Global-local Task Research Articles

Effects of alcohol and alcohol expectations on executive function of social drinkers

Objective To explore the influence on each dimension of executive function of social drinkers with moderate dose of alcohol intake and different alcohol expectations. Methods 90 university students who were social drinkers allocated randomly by a lottery method to drinking group (n=31), control group (n=30) and placebo group (n=29). The Stroop task, 1-Back task and local-global task were employed to measure executive function from three aspects respectively, namely the inhibition, updating and shifting process. Results Drinking group was compared with the Control group in the three dimensions of executive function: inhibition((61.65±26.31)ms, (42.48±32.94)ms), updating((557.23±86.24)ms, (515.02±70.24)ms), and shifting process ((718.85±246.03)ms, (553.95±151.74)ms). The differences were statistically significant (P 0.05). In the drinking group, positive expectation was negatively related to each dimension of executive function (-0.427, -0.330, -0.383). The inhibition and the shifting process appeared significant correlation(P<0.05). Negative expectation was positively related to each dimension of executive function (0.251, 0.323, 0.377). The shifting process appeared significant correlation (P<0.05). Regression analysis showed that positive expectation was significantly negative predictions of inhibition and shifting process. Conclusion Executive function of social drinkers is damaged after moderate alcohol intake, and there are differences between executive function damage of different alcohol expectancy drinkers. Key words: Alcohol; Executive function; Inhibition; Updating; Shifting process

The effect of positive affect on conflict resolution: Modulated by approach-motivational intensity

ABSTRACTThe motivational dimensional model of affect proposes that the influence of positive affect on cognitive processing is modulated by approach-motivational intensity. The present research extended this model by examining the influence of positive affect varying in approach-motivational intensity on conflict resolution—the ability to resolve interference from task-irrelevant distractors in order to focus on the target. The global–local task (Experiment 1) and letter-Flanker task (Experiment 2) were used to measure conflict resolution. Additionally, the 4:2 mapping design that assigns two kinds of task-relevant stimuli to one response key and two more to another response key was used in these two tasks to dissociate stimulus and response conflict. Results showed that positive affect varying in approach motivation had opposite influences on conflict resolution. The opposite influences are primarily reflected in low approach-motivated positive affect impairing, while high approach-motivated positive affect facilitating the resolution of response conflict. Conversely, the stimulus conflict was slightly influenced. These findings highlight the utility of distinguishing stimulus and response conflict in future research.

The devil is in the detail: brain dynamics in preparation for a global-local task.

When analyzing visual scenes, it is sometimes important to determine the relevant "grain" size. Attention control mechanisms may help direct our processing to the intended grain size. Here we used the event-related optical signal, a method possessing high temporal and spatial resolution, to examine the involvement of brain structures within the dorsal attention network (DAN) and the visual processing network (VPN) in preparation for the appropriate level of analysis. Behavioral data indicate that the small features of a hierarchical stimulus (local condition) are more difficult to process than the large features (global condition). Consistent with this finding, cues predicting a local trial were associated with greater DAN activation. This activity was bilateral but more pronounced in the left hemisphere, where it showed a frontal-to-parietal progression over time. Furthermore, the amount of DAN activation, especially in the left hemisphere and in parietal regions, was predictive of subsequent performance. Although local cues elicited left-lateralized DAN activity, no preponderantly right activity was observed for global cues; however, the data indicated an interaction between level of analysis (local vs. global) and hemisphere in VPN. They further showed that local processing involves structures in the ventral VPN, whereas global processing involves structures in the dorsal VPN. These results indicate that in our study preparation for analyzing different size features is an asymmetric process, in which greater preparation is required to focus on small rather than large features, perhaps because of their lesser salience. This preparation involves the same DAN used for other attention control operations.

A study of cognitive functions with exercise in high performance players

Recent studies show that a single bout of meditation can impact information processing. We were interested to see whether this impact extends to attentional focusing and the top-down control over irrelevant information. Healthy adults underwent brief single bouts of either focused attention meditation (FAM), which is assumed to increase top-down control, or open monitoring meditation (OMM), which is assumed to weaken top-down control, before performing a global–local task. While the size of the global-precedence effect (reflecting attentional focusing) was unaffected by type of meditation, the congruency effect (indicating the failure to suppress task-irrelevant information) was considerably larger after OMM than after FAM. Our findings suggest that engaging in particular kinds of meditation creates particular cognitive-control states that bias the individual processing style toward either goal-persistence or cognitive flexibility.

