Sex differences in serial pattern learning in mice

•Mice learned single-alternation, double-alternation, and runs patterns at levels exceeding chance.•Sex differences were observed for the runs pattern but not the single-alternation or double-alternation patterns.•Sex differences in serial pattern learning within rodents are not unique to rats.•Sex differences within serial pattern learning are more likely to be seen while acquiring more complex serial patterns. Numerous investigators have examined the hypothesis that males and females learn or perform differentially on various tasks. However, many of the behavioural investigations with nonhuman animals (e.g., rats) have used paradigms that do not permit the exploration of complex learning and memory between the sexes. To this end, we explored the ability of male versus female mice to learn three different patterns in succession in three separate experiments: single alternation (e.g., right, left, right, left), double alternation (e.g., right, right, left, left), and runs (e.g., 123, 234, 345, 456, 567, 678, 781, 812, where digits represent locations within a circular array in the counterclockwise direction). We hypothesized that sex differences, if they existed, would be most likely to appear as the pattern to be learned became more complex (required more rules to capture how elements relate to one another). The results indicated that mice can learn all three pattern types, but learning was more difficult as pattern complexity increased. Males learned the runs pattern significantly more quickly than females did; no significant differences were found between males and females for acquisition of the single-alternation or double-alternation patterns. These results suggest that sex differences in serial pattern learning within rodents are not unique to rats and are more likely to be seen during acquisition of more complex patterns.