The limit of processing capacity and the effectiveness of top-down control are 2 mechanisms that underlie distractor interference in a flanker task. The current study investigates how the interblock selection history shaped by the target number and the predictability of distractor location may modulate the effects of these 2 mechanisms on flanker interference. Experiment 1 showed that the distractor compatibility effect was eliminated when the task array contained 4 or 5 identical targets, which reflected the capacity limit. The target number and distractor location's predictability (Experiment 2) or location predictability and target-distractor proximity (Experiment 3) were manipulated across blocks, while compatibility varied within blocks, with control efficacy underlying the effects of distractor location (predictability and proximity). The interblock selection history was induced by task order, beginning with 2 or 4 targets in Experiment 2 and with a distractor at a fixed or an unpredictable location in Experiment 3. Effects of interblock selection history were found when the intertrial context did not promote an incentive for altering the processing mode. When the incentive for enacting top-down control is high, intertrial contextual factors influence flanker interference. Contextual factors related to the target number and distractor location modulate flanker interference at multiple levels.
According to the literatures, Flammulina velutipes contains biologically active components such as dietary fiber, polysaccharide, and mycosterol, whose effects in reducing blood sugar, blood pressure, and cholesterol have been proven. This study used the active components extracted from Flammulina velutipes powder (FVP) and Flammulina velutipes extract (FVE) to investigate the impact of these active components on lipid metabolism of hamsters. The results show that the total dietary fiber content in FVP and FVE is 29.34 mg/100 g and 15.08 mg/100 g, respectively. The total mycosterol content is 46.57 ± 0.37 mg/100 g and 9.01 ± 0.17 mg/100 g, respectively. The male hamsters were subjected to lipid metabolism monitoring by adding 1, 2, and 3% FVP or FVE into their diets for a period of 8 weeks. The animal assay results show that the 3% FVP and FVE groups have the lowest concentration of TC (total cholesterol), TG (triacylglycerol), LDL (low density lipoprotein cholesterol), and LDL/HDL (high density lipoprotein cholesterol) in the serum and liver (P < 0.05). Our results demonstrate that the addition of 3% FVP or FVE has a significant effect on the lipid metabolism in hamsters whose increased level of HDL in the serum was induced by high fat diet.
We investigated how the location of one's own name in a visual display influences its conscious awareness using recall and recognition tests in an inattentional blindness paradigm. The participant's own name or another person's name appeared unexpectedly in the center or the periphery of the display during a critical trial under low- or high-attentional search load. The results showed that the majority of participants detected their names under low load regardless of location and test method. Under high load, the majority of the participants could recognize or recall their names presented in the center of the display. When the person's name was in the periphery, most of the participants did not recall their names, and approximately half recognized their names. In contrast, conscious awareness of another person's name was low in all conditions. A person's own name is processed with high priority, even under a high-attentional load.
Previous research has shown that loading information on working memory affects selective attention. However, whether the load effect on selective attention is domain-general or domain-specific remains unresolved. The domain-general effect refers to the findings that load in one content (e.g. phonological) domain in working memory influences processing in another content (e.g., visuospatial) domain. Attentional control supervises selection regardless of information domain. The domain-specific effect refers to the constraint of influence only when maintenance and processing operate in the same domain. Selective attention operates in a specific content domain. This study is designed to resolve this controversy. Across three experiments, we manipulated the type of representation maintained in working memory and the type of representation upon which the participants must exert control to resolve conflict and select a target into the focus of attention. In Experiments 1a and 1b, participants maintained digits and nonverbalized objects, respectively, in working memory while selecting a target in a letter array. In Experiment 2, we presented auditory digits with a letter flanker task to exclude the involvement of resource competition within the same input modality. In Experiments 3a and 3b, we replaced the letter flanker task with an object flanker task while manipulating the memory load on object and digit representation, respectively. The results consistently showed that memory load modulated distractibility only when the stimuli of the two tasks were represented in the same domain. The magnitude of distractor interference was larger under high load than under low load, reflecting a lower efficacy of information prioritization. When the stimuli of the two tasks were represented in different domains, memory load did not modulate distractibility. Control of processing priority in selective attention demands domain-specific resources.
