skills and social functioning. It takes less than 10 minutes to complete and is administered by clinical research coordinators to parents of children during the phone screen to participants who have already completed the online screening questionnaire. A score of 15 or above is indicative of autism and is required to be eligible in the research study.