Cleal and Parker attempted to investigate what implications moderate exposure to alcohol during embryonic development has on certain cognitive aspects in adult zebrafish. They hypothesized that the moderate developmental ethanol exposure would affect aspects of learning and  memory in zebrafish. For that, the authors exposed zebrafish embryos to moderate alcohol concentrations (20 mM) or to fresh aquarium tank water with no alcohol (control) for 7 days (from 2dpf to 9 dpf). Later, when the animals were in the adult stages (3 mo), the authors performed tests of appetitive conditioning, Pavlovian fear conditioning, and Y-maze test of perseveration and repetitive alternation to evaluate the effects of ethanol treatment on aspects of learning and memory. The techniques were appropriate for the hypothesis, and the authors found a new element in the effect of exposure to ethanol. Considering that alcohol is a drug of high consumption, it is very important to understand its action on the embryonic nervous system and its role in the etiology of cognitive deficits that are neglected, since these deficits can affect the quality of life or relate to the origin and aggravation of mental illness. The result that drew the most attention was the fact that embryonic exposure to ethanol produced "a specific type of cognitive damage", and that only spontaneous alternation was altered by exposure to ethanol.