Slower RTs Research Articles

Parsing state mindfulness effects on neurobehavioral markers of cognitive control: A within-subject comparison of focused attention and open monitoring.

Over the past two decades, scientific interest in understanding the relationship between mindfulness and cognition has accelerated. However, despite considerable investigative efforts, pervasive methodological inconsistencies within the literature preclude a thorough understanding of whether or how mindfulness influences core cognitive functions. The purpose of the current study is to provide an initial "proof-of-concept" demonstration of a new research strategy and methodological approach designed to address previous limitations. Specifically, we implemented a novel fully within-subject state induction protocol to elucidate the neurobehavioral influence of discrete mindfulness states-focused attention (FA) and open monitoring (OM), compared against an active control-on well-established behavioral and ERP indices of executive attention and error monitoring assessed during the Eriksen flanker task. Bayesian mixed modeling was used to test preregistered hypotheses pertaining to FA and OM effects on flanker interference, the stimulus-locked P3, and the response-locked ERN and Pe. Results yielded strong but unexpected evidence that OM selectively produced a more cautious and intentional response style, characterized by higher accuracy, slower RTs, and reduced P3 amplitude. Follow-up exploratory analyses revealed that trait mindfulness moderated the influence of OM, such that individuals with greater trait mindfulness responded more cautiously and exhibited higher trial accuracy and smaller P3s. Neither FA nor OM modulated the ERN or Pe. Taken together, our findings support the promise of our approach, demonstrating that theoretically distinct mindfulness states are functionally dissociable among mindfulness-naive participants and that interactive variability associated with different operational facets of mindfulness (i.e., state vs. trait) can be modeled directly.

Sleep deprivation affects interference control: A diffusion model analysis.

Previous studies suggest that interference control may be unaffected by sleep deprivation based on the unchanged interference effects (reaction time [RT] differences between incongruent and congruent conditions), while ignoring the overall slower RTs after sleep deprivation. In the present study, we interpreted these results from a new angle using a variant of diffusion model, diffusion model for conflict tasks (DMC), and investigated whether and how interference control is affected by sleep deprivation. Mathematical derivations and model simulations showed that unchanged task-irrelevant information processing (i.e., unaffected interference control) may not lead to the observed unchanged interference effects when considering the overall slower RTs after sleep deprivation (due to either decreased drift rate of task-relevant information or increased decision boundary). Therefore, the unchanged interference effects do not necessarily indicate unchanged interference control. We then conducted a Simon task following one night of sleep deprivation or normal sleep, and fitted the DMC to the data. Experimental results showed that the Simon effect was reversed when most of the trials were incongruent, indicating that participants used learned spatially incompatible stimulus-response associations to predict responses. However, the Simon effects in both mean RTs and RT distributions were not significantly modulated by sleep deprivation. Model fits showed that the drift rate of task-relevant information decreased and the time-to-peak of task-irrelevant activation increased after sleep deprivation. These results suggest that central information processing was degraded after sleep loss, and most importantly, task-irrelevant activation increased after sleep deprivation as interference control was impaired. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The effect of a dynamic lighting schedule on neurobehavioral performance during a 45-day simulated space mission.

We previously reported that during a 45-day simulated space mission, a dynamic lighting schedule (DLS) improved circadian phase alignment and performance assessed once on selected days. This study aimed to evaluate how DLS affected performance on a 5-minute psychomotor vigilance task (PVT) administered multiple times per day on selected days. Sixteen crewmembers (37.4 ± 6.7 years; 5F) underwent six cycles of 2 × 8-hour/night followed by 5 × 5-hour/night sleep opportunities. During the DLS (n = 8), daytime white light exposure was blue-enriched (~6000K; Level 1: 1079, Level 2: 76 melanopic equivalent daytime illuminance (melEDI) lux) and blue-depleted (~3000-4000K; L1: 21, L2: 2 melEDI lux) 3 hours before bed. In the standard lighting schedule (SLS; n = 8), lighting remained constant (~4500K; L1: 284, L2 62 melEDI lux). Effects of lighting condition (DLS/SLS), sleep condition (5/8 hours), time into mission, and their interactions, and time awake on PVT performance were analyzed using generalized linear mixed models. The DLS was associated with fewer attentional lapses (reaction time [RT] > 500 milliseconds) compared to SLS. Lapses, mean RT, and 10% fastest/slowest RTs were worse following 5 compared to 8 hours of sleep but not between lighting conditions. There was an effect of time into mission on RTs, likely due to sleep loss. Overall performance differed by time of day, with longer RTs at the beginning and end of the day. There were more lapses and slower RTs in the afternoon in the SLS compared to the DLS condition. Future missions should incorporate DLS to enhance circadian alignment and performance. This paper is part of the Sleep and Circadian Rhythms: Management of Fatigue in Occupational Settings Collection.

