SCALAR EXPECTANCY-THEORY AND PEAK-INTERVAL TIMING IN HUMANS

The properties of the internal clock, temporal memory, and decision pr ocesses used to time short durations were investigated. The peak-inter val procedure was used to evaluate the timing of 8-, 12-, and 21-s int ervals, and analyses were conducted on the mean response functions and on individual trials. A distracter task prevented counting, and visua l feedback on accuracy and precision was provided after each trial. Me an response distributions were (a) centered at the appropriate real-ti me criteria, (b) highly symmetrical, and (c) scalar in their variabili ty. Analysis of individual trials indicated more memory variability re lative to response threshold variability. Taken together, these result s demonstrate that humans show the same qualitative timing properties that other animals do, but with some quantitative differences.