It is now widely accepted that individuals with autism have a Theory of Mind (ToM) or mentalizing deficit. This has traditionally been assessed with false-belief tasks and, more recently, with silent geometric animations, an on-line ToM task. In adults with milder forms of autism standard false-belief tests, originally devised for children, often prove insensitive, while the Frith-Happé animations have had rather better success at capturing the on-line ToM deficit in this population. However, analysis of participants' verbal descriptions of these animations, which span scenarios from “Random” to “Goal-Directed” and “ToM,” is time consuming and subjective. In this study, we developed and established the feasibility of an objective method of response through a series of multiple-choice questions. Sixteen adults with autism and 15 typically developing adults took part, matched for age and intelligence. The adults with autism were less accurate as a group at categorizing the Frith-Happé animations by the presence or absence of mental and physical interactions. Furthermore, they were less able to select the correct emotions that are typically attributed to the triangles in the mental state animations. This new objective method for assessing the understanding of the animations succeeded in being as sensitive as the original subjective method in detecting the mentalizing difficulties in autism, as well as being quicker and easier to administer and analyze. Autism Res 2011, 4: 149–154. © 2011, International Society for Autism Research, Wiley Periodicals, Inc.