Figure 4. Graphs showing the number of trials displaying the behavioral reactions to target and non-target sounds.

A. Responses to target (8) and non-target (1–7) sounds in the confirmation tests carried out as the last session of training. B. Responses to target and non-target sounds included in the recognition tests. Recognition tests were carried out one day after the confirmation test (left, 1st test; right, 2nd test). X-axis shows sound types: 1, tap water; 2, clapping hands; 3, hitting plastic carrier; 4, hitting metal plate; 5, scratching metal mesh; 6, jingling keys; 7, human vowels; and 8, footstep sound (target). Y-axis, animals tested. Note that each stimulus type is repeated 7 times per session; thus, the maximum number of positive trials is 7 (z-axis). p>0.5 for any pair between non-target sounds, while p<0.01 for any pair between target and non-target sounds (see text for statistical details).