Moving average of the collective asymmetry () vs. the total number of escaped ants ().

<p>The two dashed lines above and below the curve are the s (the standard error of the mean) of the moving average. This curve displays a high profile when the number of ants is small as well as a decrease of to a low profile when the number of ants is large. The inset shows, within the 291 individual experiments, that the number of experiments in which , and is 151, 134 and 6, respectively. and denotes the total number of ants escaping left and right, respectively. This indicates that there are no hidden biased environmental factors affecting the direction of ant movement.