The representation and processing of simple perceptual magnitudes such as the pitch of a sound, or the distance between two dots, is commonly investigated by the 'absolute identification' task. Participants are presented a small number (usually 6-10) of such stimuli, and attempt to learn the rank in the set of each one. This task is surprisingly hard, even when (as is usual) the stimuli are not confusable with their neighbours; participants can usually only perform perfectly if there are four or fewer stimuli. This project aims to examine the specific relationship between accuracy and the length of the responses taken to understand the time course of processing such information. Two experimental strands will manipulate: the influence of the time for which the stimulus is physically available to be processed the decisional or 'thinking' time that is available The results will more generally inform our thinking about stimulus-processing at the level of individual features, and the way information influences decisions over time.