The effects of task unpleasantness, justification, and its timing were investigated through two laboratory experiments.
In Experiment I, where the task was extremely unpleasant, Ss rated it more enjoyable under the condition of low justification, regardless of timing of justification.
In Experiment II, where the task was mildly unpleasant, the earlier study by Freedman (1963) was replicated: when justification was given before performing the task, the lower the justification, the greater the liking for the task; but when justification was given after completing the labor, the less the enjoyment of the task.