Transcranial Direct Current Stimulation Modulates Working Memory Maintenance Processes in Healthy Individuals.

The effects of transcranial direct current stimulation (tDCS) at the pFC are often investigated using cognitive paradigms, particularly working memory tasks. However, the neural basis for the neuromodulatory cognitive effects of tDCS, including which subprocesses are affected by stimulation, is not completely understood. We investigated the effects of tDCS on working memory task-related spectral activity during and after tDCS to gain better insights into the neurophysiological changes associated with stimulation. We reanalyzed data from 100 healthy participants grouped by allocation to receive either sham (0 mA, 0.016 mA, and 0.034 mA) or active (1 mA or 2 mA) stimulation during a 3-back task. EEG data were used to analyze event-related spectral power in frequency bands associated with working memory performance. Frontal theta event-related synchronization (ERS) was significantly reduced post-tDCS in the active group. Participants receiving active tDCS had slower RTs following tDCS compared with sham, suggesting interference with practice effects associated with task repetition. Theta ERS was not significantly correlated with RTs or accuracy. tDCS reduced frontal theta ERS poststimulation, suggesting a selective disruption to working memory cognitive control and maintenance processes. These findings suggest that tDCS selectively affects specific subprocesses during working memory, which may explain heterogenous behavioral effects.

Semantic interference and facilitation in picture naming: The effects of type of impairment and compensatory strategies

ABSTRACT We assessed effects of semantic interference in people with aphasia (PWA). Two naming tasks (continuous naming and cyclic blocking) were contrasted with tasks which required suppression of competitors but minimized lexical access (probe task) or required extra-lexical mechanisms of control (Stroop task). In continuous naming, some PWA showed increased interference compared to control participants, with slower RTs and increased omissions. Others showed normal or weaker interference effects in terms of RTs but increased semantic errors. Patterns were consistent only between naming tasks. We explain results by assuming that some PWA are slow at implementing mechanisms of control/selection which weed-out competitors. Others, instead, will have activation difficulties which will induce them to lower the threshold needed for selection. Results highlight how different kinds of brain damage may induce different compensatory strategies and how semantic relatedness may induce both interference and facilitation. Implications for models of lexical selection are discussed.

Effects Of Acute And Sustained Stress On Cognitive Performance During A 72-hour Military Training Mission

Stress can have varying impacts on cognitive function. Research shows that chronic, or sustained stress, may lead to declines in cognition, whereas acute stress may improve or impair performance depending on the cognitive domain assessed. However, research rarely examines the impacts of both acute and chronic stress on cognition within the same individual, or overlooks specialized cohorts (i.e. military personnel). Yet, Soldiers often experience varying forms and combinations of acute and sustained stressors during sustained operations (SUSOPS), i.e. encountering a firefight at the end of a multi-day mission. Thus, it is important to understand how varying aspects of cognitive function may change in response to acute and chronic stress experienced in operational environments. PURPOSE: To compare effects of acute and sustained stressors on cognitive performance over the course of a 72-hr military training exercise. METHODS: 62 active duty Soldiers (Age: 22.9 ± 3.2 yrs; 62 males), completed a series of cognitive tasks at Baseline (several weeks prior) and at three time points (T1, T2, T3) during a highly stressful 72-hr training mission. Soldiers performed Go/No-Go (GNG), N-back (NB), Task-Switching (TS), and Simple Reaction Time (SRT) tasks at T1, which occurred pre-mission following a live-fire exercise (acute stress); at T2, after approximately 36-hrs of mission activities (sustained stress); and at T3, after a second live-fire exercise at the end of the 72-hr mission (acute and sustained stress). RESULTS: Repeated Measures ANOVA’s showed main effects of Time for GNG and SRT tasks (p's < .05) Compared to Baseline, planned comparisons revealed that inhibition (GNG) declined following sustained stress, with false alarms increasing at T2 (p < .05); whereas reaction time (SRT) degraded following acute stress, with slower RTs at T1 (p < .01). GNG and SRT performance both declined due to the combined acute and sustained stress at T3 (p's < .01). Performance on TS and NB tasks remained unaffected. CONCLUSIONS: Acute and sustained stress experienced during SUSOPS differentially impacts cognition depending on the type of stress and cognitive domain assessed. These data show that effects of stress are nuanced and emphasize the importance of characterizing changes in cognition over multi-day missions. Funding: Army RDT&E