The current study used a naming task to investigate whether strategic control could modulate the process of attentional capture that is driven by working memory. The use of a naming task to engage working memory eliminates potential strategic perceptual resampling, which may have played a role in several previous studies. After naming a prime, participants performed a selection task in which they judged the direction of a moving target in each trial. Prime validity, which is the probability that the primes are identical to the selection targets, was manipulated across four experiments. The results showed that reaction times to the motion judgment were faster in the valid condition than in the invalid condition when the prime validity was 50% (Experiment 1A). These results occurred even in the presence of a highly informative spatial cue that predicted the targets location (Experiment 4). A larger capturing effect was observed when the validity was 70% (Experiments 2 and 3). When the prime validity was lower than the chance level (0% in Experiment 1B; 15% in Experiments 2 and 3), a validity effect was not observed. Thus, the results suggest that there is a strong tendency for working memory to capture attention by default when there is no reason to avoid the influence of primes. When there is a reason to avoid the influence, strategic control modulates the attentional capture that is driven by working memory.
Previous research has shown that attention to an object can trigger the retrieval of features of a preceding object. The present study investigates whether such retrieval would occur to a recently inhibited object. In three experiments, participants saw two successively presented stimuli (S1 and S2) that varied in color and orientation. The task was to respond to the color or orientation of S2 in accordance with a task cue at the beginning of each trial. In separate experiments, we manipulated the number of the trials on which the task relevant features of S1 and S2 were matched versus mismatched, and the perceived object continuation between the two stimuli. Evidence for spontaneous feature retrieval was found when S1 and S2 could be seen as different instantiations of the same object but not when they were likely to be perceived as different types of objects. These results suggest that the features of a previously inhibited object can be retrieved spontaneously. However, such retrieval and its effect on a subsequent stimulus depend on the perceived object continuity between the two successive stimuli.
Inefficient memory inhibition has been observed in nonclinical and clinical dissociators. Paradoxically, dissociators also report unusual forgetfulness. Investigating how forgetting emerges in dissociators may uncover the antecedents for their self-report memory problems. We postulated that set switch can link inefficient memory inhibition to forgetting. Recollection detour, which involves an affect switch, may elicit forgetting of previously uninhibited memories in nonclinical dissociators. This hypothesis was verified in participants with high- and low-dissociation proneness via a retrieval practice paradigm using positive and negative autobiographical memories. After the study and retrieval-practice phases, memories of the practiced affect category were tested without and with intervening recall of the unpracticed affect category in the control and detour condition, respectively. Nondissociators showed reduced recall in the control condition, replicating the retrieval-induced forgetting (RIF) effect and recollection detour did not alter the RIF effect. By contrast, nonclinical dissociators showed the RIF effect in the detour condition but not in the control condition. Detour to recollecting memories of another affect category rendered an aftereffect of forgetting of previously uninhibited memories in nonclinical dissociators.
It has been suggested that affective stimuli automatically capture attention; this preferential processing is thought to be related to the evolutionary significance of affective stimuli. However, recent evidence suggests that perceptual salience alone might explain why some affective stimuli are more likely to influence attentional processes in certain contexts. In this study, we manipulated affective and perceptual salience to better understand how affective information is processed and how it impacts attentional processes in different contexts. We used stimuli that are both affectively and perceptually salient, while varying the task requirement to encourage the processing of perceptually salient (Experiment 1) or affectively salient (Experiment 2) information. This design made it possible to observe independent and interdependent relationships between perceptual and affective salience. The results showed that when the task encouraged the processing of perceptually salient information, affective salience did not influence task performance. In contrast, when the task encouraged the processing of affectively salient information, affectively salient information impaired task performance. The findings suggest that the affective nature of the stimuli does not always influence attentional processes.
This study tests the effect of relative saliency on perceptual comparison and decision processes in the context of change detection in which distinct visual mechanisms process two features (e.g., luminance and orientation). Townsend and Nozawas (1995) systems factorial technology was used to investigate the process architecture and stopping rule when deciding whether luminance or orientation of a Gabor patch had changed. Experiment 1 found individual differences in decision strategies when we did not control relative saliency. One group of participants adopted co-active processing, and the other group adopted serial self-terminating processing to detect the change signals. When Experiment 2 eliminated the relative saliency, all but one observer adopted parallel processing and followed a self-terminating rule. These results support the relative saliency hypothesis and highlight the fact that observers adopt different change-detection strategies for two features, especially when relative saliency exists between the two feature dimensions.
