Chatbot Appearance and Loneliness Trajectories in Women With High Autistic Traits

Chatbots are increasingly explored as tools to support social and emotional well-being. However, little is known about how chatbot visual appearance influences user outcomes over time, particularly among individuals with elevated autistic traits. This study examined whether chatbot appearance shapes loneliness trajectories among women with high autistic traits who used a chatbot at least three times per week. A randomized longitudinal experiment compared two conditions that were identical in function, dialogue strategy, and usage structure. Seventy-two participants interacted for eight weeks with either a chatbot with a non-human visual appearance or a chatbot with a human-like visual appearance. Loneliness was measured at four time points and analyzed using linear mixed-effects models. We predicted that loneliness would decline in the non-human condition and that the decline would be steeper than in the human-like condition. Both predictions were supported. The Group × Time interaction was significant, and loneliness decreased in the non-human appearance condition, whereas the slope was bounded near zero in the human-like condition, 95% CI [−0.92, 0.99]. Baseline loneliness did not differ between groups. These findings suggest that chatbot appearance can influence longer-term interaction outcomes rather than only immediate impressions. For neurodiverse users, appearance is a core design dimension and warrants longitudinal evaluation.