Task difficulty modulates voluntary attention allocation, but not distraction in an auditory distraction paradigm

Auditory context-dependent distraction by unexpected visual stimuli

Research findings indicate that when a task-irrelevant stimulus feature deviates from an otherwise predictable pattern, participants performing a categorization task exhibit slower responses (deviance distraction). This deviance distraction effect reflects the violation of the sensory predictions generated by the cognitive system. In this study, we sought to examine for the first time whether these predictions can be incidentally modulated by the auditory environment. Participants categorized the duration (short vs long) of a colored shape (red square or blue circle) while instructed to disregard the stimulus' visual features and the sound played in the background (two distinct chords played by different instruments). While the two visual stimuli shapes were equiprobable across the task, one was highly likely (p=.882) and the other rare (p=.118) in one auditory context and vice versa in the other context. Our results showed that participants were significantly slower in the duration judgement task whenever the stimulus was unexpected within a given auditory context (context-dependent distraction), and that the reset of their sensory predictions was completed upon the trial following a change of context. We conclude that object features and environmental context are processed in relation to each other and that sensory predictions are produced in relation to the environmental context, evidencing the first demonstration of auditory context-dependent modulation of attention.

Children's and adults' memory for the order of events in a museum: A preliminary study about temporal memory and its development using photo-taking and event-related potentials

Remembering personal past events and their order is important. These capacities are essential to episodic and autobiographical memory theories, are needed in the creation of life stories and vital in forensic settings. As important as memory for events and their order are, relatively little is known about their development and the underlying neural processes that support them. Further, there is a paucity of studies that have examined memory and its development for autobiographical, yet controlled, events. The objective of this study was to examine memory for the temporal order of naturalistic "real world" events by directly comparing 7-11-year-olds and adults using both behavioral and event-related potential (ERP) measures. Participants photographed events at a local museum and after a delay, we used their photographs to test their memory for the temporal order of pairs of the events. We experimentally manipulated the temporal distance between the event pairs (whether the two events photographed in the pair had a short or long temporal distance between them). A memory asymmetry manipulation was also included such that at retrieval, photographs were either presented in forward direction (photograph on the top configuration was taken before photograph shown on the bottom) or vice versa. Children and adults showed sensitivity to temporal distance between events based on behavior (in some instances accuracy was higher for long compared to short temporal distance) and ERP (differential neural processing for short and long temporal distance conditions). Only adults showed sensitivity to the memory asymmetry manipulation, and only when the events occurred within a short temporal distance. A larger study is needed to confirm the present "proof of concept" study results. There is strong potential of this photo paradigm approach, combining naturalistic events with ERP, in future developmental studies, and would further our understanding of how memory behavior and the neural processes underlying memory operate in the "real world."

Unexpected sounds inhibit the movement of the eyes during reading and letter scanning

Novel sounds that unexpectedly deviate from a repetitive sound sequence are well known to cause distraction. Such unexpected sounds have also been shown to cause global motor inhibition, suggesting that they trigger a neurophysiological response aimed at stopping ongoing actions. Recently, evidence from eye movements has suggested that unexpected sounds also temporarily pause the movements of the eyes during reading, though it is unclear if this effect is due to inhibition of oculomotor planning or inhibition of language processes. Here, we sought to distinguish between these two possibilities by comparing a natural reading task to a letter scanning task that involves similar oculomotor demands to reading, but no higher level lexical processing. Participants either read sentences for comprehension or scanned letter strings of these sentences for the letter 'o' in three auditory conditions: silence, standard, and novel sounds. The results showed that novel sounds were equally distracting in both tasks, suggesting that they generally inhibit ongoing oculomotor processes independent of lexical processing. These results suggest that novel sounds may have a global suppressive effect on eye-movement control.

