a the numbers of correct responses (i.e. nosepokes to
the bottle with sucrose) were corrected for numbers of nosepokes to the
bottle with tap water located in the same corner (used as a covariate,
significant at p<0.001).
b the numbers of licks the bottle with sucrose were
corrected for numbers of licks to the bottle with tap water located in
the same corner (used as a covariate, significant at p<0.001).