We investigated the neural correlates of attentional modulation in the perceptual comparison process for detecting feature-binding changes in an event-related functional magnetic resonance imaging (fMRI) experiment. Participants performed a variant of a cued change detection task. They viewed a memory array, a spatial retro-cue, and later a probe array. Their task was to judge whether the cued item had changed between the two arrays. Change type was manipulated to be a color-location binding or a color feature change. The retro-cue onset time in the retention interval was manipulated to be early or late. As a consequence of strong inter-item competition, we found strong prefrontal activation for late cues when contrasting the binding-change with the color-change condition. In contrast, we observed a comparable behavioral and neural effect between the two types of change detection when retro-cue was presented early. More importantly, we demonstrated a significant inter-regional correlation between the prefrontal and parietal regions in both binding- and color-change conditions for late cues. In addition, extensive prefrontal-parietal-visual functional connectivity was showed for detecting binding changes in the late-cueing condition. These results support the critical role in prefrontal-parietal-visual functional coupling for resolving strong inter-item competition during the comparison process in the binding-change condition. We provide direct evidence that attention modulates neural activity associated with perceptual comparison, biasing competition in favour of the task-relevant information in order to detect binding changes.
Recent evidence has revealed that short-lived internal representations held in visual short-term memory (VSTM) can be modulated by top-down control via retrospective attention which impacts subsequent behavioral performance. However, the functional inter-regional interactions underlying these top-down modulatory effects are not fully characterized. Here we used event-related functional magnetic imaging to investigate whether the strength of functional connectivity between the frontal cortex and posterior visual areas varies with the efficacy of top-down modulation of memory traces. Top-down modulation was manipulated by the timing of retro-cuing (early or late) in a VSTM task. Univariate analyses revealed that more effective top-down modulation (early cueing vs. late cueing) increased activity in early visual areas. Importantly, coherency analyses revealed that top-down modulation produced stronger functional connectivity between frontal and posterior occipital regions. Also, participants with stronger functional connectivity exhibit better memory performance. These results suggest that augmented functional connectivity between frontal and posterior visual areas strengthens the VSTM representations of importance to behavioral goals.
People often fail to detect a change between two visual scenes and retrieval failure has been suggested as a reason. We investigated the possibility that retrieval blocking underlies this failure by examining the error pattern in recognizing the pre-change object. The results of Experiment 1 showed that participants were biased toward selecting the lure that was similar to the post-change object when they failed to recognize the pre-change object. This bias was also observed in Experiment 2 when there was sufficient time to encode and consolidate the pre-change object and the bias was as strong as correct recognition in Experiment 3 when participants divided attention during encoding and comparison. The bias in memory error remained significant even when participants had the option to select an "I dont remember" response in Experiment 4. In Experiment 5, the bias was observed after participants successfully detected a change at an invalidly cued location and after they failed to detect a change at a validly cued location. These findings suggest that blocking can lead to retrieval failure in change detection when participants are aware of a change yet unable to retrieve verbatim traces and also when participants are unaware of a change and use the post-change object to retrieve the identity of the previous object at the same location.
We investigated whether a pre-change representation is inhibited or weakened under correct change detection. Two arrays of six objects were rapidly presented for change detection in three experiments. After detection, the perceptual identification of degraded stimuli was tested in Experiments 1 and 2. The weakening of a pre-change representation was not observed under correct detection. The repetition priming effect was observed for a pre-change object and the magnitude was equivalent to the effect for a post-change object. Under change blindness, repetition priming for a pre-change representation was observed when detection did not require report of location in Experiment 1 and was not observed when location was required to be reported in Experiment 2. The results of Experiment 3 showed that a pre-change representation was recognized at a higher rate under correct detection than under change blindness, reflecting a stronger rather than a weaker pre-change representation in the former context.
