My Account

Poster A38, Tuesday, August 20, 2019, 10:15 am – 12:00 pm, Restaurant Hall

Can Language Cue the Visual Detection of Biological Motion?

Ksenija Slivac1, Alexis Hervais-Adelman2, Peter Hagoort1,3, Monique Flecken1,3;1Max Planck Institute for Psycholinguistics, 2University of Zurich, 3Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen

Motion perception is an evolutionarily salient part of our visual system, with a robust processing dichotomy between general and biological motion, reflected behaviourally and neurally (Howard et al., 1996). The perception of both of these motion patterns has been widely investigated using point-light animations, which highlight the compositional nature of their processing, and a strong reliance on Gestalt principles and prior knowledge for their successful detection (Pastukhov, 2017). The salience of motion is also reflected in language, with fine-grained distinctions in motion type and level of specificity. Studying the interaction between these two systems, we test the extent to which the detection of biological motion in a multistable, dynamic, point-light environment can be cued by language. Specifically, we test the degree of specificity required to achieve a linguistic cueing effect for biological form-from-motion detection. To this end, we carried out two psychophysical experiments (N=40 each), with motion detection (Do you see human motion, yes/no?) and motion discrimination (Is the human figure in the upright or upside down position?) tasks respectively. The experiments use a cueing paradigm to probe the detection of a human point-light figure (PLF; walker, rower, etc.), concealed within a random dot motion (RDM; predominantly upward or downward motion) mask. In addition to coherent PLFs, the participants saw either scrambled (Exp. 1) or inverted (Exp. 2) figures, shown to disrupt the biological motion detection. To ensure the priming of biological motion perception, rather than biological form or general horizontal movement, Exp. 2 included a condition with human figures frozen in a canonical pose, translated back and forth at the speed matching the RDM speed (gliders), in addition to the naturally moving PLFs (naturals). Linguistic cues varied in specificity regarding features of (biological) motion: (in)congruent biological motion (rower, dancer); biological form (brother, father); general motion (snow, smoke). Before each experiment, individual motion detection thresholds were obtained using a Bayesian adaptive staircase procedure at 75% accuracy level. During the thresholding, the coherence of the RDM was adjusted as a function of PLF detection (the less coherent the RDM was, the harder it was to detect the PLF hidden among its dots). Results show that only linguistic cues fully congruent with the biological motion of the (natural) masked PLFs enhanced motion detection (Exp. 1: accuracy, RT, C, Beta, BPPD, Exp. 2: RTs). Furthermore, general motion cues, reminiscent of general motion patterns of the RDM mask itself, decreased the detection of biological motion in Exp. 1. In Exp. 2, incongruent biological motion cues interfered with the detection of biological motion. No effect of linguistic input was found for the gliders. In the context of these results, we discuss preliminary fMRI and representational similarity analysis (RSA) data as well. Findings suggest that motion language is capable of triggering our highly specialised biological motion detection mechanism, enhancing recognition of human-like stimuli in a dynamic and noisy setting. Specifically, we show that such effects are only obtained when the language fully overlaps in degree of specificity on core biological motion features: kinematics and (human) form.

Themes: Meaning: Lexical Semantics, Multisensory or Sensorimotor Integration
Method: Other

Back