Can participants extract subtle information from gesturelike visual stimuli that are coordinated with speech without using any other cues?

Embodied cognition is the reflection of an organism's interaction with its environment on its cognitive processes. We explored the question whether participants are able to pick up on subtle cues from gestures using the Tower of Hanoi task. Previous research has shown that listeners are sensitive to the height of the gestures that they observe, and reflect this knowledge in their mouse movements (Cook & Tanenhaus, 2009). Participants in our study watched a modified video of someone explaining the Tower of Hanoi puzzle solution, so that participants only saw a black background with two moving dots representing the hand positions from the original explanation in space and time. We parametrically manipulated the location of the dots to examine whether listeners were sensitive to this subtle variation. We selected the transfer gestures from the original explanation, and tracked the hand positions with dots at varying heights relative to the original gesture height. The experimental gesture heights reflected 0%, 25%, 50%, 75% and 100% of this original height. We predicted, based on previous research (Cook in prep), that participants will be able to extract the difference in gesture height and reflect this in their mouse movements when solving the problem. Using linear model for our analysis, we found that the starting trajectory confirmed our hypothesis. However, when looking at the averaged first 15 moves (the minimum to solve the puzzle) across the five conditions, the ordered effect of the gesture heights was lost, although there were apparent differences between the gesture heights. This is an important finding because it shows that participants are able to glean subtle height information from gestures. Listeners truly interpret iconic gestures iconically.