Memory effects of conflict and cognitive control are processing stage-specific: evidence from pupillometry.

An increasing number of studies in the conflict/control and perceptual desirable difficulty literatures show memory benefits for information in high-conflict task situations. Recent work suggests that increased conflict does not produce a task-wide encoding benefit; rather, conflict must focus high-level attention on to-be-tested information to produce an encoding benefit. We used pupil dilation measures to directly assess this stage-specific model of conflict-encoding effects. We show clear performance costs of incongruency (slower RT and larger pupil dilation) with both semantic and response distractors, but show memory benefits only with semantic conflict. Further, when participants were encouraged to focus more (eliciting greater endogenous effort and control for all trials, not just incongruent trials), we observe larger and more similar pupil responses and reduced memory differences between high versus low semantic conflict conditions. These data confirm and extend a stage-specific model of conflict-encoding effects, with converging behavioural and physiological data.

Item-specific proportion congruency (ISPC) modulates, but does not generate, the backward crosstalk effect.

When both tasks in a psychological refractory period (PRP) paradigm have compatible manual responses, a compatibility benefit in RT can often be observed on Task1 performance, in apparent violation of a strict traditional response selection bottleneck model. This compatibility-based backward crosstalk effect (BCE) has been generally attributed to automatic activation of Task2 response information, in parallel with attended Task1 performance. This paper tests a potential alternative mechanism of the BCE. Item-specific proportion congruency (ISPC) effects are previously well demonstrated, where learning of associations between stimuli and task conflict (e.g., that particular Stroop items are typically incongruent) allows rapidly and automatically elicited control adjustments in performance. Similar proportion manipulations have recently been shown to modulate the BCE in dual-task performance. If participants could similarly learn associations between particular pairs of stimuli and resulting response conflict in a PRP task, this kind of mechanism could produce relative speeding versus slowing of Task1 RT on response compatible versus incompatible trials. This pattern of data directly describes the BCE, and represents a potential alternative mechanism that does not require any response crosstalk, and would reinforce a stricter view of the response selection bottleneck model, if true. Over two experiments, we demonstrate that while the BCE is sensitive to ISPC-like effects based on Task1 conflict contingencies, the BCE is insensitive to relationships between particular pairs of stimuli and associated conflict. While ISPC effects can modulate the BCE, they do not generate the BCE. These findings reinforce the current Task2 parallel response activation account of the BCE.

Subjective semantic surprise resulting from divided attention biases evaluations of an idea's creativity.

The evaluation of an idea's creativity constitutes an important step in successfully responding to an unexpected problem with a new solution. Yet, distractions compete for cognitive resources with the evaluation process and may change how individuals evaluate ideas. In this paper, we investigate whether attentional demands from these distractions bias creativity evaluations. This question is examined using 1,065 creativity evaluations of 15 alternative uses of everyday objects by 71 study participants. Participants in the distraction group (Treatment) rated the alternative uses as more creative on the novelty dimension, but not the usefulness dimension, than did participants in the baseline group (Control). Psychophysiological measurements-event-related and spectral EEG and pupillometry-confirm attentional resources in the Treatment group are being diverted to a distractor task and that the Control group expended significantly more cognitive resources on the evaluation of the alternative uses. These data show direct physiological evidence that distractor tasks draw cognitive resources from creative evaluation and that such distractions will bias judgements of creativity.

Congruency Encoding Effects on Recognition Memory: A Stage-Specific Account of Desirable Difficulty.

Recent research suggests that selectively attending to relevant stimuli while having to ignore or resist conflicting stimuli can lead to improvements in learning. While mostly discussed within a broader "desirable difficulty" framework in the memory and education literatures, some recent work has focused on more mechanistic questions of how processing conflict (e.g., from incongruent primes) might elicit increased attention and control, producing enhanced incidental encoding of high-conflict stimuli. This encoding benefit for high-control-demand or high-difficulty situations has been broadly conceptualized as a task-general property, with no strong prediction of what particular task elements should produce this effect. From stage processing models of single- and dual-task performance, we propose that memory-enhancing difficulty manipulations should strongly depend on inducing additional cognitive control at particular processing stages. Over six experiments, we show that a memory benefit is produced when increased cognitive control (via incongruency priming) focuses additional processing on the core meaning of to-be-tested stimuli at the semantic categorization stage. In contrast, incongruency priming targeted at response selection within the same task produces similar effects on initial task performance, but gives no memory benefit for high-conflict trials. We suggest that a simple model of limited-capacity and stage-specific cognitive control allocation can account for and predict where and when conflict/difficulty encoding benefits will occur, and may serve as a model for desirable difficulty effects more broadly.

A narrative review on the difficulties associated with fibromyalgia diagnosis.

