FIG. 2.

(A) Comparison of latencies (in seconds) to enter the black compartment of fish trained with a 0 V (open triangles), 1 V (closed circles), 3 V (open squares), or 9 V (closed triangles) electric shock. Data are presented as individual latencies (single dots) as well as group medians (black bar). Day 1 shows the initial latencies recorded without training, whereas day 2 shows the latencies after a single shock. Dotted lines indicate the 60- and 180-s threshold. Capital letters above groups indicate significant differences assessed by a Mann–Whitney U-test; groups that do not share corresponding letters are significantly different from each other (p≤0.0083). Asterisks (**p≤0.01 and ***p≤0.001) indicate a significant increase in latency from day 1 to 2 within a single treatment. n=the number of fish. (B) Comparison of the percentage of avoider (white), semiavoider (gray), and nonavoider (black) individuals in the different groups on day 2. Capital letters above groups indicate significant differences assessed by a chi-square test (excluding the single semiavoider fish); groups that do not share corresponding letters are significantly different from each other (p≤0.0083). Note that the numbers listed in the white and black part of the bars represent the number of avoider and nonavoider fish in each group and not the percentage of fish.