Figure 1.

Learning curves regarding olfactory discrimination for each of 14 individual minipigs. Mean percent correct responding (±standard error of the mean) on each 160-trial session. S+ was a 1% aqueous solution of ethyl acetate, and S- was water solvent. Gaps in lines denote a 1-month pause in testing during which the apparatus was optimized by moderate modifications. To master the task, individuals must obtain a minimum 75% correct responses in one 160-trial session. Success in reaching criterion is denoted by a blank circle. Females (ID F1-F8), males (ID M9-M14).