Divided Attention Paradigm Research Articles

Effects of aging and divided attention on episodic feeling-of-knowing accuracy

This research investigated the effect of aging on episodic feeling-of-knowing (FOK) using a divided attention (DA) paradigm in order to examine whether DA in younger adults mimics the effects of aging when decreasing either memory encoding or monitoring processes. To that end, four groups of participants were tested on the FOK task: young adults (control group), young adults under DA at encoding, young adults under DA when making FOK judgments, and older adults. Our results showed that DA at encoding in young adults mimicked the effect of aging on memory performance, and also on FOK magnitude and accuracy, supporting the memory-constraint hypothesis (Hertzog et al., 2010). However, our results do not completely contradict the monitoring-deficit hypothesis, as DA during FOK judgments also affected FOK accuracy, but to a lesser extent than the aging effect or DA during encoding. We suggest that the age-related FOK deficit may be due to a lower level of deep encoding, leading to difficulty retrieving target-related contextual details enabling accurate prediction of subsequent recognition.

The same-object benefit is influenced by time-on-task

Previous studies indicated that mental fatigue particularly compromises the control of attention. To our knowledge, the present study is the first to test this notion in a divided attention paradigm that involves comparing targets placed on one versus two background objects. In general, comparing targets on two objects is less efficient than on one object because it puts more demands on divided attention. This is the well-known same-object benefit. Based on the notion of lowered control of attention under fatigue, we hypothesised that this same-object benefit becomes more pronounced in fatigued participants. We tested this with an experiment in which participants performed a visual attention task (same/different task) for 2.5 hours without rest. As a function of time-on-task, participants showed a decline in performance that was significantly more pronounced in the two object condition versus the one-object condition. These findings suggest an increased same-object benefit with time-on-task, which is likely due to compromised divided attention under fatigue.

Visual attention and emotional memory: Recall of aversive pictures is partially mediated by concurrent task performance.

The emotional enhancement of memory is often thought to be determined by attention. However, recent evidence using divided attention paradigms suggests that attention does not play a significant role in the formation of memories for aversive pictures. We report a study that investigated this question using a paradigm in which participants had to encode lists of randomly intermixed negative and neutral pictures under conditions of full attention and divided attention followed by a free recall test. Attention was divided by a highly demanding concurrent task tapping visual processing resources. Results showed that the advantage in recall for aversive pictures was still present in the DA condition. However, mediation analyses also revealed that concurrent task performance significantly mediated the emotional enhancement of memory under divided attention. This finding suggests that visual attentional processes play a significant role in the formation of emotional memories.

Effects of Aging and Divided Attention on Recognition Memory Processes for Single and Associative Information

In the divided attention paradigm to test age-related associative memory deficits, whether the effects of divided attention occur at encoding or retrieval has not been clarified, and the effect on retention has not been studied. This study explored whether and how much divided attention at either encoding, retention, or retrieval diminished accuracy in recognizing a single feature (object or location) and associated features (object+location) by 23 elderly people (13 women; M age = 70.6 yr., SD = 2.8) recruited from a neighborhood community circle, and 29 female college students (M age = 20.8 yr., SD = 1.1). The results showed a significant decline in memory performance for both age groups due to divided attention in location and associative memory at retention, suggesting that the retention process demands attentional resources. Overall, regardless of their relative deficiency in associative memory, older adults showed an effect of divided attention comparable to that of younger adults in a recognition task.

Does feature similarity facilitate attentional selection?

Object-based attention enables us to simultaneously select and report two features from the same visual object. Does feature-based attention contribute similarly to visual selection? In the present study, we investigated the concurrent discrimination of two motion fields with a divided attention paradigm. We found that dual-task performance improved when the two fields conformed to a continuous optic flow, consistent with "object-based" selection. However, we found no such improvement when the two motion fields were merely similar, as would have been expected from "feature-based" selection. Therefore, feature similarity does not facilitate attentional selection in the same way as belonging to the same object does.

Does feature similarity facilitate attentional selection?