Perinatal morphine but not buprenorphine affects gestational and offspring neurobehavioral outcomes in mice

Within the national opioid epidemic, there has been an increase in the number of infants exposed to opioids in utero. Additionally, opioid agonist medications are the standard of care for women with opioid use disorder during pregnancy. Buprenorphine (BUP), a partial µ -opioid receptor agonist, has been successful in improving gestational and neonatal outcomes. However, in utero exposure has been linked to childhood cognitive and behavioral problems. Therefore, we sought to compare offspring cognitive and behavioral outcomes after prenatal exposure to a clinically relevant low dose of BUP compared to morphine (MO), a full µ -opioid receptor agonist and immediate metabolite of heroin. We used a mouse model to assess gestational and offspring outcomes. Mouse dams were injected once daily s.c. with saline (SAL, n = 12), MO (10 mg/kg, n = 15), or BUP (0.1 mg/kg, n = 16) throughout pre-gestation, gestation, and lactation until offspring were weaned on postnatal day (P)21. Offspring social interaction and exploratory behavior were assessed, along with executive function via the touchscreen 5 choice serial reaction time task (5CSRTT). We then quantified P1 brain gene expression in the frontal cortex and amygdala (AMG). Perinatal MO but not BUP exposure decreased gestational weight gain and was associated with dystocia. In adolescent offspring, perinatal MO but not BUP exposure increased social exploration in males and grooming behavior in females. In the 5CSRTT, male MO exposed offspring exhibited increased impulsive action errors compared to male BUP offspring. In the AMG of P1 MO exposed offspring, we observed an increase in gene expression of targets related to activity of microglia. Importantly, both MO and BUP caused acute hyperlocomotion in the dams to a similar degree, indicating that the selected doses are comparable, in accordance with previous dose comparisons on analgesic and reward efficacy. These data suggest that compared to MO, low dose BUP improves gestational outcomes and has less of an effect on the neonatal offspring brain and later adolescent and adult behavior.

Effect of Auditory Distractors on Speech Recognition and Listening Effort

OBJECTIVES

Everyday listening environments are filled with competing noise and distractors. Although significant research has examined the effect of competing noise on speech recognition and listening effort, little is understood about the effect of distraction. The framework for understanding effortful listening recognizes the importance of attention-related processes in speech recognition and listening effort; however, it underspecifies the role that they play, particularly with respect to distraction. The load theory of attention predicts that resources will be automatically allocated to processing a distractor, but only if perceptual load in the listening task is low enough. If perceptual load is high (i.e., listening in noise), then resources that would otherwise be allocated to processing a distractor are used to overcome the increased perceptual load and are unavailable for distractor processing. Although there is ample evidence for this theory in the visual domain, there has been little research investigating how the load theory of attention may apply to speech processing. In this study, we sought to measure the effect of distractors on speech recognition and listening effort and to evaluate whether the load theory of attention can be used to understand a listener's resource allocation in the presence of distractors.

DESIGN

Fifteen adult listeners participated in a monosyllabic words repetition task. Test stimuli were presented in quiet or in competing speech (+5 dB signal-to-noise ratio) and in distractor or no distractor conditions. In conditions with distractors, auditory distractors were presented before the target words on 24% of the trials in quiet and in noise. Percent-correct was recorded as speech recognition, and verbal response time (VRT) was recorded as a measure of listening effort.

RESULTS

A significant interaction was present for speech recognition, showing reduced speech recognition when distractors were presented in the quiet condition but no effect of distractors when noise was present. VRTs were significantly longer when distractors were present, regardless of listening condition.

CONCLUSIONS

Consistent with the load theory of attention, distractors significantly reduced speech recognition in the low-perceptual load condition (i.e., listening in quiet) but did not impact speech recognition scores in conditions of high perceptual load (i.e., listening in noise). The increases in VRTs in the presence of distractors in both low- and high-perceptual load conditions (i.e., quiet and noise) suggest that the load theory of attention may not apply to listening effort. However, the large effect of distractors on VRT in both conditions is consistent with the previous work demonstrating that distraction-related shifts of attention can delay processing of the target task. These findings also fit within the framework for understanding effortful listening, which proposes that involuntary attentional shifts result in a depletion of cognitive resources, leaving less resources readily available to process the signal of interest; resulting in increased listening effort (i.e., elongated VRT).

