A Comparative Perspective on Three Primate Species’ Responses to a Pictorial Emotional Stroop Task

The Stroop effect describes interference in cognitive processing due to competing cognitive demands. Presenting emotionally laden stimuli creates similar Stroop-like effects that result from participants’ attention being drawn to distractor stimuli. Here, we adapted the methods of a pictorial Stroop study for use with chimpanzees (N = 6), gorillas (N = 7), and Japanese macaques (N = 6). We tested all subjects via touchscreens following the same protocol. Ten of the 19 subjects passed pre-test training. Subjects who reached criterion were then tested on a standard color-interference Stroop test, which revealed differential accuracy in the primates’ responses across conditions. Next, to test for an emotional Stroop effect, we presented subjects with photographs that were either positively valenced (a preferred food) or negatively valenced (snakes). In the emotional Stroop task, as predicted, the primates were less accurate in trials which presented emotionally laden stimuli as compared to control trials, but there were differences in the apes’ and monkeys’ response patterns. Furthermore, for both Stroop tests, while we found that subjects’ accuracy rates were reduced by test stimuli, in contrast to previous research, we found no difference across trial types in the subjects’ response latencies across conditions.

Influence of cognitive load on the expression of the emotional stroop effect

The Emotional Stroop Effect (ESE) is the result of a greater delay in naming colors of written emotional words than colors of written neutral words, because of shifting attention to emotionally meaningful information. ESE is mainly used in psychopathology surveys, but its application is also promising for solving applied psychophysiological problems, from professional screening and neuromarketing to detecting lies and detecting threats from emotionally unstable individuals. Because the ESE is sensitive to testing conditions, various modifications to the Emotional Stroop Test (EST) have been investigated. Within the subtests, neutral and emotional (negatively coloured) words were presented. The inclusion of distractors in subtests (target words, names of plants and animals that were not required to be answered by keystrokes) complicates the task, which manifests itself in a considerable extension of the reaction time. When performing a task with significant cognitive load, the left hand responds to emotional stimuli longer than the right. The results obtained may indicate the formation of a special system for processing emotional information in the right hemisphere, while the left hemisphere focuses on the cognitive task. It is likely that in the case of increased cognitive load, the subsystems for processing emotional and cognitive information operate relatively autonomously, inter-hemispheric interaction is enhanced, and functional asymmetry is reduced. As cognitive pressure decreases, functional asymmetry is likely to increase inter-hemispheric interaction, and ESE is not detected. The obtained values of latent periods of reaction to emotionally significant and neutral stimuli can be used to develop scales and criteria for evaluating a person's emotional reactions when it is needed.

The Effect of Automatic vs. Reflective Emotions on Cognitive Control in Antisaccade Tasks and the Emotional Stroop Test

The article presents two studies based on the assumption that the effectiveness of cognitive control depends on the subject’s type of emotional state. Inhibitory control is taken into account, as the basic determinant of the antisaccade reactions and the emotional Stroop effect. The studies deal with differentiation of emotions on the basis of their origin: automatic (due to primary affective reactions) vs. reflective (due to deliberative evaluation). According to the main assumption, automatic emotions are diffusive, and decrease the effectiveness of cognitive control. The hypothesis predicted that performance level of both the Antisaccade Task and the Emotional Stroop Test would be lower in the automaticemotion eliciting condition than in the reflective-emotion eliciting condition. In two experimental studies, positive and negative (automatic vs. reflective) emotions were elicited. The results support the predictions, regardless of the valence of emotions.