Temporal smearing across related visual images eliminates the attentional boost effect.

Detecting a target in a rapid serial visual presentation (RSVP) enhances memory for concurrently presented images, known as the attentional boost effect (ABE). While the ABE has been observed across various background images, its application to semantically and temporally related background images has not been previously explored. We investigated whether storing related background images in chunks would spread memory enhancement across related images, potentially reducing the ABE. In three experiments, participants monitored an RSVP stream of blue and red colors, responding to a target color while ignoring distractors. Experiment 1 used 100 backpack images as background stimuli. Experiment 2 presented still photos of two natural events in chronological order, while Experiment 3 scrambled their temporal order. Results showed a significant ABE in Experiment 1, indicating that semantic relatedness alone does not disrupt the ABE. However, the ABE was eliminated in Experiments 2 and 3, suggesting that when participants form event models from related images, the ABE becomes temporally diffused. These findings identify a rare boundary condition for the typically robust ABE, suggesting that transient orienting to targets may not always produce a temporally specific boost to the memory of concurrent stimuli.