Colour priming modulates the attentional boost effect

The attentional boost effect (ABE) refers to the enhancement of memory encoding during a dual-task. To investigate the under-researched influence of target signal properties in the ABE, this study examined whether implicit colour priming influences passive attentional capture and modulates the magnitude of the ABE. Participants completed an encoding-recognition task across three priming conditions (red, green, and yellow). Each condition comprised four parts: a priming phase, an encoding phase, a wash-out period, and a recognition phase. During the priming phase, participants passively viewed a series of images predominantly associated with a specific colour. In the encoding phase, participants engaged in a dual-task requiring detection of red target signals (while ignoring green distractor signals) and simultaneous memorization of background words. Recognition performance was then assessed through an old-new classification task. Results revealed significant differences in ABE magnitude across the three colour conditions. Red priming produced the strongest memory enhancement, suggesting that congruent colour priming facilitated attentional capture. In contrast, green priming diminished the effect, which is potentially caused by interference linked to attentional shift toward the distractors. The ABE observed under the yellow control condition fell between those of the red and green conditions, establishing a valid baseline for assessing the colour-priming influences. These findings indicate that colour priming could strengthen passive attentional engagement and enhance memory encoding in divided attention conditions, highlighting the importance of feature congruence in modulating the ABE.