*** Fetterman Excepting for sundials and a few other analog devices, to time is to count. This is because the counting of events- -even random events--can yield very accurate estimates of time. It is not surprising, therefore, that major theories of timing by biological systems posit timers that work by accumulating (counting) events generated by some kind of biological pacemaker. Dr. J. Gregor Fetterman, in collaboration with Dr. Peter R. Killeen, of Arizona State University, is examining how variation (error) in the pacemaker and in the accumulator contribute to timing by such clock-accumulator systems-- the pacemaker and the counter. They are exploiting the intimate relation of timing to counting by studying parallel experimental tasks in each domain. They search for invariances in the system under a variety of tasks that require temporal perception and discrimination. They will embed these findings in a general model of clock- counter error. Because of the key role of timing in all types of behavior, the results of this research will contribute importantly to our understanding of the fundamental mechanisms of behavior. ***