Fibromyalgia presents a clinical enigma as its pathophysiology is not well understood and its symptoms are nonspecific and overlap with many disorders, making its diagnosis a challenge for clinicians and researchers. Efforts have been made to develop a set of diagnostic criteria for this disorder. However, these criteria rely heavily on expert clinician opinion and produce a large heterogeneity within the diagnosed population. With no present specific technique reflecting the underlying pathophysiology of fibromyalgia, a definitive diagnosis of fibromyalgia remains elusive. This review discusses some problems and challenges associated with fibromyalgia diagnosis and presents some novel findings on the pathophysiological nature of fibromyalgia.

Talking is harder than listening: The time course of dual-task costs during naturalistic conversation.

Many studies have shown that the cognitive demands of language use are a substantial cause of central dual-task costs, including costs on concurrent driving performance. More recently, several studies have considered whether language production or comprehension is inherently more difficult with respect to costs on concurrent performance, with mixed results. This assessment is particularly difficult given the open question of how one should best equate and compare production and comprehension demands and performance. The present study used 2 very different approaches to address this question. Experiment 1 assessed manual tracking performance concurrently with a conventional labouratory task, comparing dual-task costs with comprehension and verification versus production of category items. Experiment 2 adopted an extreme ecological and functional approach to this question by assessing dual-task manual tracking costs concurrent with continuous, naturalistic, 2-way conversation, allowing event-related analysis of continuous tracking relative to onsets and offsets of natural production and comprehension events. Over both experiments, tracking performance was worse with concurrent production versus comprehension demands. We suggest that by at least 1 important functional metric-performance in natural, everyday conversation-talking is indeed harder than listening. (PsycINFO Database Record

Dual-task backward compatibility effects are episodically mediated.

In dual-task performance, the backward compatibility effect (BCE; faster Task 1 reaction time when Task 1 and Task 2 responses are compatible) is thought to represent automatic activation of Task 2 response information in parallel with attended Task 1 performance. Work by Hommel and Eglau (Psychological Research, 66, 260-273, 2002) has suggested the BCE relies on stimulus-response learning in long-term memory. Subsequent work by Ellenbogen and Meiran (Memory and Cognition, 36, 968-978, 2008), however, proposed that the BCE is mediated by Task 2 rules held in working memory (WM) during Task 1 performance. The present study aimed to dissociate these two theoretical claims. In Experiment 1, we assessed the effects of prior single-task practice with Task 1 or Task 2 of a subsequent dual-task paradigm. Where the WM-mediated model predicts both BCE and overall reaction time improvement relative to prior task practice, an episodic learning model makes divergent predictions for BCE based on the context specificity of prior Task 2 learning. Results showed a close fit with episodic predictions and contradicted WM model predictions. Experiment 2 examined the finer grained timecourse of BCE over initial development, subsequent interference of this initial learning on BCE development with new conflicting Task 2 response mappings, and finally reestablishment of BCE in the original dual task. Data again showed close agreement with long-term learning predictions. We argue in favor of an episodic account of the BCE, and consider implications of WM and episodic mechanisms of automatic response activation on other aspects of dual-task performance.

PRP training shows Task1 response selection is the locus of the backward response compatibility effect.

The present study investigates the effect of practice in a psychological refractory period (PRP) paradigm on the backward compatibility effect (BCE), in order to determine the locus of this response priming effect on Task1 performance. In two experiments, we show that the size of the BCE is closely associated with the duration of the response selection stage in Task1. When this stage is shortened through PRP practice, the magnitude of the BCE decreases. Subsequently increasing the duration of Task1 response selection results in a larger BCE, but manipulating the same stage in Task2 does not. Our results suggest that the BCE reflects crosstalk of unattended response information for Task2 acting on the response selection stage in Task1, and that response information for two tasks may be activated simultaneously.

Being a grump only makes things worse: a transactional account of acute stress on mind wandering.

The current work investigates the influence of acute stress on mind wandering. Participants completed the Positive and Negative Affect Schedule as a measure of baseline negative mood, and were randomly assigned to either the high-stress or low-stress version of the Trier Social Stress Test. Participants then completed the Sustained Attention to Response Task as a measure of mind-wandering behavior. In Experiment 1, participants reporting a high degree of negative mood that were exposed to the high-stress condition were more likely to engage in a variable response time, make more errors, and were more likely to report thinking about the stressor relative to participants that report a low level of negative mood. These effects diminished throughout task performance, suggesting that acute stress induces a temporary mind-wandering state in participants with a negative mood. The temporary affect-dependent deficits observed in Experiment 1 were replicated in Experiment 2, with the high negative mood participants demonstrating limited resource availability (indicated by pupil diameter) immediately following stress induction. These experiments provide novel evidence to suggest that acute psychosocial stress briefly suppresses the availability of cognitive resources and promotes an internally oriented focus of attention in participants with a negative mood.

