One goal of Cognitive Psychologists is to categorise mental operations involved in a task (e.g. grocery shopping, p. 113). The Psychologists therefore assume that tasks are made up of whole sets of mental operations. This is an input & output process and mental operations generate, elaborate on & manipulate mental representations.
It is possible to formulate experiments to explore these ideas (p. 114).
parallel process - when mental comparisons can be done simultaneously
serial process - when mental comparisons can only be done one at a time
exhaustive search - all possibilities are examined
Memory comparison appears to be a serial process but many mental processes operate in parallel.