Malnutrition and behavior: the performance versus learning problem revisited.

At 100 days of age rats, whose dams suffered severe zinc deficiency and/or undernutrition throughout lactation, were tested in two learning tasks. One test was an original discrimination learning task and the other test was a more difficult reverse discrimination learning task. In the reverse learning test, performance differed significantly between rehabilitated malnourished rats and normal rats. Difference in motivation, and not learning ability, was the explanation for the differences in performance between the malnourished and normal rats.