Distraction by deviant sounds is modulated by the environmental context

Evidence shows that participants performing a continuous visual categorization task respond slower following the presentation of a task-irrelevant sound deviating from an otherwise repetitive or predictable auditory context (deviant sound among standard sounds). Here, for the first time, we explored the role of the environmental context (instrumentalized as a task-irrelevant background picture) in this effect. In two experiments, participants categorized left/right arrows while ignoring irrelevant sounds and background pictures of forest and city scenes. While equiprobable across the task, sounds A and B were presented with probabilities of .882 and .118 in the forest context, respectively, and with the reversed probabilities in the city context. Hence, neither sound constituted a deviant sound at task-level, but each did within a specific context. In Experiment 1, where each environmental context (forest and city scene) consisted of a single picture each, participants were significantly slower in the visual task following the presentation of the sound that was unexpected within the current context (context-dependent distraction). Further analysis showed that the cognitive system reset its sensory predictions even for the first trial of a change in environmental context. In Experiment 2, the two contexts (forest and city) were implemented using sets of 32 pictures each, with the background picture changing on every trial. Here too, context-dependent deviance distraction was observed. However, participants took a trial to fully reset their sensory predictions upon a change in context. We conclude that irrelevant sounds are incidentally processed in association with the environmental context (even though these stimuli belong to different sensory modalities) and that sensory predictions are context-dependent.

Aging Increases Cross-Modal Distraction by Unexpected Sounds: Controlling for Response Speed

It is well-established that task-irrelevant sounds deviating from an otherwise predictable auditory sequence capture attention and disrupt ongoing performance by delaying responses in the ongoing task. In visual tasks, larger distraction by unexpected sounds (deviance distraction) has been reported in older than in young adults. However, past studies based this conclusion on the comparisons of absolute response times (RT) and did not control for the general slowing typically observed in older adults. Hence, it remains unclear whether this difference in deviance distraction between the two age groups reflects a genuine effect of aging or a proportional effect of similar size in both groups. We addressed this issue by using a proportional measure of distraction (PMD) to reanalyze the data from four past studies and used Bayesian estimation to generate credible estimates of the age-related difference in deviance distraction and its effect size. The results were unambiguous: older adults exhibited greater deviance distraction than young adults when controlling for baseline response speed (in each individual study and in the combined data set). Bayesian estimation revealed a proportional lengthening of RT by unexpected sounds that was about twice as large in older than in young adults (corresponding to a large statistical effect size). A similar analysis was carried out on the proportion of correct responses (PC) and produced converging results. Finally, an additional Bayesian analysis comparing data from cross-modal and uni-modal studies confirmed the selective effect of aging on distraction in the first and not the second. Overall, our study shows that older adults performing a visual categorization task do exhibit greater distraction by unexpected sounds than young adults and that this effect is not explicable by age-related general slowing.

Neural Basis of Semantically Dependent and Independent Cross-Modal Boosts on the Attentional Blink

The present study recorded event-related potentials (ERPs) in a visual object-recognition task under the attentional blink paradigm to explore the temporal dynamics of the cross-modal boost on attentional blink and whether this auditory benefit would be modulated by semantic congruency between T2 and the simultaneous sound. Behaviorally, the present study showed that not only a semantically congruent but also a semantically incongruent sound improved T2 discrimination during the attentional blink interval, whereas the enhancement was larger for the congruent sound. The ERP results revealed that the behavioral improvements induced by both the semantically congruent and incongruent sounds were closely associated with an early cross-modal interaction on the occipital N195 (192–228 ms). In contrast, the lower T2 accuracy for the incongruent than congruent condition was accompanied by a larger late occurring cento-parietal N440 (424–448 ms). These findings suggest that the cross-modal boost on attentional blink is hierarchical: the task-irrelevant but simultaneous sound, irrespective of its semantic relevance, firstly enables T2 to escape the attentional blink via cross-modally strengthening the early stage of visual object-recognition processing, whereas the semantic conflict of the sound begins to interfere with visual awareness only at a later stage when the representation of visual object is extracted.