Fig. 3: Absolute turning positions across treatments.
From: Visual odometry of Rhinecanthus aculeatus depends on the visual density of the environment
Between sessions, the start area was moved across three increasingly distal positions within the tunnel to control for the use of external cues and assess distance estimation abilities. If fish were using an internal measure of distance, there would be a systematic shift in turning position according to each start area position. This was indeed observed across treatments 1–3 where spatial frequency information was provided, indicating that fish are reporting perceived travel distance. When spatial frequency information was removed in treatment 4, there was no consistent significant shift in turning position for all start area positions. Grey dashed lines indicate corresponding start area positions for the three start area positions (dark grey: +0; mid grey: +10; light grey: +20). Box plots indicate the median, interquartile range, and grey points indicate outliers. Each fish completed a maximum of 15 distance estimates for each start area position.
