Animal Cognition May 2018

First, a social learning paper by Watson, Lambeth, Schapiro, and Whiten that I believe I sent to Mike earlier as a possible Division 6 article. Here they looked at whether chimpanzees would retain a learned behavior or adopt a different behavior demonstrated by the rest of the members in their group. The behavior measured here was either sliding a door up or down to retrieve a reward. Most of the “minority” individuals adopted the method others used in their groups, which was not the case when put into dyads or when individuals were tested alone. What was interesting though is that of the “majority” individuals placed in groups, very few switched to the method demonstrated by the minority individual even though the minority individuals that did switch did so rapidly and sometimes after only seeing one or two others in their groups using the alternative method. So, the minority individuals that did switch weren’t always doing so because they were conforming to the group, but instead just one or a few others. I would be interested to see a replication of something like this with a slightly more complicated task, or if there are any differences in adopting novel behaviors demonstrated by specific individuals such as relatives or dominant group members.

Tia, Viaro, & Fadigo published a paper on tool-use enhancing cognitive performance in long-tailed macaques. They examined cognitive functions such as causal reasoning, spatial cognition, numerosity, and generalizability of tool use using the Primate Cognition Test Battery (PCTB). Three monkeys were trained to use a rake to acquire a reward, and three control monkeys acquired the reward by grasping. None of the trained monkeys generalized this ability to the tool-use task of the PCTB. Tool-use trained monkeys performed better on causal cognition tasks and slightly better on spatial cognition tasks than control monkeys, but this effect wasn’t present when looking at individual tasks within the battery and did not persist after 35-days. Also, I didn’t see anything about what prior experience these monkeys had and would have liked to see some more subjects for the groups, or a different training paradigm (maybe with more consistency of training sessions across subjects?).

Next, a paper by Bell-Garrison, Rice, and Kyonka looked at adaptive learning, forgetting, and memory in pigeons. Subjects were tested in operant conditioning boxes on differing reinforcement schedules. Testing sessions were run back to back so that each testing day they would finish the second half of one session and start the first half of another session. Session changes were either signaled or unsignaled and each session contained varying reward ratios and intervals. In general, pigeons were able to remember reinforcer ratios, but not the reinforcer intervals after the 23-hour break (that is, they were able to remember the spatial distribution of rewards better than the temporal distribution). Subjects forgot response contingencies gradually when session changes were unsignaled, but contingencies from the previous session were forgotten immediately when session changes were signaled.

For those who have any interest in spatial cognition: A paper by Presotto et al looked at the routes of wild bearded capuchin monkeys to look for differences in “change point locations” (where individuals changed travel direction) that were located either along a path route or at an intersection of path routes. Other primate species such as baboons and gibbons tend to change direction near certain landmarks, but no other studies had looked at differences in types of change point locations. They found that change point locations associated with intersections of paths were associated with specific landmarks such as steeper terrain, important resources, and best visibility.

Next, some problem solving and inhibitory control in a paper looking at predictors of “innovation” in captive spotted hyenas. Ten captive hyenas were tested on a multi-access box (MAB) with four possible solutions. The authors found measures of inhibitory control in individuals did not predict repeated innovation with the multi-access box. Instead a set of traits such as high persistence, high motor diversity, high activity, and low neophobia were associated with repeated innovation on the apparatus. These results contradict previous work showing a relationship between problem-solving and inhibitory control, but its also important to note a small sample size, especially of the subjects that learned more than one solution, and some possible methodological issues/ lots of different measures.

Finally, rats that were socially enriched performed better on a memory task in which they were required to identify a novel individual among other conspecifics. Socially enriched rats performed above chance when discriminating between 5 choices of conspecifics, whereas socially separated rats could only do so when discriminating between 3 choices of conspecifics. However, there was variability in performance between groups and tasks. For example, standard housed rats (lived in groups of 3) were not above chance at any level of this social memory task. Also, the socially enriched rats (lived in groups of 10) failed to perform above chance when discriminating between 4 choices of conspecifics, despite being above chance in the 3 and 5 choices conditions.

These and the other articles published in the May issue can be found here: https://link.springer.com/journal/10071/21/3/page/1