Feature binding and the processing of global-local shapes in bilingual and monolingual children.

In the present study, we examined the effects of bilingualism and age on a color-shape binding task (assessing visual working memory) and a global-local task (assessing inhibitory processes) in a sample of 55 bilingual and 49 monolingual children 8 and 10 years old. In the color-shape binding task, corrected recognition scores increased in older children; bilingual children performed better than monolinguals in the shape-only condition, but the two groups were equally accurate in the color-only and combination conditions. In the global-local task, accuracy was higher in bilingual than in monolingual children, particularly on incongruent trials; monolingual children showed a strong global precedence effect (higher accuracy in the global than in the local conditions and greater global-to-local interference), whereas bilingual children exhibited a small, but significant, local precedence effect (higher accuracy in the local than in the global conditions and greater local-to-global interference). These findings confirm and extend previous evidence indicating that the bilingualism advantage is more pronounced in working memory tasks involving inhibitory processes.

Impairment in local and global processing and set-shifting in body dysmorphic disorder

Body dysmorphic disorder (BDD) is characterized by distressing and often debilitating preoccupations with misperceived defects in appearance. Research suggests that aberrant visual processing may contribute to these misperceptions. This study used two tasks to probe global and local visual processing as well as set-shifting in individuals with BDD. Eighteen unmedicated individuals with BDD and 17 non-clinical controls completed two global-local tasks. The embedded figures task requires participants to determine which of three complex figures contains a simpler figure embedded within it. The Navon task utilizes incongruent stimuli comprised of a large letter (global level) made up of smaller letters (local level). The outcome measures were response time and accuracy rate. On the embedded figures task, BDD individuals were slower and less accurate than controls. On the Navon task, BDD individuals processed both global and local stimuli slower and less accurately than controls, and there was a further decrement in performance when shifting attention between the different levels of stimuli. Worse insight correlated with poorer performance on both tasks. Taken together, these results suggest abnormal global and local processing for non-appearance related stimuli among BDD individuals, in addition to evidence of poor set-shifting abilities. Moreover, these abnormalities appear to relate to the important clinical variable of poor insight. Further research is needed to explore these abnormalities and elucidate their possible role in the development and/or persistence of BDD symptoms.

Self-related Information Modulates Global Advantage Effect in Visual Selection

It has been well documented that that personal significance modulates the high-level cognitive processes, including face recognition, memory and thinking. How personal significance(i.e., the self) modulates the visual selection remains poorly understood, however. Here by combining recent developed self-associative learning approach and a global-local task, this article present the evidence that self-salience impacted on visual selection–eliminating the effect of global advantage. The pattern consistently occurred in both divided and focused attention tasks. In contrast, this was not the case for friend-associations. The present study report 3 experiments to test how the self-salience modulated the selection of attention. It first developed a baseline experiment showing a global advantage effect in Experiment 1; 24 participants participated in Experiment 1 and carried out two tasks – a self-associative learning task following by a global-local task. In the self-associative learning task, three geometric shapes were randomly assigned to three persons(self, friend, and a stranger). Having formed a personal association, participants performed theglobal-local task where they were presented compound shapes(e.g. a global circle formed by local squares, self – square, stranger – circle, local self forming global stranger) and had to identify the shape-associated person(self vs. friend). Targets randomly appeared at either the global or local level. Reaction time and accuracy performance were measured and analyzed using repeated-measures analyses of variance(ANOVAs) with Social Relevance(self vs. friend) and Attention Level(global vs. local). Experiment 2 was identical to Experiment 1 except that the stranger-related shapes were targets while the self- and friend-related shapes had to be ignored. There were 20 participants in Experiment 2. Different from Experiments 1 and 2 where the divided attention task was employed, Experiment 3 used a focus attention task where participants were instructed to complete either a local or global task in different blocks. There were three within-subjects factors with 2(Social Relevance: self vs. friend) × 2(Saliency Level: global saliency vs. local saliency) × 2(Attention Level: global vs. local). 24 participants participated in Experiment 3. The results in Experiment 1 showed a reliable self-advantage effect where faster responses to global than local level targets occurred in both the self- and friend-related target conditions. In contrast, the global advantage to targets(stranger-shapes) was eliminated in the presence of self-related distractors while the effect survived in the presence of friend-related distractors in Experiment 2. The interference effect of self-salience was verified in Experiment 3where the focused rather than divided attention task(in Experiment 2) was used. In conclusion, the results demonstrated that compared with friend-related information, the self as distractors affected the global advantage effect, and the effect appeared at both global and local levels unanimously and cannot be influenced by task. The data indicate that self-saliency can modulate basic visual selection.

