The Attentional Boost Effect (ABE) refers to the phenomenon that the memory of background materials presented simultaneously with the detection stimuli is enhanced in learning phase. Previous studies have found that incidental encoding of memory materials can also produce a significant ABE. To further explore the impact of intentionality of encoding on ABE, the present study adopted a learning-test paradigm, in which the intentional and incidental encoding conditions were manipulated in learning phase with detection stimulus and vocabulary were presented together for 500 ms (Experiment 1) or 200 ms (Experiment 2), and setting a recognition task and “remember/know” (R/K) judgment task in the test phase. The results showed that in the intentional encoding condition, a significant ABE was found in both experiments, and the target detection mainly promoted the “R” response of the words; in the incidental encoding condition, significant ABE was found in Experiment 1, but not in Experiment 2. Therefore, ABE is stable in the intentional encoding condition, but the generation of it in the incidental encoding condition is conditional, and if the background materials fail to receive any attention resources, ABE will not occur.
