Does the Macaque Monkey Provide a Good Model for Studying Human Executive Control? A Comparative Behavioral Study of Task Switching

Abstract

The ability to swiftly and smoothly switch from one task set to another is central to intelligent behavior, because it allows an organism to flexibly adapt to ever changing environmental conditions and internal needs. For this reason, researchers interested in executive control processes have often relied on task-switching paradigms as powerful tools to uncover the underlying cognitive and brain architecture. In order to gather fundamental information at the single-cell level, it would be greatly helpful to demonstrate that non-human primates, especially the macaque monkey, share with us similar behavioral manifestations of task-switching and therefore, in all likelihood, similar underlying brain mechanisms. Unfortunately, prior attempts have provided negative results (e.g., Stoet & Snyder, 2003b), in that it was reported that macaques do not show the typical signature of task-switching operations at the behavioral level, represented by switch costs. If confirmed, this would indicate that the macaque cannot be used as a model approach to explore human executive control mechanisms by means of task-switching paradigms. We have therefore decided to re-explore this issue, by conducting a comparative experiment on a group of human participants and two macaque monkeys, whereby we measured and compared performance costs linked to task switching and resistance to interference across the two species. Contrary to what previously reported, we found that both species display robust task switching costs, thus supporting the claim that macaque monkeys provide an exquisitely suitable model to study the brain mechanisms responsible for maintaining and switching task sets.

Synchronous Oscillatory Neural Ensembles for Rules in the Prefrontal Cortex

“…Monkeys performed well (~90% of trials were correct) but, like humans, were slower to respond on the first trial after switch, compared to repeated rule trials (Allport et al, 1994; Rogers and Monsell, 1995; Caselli and Chelazzi, 2011). This reaction time “switch cost” is thought to reflect the cognitive effort needed to change rules.…”

Rapid cognitive flexibility of rhesus macaques performing psychophysical task-switching

“…Caselli and Chelazzi (2011) presented a dissenting view, contesting Stoet and Snyder’s general result and arguing that although macaques consistently display task interference effects, they also display the task-switching delay characteristic of human performance. However, their analysis of reaction times is suspect for several reasons.…”

“…In particular, rapid task-switching (of the sort that may be of particular interest to clinical measures of impaired cognitive performance) consistently engenders considerable interference between task representations in rhesus macaques, even with extended training. Further comparative research is needed to determine whether this arises as a merely quantitative difference, or instead as a qualitative difference, such as a species-wide bias with respect to speed–accuracy tradeoffs (Caselli and Chelazzi 2011). …”

The long and the short of it: Rule-based relative length discrimination in carrion crows, Corvus corone

“…However, when Stoet and Snyder (2003) decreased the intertrial interval down to 170 ms, significant switch costs began to appear in monkey performance. Recently, Caselli and Chelazzi (2011) did report switch costs in monkeys that were comparable in size to those paid by humans. This indicates that switch costs are present in animals, but are very sensitive to the precise task contingencies applied.…”