Threatening stimuli facilitate location-probability-based learned distractor suppression

Abstract: Previous studies have shown that the physical salience of stimuli enhances learned distractor suppression. However, it remains unclear whether emotional salience enhances or weakens learned distractor suppression, particularly in the case of threatening stimuli that hold hard-wired priority in attention processing.
In the current study, we hypothesized that threatening stimuli would enhance learned distractor suppression. To test this hypothesis, we used a threat conditioning task and a visual search task. In the threat conditioning task, a color object was paired with an electric shock, serving as a threat stimulus. Another color object was not paired with an electric shock and served as a non-threat stimulus. In the visual search task, we manipulated the spatial location probabilities of these two types of stimuli to examine their effects on learned distractor suppression.
This study consisted of three experiments. Experiment 1 (n = 30) investigated whether threat feature influence learned distractor suppression. The results showed that individuals’ response times to the target were significantly faster when distractors appeared at high-probability locations than when they appeared at low-probability locations. However, there was no significant difference in response times when threat-feature and non-threat-feature distractors were presented at high-probability locations, indicating that threatening features do not affect learned distractor suppression. Experiment 2 (n = 31) examined whether threatening objects influence learned distractor suppression. Results showed that individuals responded significantly faster when distractors were located at high-probability positions and when threatening objects were presented at high-probability positions than when non-threatening objects were presented. However, at low-probability positions, due to possible threat generalization effects, there was no significant difference in reaction times between the two types of stimuli. These results suggest that threatening objects enhance learned distractor suppression at high-probability locations.  Experiment 3 (n = 31) further validated the role of threatening objects in learned distractor suppression by eliminating the confounding factor of threat generalization. Consistent with Experiment 2, when the distractor appeared at a high-probability location, individuals responded faster to the target. Threatening objects outperformed non-threatening objects, further supporting the notion that threatening objects enhance learned distractor suppression.
In summary, threat stimuli enhance learned distractor suppression through the threatening object rather than a single threatening feature. This finding broadens the scope of application of the salience-specific distraction suppression theory, expanding it from traditional physical salience to emotional salience. This highlights the central role of emotional information in attention learning mechanisms.