Distinct mechanisms underlying cross-modal semantic conflict and response conflict processing.

Interference from task-irrelevant stimuli can occur during the semantic and response processing stages. Previous studies have shown both common and distinct mechanisms underlying semantic conflict processing and response conflict processing in the visual domain. However, it remains unclear whether common and/or distinct mechanisms are involved in semantic conflict processing and response conflict processing in the cross-modal domain. Therefore, the present electroencephalography study adopted an audiovisual 2-1 mapping Stroop task to investigate whether common and/or distinct mechanisms underlie semantic conflict and response conflict. Behaviorally, significant cross-modal semantic conflict and significant cross-modal response conflict were observed. Electroencephalography results revealed that the frontal N2 amplitude and theta power increased only in the semantic conflict condition, while the parietal N450 amplitude increased only in the response conflict condition. These findings indicated that distinct neural mechanisms were involved in cross-modal semantic conflict and response conflict processing, supporting the domain-specific cognitive control mechanisms from a cross-modal multistage conflict processing perspective.

Distinct and common mechanisms of cross-model semantic conflict and response conflict in an auditory relevant task.

The mechanisms of semantic conflict and response conflict in the Stroop task have mainly been investigated in the visual modality. However, the understanding of these mechanisms in cross-modal modalities remains limited. In this electroencephalography (EEG) study, an audiovisual 2-1 mapping Stroop task was utilized to investigate whether distinct and/or common neural mechanisms underlie cross-modal semantic conflict and response conflict. The response time data showed significant effects on both cross-modal semantic and response conflicts. Interestingly, the magnitude of semantic conflict was found to be smaller in the fast response time bins than in the slow response time bins, whereas no such difference was observed for response conflict. The EEG data demonstrated that cross-modal semantic conflict specifically increased the N450 amplitude. However, cross-modal response conflict specifically enhanced theta band power and theta phase synchronization between the medial frontal cortex (MFC) and lateral prefrontal electrodes as well as between the MFC and motor electrodes. In addition, both cross-modal semantic conflict and response conflict led to a decrease in P3 amplitude. Taken together, these findings provide cross-modal evidence for domain-specific mechanism in conflict detection and suggest both domain-specific and domain-general mechanisms exist in conflict resolution.

Distributional analyses reveal the polymorphic nature of the Stroop interference effect: It's about (response) time.

The study addressed the still-open issue of whether semantic (in addition to response) conflict does indeed contribute to Stroop interference (which along with facilitation contributes to the overall Stroop effect also known as Congruency effect). To this end, semantic conflict was examined across the entire response time (RT) distribution (as opposed to mean RTs). Three (out of four) reported experiments, along with cross-experimental analyses, revealed that semantic conflict was absent in the participants' faster responses. This result characterizes Stroop interference as a unitary phenomenon (i.e., driven uniquely by response conflict). When the same participants' responses were slower, Stroop interference became a composite phenomenon with an additional contribution of semantic conflict that was statistically independent of both response conflict and facilitation. While the present findings allow us to account for the fact that semantic conflict has not been consistently found in past studies, further empirical and theoretical efforts are still needed to explain why exactly it is restricted to longer responses. Indeed, since neither unitary nor composite models can account for this polymorphic nature of Stroop interference on their own, the implications for the current state of theory are outlined.

Fast habituation to semantic interference generated by taboo connotation in reading aloud.

The recognition of taboo words - i.e. socially inappropriate words - has been repeatedly associated to semantic interference phenomena, with detrimental effects on the performance in the ongoing task. In the present study, we investigated taboo interference in the context of reading aloud, a task configuration which prompts the overt violation of conventional sociolinguistic norms by requiring the explicit utterance of taboo items. We assessed whether this form of semantic interference is handled by habituative or cognitive control processes. In addition to the reading aloud task, participants performed a vocal Stroop task featuring different conditions to dissociate semantic, task, and response conflict. Taboo words were read slower than non-taboo words, but this effect was subject to a quick habituation, with a decreasing interference over the course of trials, which allowed participants to selectively attend to goal-relevant information. In the Stroop task, only semantic conflict was significantly reduced by habituation. These findings suggest that semantic properties can be quickly and flexibly weighed on the basis of contextual appropriateness, thus characterising semantic processing as a flexible and goal-directed component of reading aloud.

HPnet: Hybrid Parallel Network for Human Pose Estimation.

Hybrid models which combine the convolution and transformer model achieve impressive performance on human pose estimation. However, the existing hybrid models on human pose estimation, which typically stack self-attention modules after convolution, are prone to mutual conflict. The mutual conflict enforces one type of module to dominate over these hybrid sequential models. Consequently, the performance of higher-precision keypoints localization is not consistent with overall performance. To alleviate this mutual conflict, we developed a hybrid parallel network by parallelizing the self-attention modules and the convolution modules, which conduce to leverage the complementary capabilities effectively. The parallel network ensures that the self-attention branch tends to model the long-range dependency to enhance the semantic representation, whereas the local sensitivity of the convolution branch contributes to high-precision localization simultaneously. To further mitigate the conflict, we proposed a cross-branches attention module to gate the features generated by both branches along the channel dimension. The hybrid parallel network achieves 75.6% and 75.4%AP on COCO validation and test-dev sets and achieves consistent performance on both higher-precision localization and overall performance. The experiments show that our hybrid parallel network is on par with the state-of-the-art human pose estimation models.

