Abstract
There is growing evidence that motor regions are engaged not only in action execution and perception but also in action word comprehension. However, the underlying mechanisms connecting action perception and linguistic understanding remain unclear. The present study aims to examine the role of rhythmic processes in linking action-word comprehension with recognition of body movements from visual input. Rhythmic processes can be revealed by stimulus-locked oscillations in behavioral performance, reflecting the interactions between a current stimulus (i.e., probe action) and the state of ongoing activity elicited by a prior verbal stimulus (i.e., prime word), when manipulating the timing between prime and probe (stimulus onset asynchrony, SOA). In Experiment 1, participants viewed an uninformative (.5 predictive probability) action word (walk or run) for 500 ms. After a prime-to-probe SOA varying from 33 to 1500 ms with 25 levels evenly spaced in log-space, participants viewed an ambiguous point-light action morphed between a runner and a walker (with a morph weight of .7) for 400 ms. Fast Fourier transform on response times revealed reliable oscillatory patterns in the theta band (3-5 Hz) and alpha band (10-12 Hz). In Experiment 2, we increased the predictive probability of the action word to .67. SOAs were equally spaced in the range of 33 to 825 ms in increments of 33 ms. A facilitation effect was found when the word and subsequent action were congruent in comparison to the incongruent condition. We again found strong behavioral oscillations at theta and alpha bands, but with greater amplitudes than for the uninformative words used in Experiment 1. Our findings suggest that behavioral oscillatory effects do not only arise in low-level tasks, but also can be found in high-level visual tasks. Rhythmicity may serve as a core mechanism for binding distinct processes, such as action perception and linguistic meaning.
Meeting abstract presented at VSS 2018