Foundations Of Cognitive Science

Serial Search

A type of memory search in which information is retrieved one piece after another. Serial searches are represented by a linear function. That is, when retrieval time is plotted against the number of items to be retrieved the slope of the graph is constant, and is equivalent to the amount of time that it takes to retrieve a single piece odf information.

Serial memory search is often contrasted with parallel memory search in which a number of pieces of information are retrieved at the same time. Graphically, the slope of the line representing parallel search is zero. That is, as the number of items to be retreived increases the amount of time that it takes to retrieve these items remains constant.

Sternberg (1969) argued that retrievel from short term memory relies upon serial type searches, whereas retrieval from long term memory relies upon parallel type searches.

However, it has also been argued that search latency functions cannot be used to determine whether search is serial or parallel, because increased load might slow down parallel search, giving its search latency function a "serial" appearance (Townsend, 1971, 1990).


  1. Sternberg, S. (1969). Memory-scanning: Mental processes revealed by reaction-time experiments. American scientist, 4, 421-457.
  2. Townsend, J. T. (1971). Note on identifiability of parallel and serial processes. Perception & Psychophysics, 10(3), 161-163.
  3. Townsend, J. T. (1990). Serial vs parallel processing: Sometimes they look like Tweedledum and Tweedledee but they can (and should) be distinguished. Psychological Science, 1(1), 46-54.

(Revised October 2010)