Incidental and Non-Incidental Processing of Biological Motion: Orientation, Attention and Life Detection

Based on the unique traits of biological motion perception, the existence of a “life detector”, a special sensitivity to perceiving motion patterns typical for animals, seems to be plausible (Johnson, 2006). Showing motion displays upsidedown or with changes in global structure is known to disturb processing in different ways, but not much is known yet about how inversion affects attention and incidental processing. To examine the perception of upright and inverted point-light walkers regarding incidental processing, we used a flanker paradigm (Eriksen & Eriksen, 1974) adapted for biological motion (Thornton & Vuong, 2004), and extended it to include inverted and scrambled figures. Results show that inverted walkers do not evoke incidental processing and they allow high accuracy in performance only when attentional capacities are not diminished. An asymmetrical interaction between upright and inverted figures is found which alludes to qualitatively different pathways of processing.