Response times with a memory-dependent decision task.

4 experiments were conducted to determine the time required to make some simple memory-dependent decisions. S's task was to decide whether any of the items of a memorized check list were contained in a visually displayed search list, and to register his decision as quickly as possible by pressing 1 of 2 response keys. RT varied directly both with the number of items in the check list and the number in the search list, and inversely with the number of items common to both lists. Practice reduced RT across conditions, and it also decreased, but did not eliminate, the effects of the independent variables. Decreases in RT with practice were accompanied, in most cases, with increases in the frequency of errors. How does the search of a memory representation of a visual display compare with the search of the visual display itself? Suppose that 6 is given the task of deciding whether two visually presented sets of characters have any items in common. If one set is presented only after the other has been erased, then the task is memory dependent and may be described either as that of determining whether any of the items in the memory representation are included in the visual display, or, conversely, as that of deciding whether any of the displayed items are included in the memory representation. Consider in particular two contrast