Event-related potentials as brain correlates of item specific proportion congruent effects.

The item-specific proportion congruency (ISPC) effect is consistent with the idea that control processes can be applied rapidly in accord with previously experienced conflict for a particular category. An alternative account of this effect is that it reflects item-specific learning processes unrelated to control at the level of the category. The accounts predict the same behaviour but differ in terms of electrophysiological predictions. Two experiments examined the ISPC effect with a particular focus on neural correlates that might reveal whether, and how early in processing, high and low proportion congruent items are treated as distinct classes of stimuli. For both tasks, the proportion congruency category was distinguished prior to the congruence of the specific stimulus, as early as 100 ms post-stimulus onset for the global/local identification task (Experiment 1) and 150 ms for the Stroop task (Experiment 2). The results support an on-line control account of ISPC effects.

Information continuity across the response selection bottleneck: early parallel Task 2 response activation contributes to overt Task 2 performance.

Several studies of dual-task performance have demonstrated Task 2 to Task 1 response priming (backward compatibility effects), indicating some degree of parallel response computation for concurrent tasks and suggesting that the well-established response selection bottleneck (RSB) model may be incomplete. However, the RSB might be considered to remain informationally intact if this early parallel Task 2 response information does not persist across the attentional shift between tasks to contribute to overt Task 2 performance. We used an adapted psychological refractory period paradigm with an additional early transient Task 2 stimulus to examine whether response information generated for Task 2 in parallel with overt Task 1 response selection could persist across the bottleneck to influence eventual overt Task 2 performance. After controlling for potential indirect effects of Task 1 processing stage variability propagating onto Task 2 reaction time via locus of slack effects, we observed reliable and consistent effects of early Task 2 response information facilitating Task 2 reaction times. These effects were observed only when the responses to both tasks of the dual-task pair were compatible, under both univalent and bivalent response mappings across tasks. These findings may represent evidence of a variably sensitive response gating or suppression mechanism in dual-task performance and support the idea that backward response compatibility effects represent transient informational influences on central response codes, rather than later postbottleneck response execution processes.

Priming honesty reduces subjective bias in self-report measures of mind wandering.

Using self-report as a measure of conscious experience has been a point of contention in mind wandering research. Whereas prior work has focused on the introspective component of self-report validity, the current research introduces an honesty prime task to the current paradigm in order to assess the role of goal states and social factors on self-report accuracy. Findings provide evidence for an inflated report of mind wandering frequency arising from demand characteristics, intensified by the divergent properties of the subjective and behavioural measures and the general deficit in meta-awareness of off task episodes.

Differential visual processing for equivalent retinal information from near versus far space.

Converging evidence from animal neurophysiology and human clinical studies has suggested that visual information arising from near versus far space may be mediated predominantly by different visual subsystems in the human brain. In five experiments, healthy observers either detected or identified brief peripheral targets presented in near (peripersonal) versus far (extrapersonal) space. Apparent size (subtended visual angle) and luminance were equated to provide equivalent retinal information across near and far viewing conditions. Peripheral detection accuracy declined more rapidly with increasing target eccentricity in far viewing versus near viewing conditions. Peripheral identification accuracy under similar conditions showed no such dissociation of near versus far processing with eccentricity. These data suggest that retinal information from near versus far space may be preferentially processed by substantially different neural substrates, with active modulation of the relative contributions of involved magnocellular-dorsal and parvocellular-ventral visual pathways, depending on various potential ecological uses of the retinal information.

Parallel response selection in dual-task situations via automatic category-to-response translation.

In contrast to the response selection bottleneck theory of dual-task performance, recent studies have demonstrated compatibility effects between secondary and primary responses on Task 1, suggesting that response information for two tasks may be generated in parallel. In two experiments, we examined the nature of Task 2 response activation in parallel with Task 1, using a psychological refractory period paradigm. Evidence of Task 2 to Task 1 response priming when each Task 2 stimulus was unique indicated that automatic parallel generation of response information occurred for Task 2 via abstract semantic category-to-response translation processes, independent of any direct stimulus-response influences. These findings are discussed in terms of their implications for the traditional response selection bottleneck theory of dual-task performance.

Phonological facilitation from pictures in a word association task: evidence for routine cascaded processing in spoken word production.

