Elsevier

Behavioural Processes

Volume 70, Issue 3, 1 November 2005, Pages 209-222
Behavioural Processes

Review
Timing, memory for intervals, and memory for untimed stimuli: The role of instructional ambiguity

https://doi.org/10.1016/j.beproc.2005.07.001Get rights and content

Abstract

Theories of animal timing have had to account for findings that the memory for the duration of a timed interval appears to be dramatically shorted within a short time of its termination. This finding has led to the subjective shortening hypothesis and it has been proposed to account for the poor memory that animals appear to have for the initial portion of a timed interval when a gap is inserted in the to-be-timed signal. It has also been proposed to account for the poor memory for a relatively long interval that has been discriminated from a shorter interval. I suggest here a simpler account in which ambiguity between the gap or retention interval and the intertrial interval results in resetting the clock, rather than forgetting the interval. The ambiguity hypothesis, together with a signal salience mechanism that determines how quickly the clock is reset at the start of the intertrial interval can account for the results of the reported timing experiments that have used the peak procedure. Furthermore, instructional ambiguity rather than memory loss may account for the results of many animal memory experiments that do not involve memory for time.

Section snippets

Interval timing: the peak procedure

Fixed interval schedules of reinforcement have been used to study the ability of animals to judge the passage of time. With these schedules, the first response that occurs after a fixed time results in reinforcement. In the free-operant version of this schedule, the interval begins with the prior reinforcement. In the discrete-trials version of this schedule used most often to study the timing ability of animals, the interval begins with the onset of a stimulus (e.g., a light or a tone).

Interval discrimination

The typical interval discrimination procedure involves a variation of matching-to-sample or a conditional discrimination. Each trial generally starts with a sample stimulus that is presented either for a short interval or a long interval (e.g., at the start of the trial the houselight comes on for either 2 or 10 s). Following the offset of the houselight two comparison stimuli appear (e.g., a red light and green light, one on the left the other on the right). Responses to the red light will be

General support for the ambiguity hypothesis

The focus of this article has been animal timing but as suggested in the introduction, the issues raised have implications for a broader area of study. In general, one must be careful in interpreting the results of any manipulation that involves the transfer of training or the assessment of memory some time after training. Any decrement in performance found may be attributable not only to the variable under study (e.g., memory) but also to the failure of instructions (i.e., a generalization

Conclusions

Much of the research that has attempted to assess memory for time intervals in animals has suffered from what can be called instructional ambiguity. Most often that ambiguity has come from the similarity between the retention interval and the intertrial interval during training. However, other sources of ambiguity may also produce confounds that may obscure temporal memory assessment. Among those are dissimilarity in behavior during the interval to be timed and the retention interval, and the

Acknowledgement

Preparation of this article was facilitated by Grant MH 63726 from the National Institute of Mental Health.

References (39)

  • J. Gibbon

    The structure of subjective time: How time flies

  • D.S. Grant

    Effect of sample presentation time on long-delay matching in the pigeon

    Learn. Motiv.

    (1976)
  • C.V. Buhusi et al.

    Differential effects of methamphetamine and haloperidol on the control of the internal clock

    Behav. Neur.

    (2002)
  • C.V. Buhusi et al.

    Memory for timing visual and auditory signals in albino and pigmented rats

    J. Exp. Psych.: Anim. Behav. Proc.

    (2005)
  • C.V. Buhusi et al.

    Temporal integration as a function of signal and gap intensity in rats (Rattus norvegicus) and pigeons (Columba livia)

    J. Comp. Psych.

    (2002)
  • S. Cabeza de Vaca et al.

    Internal clock and memory processes in animal timing

    J. Exp. Psych.: Anim. Behav. Proc.

    (1994)
  • R.M. Church

    The internal clock

  • R.M. Church et al.

    Bisection of temporal intervals

    J. Exp. Psych.: Anim. Behav. Proc.

    (1977)
  • T.S. Clement et al.

    Development of a single-code/default coding strategy in pigeons

    Psych. Sci.

    (2000)
  • R.M. Colwill

    Disruption of short-term memory for reinforcement by ambient illumination

    Quart. J. Exp. Psych.

    (1984)
  • R.G. Crowder

    Proactive and retroactive inhibition in the retention of a T-maze habit in rats

    J. Exp. Psych.

    (1967)
  • B.R. Dorrance et al.

    Event duration discrimination by pigeons: the choose-short effect may result from retention-test novelty

    Anim. Learn. Behav.

    (2000)
  • S.C. Gaitan et al.

    The role of “nothing” in memory for event duration in pigeons

    Anim. Learn. Behav.

    (2000)
  • J. Gibbon et al.

    Sources of variance in an information processing theory of timing

  • D.S. Grant

    Symmetrical and asymmetrical coding of food and no-food samples in delayed matching in pigeons

    J. Exp. Psych.: Anim. Behav. Proc.

    (1991)
  • D.H. Kaiser et al.

    Timing in pigeons: effects of the similarity between intertrial interval and gap in a timing signal

    J. Exp. Psych.: Anim. Behav. Proc.

    (2002)
  • K. Kirkpatric-Steger et al.

    Cyclic responding by pigeons on the peak timing procedure

    J. Exp. Psych.: Anim. Behav. Proc.

    (1996)
  • P.J. Kraemer et al.

    The choose-short effect in pigeon memory for stimulus duration: subjective shortening versus coding models

    Anim. Learn. Behav.

    (1985)
  • E.F. Loftus

    Memory for a past that never was

    Cur. Dir. Psych. Sci.

    (1997)
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