Pigeons may not use dual coding in the radial maze analog task.

Abstract

Using a radial maze analog task, T. R. Zentall, J. N. Steirn, and P. Jackson-Smith (1990) found evidence that when a delay was interpolated early in a trial, pigeons coded locations retrospectively, but when the delay was interpolated late in the trial, they coded locations prospectively (support for a dual coding hypothesis). In Experiment 1 of the present study, the authors replicated the original finding of dual coding. In Experiments 2 and 3, they used a 2-alternative test procedure that does not require the assumption that pigeons' choice criterion, which changes over the course of the trial, is the same on delay and control trials. Under these conditions, the pigeons no longer showed evidence for dual coding. Instead, there was some evidence that they showed prospective coding, but a more parsimonious account of the results may be that the delay produced a relatively constant decrement in performance at all points of delay interpolation. The original finding of dual coding by Zentall et al. might have been biased by more impulsive choices early in control trials but not in delay trials and by a more stringent choice criterion late in delay trials.

Delayed matching-to-sample: A tool to assess memory and other cognitive processes in pigeons

“…11). Instead of considering the probability of each sample given the pair of comparison stimuli presented, it appears that they considered the overall probability that it was the red sample, in spite of the fact that half of those presentations were not relevant to the two comparisons presented on that trial (see also, DiGian and Zentall, 2007;Zentall et al, 2008). Thus, it appears that animals too are susceptible to base-rate neglect and that basic behavioral processes are involved (see also Goodie and Fantino, 1996).…”

Coding of stimuli by animals: Retrospection, prospection, episodic memory and future planning

“…By giving the pigeon a two-alternative choice following each delay, regardless of the point in the trial at which the delay occurs, one does not have to correct for opportunity because the opportunities are equal and the probability of making an error by chance does not increase as the trial progresses. When we conducted such an experiment, we found that the probability of making an error decreased as the trial progressed (DiGian & Zentall, 2007), suggesting that the pigeons were using a prospective memory code throughout the trial (see Figure 7). …”

“…The effect of a delay inserted during a trial with pigeons using the radial maze analog as a function of the point of delay interpolation and controlling for the opportunity to make an error by providing only two-alternative choices (after DiGian & Zentall, 2007). …”

Monkeys exhibit prospective memory in a computerized task

“…Zentall, Steirn, and Jackson-Smith (1990) also found evidence for this kind of prospective coding in pigeons using a radial maze analog. However, DiGian and Zentall (2007) did not find similar results, and Klein, Evans, and Beran (2011) reported that monkeys did not show evidence of a dual-coding strategy in a computerized analog of the radial arm maze, relying instead on retrospective coding alone. Thus, there is mixed evidence as to whether or not animals prospectively code information in that experimental paradigm.…”