Nice and easy: Mismatch negativity responses reveal a significant correlation between aesthetic appreciation and perceptual learning.

Neurocomputational models of cognition have framed aesthetic appreciation within the domain of knowledge acquisition and learning, suggesting that aesthetic appreciation might be considered as a hedonic feedback on successful perceptual learning dynamics. Such hypothesis, however, has never been empirically demonstrated yet. In order to investigate the relationship between aesthetic appreciation and learning, we measured the EEG mismatch negativity (MMN) response to more or less appreciated musical intervals, which is considered as a reliable index of perceptual learning. To this end, we measured the MMN to frequency (Hz) standard and frequency deviant musical intervals (Experiment 1) while participants were asked to judge their beauty. For each single stimulus, we also computed an information-theoretic index of perceptual learning (Bayesian surprise). We found that more appreciated musical intervals were associated with a larger MMN responses, which, in turn, correlated with trial-by-trial fluctuations in Bayesian surprise (Experiment 1). Coherently with previous results, Bayesian surprise was also found to correlate with slower RTs in a detection task of the same stimuli, evidencing that motor behavior is inhibited in presence of surprising sensory states triggering perceptual learning (Experiment 2). Our results provide empirical evidence of the existence of a positive correlation between aesthetic appreciation and EEG indexes of perceptual learning. We argue that the sense of beauty might have evolved to signal the nervous system new sensory knowledge acquisition and motivate the individual to search for informationally profitable stimuli. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Top\u2013down task-specific determinants of multisensory motor reaction time enhancements and sensory switch costs

This study was designed to investigate the complex interplay between multisensory processing, top–down processes related to the task relevance of sensory signals, and sensory switching. Thirty-five adults completed either a speeded detection or a discrimination task using the same auditory and visual stimuli and experimental setup. The stimuli consisted of unisensory and multisensory presentations of the letters ‘b’ and ‘d’. The multisensory stimuli were either congruent (e.g., the grapheme ‘b’ with the phoneme /b/) or incongruent (e.g., the grapheme ‘b’ with the phoneme /d/). In the detection task, the participants had to respond to all of the stimuli as rapidly as possible while, in the discrimination task, they only responded on those trials where one prespecified letter (either ‘b’ or ‘d’) was present. Incongruent multisensory stimuli resulted in faster responses as compared to unisensory stimuli in the detection task. In the discrimination task, only the dual-target congruent stimuli resulted in faster RTs, while the incongruent multisensory stimuli led to slower RTs than to unisensory stimuli; RTs were the slowest when the visual (rather than the auditory) signal was irrelevant, thus suggesting visual dominance. Switch costs were also observed when switching between unisensory target stimuli, while dual-target multisensory stimuli were less likely to be affected by sensory switching. Taken together, these findings suggest that multisensory motor enhancements and sensory switch costs are influenced by top–down modulations determined by task instructions, which can override the influence of prior learnt associations.