Object-based attention enables us to simultaneously select and report two features from the same visual object. Does feature-based attention contribute similarly to visual selection? In the present study, we investigated the concurrent discrimination of two motion fields with a divided attention paradigm. We found that dual-task performance improved when the two fields conformed to a continuous optic flow, consistent with “object-based” selection. However, we found no such improvement when the two motion fields were merely similar, as would have been expected from “feature-based” selection. Therefore, feature similarity does not facilitate attentional selection in the same way as belonging to the same object does.

Are children’s memory illusions created differently from those of adults? Evidence from levels-of-processing and divided attention paradigms

In two experiments, we investigated the robustness and automaticity of adults’ and children’s generation of false memories by using a levels-of-processing paradigm (Experiment 1) and a divided attention paradigm (Experiment 2). The first experiment revealed that when information was encoded at a shallow level, true recognition rates decreased for all ages. For false recognition, when information was encoded on a shallow level, we found a different pattern for young children compared with that for older children and adults. False recognition rates were related to the overall amount of correctly remembered information for 7-year-olds, whereas no such association was found for the other age groups. In the second experiment, divided attention decreased true recognition for all ages. In contrast, children’s (7- and 11-year-olds) false recognition rates were again dependent on the overall amount of correctly remembered information, whereas adults’ false recognition was left unaffected. Overall, children’s false recognition rates changed when levels of processing or divided attention was manipulated in comparison with adults. Together, these results suggest that there may be both quantitative and qualitative changes in false memory rates with age.

The schema-driven chameleon: How mimicry affects executive and self-regulatory resources.

The authors propose that behavioral mimicry is guided by schemas that enable efficient social coordination. If mimicry is schema driven, then the operation of these schemas should be disrupted if partners behave in counternormative ways, such as mimicking people they generally would not or vice versa, rendering social interaction inefficient and demanding more executive and self-regulatory resources. To test this hypothesis, Experiments 1-3 used a resource-depletion paradigm in which participants performed a resource-demanding task after interacting with a confederate who mimicked them or did not mimic them. Experiment 1 demonstrated impaired task performance among participants who were not mimicked by a peer. Experiments 2 and 3 replicated this effect and also demonstrated a significant reversal in social contexts where mimicry is counternormative, suggesting that inefficiency emerges from schema inconsistency, not from the absence of mimicry per se. Experiment 4 used a divided attention paradigm and found that resources are taxed throughout schema-inconsistent interactions. These findings suggest that much-needed resources are preserved when the amount of mimicry displayed by interacting individuals adheres to norms, whereas resources are depleted when mimicry norms are violated.

Comparing perception of Stroop stimuli in focused versus divided attention paradigms: Evidence for dramatic processing differences

A huge set of focused attention experiments show that when presented with color words printed in color, observers report the ink color faster if the carrier word is the name of the color rather than the name of an alternative color, the Stroop effect. There is also a large number (although not so numerous as the Stroop task) of so-called “redundant targets studies” that are based on divided attention instructions. These almost always indicate that observers report the presence of a visual target (‘redness’ in the stimulus) faster if there are two replications of the target (the word RED in red ink color) than if only one is present (RED in green or GREEN in red). The present set of four experiments employs the same stimuli and same participants in both designs. Evidence supports the traditional interference account of the Stroop effect, but also supports a non-interference parallel processing account of the word and the color in the divided attention task. Theorists are challenged to find a unifying model that parsimoniously explains both seemingly contradictory results.

