For social animals, attending to and recognizing the emotional expressions of other individuals is of crucial importance for their survival and likely has a deep evolutionary origin. Gaining insight into how emotional expressions evolved as adaptations over the course of evolution can be achieved by making direct cross-species comparisons. To that extent, experimental paradigms that are suitable for investigating emotional processing across species need to be developed and evaluated. The emotional dot-probe task, which measures attention allocation toward emotional stimuli, has this potential. The task is implicit, and subjects need minimal training to perform the task successfully. Findings in nonhuman primates, although scarce, show that they, like humans, have an attentional bias toward emotional stimuli. However, the wide literature on human studies has shown that different factors can have important moderating effects on the results. Due to the large heterogeneity of this literature, these moderating effects often remain unnoticed. We here review this literature and show that subject characteristics and differences in experimental designs affect the results of the dot-probe task. We conclude with specific recommendations regarding these issues that are particularly relevant to take into consideration when applying this paradigm to study animals.
Keywords: Attention; Comparative; Cross-species; Dot-probe task; Emotion.