Jan P. Röer

Habituation of the Irrelevant Sound Effect: Evidence for an Attentional Theory of Short-Term Memory Disruption.

Immediate serial recall is seriously disrupted by to-be-ignored sound. According to the embedded-processes model, auditory distractors elicit attentional orienting that draws processing resources away from the recall task. The model predicts that interference should be attenuated after repeated exposure to the auditory distractors. Previous failures to observe evidence for habituation can be explained by assuming that habituation to complex distractor features depends on the availability of working memory resources. Here we demonstrate that the irrelevant sound effect is attenuated after passive listening to the auditory distractors during a preexposure phase prior to the serial recall task. Experiment 1 shows that the irrelevant sound effect is abolished after 20 min of passive listening to the distractor speech. Experiments 2-4 show that irrelevant sound interference is significantly reduced after listening to distractors for 45 s. As predicted by the habituation hypothesis, an attenuation of interference occurs only when the distractor material matches the material played in the preexposure phase (Experiment 5). The results support an attentional conceptualization of the irrelevant sound effect.

The role of habituation and attentional orienting in the disruption of short-term memory performance

A series of experiments explored habituation and dishabituation to repeated auditory distractors. Participants memorised lists of visually presented items in silence or while ignoring continuously presented auditory distractors. No habituation could be observed, in that the size of the auditory distractor effect did not decrease during the experiment. However, there was evidence for attentional orienting when novel auditory material was presented after a long period of repetitive stimulation, in that a change of distractors was associated with a temporary decrease in recall performance. The results are most consistent with theoretical accounts that claim that the auditory distractor effect is caused primarily by automatic interference, but that still allow attention to play a limited role in the short-term maintenance of information.

Self-relevance increases the irrelevant sound effect: Attentional disruption by one's own name

Memory performance is severely disrupted when task-irrelevant sound is played during item presentation or in a retention interval. Working memory models make contrasting assumptions on whether the semantic content of the auditory distractors modulates the irrelevant sound effect. In the present study, participants made more errors in serial recall when they had to ignore sentences containing their own name as opposed to that of a yoked-control partner. These results are only consistent with working memory models that allow for attentional processes to play a role in the explanation of the irrelevant sound effect. With repeated presentation the disruptive effect of ones own name decreased, whereas the disruptive effect of the auditory distractors in the control condition remained constant. The latter finding is most consistent with the duplex model of auditory attention, which assumes that the irrelevant sound effect is primarily caused by automatic interference of acoustic distractor features, but at the same time allows for a disruption of encoding due to attentional capture by unexpected deviants. However, to explain the present results, the mechanism responsible for the attentional capture has to be extended to highly (self-)relevant auditory distractors.

Is the survival-processing memory advantage due to richness of encoding?

Memory for words rated according to their relevance in a grassland survival context is exceptionally good. According to Nairne, Thompson, and Pandeiradas (2007) evolutionary-based explanation, natural selection processes have tuned the human memory system to prioritize the processing of fitness-relevant information. The survival-processing memory advantage has been replicated numerous times, but very little is known about the proximate mechanisms behind it. The richness-of-encoding hypothesis (Kroneisen & Erdfelder, 2011) implies that rating the usefulness of items in a survival context leads to the generation of a large number of ideas that may be used as retrieval cues at test to boost recall. In Experiment 1, the typical survival-processing recall advantage was obtained when words were rated according to their usefulness in 1 of 3 fictional contexts. In Experiment 2, participants were asked to write down any ideas that came to mind when thinking about the usefulness of the words. Consistent with the richness-of-encoding hypothesis, participants generated more ideas in the survival condition than in the fitness-irrelevant control conditions. In Experiment 3, participants generated more ideas for congruent than for incongruent words, demonstrating that the richness-of-encoding hypothesis can also account for the previously obtained congruency effect on recall (Butler, Kang, & Roediger, 2009). In both experiments the number of ideas written down predicted future recall performance well. Our results provide further evidence for the assumption that richness of encoding is an important proximate mechanism involved in memory performance in the survival-processing paradigm.

Adaptive memory: The survival-processing memory advantage is not due to negativity or mortality salience

Recent research has highlighted the adaptive function of memory by showing that imagining being stranded in the grasslands without any survival material and rating words according to their survival value in this situation leads to exceptionally good memory for these words. Studies examining the role of emotions in causing the survival-processing memory advantage have been inconclusive, but some studies have suggested that the effect might be due to negativity or mortality salience. In Experiments 1 and 2, we compared the survival scenario to a control scenario that implied imagining a hopeless situation (floating in outer space with dwindling oxygen supplies) in which only suicide can avoid the agony of choking to death. Although this scenario was perceived as being more negative than the survival scenario, the survival-processing memory advantage persisted. In Experiment 3, thinking about the relevance of words for survival led to better memory for these words than did thinking about the relevance of words for death. This survival advantage was found for concrete, but not for abstract, words. The latter finding is consistent with the assumption that the survival instructions encourage participants to think about many different potential uses of items to aid survival, which may be a particularly efficient form of elaborate encoding. Together, the results suggest that thinking about death is much less effective in promoting recall than is thinking about survival. Therefore, the survival-processing memory advantage cannot be satisfactorily explained by negativity or mortality salience.