Rapid switching may underlie the disruption of some integrated thought processes that characterize dissociation in both nonclinical and clinical populations. We investigated the set switching function under negative emotion with three groups of nonclinical participants that had different degrees of dissociation proneness. In the experiment, participants judged whether the digit in a predefined target color was odd or even on the preswitch trials. In a perseverance condition, participants were required to switch to a new target color while the previous target color became the distractor color. In a learned irrelevance condition, the previously ignored color became the new target color. The results showed that the three groups did not differ in focusing attention in the preswitch trials, for set switching in the baseline condition (in which emotion was not engaged), or for switching in the learned irrelevance condition under negative emotion. However, high dissociators under negative emotion showed faster switching in the perseverance condition. This enhanced ability to divert attention to a new mental set under negative emotion may be a coping strategy related to cognitive symptoms in dissociative disorders.
Although participants with dissociation proneness showed inefficient cognitive inhibition, whether and under what stimulus-task contexts dissociators show inefficient memory inhibition remains inconclusive. This study investigated the relationship between trait dissociation and basic operation of memory control using a non-clinical sample. To reduce the involvement of strategic control and the influence of emotionality, the retrieval-practice paradigm was adopted to examine unintentional memory inhibition of neutral materials. Both the low- and middle-dissociation groups showed the forgetting effect, resulting from suppressing competing memories while retrieving a target. In contrast, the high-dissociation group did not show the forgetting effect although their performance in the baseline condition and in recalling practiced items was comparable to the other two groups. High dissociation proneness is linked with weakened memory inhibition that may cause diverse memory problems in clinical patients.
Distractor dilution, which reflects little distractor interference in a context of high display load but easy target processing, has sparked debate between theoretical viewpoints. These two viewpoints can be integrated into a model in which grouping and the efficacy of attention control influence the relative activation strength between the distractor and nontarget representations. In a context in which nontargets and a distractor were presented in separate task-irrelevant regions, the dilution effect was replicated when nontargets were grouped with the target, and the effect was reduced when the distractor was grouped with the target (Experiments 1 to 3). When nontargets were presented in a task-relevant region and the distractor was presented in a task-irrelevant region, the dilution effect was replicated when attention control was effective in accumulating nontarget information (Experiment 4b). The dilution effect was reduced when control was ineffective in a short stimulus duration of 50 ms (Experiment 4a), in a circular arrangement of stimuli (Experiment 5), or in a context in which the distractor location was random (Experiment 6). The dilution effect occurred either before (Experiment 1b) or after (Experiment 4b) the engagement of attention control on a continuum of visual selection through bottom-up and top-down process interactions.
Orienting attention to the to-be-tested representations can enhance representations and protect them from interference. Previous studies have found that this effect on feature and bound representations was comparable despite their difference in stability. This may have occurred because participants were tested in a block design, which is susceptible to participants effective top-down control on the cued representations based on the predictability of the design. In this study, we investigated how the foreknowledge of when and what to expect would affect visual representations in a change-detection task. Cue onset time was either early or late; changes included either features or feature bindings. When predictability was maximized via a block design (Experiments 1, 5, and 6), early cues equally facilitated both representations while late cues did not affect either representation. When either cue onset time (Experiment 2) or change type (Experiment 3) was unpredictable, early cues consistently facilitated feature representations, while bound representations were enhanced only when cue onset time was predictable. Additionally, late cuing only cost bound representations. Finally, when both factors were no longer predictable via an intermixed design (Experiment 4), early-cuing benefit was eliminated, with a late cuing cost for the bound representations. These results highlight the critical role of effective top-down control in memory maintenance for visual representations.
Different hypotheses exist for the relationship among trauma, dissociation, and recovered memory. According to one view, recovered memory results from dissociation that a survivor adopts as a defense mechanism during a traumatizing event to avoid emotional pain. From this perspective, trauma is a necessary antecedent to relate dissociative symptoms with recovered memory. Another view emphasizes the characteristics of the victim, such as fantasy proneness and atypical cognitive operations. This alternate view holds that trauma is not necessary in relating dissociation to recovered memory. We tested these two hypotheses, measuring recovered memory, dissociative symptoms, childhood interpersonal adversity, and fantasy proneness in a nonclinical sample of college students. Our results showed a significant correlation between recovered memory and dissociative symptoms; the correlation cannot be accounted for by childhood interpersonal adversity, fantasy proneness, or absorption. Recovered events can be negative, neutral, or even positive. Trauma is not necessary in relating recovered memory to dissociative symptoms.
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