REDUCTION OF OCULAR MOTILITY FOLLOWING VISUOSPATIAL QUESTIONS - A TEST OF THE VISUAL INTERFERENCE HYPOTHESIS

Studies in which lateral eye movements (LEMs) were used as indices of differential hemispheric activation during cognitive processing have found a greater proportion of ‘stares’ following visuo-spatial questions than following verbal questions. This phenomenon was explained by a visual interference hypothesis (VIH): assuming that solving spatial questions involves visual imagery, and that visual stimuli may interfere with internally generated visual images, interference can be limited by suppressing eye movements (EMS). No support to the VIH came from investigations predicting a greater proportion of stares in visually enriched environments. However assuming that the ‘gating out’ of visual inputs during the processing ofvisuo-spatial questions is a well-established habit, experimental manipulation of the visual environment may be ineffective in modifying the rate of stares. Based on the VIH, we tested a different prediction: instances in which spatial questions are followed by an EM should be characterized by longer reflection latencies (RL). Data from 32 female Ss. tested in a LEMs experiment confirmed that RLs for spatial questions followed by an EM are significantly longer CM= 10.33”) than those followed by stares (M = 6.34”). Since this could be due to the fact that EMS might have a greater probability of occurring in longer time intervals, analysis was repeated with a 2” cut off for EMS. The effect of interference was confirmed, RL for questions followed by an EM being equal to 8.05” and for those followed by stares being equal to 5.10”. Further analyses for verbal questions will reveal whether the interference effect is specific to visuo-spatial processing.