Fig. 3. (A) Each session (S1–S10) of training, which included 20 trials, is shown on the x-axis, plotted against choice frequency. Fish A (diamond) required four sessions before discriminating the reference e-vector. Fish B (square) required seven sessions, whereas fish C (triangle) required three, and fish D (circle) required six sessions. Positive response was a correct choice frequency of 70% or above. (B) Time to respond. The time to respond was recorded from the opening of the gate until fish chose an e-vector within the choice area. The time to respond (mean ± S.E.M.) diminished with the training sessions for each fish.