Gorillas (Gorilla gorilla gorilla) fail to learn abstract cues of differential outcomes in a novel cognitive bias test

Abstract

Citation - McGuire, M.C., & Vonk, J. (2018). Gorillas (Gorilla gorilla gorilla) fail to learn abstract cues of differential outcomes in a novel cognitive bias test. Animal Behavior and Cognition, 5(1) Abstract -In order to assess mood state in three male western lowland gorillas housed in a bachelor group, we developed a novel version of a cognitive bias task. The background color of a touchscreen presented a conditional 'if, then…" rule relating to outcomes involving differential amounts of food rewards. The gorillas struggled to reach a criterion of 80% responding required for testing. In follow-up experiments, we assessed whether the gorillas did in fact prefer three pieces of food to one piece of food when presented with images of food quantities and actual food quantities. Gorillas did not learn to select the stimulus that indicated three food items over one food item when we used images of actual quantities of the rewarded food but they did prefer three actual pieces of food. Thus, like other primates, gorillas may respond differently to quantities of edible and inedible items. In addition, they may struggle with learning conditional discriminations when cues to differential responses and outcomes are arbitrary rather than intuitively connected. These studies highlight the importance of methodology when devising tests to assess cognition or affect in nonhuman primates.

Bearing fruit: Piloting a novel judgment bias task in an American black bear

“…The small number of trials required for Migwan to learn the contingencies of the task indicates that black bears, like brown bears (Keen et al, 2014) are capable of conditional discrimination learning. This black bear significantly outperformed gorillas tested previously that never reached a criterion level of responding (McGuire & Vonk, 2018). In addition to the fact that she chose the left stimulus at high levels only when it was correct (e.g., on white background trials), her response times also indicate that she anticipated receiving a smaller reward on black background trials compared to white background trials.…”

A review of zoo‐based cognitive research using touchscreen interfaces

“…In addition to promoting welfare, touchscreen systems can be a valuable tool for measuring welfare. Researchers have used a novel cognitive task, referred to as a judgment bias task, to measure the emotional state of animals and to assess their wellbeing (Harding, Paul, & Mendl, ; McGuire & Vonk, ; McGuire, Vonk, & Johnson‐Ulrich, ). Judgment bias tasks require animals to learn abstract cues that can be either positive or negative, and then they are presented and tested on new cues.…”

In or out: Response slowing across housing conditions as a measure of affect in three Western lowland gorillas (Gorilla gorilla gorilla)

“…Although not immune to interpretation ambiguities, the response slowing method of measuring affect may be the best method available for subjects that are ill-suited to the extensive training required for other methods (such as the methods described in previous experiments; McGuire & Vonk, 2018 ; McGuire et al, 2017 ; McGuire, Vonk & Johnson-Ulrich, 2017 ). Because there is minimal training necessary to implement this measure, it could be a quick and efficient tool for measuring animal affect.…”

“…Gorillas were separated into individual holding areas prior to data collection. These gorillas had previously been trained to use the touch screen for other studies ( McGuire & Vonk, 2018 ; McGuire et al, 2017 ; McGuire, Vonk & Johnson-Ulrich, 2017 ; Vonk et al, 2014 ). Training and testing with these animals was approved by the IACUC of Oakland University (12063-R1-A1), and the activities were presented as a form of cognitive enrichment in addition to serving to assess affect.…”

“…Researchers have increasingly made use of cognitive bias tests, such as judgement bias tests ( Harding, Paul & Mendl, 2004 ; Mendl et al, 2009 ; Paul, Harding & Mendl, 2005 ), to assess when animals are optimistic or pessimistic, but these tests often reveal contradictory patterns of results and may not assess affective states at all ( Perdue, 2017 ). Furthermore, they often require long periods of training and animals may fail to reach training criteria, making it impossible to conduct the tests that assess affect ( McGuire & Vonk, 2018 ; McGuire et al, 2017 ; McGuire, Vonk & Johnson-Ulrich, 2017 ). Despite some question about their interpretation, previous studies have shown that judgement bias tests can be sensitive to affect changes in domestic animals following manipulations of housing conditions (for review see Baciadonna & McElligott, 2015 ).…”