Subitizing

Subitizing is the rapid, accurate, and confident judgements of numbers performed for small numbers of items. The term was coined in 1949 by E.L. Kaufman et al., and is derived from the Latin adjective subitus (meaning "sudden") and captures a feeling of immediately knowing how many items lie within the visual scene, when the number of items present falls within the subitizing range. Number judgments for larger set-sizes are referred to either as estimating if insufficient time is available for observers to accurately count all the items present, or counting otherwise.