While most authors now agree that the language production system is in principle cascaded, the strength with which cascaded lemma-to-phoneme activation typically occurs is debated. Picture naming has been shown to be facilitated by phonologically related distractor pictures, but no such facilitation from pictures has been shown for word reading. Picture-picture paradigms have recently been suggested to represent an attentionally facilitated and unusually strong case of cascaded phonological facilitation, not typical of a more general weakly cascaded production system. We used a novel procedure based on picture-word interference paradigms, where participants made speeded verbal free association responses to presented words, with irrelevant picture distractors that were phonologically related to their predicted high-associate responses. Phonological facilitation effects from related picture names were observed on free associate verbal production latencies. These findings represent a far more general demonstration of routine cascaded language production and suggest that the strength and extent of cascaded activation is more substantial than that suggested by traditional picture-word paradigms.

Modality-specific control processes in verbal versus spatial working memory.

Over the past decade, neuroimaging and electrophysiological studies of working memory (WM) have made progress in distinguishing the neural substrates of central executive (CE) functions from substrates of temporary storage subsystems. However, the degree to which CE-related processes and their substrates may be further fractionated is less clear. The present study measured event-related potentials (ERPs) in a running memory paradigm, to study modality-specific CE-related processes in verbal and spatial WM. Participants were asked to remember either verbal (digit identity) or spatial (digit location) information for the first or last three items in a variable length sequence of spatially distributed digit stimuli. Modality-specific WM demand-sensitive ERP amplitude effects were selectively observed over left prefrontal areas under verbal WM performance and over right prefrontal areas under spatial WM performance. In addition, distinct patterns of item-by-item sensitivity under high-CE-demand conditions suggested qualitatively different processing strategies for verbal versus spatial tasks. These results suggest that both modality-specific and task-general CE-related processes are likely operational in many WM situations and that careful dissociative methods will be needed to properly further fractionate and characterize these component CE-related processes and their neurological substrates.

Task switching in video game players: Benefits of selective attention but not resistance to proactive interference.

Research into the perceptual and cognitive effects of playing video games is an area of increasing interest for many investigators. Over the past decade, expert video game players (VGPs) have been shown to display superior performance compared to non-video game players (nVGPs) on a range of visuospatial and attentional tasks. A benefit of video game expertise has recently been shown for task switching, suggesting that VGPs also have superior cognitive control abilities compared to nVGPs. In two experiments, we examined which aspects of task switching performance this VGP benefit may be localized to. With minimal trial-to-trial interference from minimally overlapping task set rules, VGPs demonstrated a task switching benefit compared to nVGPs. However, this benefit disappeared when proactive interference between tasks was increased, with substantial stimulus and response overlap in task set rules. We suggest that VGPs have no generalized benefit in task switching-related cognitive control processes compared to nVGPs, with switch cost reductions due instead to a specific benefit in controlling selective attention.

SayWhen: an automated method for high-accuracy speech onset detection.

Many researchers across many experimental domains utilize the latency of spoken responses as a dependent measure. These measurements are typically made using a voice key, an electronic device that monitors the amplitude of a voice signal, and detects when a predetermined threshold is crossed. Unfortunately, voice keys have been repeatedly shown to be alarmingly errorful and biased in accurately detecting speech onset latencies. We present SayWhen--an easy-to-use software system for offline speech onset latency measurement that (1) automatically detects speech onset latencies with high accuracy, well beyond voice key performance, (2) automatically detects and flags a subset of trials most likely to have mismeasured onsets, for optional manual checking, and (3) implements a graphical user interface that greatly speeds and facilitates the checking and correction of this flagged subset of trials. This automatic-plus-selective-checking method approaches the gold standard performance of full manual coding in a small fraction of the time.

Control processes in verbal working memory: an event-related potential study.

Event-related potentials (ERPs) were recorded using a large electrode array while subjects engaged in tasks designed to dissociate control from storage/maintenance processes in verbal working memory (WM). Increased ERP negativity (450-900 ms post-stimulus onset) over left frontal regions emerged only when required dynamic updating/revision of WM stores was initiated, with augmentation of right frontal negativity in the same epoch relative to more general overall task demands. Increased ERP positivity in a similar time window over parietal regions reflected initiation of required rehearsal/maintenance of memory set contents, with progressive amplitude increases with repeated dynamic updating/revision of memory stores, suggesting increased effortful activity to resist proactive interference effects. These findings are consistent with a left frontal-parietal network for process control in verbal working memory.

Automatic face identity encoding at the N170.

The N170 event-related potential component is currently under investigation for its role in face identity processing. Using a location-matching paradigm, in which face identity is task irrelevant, we observed a progressive decrease in N170 amplitude to multiple repetitions of upright faces presented at unattended locations. In contrast, we did not observe N170 habituation for repeat presentations of inverted faces. The findings suggest that the N170 repetition effects reflect early face identity processes that are part of familiarity acquisition of new faces.