Do monkeys choose to choose?

Abstract

There is empirical and anecdotal support that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys will choose to choose. We used a modified version of the SELECT task – a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the current experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other icon led to assignment of task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. Tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer assigned task order that was yoked to their own previous choice selection. The results indicate that monkeys prefer to choose when all other aspects of the task are equated.

Exploring decoy effects on computerized task preferences in rhesus monkeys (Macaca mulatta).

“…We found no performance differences when monkeys chose to complete a task (in binary and trinary choice sets) versus when it was assigned to them (in forced Training trials). This finding was inconsistent with previous work using the SELECT battery with rhesus monkeys (Washburn et al, 1991) and capuchin monkeys (Perdue et al, 2014). However, unlike in those previous task batteries, the current task options were limited to relatively few choices (two tasks versus up to five tasks).…”

“…For example, monkeys performed better on some tasks when they had chosen them (i.e., choice trials) than when the same tasks were simply assigned to them (i.e., forced trials). Later work replicated and extended this result with capuchin monkeys (Beran, Klein, Evans, Antworth, & Chan, 2007;Perdue, Evans, Washburn, Rumbaugh, & Beran, 2014).…”

“…We tested seven adult male rhesus monkeys between the ages of 13 and 34 years. All monkeys previously had been trained to use the computerized apparatus and had experience with the MTS and PURSUIT tasks (Evans, Beran, Chan, Klein, & Menzel, 2008;Richardson, Washburn, Hopkins, Savage-Rumbaugh, & Rumbaugh, 1990), including in tests in which the SELECT procedure was used (Beran et al, 2007;Perdue et al, 2014). Monkeys had access to the computer in test sessions that typically ranged from 4 -8 hrs during which time the software program was available onscreen.…”

Systematic assessment of food item preference and reinforcer effectiveness: Enhancements in training laboratory-housed rhesus macaques

“…Westlund (2012) proposed that the use of preference tests may also result in a reduction in the need for fluid and food restriction in laboratory-housed primates. Finally, given the fact that nonhuman primates have been shown to prefer choice conditions (Perdue et al, 2014), the simple act of choosing a reinforcer may, in itself, provide a welfare benefit to animals.…”

Cognitive enrichment and welfare: Current approaches and future directions

“…Sambrook and Buchanan-Smith suggest that for captive animal enrichment, controllability appears more important than complexity although they focus on the characteristics of novel objects. Furthermore, Perdue, Evans, Washburn, Rumbaugh, and Beran (2014) demonstrated that capuchin monkeys and rhesus macaques "choose to choose," in the sense that they will choose the order in which they complete various psychomotor and cognitive tasks on a computerized system.…”