Staddon, J. E. R., & Higa, J. J. (1999).
Time and memory: Towards a pacemaker-free theory of interval timing.
Journal of the Experimental Analysis of Behavior,
71, 215-251.
A popular view of interval timing in animals is that it is driven
by a discrete pacemaker-accumulator mechanism that yields a
linear scale for encoded time. But these mechanisms are
fundamentally at odds with the Weber law property of interval
timing, and experiments that support linear encoded time can be
interpreted in other ways. We argue that the dominant
pacemaker-accumulator theory, scalar expectancy theory (SET),
fails to explain some basic properties of operant behavior on
interval-timing procedures and can only accommodate a number of
discrepancies by modifications and elaborations that raise
questions about the entire theory. We propose an alternative that
is based on principles of memory dynamics derived from the
multiple-time-scale (MTS) model of habituation. The MTS timing
model can account for data from a wide variety of time-related
experiments: proportional and Weber law temporal discrimination,
transient as well as persistent effects of reinforcement omission
and reinforcement magnitude, bisection, the discrimination of
relative as well as absolute duration, and the choose-short
effect and its analogue in number-discrimination experiments.
Resemblances between timing and counting are an automatic
consequence of the model. We also argue that the transient and
persistent effects of drugs on time estimates can be interpreted
as well within MTS theory as in SET. Recent real-time
physiological data conform in surprising detail to the
assumptions of the MTS habituation model. Comparisons between the
two views suggest a number of novel experiments.
Key words: timing, clock, habituation, recall, Weber law, choose
short, pacemaker