Figure 4.

Odor preference measured by lick ratio in experiment 3. (A) For all animals, there is no preference between C[−] and L[−] before conditioning. After conditioning, animals preferred C[−]. (B) Animals of group 1 preferred L[−] over I before conditioning. After conditioning, this spontaneous preference disappeared. (C) There is no preference for animals of group 2 between C[+] and E before and after conditioning. (D) All animals preferred G over C[−] before conditioning. After conditioning, preference changed and animals preferred C[−] over G. Data are presented as means of ratio (number of licks for the bottle on the sum of the number of licks for the two bottles) + s.e.m. over the two successive pretest/test days (Wilcoxon tests; ^*p < 0.05; ^**p < 0.01; ^***p < 0.001).