Examining the Trainability and Transferability of Working-Memory Gating Policies

Internal working memory (WM) gating control policies have been suggested to constitute a critical component of task-sets that can be learned and transferred to very similar task contexts (Bhandari and Badre (Cognition, 172, 33–43, 2018). Here, we attempt to expand these findings, examining whether such control policies can be also trained and transferred to other untrained cognitive control tasks, namely to task switching and AX-CPT. To this end, a context-processing WM task was used for training, allowing to manipulate either input (i.e., top-down selective entry of information into WM) or output (i.e., bottom-up selective retrieval of WM) gating control policies by employing either a context-first (CF) or context-last (CL) task structure, respectively. In this task, two contextual cues were each associated with two different stimuli. In CF condition, each trial began with a contextual cue, determining which of the two subsequent stimuli is target relevant. In contrast, in the CL condition the contextual cue appeared last, preceded by a target and non-target stimulus successively. Participants completed a task switching baseline assessment, followed by one practice and six training blocks with the WM context-processing training task. After completing training, task-switching and AX-CPT transfer blocks were administrated, respectively. As hypothesized, compared to CL training condition, CF training led to improved task-switching performance. However, contrary to our predictions, training type did not influence AX-CPT performance. Taken together, the current results provide further evidence that internal control policies are (1) inherent element of task-sets, also in task switching and (2) independent of S-R mappings. However, these results need to be cautiously interpreted due to baseline differences in task-switching performance between the conditions (overall slower RTs in the CF condition). Importantly though, our results open a new venue for the realm of cognitive enhancement, pointing here for the first time to the potential of control policies training in promoting wider transfer effects.

The Shape of Things to Come in Speech Production: A Functional Magnetic Resonance Imaging Study of Visual Form Interference during Lexical Access.

Studies of context effects in speech production have shown that semantic feature overlap produces interference in naming of categorically related objects. In neuroimaging studies, this semantic interference effect is consistently associated with involvement of left superior and middle temporal gyri. However, at least part of this effect has recently been shown to be attributable to visual form similarity, as categorically related objects typically share visual features. This fMRI study examined interference produced by visual form overlap in the absence of a category relation in a picture-word interference paradigm. Both visually similar and visually dissimilar distractors led to increased BOLD responses in the left inferior frontal gyrus compared with the congruent condition. Naming pictures in context with a distractor word denoting an object visually similar in form slowed RTs compared with unrelated words and was associated with reduced activity in the left posterior middle temporal gyrus. This area is reliably observed in lexical level processing during language production tasks. No significant differential activity was observed in areas typically engaged by early perceptual or conceptual feature level processing or in areas proposed to be engaged by postlexical language processes, suggesting that visual form interference does not arise from uncertainty or confusion during perceptual or conceptual identification or after lexical processing. We conclude that visual form interference has a lexical locus, consistent with the predictions of competitive lexical selection models.

Causal Evidence for the Role of Neuronal Oscillations in Top-Down and Bottom-Up Attention.

Beta and gamma frequency neuronal oscillations have been implicated in top-down and bottom-up attention. In this study, we used rhythmic TMS to modulate ongoing beta and gamma frequency neuronal oscillations in frontal and parietal cortex while human participants performed a visual search task that manipulates bottom-up and top-down attention (single feature and conjunction search). Both task conditions will engage bottom-up attention processes, although the conjunction search condition will require more top-down attention. Gamma frequency TMS to superior precentral sulcus (sPCS) slowed saccadic RTs during both task conditions and induced a response bias to the contralateral visual field. In contrary, beta frequency TMS to sPCS and intraparietal sulcus decreased search accuracy only during the conjunction search condition that engaged more top-down attention. Furthermore, beta frequency TMS increased trial errors specifically when the target was in the ipsilateral visual field for the conjunction search condition. These results indicate that beta frequency TMS to sPCS and intraparietal sulcus disrupted top-down attention, whereas gamma frequency TMS to sPCS disrupted bottom-up, stimulus-driven attention processes. These findings provide causal evidence suggesting that beta and gamma oscillations have distinct functional roles for cognition.

Developmental Shifts in Detection and Attention for Auditory, Visual, and Audiovisual Speech.