Executive functions and intraindividual variability following concussion

The long-term outcomes of executive functions and intraindividual variability (IIV; i.e., trial-to-trial or across-task variability in cognitive performance) following concussion are unclear due to inconsistent and limited research findings, respectively. Objective: Responding to these gaps in scientific understanding, the current study aimed to assess the utility of both executive functions and IIV at predicting concussion history. Method: Altogether 138 self-identified athletes (Mage = 19.9 ± 1.91 years, 60.8% female, 19.6% with one concussion, 18.1% with two or more concussions) completed three executive-related cognitive tasks (i.e., n-back, go/no-go, global–local). Ordinal logistic regression analyses examined the joint effect of person-mean and IIV as predictors of concussion status. Results: Only mean response time for the global–local task predicted the number of past concussions, while no IIV variables reached unique significance. Conclusions: IIV research on concussion remains limited; however, the preliminary results do not indicate any additional value of IIV indices above mean performances at predicting past concussion. For executive functions, shifting appears most sensitive at detecting concussion group differences, with past researchers identifying post concussion impairment in attentional processing.

Subcortical volume analysis in traumatic brain injury: The importance of the fronto-striato-thalamic circuit in task switching

Traumatic brain injury (TBI) is associated with neuronal loss, diffuse axonal injury and executive dysfunction. Whereas executive dysfunction has traditionally been associated with prefrontal lesions, ample evidence suggests that those functions requiring behavioral flexibility critically depend on the interaction between frontal cortex, basal ganglia and thalamus.To test whether structural integrity of this fronto-striato-thalamic circuit can account for executive impairments in TBI we automatically segmented the thalamus, putamen and caudate of 25 patients and 21 healthy controls and obtained diffusion weighted images. We assessed components of executive function using the local-global task, which requires inhibition, updating and switching between actions.Shape analysis revealed localized atrophy of the limbic, executive and rostral-motor zones of the basal ganglia, whereas atrophy of the thalami was more global in TBI. This subcortical atrophy was related to white matter microstructural organization in TBI, suggesting that axonal injuries possibly contribute to subcortical volume loss. Global volume of the nuclei showed no clear relationship with task performance. However, the shape analysis revealed that participants with smaller volume of those subregions that have connections with the prefrontal cortex and rostral motor areas showed higher switch costs and mixing costs, and made more errors while switching. These results support the idea that flexible cognitive control over action depends on interactions within the fronto-striato-thalamic circuit.

Plasticity of visual attention in Isha yoga meditation practitioners before and after a 3-month retreat

Meditation has lately received considerable interest from cognitive neuroscience. Studies suggest that daily meditation leads to long lasting attentional and neuronal plasticity. We present changes related to the attentional systems before and after a 3 month intensive meditation retreat. We used three behavioral psychophysical tests - a Stroop task, an attentional blink task, and a global-local letter task-to assess the effect of Isha yoga meditation on attentional resource allocation. 82 Isha yoga practitioners were tested at the beginning and at the end of the retreat. Our results showed an increase in correct responses specific to incongruent stimuli in the Stroop task. Congruently, a positive correlation between previous meditation experience and accuracy to incongruent Stroop stimuli was also observed at baseline. We also observed a reduction of the attentional blink. Unexpectedly, a negative correlation between previous meditation experience and attentional blink performance at baseline was observed. Regarding spatial attention orientation as assessed using the global-local letter task, participants showed a bias toward local processing. Only slight differences in performance were found pre- vs. post- meditation retreat. Biasing toward the local stimuli in the global-local task and negative correlation of previous meditation experience with attentional blink performance is consistent with Isha practices being focused-attention practices. Given the relatively small effect sizes and the absence of a control group, our results do not allow clear support nor rejection of the hypothesis of meditation-driven neuronal plasticity in the attentional system for Isha yoga practice.