Evidence for habituation of the irrelevant-sound effect on serial recall

Working memory theories make opposing predictions as to whether the disruptive effect of task-irrelevant sound on serial recall should be attenuated after repeated exposure to the auditory distractors. Although evidence of habituation has emerged after a passive listening phase, previous attempts to observe habituation to to-be ignored distractors on a trial-by-trial basis have proven to be fruitless. With the present study, we suggest that habituation to auditory distractors occurs, but has often been overlooked because past attempts to measure habituation in the irrelevant-sound paradigm were not sensitive enough. In a series of four experiments, the disruptive effects of to-be-ignored speech and music relative to a quiet control condition were markedly reduced after eight repetitions, regardless of whether trials were presented in blocks (Exp. 1) or in a random order (Exp. 2). The auditory distractor’s playback direction (forward, backward) had no effect (Exp. 3). The same results were obtained when the auditory distractors were only presented in a retention interval after the presentation of the to-be-remembered items (Exp. 4). This pattern is only consistent with theoretical accounts that allow for attentional processes to interfere with the maintenance of information in working memory.

Specific foreknowledge reduces auditory distraction by irrelevant speech.

In a series of experiments, it was tested whether distraction by changing-state irrelevant speech is inevitable or can be modulated by foreknowledge of an imminent to-be-ignored distractor sequence. Participants were required to remember visually presented digits while ignoring background speech. In the foreknowledge condition of Experiment 1, the upcoming to-be-ignored sentence was presented auditorily and visually before each trial. With specific foreknowledge, the changing-state irrelevant sound effect (here, increased disruption by sentences compared with repeated words) was significantly attenuated relative to a condition without foreknowledge. This finding was replicated in Experiment 2, in which the information about the upcoming auditory distractor speech was presented only in the visual modality. Experiment 3 showed that only specific foreknowledge of the auditory distractor material has beneficial effects on the ability to ignore distraction. The mere notification that an unspecified distractor sentence would be presented next had no effect on distraction. In Experiment 4, there was only a small and not statistically significant reduction of the irrelevant speech effect when lists of randomly selected words were used as distractor material, suggesting that foreknowledge effects are more pronounced for highly variable, meaningful distractor material. We conclude that the disruption of short-term memory by irrelevant speech is not purely a stimulus-driven process that is immune to top-down control. A significant proportion of the effect can be modulated by specific knowledge about an imminent distractor sequence.

Irrelevant Speech Disrupts Item-Context Binding

The present study examines the effects of irrelevant speech on immediate memory. Previous research led to the suggestion that auditory distractors particularly impair memory for serial order. These findings were explained by assuming that irrelevant speech disrupts the formation and maintenance of links between adjacent items in a to-be-remembered sequence, resulting in a loss of order information. Here we propose a more general explanation of these findings by claiming that the capacity to form and maintain item-context bindings is generally impaired by the presence of auditory distractors. The results of Experiment 1 show that memory for the association between an item and its background color is drastically impaired by irrelevant speech, just as memory for the association between an item and its serial position. In Experiment 2 it was examined whether the disrupting effects of irrelevant sound are limited to memory for item-context associations or whether item memory is also affected by the auditory distractors. The results revealed that irrelevant speech disrupts both item memory and item-context binding. The results suggest that the effects of irrelevant sound on immediate memory are more general than previously assumed, which has important theoretical and applied implications.

Adaptive Memory: Thinking about Function.

Rating the relevance of words for the imagined situation of being stranded in the grasslands without survival material leads to exceptionally good memory for these words. This survival processing effect has received much attention because it promises to elucidate the evolutionary foundations of memory. However, the proximate mechanisms of the survival processing effect have to be identified before informed speculations about its adaptive function are possible. Here, we test and contrast 2 promising accounts of the survival processing effect. According to the 1st account, the effect is the consequence of the prioritized processing of threat-related information. According to the 2nd account, thinking about the relevance of items for survival stimulates thinking about object function, which is a particularly elaborate form of encoding. Experiment 1 showed that the emotional properties of the survival scenario, as manipulated by the negative or positive framing of the scenario, did not influence recall. A focus on threat at encoding led to worse recall than a focus on function. The latter finding was replicated in Experiment 2, which further showed that focusing on threat did not lead to a memory advantage over a pleasantness control condition. The beneficial effect of inducing a functional focus at encoding even surpasses that of the standard survival processing instruction. Together, the results support the theory that thinking about function is an important component of the survival processing effect.

Please silence your cell phone: Your ringtone captures other people's attention

Ringtones are designed to draw attention away from on-going activities. In the present study, it was investigated whether the disruptive effects of a ringing cell phone on short-term memory are inevitable or become smaller as a function of exposure and whether (self-) relevance plays a role. Participants performed a serial recall task either in silence or while task-irrelevant ringtones were presented. Performance was worse when a ringing phone had to be ignored, but gradually recovered compared with the quiet control condition with repeated presentation of the distractor sound. Whether the participants own ringtone was played or that of a yoked-control partner did not affect performance and habituation rate. The results offer insight into auditory distraction by highly attention-demanding distractors and recovery therefrom. Implications for work environments and other applied settings are discussed.