Stroop interference is a composite phenomenon: Evidence from distinct developmental trajectories of its components.

Only one previous developmental study of Stroop task performance (Schiller, 1966) has controlled for differences in processing speed that exist both within and between age groups. Therefore, the question of whether the early developmental change in the magnitude of Stroop interference actually persists after controlling for processing speed needs further investigation; work that is further motivated by the possibility that any remaining differences would be caused by process(es) other than processing speed. Analysis of data from two experiments revealed that, even after controlling for processing speed using z-transformed reaction times, early developmental change persists such that the magnitude of overall Stroop interference is larger in 3rd- and 5th graders as compared to 1st graders. This pattern indicates that the magnitude of overall Stroop interference peaks after 2 or 3 years of reading practice (Schadler & Thissen, 1981). Furthermore, this peak is shown to be due to distinct components of Stroop interference (resulting from specific conflicts) progressively falling into place. Experiment 2 revealed that the change in the magnitude of Stroop interference specifically results from joint contributions of task, semantic and response conflicts in 3rd- and 5th graders as compared to a sole contribution of task conflict in 1st graders. The specific developmental trajectories of different conflicts presented in the present work provide unique evidence for multiple loci of Stroop interference in the processing stream (respectively task, semantic and response conflict) as opposed to a single (i.e. response) locus predicted by historically - favored response competition accounts.

The neural mechanisms of semantic and response conflicts: an fMRI study of practice-related effects in the Stroop task.

Previous studies have demonstrated that there are separate neural mechanisms underlying semantic and response conflicts in the Stroop task. However, the practice effects of these conflicts need to be elucidated and the possible involvements of common neural mechanisms are yet to be established. We employed functional magnetic resonance imaging (fMRI) in a 4-2 mapping practice-related Stroop task to determine the neural substrates under these conflicts. Results showed that different patterns of brain activations are associated with practice in the attentional networks (e.g., dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), and posterior parietal cortex (PPC)) for both conflicts, response control regions (e.g., inferior frontal junction (IFJ), inferior frontal gyrus (IFG)/insula, and pre-supplementary motor areas (pre-SMA)) for semantic conflict, and posterior cortex for response conflict. We also found areas of common activation in the left hemisphere within the attentional networks, for the early practice stage in semantic conflict and the late stage in "pure" response conflict using conjunction analysis. The different practice effects indicate that there are distinct mechanisms underlying these two conflict types: semantic conflict practice effects are attributable to the automation of stimulus processing, conflict and response control; response conflict practice effects are attributable to the proportional increase of conflict-related cognitive resources. In addition, the areas of common activation suggest that the semantic conflict effect may contain a partial response conflict effect, particularly at the beginning of the task. These findings indicate that there are two kinds of response conflicts contained in the key-pressing Stroop task: the vocal-level (mainly in the early stage) and key-pressing (mainly in the late stage) response conflicts; thus, the use of the subtraction method for the exploration of semantic and response conflicts may need to be further examined.

Some further clarifications on age-related differences in the Stroop task: New evidence from the two-to-one Stroop paradigm.

Previous studies (Augustinova et al., Psychonomic Bulletin & Review, 25(2), 767-774, 2018; Li & Bosman, Aging, Neuropsychology, and Cognition, 3(4), 272-284, 1996) have shown that the larger Stroop effects reported in older adults is specifically due to age-related differences in the magnitude of response - and not semantic - conflict, both of which are thought to contribute to overall Stroop interference. However, the most recent contribution to the issue of the unitary versus composite nature of the Stroop effect argues that semantic conflict has not been clearly dissociated from response conflict in these or any other past Stroop studies, meaning that the very existence of semantic conflict is at present uncertain. To distinguish clearly between the two types of conflict, the present study employed the two-to-one Stroop paradigm with a color-neutral word baseline. This addition made it possible to isolate a contribution of semantic conflict that was independent of both response conflict and Stroop facilitation. Therefore, this study provides the first unambiguous empirical demonstration of the composite nature of Stroop interference - as originally claimed by multi-stage models of Stroop interference. This permitted the further observation of significantly higher levels of semantic conflict in older adults, whereas the level of response conflict in the present study remained unaffected by healthy aging - a finding that directly contrasts with previous studies employing alternative measures of response and semantic conflict. Two qualitatively different explanations of this apparent divergence across studies are discussed.

Emotion concept in perception of facial expressions: Effects of emotion-label words and emotion-laden words.

