Figure 2. Effect of limiting headings to ±45°.

In a subset of 6 subjects (#1,2,3, 7, 8, and 9) the task was repeated with the possible headings limited to ±45°. This task was initially done with the responses mechanically limited to ±45° (squares) and subsequently in the same session with the full range of responses available (triangles). Each data point represents the median response with error bars representing 25^th to 75^th percentiles. The responses with a full range of possible headings and responses are shown as circles, these are the same responses plotted in Fig. 1 but for the subset of subjects who also completed the limited heading task. Squares marked with ‘X’ indicate the perceived headings during the 45° response limited condition were significantly different than the perceived headings when the full range of headings was delivered. Triangles marked with dots indicate a significant difference (p<0.01) between conditions where the responses were limited to ±45° and the condition where only the headings were limited to ±45°, this was uncommon and limited to the visual stimulus for headings of ±40° and ±45°.