Successful speech processing depends on our ability to detect and integrate multisensory cues, yet there is minimal research on multisensory speech detection and integration by children. To address this need, we studied the development of speech detection for auditory (A), visual (V), and audiovisual (AV) input. Participants were 115 typically developing children clustered into age groups between 4 and 14 years. Speech detection (quantified by response times [RTs]) was determined for 1 stimulus, /buh/, presented in A, V, and AV modes (articulating vs. static facial conditions). Performance was analyzed not only in terms of traditional mean RTs but also in terms of the faster versus slower RTs (defined by the 1st vs. 3rd quartiles of RT distributions). These time regions were conceptualized respectively as reflecting optimal detection with efficient focused attention versus less optimal detection with inefficient focused attention due to attentional lapses. Mean RTs indicated better detection (a) of multisensory AV speech than A speech only in 4- to 5-year-olds and (b) of A and AV inputs than V input in all age groups. The faster RTs revealed that AV input did not improve detection in any group. The slower RTs indicated that (a) the processing of silent V input was significantly faster for the articulating than static face and (b) AV speech or facial input significantly minimized attentional lapses in all groups except 6- to 7-year-olds (a peaked U-shaped curve). Apparently, the AV benefit observed for mean performance in 4- to 5-year-olds arose from effects of attention. The faster RTs indicated that AV input did not enhance detection in any group, but the slower RTs indicated that AV speech and dynamic V speech (mouthing) significantly minimized attentional lapses and thus did influence performance. Overall, A and AV inputs were detected consistently faster than V input; this result endorsed stimulus-bound auditory processing by these children.

Everything is worth when it is close to my body: How spatial proximity and stimulus valence affect visuo-tactile integration

The peripersonal space (PPS) is the space surrounding our body, represented in a multisensory fashion by integrating stimuli of different modalities. Recently, it has been demonstrated that PPS is emotionally connoted, being sensitive to the different affective valence of the stimuli located inside it. However, how visuo-tactile interactions can be spatially shaped by intrinsic or acquired valence of stimuli is not clear. To investigate this, we conducted three experiments in which participants performed a visuo-tactile interaction task, while the intrinsic valence (Exp. 1 and 2) or the learned valence (Exp. 3) of visual stimuli was manipulated. Participants were asked to respond as fast as possible to a tactile stimulus that was delivered while a visual stimulus was approaching (Exp.1 and 3) or receding (Exp.2) from the hand. Touch was synchronized with different distances of the visual stimulus from the hand. We found that both the expectancy of stimulus and the distance of the visual one from the hand impact RTs to tactile targets. Crucially, we found that spatial modulation was also influenced by stimulus valence, but only for the approaching and not the receding stimuli. At far distances, neutral stimuli yielded overall slower RTs than intrinsically positive or negative stimuli (Experiment 1), while no modulation was exerted by the level of conditioning (Experiment 3). At near distances, response to touches accompanied by looming neutral stimuli became as fast as that occurring with positive and negative ones. Stimulus valence did not interact with the expectancy of a tactile stimulus (Experiment 2). Overall, these findings support the vision that visuo-tactile interactions can be dynamically modulated by the valence of looming visual stimuli when these are located at longer distances from the body. When closer to it, all stimuli acquire saliency, regardless of their intrinsic or acquired valence, due to their proximity, and then relevance, to the body. Overall, a view of PPS as a gradient modulating visuo-tactile integration, also based on stimulus valence, is discussed.

Differential inter-trial effects in the visual search of children, adolescents, and young adults

We examined the age-related variation in one type of inter-trial effect of visual search, the distractor previewing effect (DPE), in affectively neutral and affectively charged contexts. In Experiment 1, children, adolescents, and young adults were faster to identify the shape of a color target when the color of the current distractors had already been previewed than when the target had been previewed in the preceding target-absent trial, indicative of a color-based DPE. The results revealed a greater DPE in children than in adolescents and young adults, but it can be attributed to children's slower RTs than the other two groups. In Experiment 2, children, adolescents, and young adults were instructed to respond to a schematic face that was different from the other two faces. Young adults were faster in searching for a threatening face among friendly ones when they had previewed a target-absent display consisting of friendly faces than that of threatening faces, indicating an emotional DPE. By contrast, children showed a reversed DPE under the same condition, whereas adolescents showed no DPE. Taken together, these results suggested that the three age groups were all able to create an inhibitory attentional bias on the basis of trial history in affectively neutral context, whereas children and adolescents were not able to create such an inhibitory attentional bias in affectively charged contexts in the same way as adults did. These findings implied that the development of attentional inhibition abilities in affectively charged contexts might be delayed compared to those in affectively neutral contexts.