Fractionation of the Component Processes Underlying Successful Episodic Encoding: A Combined fMRI and Divided-attention Study

Considerable evidence suggests that attentional resources are necessary for the encoding of episodic memories, but the nature of the relationship between attention and neural correlates of encoding is unclear. Here we address this question using functional magnetic resonance imaging and a divided-attention paradigm in which competition for different types of attentional resources was manipulated. Fifteen volunteers were scanned while making animacy judgments to visually presented words and concurrently performing one of three tasks on auditorily presented words: male/female voice discrimination (control task), 1-back voice comparison (1-back task), or indoor/outdoor judgment (semantic task). The 1-back and semantic tasks were designed to compete for task-generic and task-specific attentional resources, respectively. Using the "remember/know" procedure, memory for the study words was assessed after 15 min. In the control condition, subsequent memory effects associated with later recollection were identified in the left dorsal inferior frontal gyrus and in the left hippocampus. These effects were differentially attenuated in the two more difficult divided-attention conditions. The effects of divided attention seem, therefore, to reflect impairments due to limitations at both task-generic and task-specific levels. Additionally, each of the two more difficult divided-attention conditions was associated with subsequent memory effects in regions distinct from those showing effects in the control condition. These findings suggest the engagement of alternative encoding processes to those engaged in the control task. The overall pattern of findings suggests that divided attention can impact later memory in different ways, and accordingly, that different attentional resources, including task-generic and task-specific resources, make distinct contributions to successful episodic encoding.

Attention, segregation, and textons: Bridging the gap between object-based attention and texton-based segregation

Studies of object-based attention (OBA) have suggested that attentional selection is intimately associated with discrete objects. However, the relationship of this association to the basic visual features (‘textons’) which guide the segregation of visual scenes into ‘objects’ remains largely unexplored. Here we study this hypothesized relationship for one of the most conspicuous features of early vision: orientation. To do so we examine how attention spreads through uniform (one ‘object’) orientation-defined textures (ODTs), and across texture-defined boundaries in discontinuous (two ‘objects’) ODTs. Using the divided-attention paradigm we find that visual events that are known to trigger orientation-based texture segregation, namely perceptual boundaries defined by high orientation and/or curvature gradients, also induce a significant cost on attentional selection. At the same time we show that no effect is incurred by the absolute value of the textons, i.e., by the general direction (or, the ‘grain’) of the texture—in conflict with previous findings in the OBA literature. Collectively these experiments begin to reveal the link between object-based attention and texton-based segregation, a link which also offers important cross-disciplinary methodological advantages.

The role of closure in defining the “objects” of object-based attention

Many recent studies have concluded that the underlying units of visual attention are often discrete objects whose boundaries constrain the allocation of attention. However, relatively few studies have explored the particular stimulus cues that determine what counts as an "object" of attention. We explore this issue in the context of the two-rectangles stimuli previously used by many investigators. We first show, using both spatial-cuing and divided-attention paradigms, that same-object advantages occur even when the ends of the two rectangles are not drawn. This is consistent with previous reports that have emphasized the importance of individual contours in guiding attention, and our study shows that such effects can occur in displays that also contain grouping cues. In our divided-attention experiment, however, this contour-driven same-object advantage was significantly weaker than that obtained with the standard stimulus, with the added cue of closure--demonstrating that contour-based processes are not the whole story. These results confirm and extend the observation that same-object advantages can be observed even without full-fledged objects. At the same time, however, these studies show that boundary closure-one of the most important cues to objecthood per se-can directly influence attention. We conclude that object-based attention is not an all-or-nothing phenomenon; object-based effects can be independently strengthened or weakened by multiple cues to objecthood.

The Influence of Sertraline on Attention and Verbal Memory in Children and Adolescents with Anxiety Disorders

This study investigated the cognitive side effects of a 6-week course of sertraline treatment on verbal memory and attention in children and adolescents. Children with various anxiety disorders (social phobia, generalized and separation anxiety disorder; n = 28), between 8 and 17 years of age, received a standardized, computerized neuropsychological assessment before treatment and another 6 weeks after treatment onset with sertraline (daily dose range between 25 and 100 mg). The patient group was compared to healthy controls (n = 28), who were matched for age and IQ and were also tested twice over a 6-week period. Sertraline did not have any negative effects on attentional performance (p > 0.05) but did increase response speed in a divided attention paradigm (p = 0.02). By contrast, performance of the interference part of a verbal memory task decreased (p = 0.05). The described results also remained stable over a 12-week period after treatment onset. Thus, the cognitive side effects of sertraline seemed to differ slightly between pediatric patients and those described in adult patient groups, should, therefore, be carefully assessed.

