Does the Attentional Boost Effect Depend on the Intentionality of Encoding? Investigating the Mechanisms Underlying Memory for Visual Objects Presented at Behaviorally Relevant Moments in Time

The Attentional Boost Effect in Older Adults: Examining the Vulnerable Boost Hypothesis

INTRODUCTION

The Attentional Boost Effect (ABE) occurs whenever participants recognize stimuli paired earlier with to-be-responded targets better than stimuli earlier paired with to-be-ignored distractors or presented on their own (baseline). Previous studies showed that the ABE does not occur in older adults when the encoding time is too short (500 ms/word) or when encoding is incidental, likely due to aging-related reductions in cognitive resources or limitations of processing speed.

METHOD

In the present study, younger and older adults encoded words presented for 1000 ms under intentional instructions. In addition, to determine the potential impact of the retention interval, the recognition task was performed after a delay of 2 minutes (Experiment 1) or 20 minutes (Experiment 2).

RESULTS

Under these conditions, older adults showed a significant ABE and the size of the effect was comparable to that achieved by younger adults. The magnitude of the ABE was vulnerable to the passage of time because the recognition advantage of target-paired words decreased sharply from 2 to 20 minutes.

CONCLUSIONS

Taken together, our data demonstrate that younger and older adults may have comparable ABE effects under specific conditions and are similarly sensitive to interference.

Memory and attention: A double dissociation between memory encoding and memory retrieval

Research has found substantial negative effects of divided attention (DA) during encoding but less substantial effects when attention is divided during retrieval, an asymmetry which has been interpreted as indicating that different control processes or forms of attention are involved in encoding and retrieval (e.g., Chun & Johnson, 2011; Craik, Govoni, Naveh-Benjamin, & Anderson, 1996; Long, Kuhl, & Chun, 2018). The extant evidence, however, is not strong support for qualitative differences and might simply indicate differential sensitivity. The present experiments document a stronger, double dissociation by focusing on the Attentional Boost Effect (ABE) - a phenomenon in which the detection of targets in a secondary task enhances encoding of co-occurring stimuli. The dual-task interaction account proposes that the classical negative effects produced by dual-task interference are offset by a transient increase in externally-directed attention brought about by target detection. Since externally-directed attention is less valuable for retrieval processes, the ABE should result in a net negative effect when applied in the test phase because the dual-task interference would no longer be offset by the externally-directed boost occurring during target trials. Experiments 1, 2 and 4 confirmed the predictions by showing that test words paired with target stimuli were recognized significantly worse than test words paired with distractor stimuli. In contrast, Experiments 3 and 4 replicated the usual positive effects of the ABE with respect to encoding. We discuss these findings in light of recent theoretical proposals suggesting that encoding and retrieval processes are subserved by different forms of attention (external [perceptual] vs. internal [reflective]). Implications for the Transfer-Appropriate-Processing view of memory are also illustrated.

Motor engagement enhances incidental memory for task-irrelevant items

Actions shape what we see and memorize. A previous study suggested the interaction between motor and memory systems by showing that memory encoding for task-irrelevant items was enhanced when presented with motor-response cues. However, in the studies on the attentional boost effect, it has been revealed that detection of the target stimulus can lead to memory enhancement without requiring overt action. Thus, the direct link between the action and memory remains unclear. To exclude the effect of the target detection process as a potential confounder, this study assessed the benefit of action for memory by separating items from the response cue in time. In our pre-registered online experiment (N = 142), participants responded to visual Go cues by pressing a key (i.e., motor task) or counting (i.e., motor-neutral cognitive task) while ignoring No-go cues. In each trial, two task-irrelevant images were sequentially presented after the cue disappearance. After encoding the Go/No-go tasks, participants performed a surprise recognition memory test for those images. Importantly, we quantified the impact of overt execution of the action by comparing memories with and without motor response and the impact of covert motor processes (e.g., preparation and planning of action) by comparing memory between the motor and cognitive tasks. The results showed no memory differences between Go and No-go trials in the motor task. This means that the execution itself was not critical for memory enhancement. However, the memory performance in the motor No-go trials was higher than that in the cognitive No-go trials, only for the items presented away from the cues in time. Therefore, engaging the motor task itself could increase incidental memory for the task-irrelevant items compared to a passive viewing situation. We added empirical evidence on the online interaction between action and memory encoding. These memory advantages could be especially brought in action preparation and planning. We believe this fact may expand our present understanding of everyday memory, such as active learning.

Grounding the Attentional Boost Effect in Events and the Efficient Brain

Attention and memory for everyday experiences vary over time, wherein some moments are better attended and subsequently better remembered than others. These effects have been demonstrated in naturalistic viewing tasks with complex and relatively uncontrolled stimuli, as well as in more controlled laboratory tasks with simpler stimuli. For example, in the attentional boost effect (ABE), participants perform two tasks at once: memorizing a series of briefly presented stimuli (e.g., pictures of outdoor scenes) for a later memory test, and responding to other concurrently presented cues that meet pre-defined criteria (e.g., participants press a button for a blue target square and do nothing for a red distractor square). However, rather than increasing dual-task interference, attending to a target cue boosts, rather than impairs, subsequent memory for concurrently presented information. In this review we describe current data on the extent and limitations of the attentional boost effect and whether it may be related to activity in the locus coeruleus neuromodulatory system. We suggest that insight into the mechanisms that produce the attentional boost effect may be found in recent advances in the locus coeruleus literature and from understanding of how the neurocognitive system handles stability and change in everyday events. We consequently propose updates to an early account of the attentional boost effect, the dual-task interaction model, to better ground it in what is currently known about event cognition and the role that the LC plays in regulating brain states.

The attentional boost effect facilitates the encoding of contextual details: New evidence with verbal materials and a modified recognition task

In the attentional boost effect (ABE), words or images encoded with to-be-responded targets are later recalled better than words or images encoded with to-be-ignored distractors. The ABE has been repeatedly demonstrated to improve item memory, whereas evidence concerning contextual memory is mixed, with studies showing both significant and null results. The present three experiments investigated whether the ABE could enhance contextual memory when using a recognition task that allowed participants to reinstate the original study context, by simultaneously manipulating the nature of the instructions provided at encoding. Participants studied a sequence of colored words paired with target (gray circles) or distractor (gray squares) stimuli, under the instructions to remember either the words and their colors (Exps. 1–2) or only the words (Exp. 3) and simultaneously press the space bar whenever a gray circle appeared on the screen. Then, after a brief interval, they were administered a modified recognition task involving two successive stages. First, participants were presented with two different words and had to decide which word was originally encoded; second, they were presented with five colored versions of the (correct) old words and had to remember the color in which they were studied. Results converged in showing that the ABE enhanced contextual memory, although the effect was more robust with intentional encoding instructions.