Perceived numerosity: An information processing analysis.

Presented 3 university students with matrices of from 1 to 16 dots and asked them to count the dots they could see. In Condition 1 a visual noise pattern followed the display of dots by one of several intervals in order to control the time available to process them. In Condition 2 no mask was used, but the exposure duration was varied. In the processing time condition, dots were counted at a rate of 4 msec/dot when less than 6 dots were presented, and at a rate of 60 msec/dot for all dots in excess of 6. If enough time was given to process all the dots presented, virtually all were reported, whereas, if enough time was given to count only some of the dots, virtually none of the excess were counted. In the duration condition, in which processing time was not restricted, counting appeared to be a function of the visibility of the dots, as shown by a family of more linear functions between number of dots presented and number counted, with the slope determined by the duration of exposure. Data are consistent with a serial processing interpretation of dot counting occurring at a very early stage of information extraction, in which there is a serial scanning mechanism which extracts information from an initial brief store and transfers it to a 2nd store for actual counting. (French summary) (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)