sleeper effect
the finding that the impact of a persuasive message increases over time. This effect is most likely to occur when a person carefully scrutinizes a message with relatively strong arguments and then subsequently receives a discounting cue (i.e., some piece of information suggesting that the message should be disregarded). The discounting cue weakens the initial impact of the message, but if the cue and the arguments in the message are not well integrated in memory, the cue may gradually be forgotten. If this occurs, the impact of the arguments will be greater at a later point in time than they were at the time of their initial presentation.