Please choose your delivery country and your customer group
Fields of dots, ranging in number from 1-30, were projected on a screen. S's were instructed to report the number of these dots, and they were given all the time they needed to do so. From the data, analyzed in terms of accuracy of report and the time between the stimulus and the report, the following conclusions were made: (1) S's reports of 1-30 dots were on the average highly accurate. (2) The first derivative of the function relating report-time and number of dots presented is discontinuous at about 6 stimulus-dots. (3) The function relating report-time and number of dots presented has a characteristic shape. This is most clearly seen when the data are transformed by a reciprocal equation and plotted on semilogarithmic coordinates. On these coordinates the first 5 or 6 points fall along a straight line which has a high negative slope. The remaining points fall along a shallow, decelerating curve. (4) S's subitized (i.e., handled accurately, without counting) up to 5 or 6 dots and counted the rest. They subitized up to 5 or 6 dots even though accuracy was stressed, and they were given time enough to count. (Author)