Ocular-Vestibular Integration, Height Anxiety and the Environmental Vertical Illusion

The ocular-vestibular system integrates visual, vestibular, and proprioceptive information in order to aid individuals in navigating the environment. Individual differences arise in the relative weight that individuals give to visual information over kinesthetic information. Individuals relying more on visual information tend to experience a greater fear of heights than those accurately interpreting bodily information. Previous research has suggested that a fear of heights correlates with a greater over-exaggeration of vertical surfaces. However, no research has linked cognitive ocular-vestibular mechanisms to individual differences in visual height perception. The current study investigated how visual dependency as well as static and dynamic postural control related to height anxiety and estimates of vertical surfaces. Although the current study did not find the predicted relationship between height anxiety and vertical distance estimates, both balance and visual field dependence measures related to these variables in the predicted directions. Results suggest that greater visual field dependence and poor dynamic balance play an important role in the overestimation of vertical surfaces. Results replicated previous findings that poor balance and visual field dependence positively related to height anxiety, perhaps through the interaction with individual differences in vertical perception. Data from this study suggest that development of navigational abilities may influence visual vertical perception and height anxiety in a relatively similar yet independent manner. Implications may include the treatment of height anxiety through exercise of bodily kinesthetics. Future research focus on determining the malleability and causal effects of balance and visual field dependence.