The Role of Closure in Defining the 'Objects' of Object-Based Attention

Many recent studies have concluded that the underlying units of visual attention are often discrete objects whose boundaries constrain the allocation of attention. However, relatively few studies have explored the particular stimulus cues that determine what counts as an “object” of attention. We explore this issue in the context of the two-rectangles stimuli previously used by many investigators. We first show, using both spatial-cuing and divided-attention paradigms, that same-object advantages occur even when the ends of the two rectangles are not drawn. This is consistent with previous reports that have emphasized the importance of individual contours in guiding attention, and our study shows that such effects can occur in displays that also contain grouping cues. In our divided-attention experiment, however, this contour-driven same-object advantage was significantly weaker than that obtained with the standard stimulus, with the added cue of closure—demonstrating that contour-based processes are not the whole story. These results confirm and extend the observation that same-object advantages can be observed even without full-fledged objects. At the same time, however, these studies show that boundary closure—one of the most important cues to objecthood per se—can directly influence attention. We conclude that object-based attention is not an all-or-nothing phenomenon; object-based effects can be independently strengthened or weakened by multiple cues to objecthood.

Two routes to emotional memory: distinct neural processes for valence and arousal.

Prior investigations have demonstrated that emotional information is often better remembered than neutral information, but they have not directly contrasted effects attributable to valence and those attributable to arousal. By using functional MRI and behavioral studies, we found that distinct cognitive and neural processes contribute to emotional memory enhancement for arousing information versus valenced, nonarousing information. The former depended on an amygdalar-hippocampal network, whereas the latter was supported by a prefrontal cortex-hippocampal network implicated in controlled encoding processes. A behavioral companion study, with a divided-attention paradigm, confirmed that memory enhancement for valenced, nonarousing words relied on controlled encoding processes: concurrent task performance reduced the enhancement effect. Enhancement for arousing words occurred automatically, even when encoding resources were diverted to the secondary task.

What Neural Correlates Underlie Successful Encoding and Retrieval? A Functional Magnetic Resonance Imaging Study Using a Divided Attention Paradigm

If attention is divided during learning, memory suffers. Nevertheless, individuals can learn information with divided attention. This event-related functional magnetic resonance imaging (fMRI) study (n = 17) investigated what neural processes support (1) learning with divided attention and (2) retrieval of information learned with divided attention. Participants encoded words (Is the word abstract or concrete?) while performing an auditory discrimination task (press a button whenever an auditory pattern changes). The auditory task was easy or hard, depending on the similarity of the patterns. A behavioral study indicated that detailed ("recollective") information was more likely to be present for words encoded with the easy versus the hard concurrent task. Words encoded with the hard versus the easy concurrent task, in contrast, were more likely to rely on less detailed ("familiarity"-based) information. fMRI revealed encoding-related activation in the left prefrontal cortex (PFC) and left hippocampus that was linked to successful memory formation only for items encoded with the easy task. In contrast, activation in the right PFC and left parahippocampal gyrus was linked to successful memory for all items. Thus, successful encoding with the hard concurrent task was supported by a subset of the regions recruited for successful encoding with the easy task. The neural processes recruited for successful retrieval also depended on the encoding condition: The left PFC was disproportionately recruited for retrieval of items encoded with the easy task, whereas the right PFC was disproportionately recruited for retrieval of items encoded with the hard task. These findings may reflect left-sided specialization for recollective memories and right-sided specialization for familiarity-based traces.

