Figure 3. The proportion of time spent in the preference areas to the total observation time ((time left + time right)/600sec) is shown for each stage. The dashed line represents the null expectation of 66% of the time spent in the preference areas. The circles represent the means for each stage. The letters A and B designate groups that are significantly different. The increase in the time spent in the preference areas between early flexion stage and the post flexion stage suggests the onset of shoaling behavior (Engeszer et al, 2007).