Delayed nonmatch to sample

Delayed match-to-sample tasks, or DMTS, are very similar to match-to-sample tasks except before choosing the correct response, there is a short delay. This delay can vary in length in order to determine how long the subject can retain information in their working memory. If the subject responds correctly over fifty percent of the time, it shows that the subject has held that information (sample stimulus - see above) in memory.

The amount of information that subjects can retain differs with species. For instance, a study by Grant in 1975, found that pigeons' ability to correctly choose the comparison stimuli (see above) declined as the delay between stimuli presentations increased. On average, a ten-second delay resulted in a correct response choice of around sixty-six percent. In a much more developed species, capuchin monkeys, D'Amato found (in 1973) that monkeys are able to choose the correct stimuli with a sixty-six percent rate, but with a much longer delay.