Although comparative psychologists have made considerable strides in the past several decades, expanding the breadth of species and questions examined, the field still suffers from an overemphasis on top-down approaches that begin and end with a focus on humans. This top-down perspective leads to biases and oversights that hamper the further development of the field. A bottom-up approach that considers species-specific abilities and behaviors in the context of theoretically relevant comparisons will be most useful in advancing knowledge of species-specific and shared abilities. This will allow a better determination of the extent to which continuities and discontinuities exist as a function of different ecological forces. In addition, a bottom-up approach will facilitate a shift in focus from using animals to better understand humans, to understanding animals themselves. This new approach will allow for an appreciation of how humans can benefit other species.

We adapted the emotional Stroop task developed for primates to test whether gorillas would show response slowing for images of ‘negative’ compared to images of ‘positive’ items placed within previously reinforced borders. Three zoo-housed male gorillas participated in six phases of an emotional Stroop paradigm. In Phase One, they learned to select blue borders over yellow borders in a forced choice task presented on the touchscreen. In Phase Two, neutral yellow or blue two-dimensional shapes were placed within the borders. On congruent trials, blue images were presented within both blue and yellow borders. On incongruent trials, yellow images were placed within both blue and yellow borders. We continued to use these trials as control trials in subsequent phases. We predicted that response latencies would be slower and accuracy would be lower on incongruent trials. Although the gorillas responded more quickly to incongruent trials, in contrast to predictions, they were more accurate on congruent trials, consistent with predictions. Therefore, we proceeded with Phase Three in which photographs of images assumed to have positive and negative valences for the gorillas were placed within the borders. On test trials, the same positive or negative image was placed within both borders. In Phase Four, a positive image was paired with a negative image on each trial and the positive image appeared in either the blue (congruent trials) or yellow border (incongruent trials). Phases Five and Six replicated Phases Three and Four with images of novel positive and negative items. The gorillas responded more quickly on congruent trials compared to incongruent trials on test trials but not on control trials throughout Phases 3–6. These findings provide some validation for the emotional Stroop task to test attentional shift with emotionally valenced items.

Although categorization abilities may serve as the foundation for most other complex cognitive processes, this topic has been grossly understudied in the order Carnivora. However, there are a growing number of studies examining the abilities of bears, felines, and canines to discriminate among stimuli that could represent conceptual categories. These studies are few in number compared to the extensive work conducted on non-human primates, but, thus far, results suggest that carnivores show comparable abilities to, for example; form natural categories, discriminate quantities, recognize cues of human emotion, and to discriminate kin. There is little existing work exploring concepts of sameness and relational reasoning in carnivores, and work on social concepts, such as representations of mental states, exist only in canines. Future studies are necessary to better understand the mechanisms underlying carnivores’ categorization abilities and conceptual representations. Furthermore, future work should focus on differences in conceptual ability as a function of social lifestyle and dietary preferences within carnivores. Such studies will be helpful in understanding the evolutionary pressures responsible for conceptual processes in a variety of species, including humans.

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Although felids in general tend to be relatively asocial, domestic cats live closely with humans and other domestic species and thus, might be expected to respond to cues indicating, for example, the reputation of others. Furthermore, recent research with other less social species suggests that social learning is not unique to group-housed animals. Therefore, here we tested seven cat dyads with one cat interacting directly with unfamiliar humans, and another indirectly observing the interactions, to determine whether they would learn the ‘friendly’ and ‘aggressive’ reputations of the unfamiliar humans. Cats did not show a tendency to interact less, or more cautiously, with aggressive experimenters based on contact duration and latency to approach. Cats that observed the interactions indirectly spent more time near both experimenters and approached more quickly on test trials compared to cats that directly interacted with the experimenters, but this may have been due to spending more time crated between trials. We hesitate to conclude that cats are incapable of inferring reputation based on this small sample. It is possible that cats would behave more discriminately if tested in familiar environments.