When listening to rain sounds boosts arithmetic ability.

Studies in the literature have provided conflicting evidence about the effects of background noise or music on concurrent cognitive tasks. Some studies have shown a detrimental effect, while others have shown a beneficial effect of background auditory stimuli. The aim of this study was to investigate the influence of agitating, happy or touching music, as opposed to environmental sounds or silence, on the ability of non-musician subjects to perform arithmetic operations. Fifty university students (25 women and 25 men, 25 introverts and 25 extroverts) volunteered for the study. The participants were administered 180 easy or difficult arithmetic operations (division, multiplication, subtraction and addition) while listening to heavy rain sounds, silence or classical music. Silence was detrimental when participants were faced with difficult arithmetic operations, as it was associated with significantly worse accuracy and slower RTs than music or rain sound conditions. This finding suggests that the benefit of background stimulation was not music-specific but possibly due to an enhanced cerebral alertness level induced by the auditory stimulation. Introverts were always faster than extroverts in solving mathematical problems, except when the latter performed calculations accompanied by the sound of heavy rain, a condition that made them as fast as introverts. While the background auditory stimuli had no effect on the arithmetic ability of either group in the easy condition, it strongly affected extroverts in the difficult condition, with RTs being faster during agitating or joyful music as well as rain sounds, compared to the silent condition. For introverts, agitating music was associated with faster response times than the silent condition. This group difference may be explained on the basis of the notion that introverts have a generally higher arousal level compared to extroverts and would therefore benefit less from the background auditory stimuli.

The Cost of Structure Learning.

Human learning is highly efficient and flexible. A key contributor to this learning flexibility is our ability to generalize new information across contexts that we know require the same behavior and to transfer rules to new contexts we encounter. To do this, we structure the information we learn and represent it hierarchically as abstract, context-dependent rules that constrain lower-level stimulus-action-outcome contingencies. Previous research showed that humans create such structure even when it is not needed, presumably because it usually affords long-term generalization benefits. However, computational models predict that creating structure is costly, with slower learning and slower RTs. We tested this prediction in a new behavioral experiment. Participants learned to select correct actions for four visual patterns, in a setting that either afforded (but did not promote) structure learning or enforced nonhierarchical learning, while controlling for the difficulty of the learning problem. Results replicated our previous finding that healthy young adults create structure even when unneeded and that this structure affords later generalization. Furthermore, they supported our prediction that structure learning incurred a major learning cost and that this cost was specifically tied to the effort in selecting abstract rules, leading to more errors when applying those rules. These findings confirm our theory that humans pay a high short-term cost in learning structure to enable longer-term benefits in learning flexibility.

Looking forward to safer HGVs: The impact of mirrors on driver reaction times

Heavy Goods Vehicle (HGV) collisions are responsible for a disproportionate number of urban vulnerable road user casualties (VRU – cyclists and pedestrians). Blind-spots to the front and side of HGVs can make it difficult (sometimes impossible) to detect close proximity VRUs and may be the cause of some collisions. The current solution to this problem is to provide additional mirrors that can allow the driver to see into the blind-spots. However, keeping track of many mirrors requires frequent off-road glances which can be difficult to execute during demanding driving situations. One suggestion is that driving safety could be improved by redesigning cabs in order to reduce/remove blind-spot regions, with the aim of reducing the need for mirrors, and increasing detection rates (and thereby reducing collisions). To examine whether mirrors delay driver responses we created a series of simulated driving tasks and tested regular car drivers and expert HGV drivers. First we measured baseline reaction times to objects appearing when not driving (‘Parked’). Participants then repeated the task whilst driving through a simulated town (primary driving tasks were steering, braking, and following directional signs): driving slowed reaction times to objects visible in mirrors but not to objects visible through the front windscreen. In a second experiment cognitive load was increased, this slowed RTs overall but did not alter the pattern of responses across windows and mirrors. Crucially, we demonstrate that the distribution of mirror RTs can be captured simply by the mirror’s spatial position (eccentricity). These findings provide robust evidence that drivers are slower reacting to objects only visible in eccentric mirrors compared to direct viewing through the front windscreen.