Altered structural networks and executive deficits in traumatic brain injury patients

Recent research on traumatic brain injury (TBI) has shown that impairments in cognitive and executive control functions are accompanied by a disrupted neural connectivity characterized by white matter damage. We constructed binary and weighted brain structural networks in 21 patients with chronic TBI and 17 healthy young adults utilizing diffusion tensor tractography and calculated topological properties of the networks using a graph theoretical method. Executive function was assessed with the local global task and the trail making task, requiring inhibition, updating, and switching. The results revealed that TBI patients were less successful than controls on the executive tasks, as shown by the higher reaction times, higher switch costs, and lower accuracy rates. Moreover, both TBI patients and controls exhibited a small world topology in their white matter networks. More importantly, the TBI patients demonstrated increased shortest path length and decreased global efficiency of the structural network. These findings suggest that TBI patients have a weaker globally integrated structural brain network, resulting in a limited capacity to integrate information across brain regions. Furthermore, we showed that the white matter networks of both groups contained highly connected hub regions that were predominately located in the parietal cortex, frontal cortex, and basal ganglia. Finally, we showed significant correlations between switching performance and network property metrics within the TBI group. Specifically, lower scores on the switching tasks corresponded to a lower global efficiency. We conclude that analyzing the structural brain network connectivity provides new insights into understanding cognitive control changes following brain injury.

The role of visual perceptual style and personality disorder traits in event-based prospective memory

The aim of this study was to investigate the role of global/local processing style, field-(in)dependence, and personality disorder traits in event-based prospective memory performance. One hundred and fifty participants took part in an experiment, where they were administered a computerized version of Navon’s global–local task. The PM task required participants to press a designated key whenever a blue compound stimulus was presented. Participants were then administered measures of field-(in)dependence and personality disorder traits. Data were submitted to logistic regression and hierarchical regression, separately for the two conditions (global/local). Results indicated that with respect to condition, global/local processing style, field-(in)dependence, and specific personality disorder traits differently affect PM performance.

Role of Attention in Complex Decisions: Further Explorations of Unconscious Thought Theory

According to Unconscious Thought Theory (UTT) there are two modes of thought: Conscious and Unconscious. Unconscious Thought is defined as thought without attention or with attention directed elsewhere. More participants made better decisions following unconscious thought. According to UTT, unconscious thought does not have capacity limitations and takes in consideration all information which results in better decision. Studies on Unconscious Thought have not explored how much information is exactly processed during unconscious thought. It is possible that unconscious thought also focuses on a subset of attributes. To test this possibility and to further explore how attribute information is combined, computer simulations were performed on datasets used by previous researchers. The simulations showed that considering a small subset (3–4) of attributes, yields results comparable to previous studies. There is no need to posit infinite capacity in the unconscious thought condition. The results also suggest that weight information is used for attribute selection that could potentially explain the difficulties in replicating the deliberation-without-attention effect. UTT also tends to treat attention as a unitary mechanism and defines unconscious thought depending on whether attention is absent/not directed. Attention literature suggests that different types of attention (focused and distributed) affects cognitive processes differently. In another study, attention was manipulated during unconscious thought using a global-local task to explore whether it differently affects decisions. Strength of preference for the choice and memory of recall were both significantly higher in the global task group. Even quality of choice was better in the global-group but failed to reach significance. These results also suggest that unconscious Thought is neither purely online nor purely offline.

Flexible Visual Processing in Young Adults with Autism: The Effects of Implicit Learning on a Global–Local Task

We utilized a hierarchical figures task to determine the default level of perceptual processing and the flexibility of visual processing in a group of high-functioning young adults with autism (n=12) and a typically developing young adults, matched by chronological age and IQ (n=12). In one task, participants attended to one level of the figure and ignored the other in order to determine the default level of processing. In the other task, participants attended to both levels and the proportion of trials in which a target would occur at either level was manipulated. Both groups exhibited a global processing bias and showed similar flexibility in performance, suggesting that persons with autism may not be impaired in flexible shifting between task levels.

An Updated Update to Personality and Error Monitoring

An Updated Update to Personality and Error Monitoring

The impact of a migraine attack and its after-effects on perceptual organization, attention, and working memory

Many migraine patients report cognitive complaints during the first hours or days following a migraine attack. The aim of this study was to assess whether and which cognitive (perceptual, attentional, or memory) processes are impaired during the first 48 hours after a migraine attack. Three different cognitive tasks (global-local task, the attentional network task, and N-back task) were administered to 16 migraine patients (13 migraine without aura; mean age 58 years, 15 female) and 18 controls (59 years, 15 female), matched on age, gender, and educational level. Tasks were administered at three time points; during the first headache free day following a migraine attack (first session), 24 hours later (second session), and 12 days after the attack (third session). The attentional network and N-back tasks showed no significant differences between migraineurs and controls. In the global-local task, controls showed faster reaction times to global than to local stimuli, which is the standard global-precedence effect. This effect was absent in the migraineurs in all three sessions, especially if they used prophylaxis. Migraineurs had no impaired attentional or working-memory functioning in the 2 days after an attack. They did show impairments in the processing of global visual features compared with controls, both between and immediately after an attack.

