1. Extracting cues to intention utilising animacy displays derived from human activity Phil McAleer & Frank E. Pollick Department of Psychology, University of Glasgow phil@psy.gla.ac.uk http://paco.psy.gla.ac.uk & www.psy.gla.ac.uk/~phil IntroductionStimulus Production Experiment 1: Forced Choice Task Experiment 2: Free Response Task Conclusions References Heider and Simmel (1944) showed that people, on viewing a simple animation involving geometric shapes, would attribute emotions and intentions to the shapes based on their movements. Our previous research introduced a new method to create animacy displays directly from human motion, and results showed a bias towards displays viewed from an overhead perspective (McAleer et al. 2004). We continue to use the method to examine the perception of animacy and in particular, the six specific intentions put forward by Blythe, Todd & Miller (1999) of Chasing, Fighting, Playing, Flirting, Guarding & Following. We investigate: (1) the effect of viewpoint on these intentions, (2) the effect of cues to occlusion and context on distinguishing these displays, and finally (3) differences when a forced choice task is employed compared to a free response task. 6 Intentions: CHASE, FIGHT, PLAY, FLIRT, GUARD & FOLLOW 2 Viewpoints: OVERHEAD & SIDE & 4 display conditions (2 X 2): Occlusion & Context Results No Effect of Display Condition Effect of Viewpoint, 0.52 Vs. 0.32 respectively F(1,16)=17.54, p=0.001. Control Experiment Displays presented to observers who were asked whether they were viewing an overhead or side display 82% correct for overhead Vs. 80% for side TASK - 6 Alternative Forced Choice task (n=17) Same design as Experiment 1: 6 Intentions, 2 Viewpoints, 4 Display Conditions. TASK - Free Response Task (n=14) Watch Display & describe what happened? 2 Raters of Responses – Overall, 89% agreement in scoring Large variability in subjects. Mean of 53.9% of displays described in animate terms. Overhead displays are described in animate terms more often than side view displays. Displays depicting chase or follow are described correctly more often than other intentions. Actors were filmed performing six intentions on a 10ft square stage using two digital video cameras: one positioned directly above centre stage (Overhead); the second positioned inline with the centre of the side of the stage (SideView). 4 experimental display conditions were created to give either occlusion cues (o), contextual cues (c), neither (no,nc) or both (o,c). These co-ordinates were filtered to reduce noise and used to create QuickTime movies depicting white/black disk(s) on a grey background. The X and Y co-ordinates were extracted from the footage using the EyesWeb open platform for multimedia production and motion analysis, which tracks the centre of mass of the silhouette image for each respective person. (www.eyesweb.org). no,nc no,c o,nc o,c Overhead Side Blythe, P.W., Todd, P.M., and Miller, G.F. (1999). Judging intention from motion: Basic mechanisms for social rationality. In G. Gigerenzer, P.M. Todd, and the ABC Research Group, Simple heuristics that make us smart. New York: Oxford University Press. Heider, F., & Simmel, M., (1944). An Experimental Study of Apparent Behavior, American Journal of Psychology, 57:2. McAleer, P., Mazzarino, B., Volpe, G., Camurri, A., Patterson, H., & Pollick, F. (2004). Perceiving Animacy and Arousal in Transformed Displays of Human Interaction. Journal of Vision, 4(8), 230a. This technique for the creation of animacy displays validates the intention categories proposed by Blythe, Todd & Miller (1999) for human actions. Experiment 1 indicates that observers are proficient at attributing the correct intention when given the appropriate set of categories. The follow-up control experiment shows that the effect of Viewpoint is not due to subjects misinterpreting the display. Experiment 2 suggests that observers do attribute intention to the animacy displays, but use fewer categories when given no guidance to the intention displayed. Furthermore, it again shows a difference in viewpoint, with Overhead displays being described in animate terms more often than Side View displays. Current research is looking at perception of the six intentions in a clinical population of people with Autistic Spectrum Condition.