The results of experiment 1. (a) 2D heatmaps of the fish’s swimming positions in each of the 1-minute time bins. The density is calculated by dividing the amount of time that the fish stayed at each position by the total amount of time in each time bin and then scaled to [0, 1]. The warmer the color, the more frequently the fish stayed at this position. The bottom side is the screen on which the upright BM stimuli were presented. (b) Average oriented direction of each fish in each ROI. Each dot on the circle represents one fish. The orange and green dots represent the fish in ROI 1 and ROI 2, respectively. The tail of the dot points to the average oriented direction of the fish across frames, with its length inversely representing the variation. The shorter the length, the larger the variation. The central two rods show the average vector of direction focus across fish in each ROI. (c) The relative percentage of time the fish spent in each ROI over separate time bins as well as the average (test minus baseline). (d) The relative percentage of time the fish oriented towards the nearby stimulus in each ROI. (e) The relative magnitude of the mean direction focus of the fish towards the nearby stimulus in each ROI (the ). The circles (or squares) and the error bars represent the sample . Note: , with FDR corrected for separate time bins; #, uncorrected; †. The orange and green signs mark the significant differences between the test and the baseline periods for the upright BM and the non-BM stimuli, respectively, while the black ones mark the significant differences between the upright BM and the non-BM stimuli during the test period.