Khat Use Is Associated with Impaired Working Memory and Cognitive Flexibility

RationaleKhat consumption has increased during the last decades in Eastern Africa and has become a global phenomenon spreading to ethnic communities in the rest of the world, such as The Netherlands, United Kingdom, Canada, and the United States. Very little is known, however, about the relation between khat use and cognitive control functions in khat users.ObjectiveWe studied whether khat use is associated with changes in working memory (WM) and cognitive flexibility, two central cognitive control functions.MethodsKhat users and khat-free controls were matched in terms of sex, ethnicity, age, alcohol and cannabis consumption, and IQ (Raven's progressive matrices). Groups were tested on cognitive flexibility, as measured by a Global-Local task, and on WM using an N-back task.ResultKhat users performed significantly worse than controls on tasks tapping into cognitive flexibility as well as monitoring of information in WM.ConclusionsThe present findings suggest that khat use impairs both cognitive flexibility and the updating of information in WM. The inability to monitor information in WM and to adjust behavior rapidly and flexibly may have repercussions for daily life activities.

Impaired holistic processing in congenital prosopagnosia

It has long been argued that face processing requires disproportionate reliance on holistic or configural processing, relative to that required for non-face object recognition, and that a disruption of such holistic processing may be causally implicated in prosopagnosia. Previously, we demonstrated that individuals with congenital prosopagnosia (CP) did not show the normal face inversion effect (better performance for upright compared to inverted faces) and evinced a local (rather than the normal global) bias in a compound letter global/local (GL) task, supporting the claim of disrupted holistic processing in prosopagnosia. Here, we investigate further the nature of holistic processing impairments in CP, first by confirming, in a large sample of CP individuals, the absence of the normal face inversion effect and the presence of the local bias on the GL task, and, second, by employing the composite face paradigm, often regarded as the gold standard for measuring holistic face processing. In this last task, we show that, in contrast with controls, the CP group perform equivalently with aligned and misaligned faces and was impervious to (the normal) interference from the task-irrelevant bottom part of faces. Interestingly, the extent of the local bias evident in the composite task is correlated with the abnormality of performance on diagnostic face processing tasks. Furthermore, there is a significant correlation between the magnitude of the local bias in the GL and performance on the composite task. These results provide further evidence for impaired holistic processing in CP and, moreover, corroborate the critical role of this type of processing for intact face recognition.

Shared and selective neural correlates of inhibition, facilitation, and shifting processes during executive control

A network of prefrontal and parietal regions has been implicated in executive control processes. However, the extent to which individual regions within this network are engaged in component control processes, such as inhibition of task-irrelevant stimulus attributes or shifting (switching) between attentional foci, remains controversial. Participants (N=17) underwent functional magnetic resonance imaging while performing a global–local task in which the global and local levels could facilitate or interfere with one another. Stimuli were presented in blocks in which participants either constantly shifted between the global and local levels, or consistently responded to one level only. Activations related to inhibition and shifting processes were observed in a large network of bilateral prefrontal, parietal, and basal ganglia regions. Region of interest analyses were used to classify each region within this network as being common to inhibition and shifting, or preferential to one component process. Several regions were classified as being preferential to inhibition, including regions within the dorsolateral and ventrolateral prefrontal cortex, the parietal lobes, and the temporal–parietal junction. A limited set of regions in the parietal lobes and left dorsolateral prefrontal cortex were classified as preferential to shifting. There was a very large set of regions displaying activation common to both inhibition and shifting processes, including regions within the dorsolateral prefrontal cortex, anterior cingulate, and basal ganglia. Several of these common regions were also involved during facilitation, suggesting that they are responsive to the number of task-salient channels of information, rather than purely to demands on control processes.

Buddha as an Eye Opener: A Link between Prosocial Attitude and Attentional Control

Increasing evidence suggests that religious practice induces systematic biases in attentional control. We used Navon's global–local task to compare attentional bias in Taiwanese Zen Buddhists and Taiwanese atheists; two groups brought up in the same country and culture and matched with respect to race, intelligence, sex, and age. Given the Buddhist emphasis on compassion for the physical and social environment, we expected a more global bias in Buddhist than in Atheist participants. In line with these expectations, Buddhists showed a larger global-precedence effect and increased interference from global distracters when processing local information. This pattern reinforces the idea that people's attentional processing style reflects biases rewarded by their religious practices.