Processing DOM in relative clauses

AbstractEarly heritage bilinguals have been repeatedly found to differ from late bilinguals and from monolinguals (e.g.,Montrul, 2008,2011). In the realm of Spanish Differential Object Marking (DOM), both early heritage bilinguals (Montrul et al., 2015) and late bilinguals (e.g.,Bowles &amp; Montrul, 2008;Guijarro-Fuentes, 2012) exhibit difficulties. DOM in a complex structure such as relative clauses (RCs) provides an ideal setting to differentiate early from late bilinguals, but it has only been explored offline (Perpiñán &amp; Moreno-Villar, 2013). This study fills this gap by examining the role of word order (SVO, OSV, OVS), optionality (obligatory vs. optional contexts), and saliency (bound vs. unbound morphology) on the processing of DOM in embedded RCs in Spanish, by Spanish monolinguals, and advanced early heritage and late bilinguals of Spanish. The results of a word-by-word non-cumulative self-paced reading task revealed that all participants were more accurate but were slower in subject than object RCs, and in OSV than OVS RCs. Slower RTs in subject RCs were due to the presence of DOM, and in OSV to interpreting OVS as SVO. Also, all participants were both more accurate as well as faster in obligatory than optional DOM, unbound than bound morphology, and masculine than feminine RC NPs. These findings reveal that processing difficulties in RCs result from the interaction of word order and DOM, and that processing DOM depends on both salience and, to a lesser extent, gender. Finally, this study shows that early heritage bilinguals are closer to monolinguals than late bilinguals in terms of morphosyntactic processing patterns.

Aging and guided visual search: the role of visual working memory

ABSTRACTIn the present study, we examined age-related differences in utilizing learned associations to guide visual search. Participants viewed an object cue that was associated with 1 or 2 target colors, followed by a search array. Older adults showed slower RTs, larger visual search slopes, and reduced cue–target association knowledge than did younger adults. We also found increased search RTs and higher error rates when the cue was associated with 2 colors instead of 1. However, visual search slopes did not vary with the number of associated colors. This indicates that participants could activate multiple templates simultaneously to guide the search or retrieve associative information directly from the long-term memory. Furthermore, regression analyses showed that VWMC can predict both visual search performances and cue–target association knowledge. More broadly, our results demonstrate that VWMC can modify the effects of age on cued visual search performance.

Pace Yourself: Intraindividual Variability in Context Use Revealed by Self-paced Event-related Brain Potentials.

Event-related brain potentials (ERPs) have revealed multiple mechanisms by which contextual constraints impact language processing. At the same time, little work has examined the trial-to-trial dynamics of context use in the brain. In the current study, we probed intraindividual variability in behavioral and neural indices of context processing during reading. In a concurrent self-paced reading and ERP paradigm, participants read sentences that were either strongly or weakly constraining completed with an expected or unexpected target word. Our findings revealed substantial within-subject variability in behavioral and neural responses to contextual constraints. First, context-based amplitude reductions of the N400, a component linked to semantic memory access, were largest among trials eliciting the slowest RTs. Second, the RT distribution of unexpected words in strongly constraining contexts was positively skewed, reflecting an increased proportion of very slow RTs to trials that violated semantic predictions. Among those prediction-violating trials eliciting faster RTs, a late sustained anterior positivity was observed. However, among trials producing the differentially slowed RTs to prediction violations, we observed a markedly earlier effect of constraint in the form of an anterior N2, a component linked to conflict resolution and the cognitive control of behavior. The current study provides the first neurophysiological evidence for the direct role of cognitive control functions in the volitional control of reading. Collectively, our findings suggest that context use varies substantially within individual participants and that coregistering behavioral and neural indices of online sentence processing offers a window into these single-item dynamics.