Eye movements through space interfere with visual processing of time-related words
When people make lexical decisions to words referring to the past or the future, they are faster when their manual responses are compatible with the mental timeline (MTL). That is, future words are responded to faster on the right than the left, while past words are responded to faster on the left than the right. This space-time congruency effect is interpreted to suggest that time words are represented along a spatial continuum that goes from left to right (past to future), at least in Western cultures that use reading-writing systems operating from left to right. All previous experiments used lateralized hand movements to register responses, which would evoke the directionality of writing. To evoke the directionality of reading, we investigated whether the space-time congruency effect would be replicated in a language task when responses were given using the eyes rather than the hand. Thus, participants were asked to make lateralized eye movements to indicate whether letter stimuli were real words or not (lexical decision). Eye movements were perturbed for responses incompatible with the direction of the MTL, both in terms of decision time and motor amplitude. These results confirm that time-related words are embodied through spatial movement in effector-independent motor networks and suggests that the spatial representation of time operates in a body-centered reference frame.