Memory load and latency in recognition of pictures.

Color photographs of common scenes were used as memory and test items in two memory search experiments. Memory load varied from 2 to 24 items in one experiment and from 4 to 64 in the other. Latency of classification of test items increased with memory load. The increase is verb' close to linear for loads up to six items, but for the full range of memory loads, it is negatively accelerated and approximately logarithmic. Sternberg's (1966, 1969) serial theory of memory search, which predicts linear functions, holds for small memory loads of pictures. If serial search takes place for large memory loads, the speed of search must be faster than for small loads. It is also possible that items in memory loads of all sizes are accessed by a single process that generates a negatively accelerated relation between size of load and latency.