Divided Attention After Closed Head Injury

Abstract: One of the most persisting sequelae of closed head injury (CHI) is a general slowing of information processing. With neuropsychological testing, the effect is already apparent in simple reaction time tests. The slowing is more pronounced in complex tasks requiring divided attention. This study aims at explaining impairments in divided attention in terms of reduced speed of information processing, and impaired mental flexibility. Three types of mental flexibility are proposed: Stimulus driven (four choice reaction time and auditory reaction time task), memory driven (Trailmaking B test), and strategy driven flexibility tasks (continuous tracking task and arrow identification task). Divided attention paradigms were studied in 26 subacute CHI patients and 25 orthopedic control subjects. Results demonstrated that a reduced speed of information processing was largely responsible for divided attention impairments. Additional impairments in complex divided attention tasks only emerged in the most complex tasks (that is in the strategy driven flexibility task).

Divided Attention After Closed Head Injury

Abstract: One of the most persisting sequelae of closed head injury (CHI) is a general slowing of information processing. With neuropsychological testing, the effect is already apparent in simple reaction time tests. The slowing is more pronounced in complex tasks requiring divided attention. This study aims at explaining impairments in divided attention in terms of reduced speed of information processing, and impaired mental flexibility. Three types of mental flexibility are proposed: Stimulus driven (four choice reaction time and auditory reaction time task), memory driven (Trailmaking B test), and strategy driven flexibility tasks (continuous tracking task and arrow identification task). Divided attention paradigms were studied in 26 subacute CHI patients and 25 orthopedic control subjects. Results demonstrated that a reduced speed of information processing was largely responsible for divided attention impairments. Additional impairments in complex divided attention tasks only emerged in the most compl...

Cortical acetylcholine and processing capacity: effects of cortical cholinergic deafferentation on crossmodal divided attention in rats

The effects of 192 IgG-saporin-induced lesions of the corticopetal cholinergic neurons of the basal forebrain on divided attention were assessed in rats. Divided attention was measured using an operant version of the crossmodal divided attention paradigm. This task utilized the propositional response rules of visual and auditory conditional discriminations. Presentation of only visual or only auditory stimuli constituted performance under the condition of modality certainty. Conversely, the presentation of a randomized sequence of all possible stimuli represented the condition of modality uncertainty and was hypothesized to tax processing capacity. A single session was composed of two unimodal blocks of trials (20 trials each), followed by a bimodal block of 60 trials. Animals were extensively trained in this task and baseline performance was characterized by high response accuracy (>80%) in both conditions. Compared to unimodal trials, the response latencies in the bimodal block of trials were 160 ms longer. The lesion of the cholinergic system increased the response latencies exclusively under the condition of modality uncertainty. The extent of the lesion-induced decrease in cortical cholinergic fiber density correlated highly with the differences between uni- and bimodal response latencies. These results demonstrate a lesion-induced decrease in processing capacity and a preservation of response accuracy at the cost of response latency, i.e., a speed-accuracy tradeoff. Cortical acetylcholine is suggested to mediate the regulation and allocation of processing resources.

Visual attention and perception in patients with Huntington's disease: Comparisons with other subcortical and cortical dementias

Shifts in attention were examined in patients with Huntington's disease (HD) using a divided attention paradigm that involved the presentation of global-local stimuli. The HD patients' pattern of performance was compared to the previously reported results of groups of patients with Alzheimer's disease (AD; Filoteo et al., 1992) or Parkinson's disease (PD; Filoteo et al., 1994). Across consecutive trials of the divided attention task, a visual target could appear at either the same global-local level or at a different level. When the target changed levels across consecutive trials, the AD patients demonstrated an impairment in disengaging attention from the level at which the last target appeared, whereas the PD patients were impaired in maintaining their attention at the previously attended level. In contrast to these patterns of performances, the HD patients did not demonstrate a significant impairment in shifting attention between hierarchical levels. Both the AD and the PD patients' abnormal shifting ability was significantly related to the number of errors they made in identifying target stimuli; however, the pattern of the relationship was qualitatively distinct. These results suggest that different attentional mechanisms may underlie AD and PD patients' visual-perceptual deficits. The HD patients' shifting ability was not related to the number of errors they made in identifying target stimuli, suggesting that a different mechanism may account for the visual-perceptual impairments exhibited by these patients.