An assessment of touchscreens for testing primate food preferences and valuations

Abstract

Typically, animals' food preferences are tested manually, which can be both time-consuming and vulnerable to experimenter biases. Given the utility of ascertaining animals' food preferences for research and husbandry protocols, developing a quick, reliable, and flexible paradigm would be valuable for expediting many research protocols. Therefore, we evaluated the efficacy of using a touchscreen interface to test nonhuman primates' food preferences and valuations, adapting previously validated manual methods. We tested a nonhuman primate subject with four foods (carrot, cucumber, grape, and turnip). Preference testing followed a pairwise forced choice protocol with pairs of food images presented on a touchscreen: The subject was rewarded with whichever food was selected. All six possible pairwise combinations were presented, with 90 trials per pairing. Second, we measured how hard the subject was willing to work to obtain each of the four foods, allowing us to generate demand curves. For this phase, a single image of a food item was presented on the touchscreen that the subject had to select in order to receive the food, and the number of selections required increased following a quarter-log scale, with ten trials per cost level (1, 2, 3, 6, 10, and 18). These methods allowed us to ascertain the subject's relative preferences and valuations of the four foods. The success of this touchscreen protocol for testing the subject's food preferences, from both a practical and a theoretical standpoint, suggests that the protocol should be further validated with other foods with this subject, with other subjects, and with other test items.

A review of zoo‐based cognitive research using touchscreen interfaces

“…; Micheletta, Whitehouse, Parr, & Waller, ; Waller, Peirce, Mitchell, & Micheletta, ; Whitehouse et al, , ). There has also been growth in more applied science in zoos using touchscreens, with researchers exploring welfare implications of cognitive testing (Tarou et al, ; Wagner et al, ), preferences (Hopper et al, in press; Perdue, ), personality (Altschul, Wallace, Sonnweber, Tomonaga, & Weiss, ), and mood (Allritz et al, ; Cronin et al, ; Kret, Jaasma, Bionda, & Wijnen, ) in several species.…”

“…Alternatively, researchers can collaborate with experienced software developers to create a program that meets their needs (Hopper et al, in press; Martin, ). Consideration should be given to the degree to which third‐party developers will be available to maintain the program as operating systems are updated over time, and the cost of purchasing tailor‐made software, or even off‐the counter software.…”

“…Computerized systems also have the potential of being automated such that a researcher need not to be present during the entire experimental session (Butler & Kennerley, in press). These factors can help contribute to time‐savings as well as helping to remove potential experimenter bias (Beran, ; Hopper, Egelkamp, Fidino, & Ross, in press). While many of the first computerized systems were controlled by buttons and joysticks (e.g., Washburn & Rumbaugh, ), many contemporary efforts utilize touchscreens (e.g., Elsmore, Parkinson, & Mellgren, ) due in part to their intuitive nature created by the direct relationship between the projected stimuli on the screen and the animals’ reaction to that stimuli.…”

High-Tech and Tactile: Cognitive Enrichment for Zoo-Housed Gorillas

“…Computer touchscreen systems can also help to evaluate other forms of enrichment; McGuire et al (2017) recently employed a computer touchscreen system to measure the effect of browse presence on gorilla cognitive bias or “mood” (i.e., to evaluate browse as a form of enrichment). Hopper et al (2018) used a computer touchscreen to assess food preferences in a single zoo gorilla, which could then inform which foods were used as rewards for this individual in future enrichment. Touchscreen systems can be extremely beneficial to enrichment efforts, because subjects’ responses to virtual (on-screen) stimuli can be logged automatically, and many digital stimulus combinations can be provided without the need for cumbersome or expensive physical apparatus (Cronin et al, 2017).…”

Training rhesus macaques to take daily oral antiretroviral therapy for preclinical evaluation of HIV prevention and treatment strategies

“…Behavioral research of captive animal food preferences have detailed how to choose effective reinforcers to improve training efficacy, husbandry and animal welfare [17]. Specifically, nonhuman primate researchers have experimentally determined primate food valuation and showed that the use of preferred foods increases engagement during training sessions [18, 19]. In this study, preferred foods were determined based on caregiver observations of increased consumption, and these foods were used as reinforcers during PRT.…”