Emotion perception, the ability to detect and categorize the emotions of others, is an important component of social competence. The basic emotion theory and constructed emotion theory remain controversial over the role of emotional semantic information in the processing of facial expressions. In the present study, in order to explore the mechanism of emotional semantic information in different processing stages of facial expressions, we used the ERPs to investigate the effects of emotion-label words (e.g., happy, disgusted) and emotion-laden words (e.g., flower, maggot) on the perception of happy and disgusted faces. The results showed that disgusted faces were more susceptible to emotion words, and there were differences between word types and consistency conditions in the N170 component. More importantly, disgusted faces showed a significant N400 effect in the emotion-label words condition, that is, the amplitude in the emotion inconsistent condition was negative compared with that in the emotion consistent condition. The processing of happy faces was not significantly affected by the emotional information of words, and no significant effects related to consistency or to word types were found. These results found that disgusted faces exhibited emotional semantic conflict in the inconsistent emotion-label words condition, suggesting that emotion words moderated the perception of disgusted faces, supporting the hypothesis that emotional semantic information influenced the perception of facial expressions.

Semantic Expectation Effects on Object Detection: Using Figure Assignment to Elucidate Mechanisms.

Recent evidence suggesting that object detection is improved following valid rather than invalid labels implies that semantics influence object detection. It is not clear, however, whether the results index object detection or feature detection. Further, because control conditions were absent and labels and objects were repeated multiple times, the mechanisms are unknown. We assessed object detection via figure assignment, whereby objects are segmented from backgrounds. Masked bipartite displays depicting a portion of a mono-oriented object (a familiar configuration) on one side of a central border were shown once only for 90 or 100 ms. Familiar configuration is a figural prior. Accurate detection was indexed by reports of an object on the familiar configuration side of the border. Compared to control experiments without labels, valid labels improved accuracy and reduced response times (RTs) more for upright than inverted objects (Studies 1 and 2). Invalid labels denoting different superordinate-level objects (DSC; Study 1) or same superordinate-level objects (SSC; Study 2) reduced accuracy for upright displays only. Orientation dependency indicates that effects are mediated by activated object representations rather than features which are invariant over orientation. Following invalid SSC labels (Study 2), accurate detection RTs were longer than control for both orientations, implicating conflict between semantic representations that had to be resolved before object detection. These results demonstrate that object detection is not just affected by semantics, it entails semantics.

Is There Semantic Conflict in the Stroop Task?

This research addressed current controversies concerning the contribution of semantic conflict to the Stroop interference effect and its reduction by a single-letter coloring and cueing procedure. On the first issue, it provides, for the first time, unambiguous evidence for a contribution of semantic conflict to the (overall) Stroop interference effect. The reported data remained inconclusive on the second issue, despite being collected in a considerable sample and analyzed with both classical (frequentist) and Bayesian inferential approaches. Given that in all past Stroop studies, semantic conflict was possibly confounded with either response conflict (e.g., when semantic-associative items [SKYblue] are used to induce semantic conflict) or with facilitation (when color-congruent items [BLUEblue] are used as baseline to derive a magnitude for semantic conflict), its genuine contribution to the Stroop interference effect is the most critical result reported in the present study. Indeed, it leaves no doubt - in complete contrast to dominant single-stage response competition models (e.g., Roelofs, 2003) - that selection occurs at the semantic level in the Stroop task. The immediate implications for the composite (as opposed to unitary) nature of the Stroop interference effect and other still unresolved issues in the Stroop literature are outlined further.

The Loci of Stroop Interference and Facilitation Effects With Manual and Vocal Responses.

Several accounts of the Stroop task assume that the Stroop interference effect has several distinct loci (as opposed to a single response locus). The present study was designed to explore whether this is the case with both manual and vocal responses. To this end, we used an extended form of the Stroop paradigm (Augustinova et al., 2018b) that successfully distinguishes between the contribution of the task vs. semantic vs. response conflict to overall Stroop interference. In line with past findings, the results of Experiment 1 yielded an important response modality effect: the magnitude of Stroop interference was substantially larger when vocal responses were used (as opposed to key presses). Moreover, the present findings show that the response modality effect is specifically due to the fact that Stroop interference observed with vocal responses results from the significant contribution of task, semantic, and response conflicts, whereas only semantic and response conflicts clearly significantly contribute to Stroop interference observed with manual responses (no significant task conflict was observed). This exact pattern was replicated in Experiment 2. Also, and importantly, Experiment 2 also investigated whether and how the response modality effect affects Stroop facilitation. The results showed that the magnitude of Stroop facilitation was also larger when vocal as opposed to manual responses were used. This was due to the fact that semantic and response facilitation contributed to the overall Stroop facilitation observed with vocal responses, but surprisingly, only semantic facilitation contributed with manual responses (no response facilitation was observed). We discuss these results in terms of quantitative rather than qualitative differences in processing between vocal and manual Stroop tasks, within the framework of an integrative multistage account of Stroop interference (Augustinova et al., 2018b).

An fMRI Study of Response and Semantic Conflict in the Stroop Task.

An enduring question in selective attention research is whether we can successfully ignore an irrelevant stimulus and at what point in the stream of processing we are able to select the appropriate source of information. Using methods informed by recent research on the varieties of conflict in the Stroop task the present study provides evidence for specialized functions of regions of the frontoparietal network in processing response and semantic conflict during Stroop task performance. Specifically, we used trial types and orthogonal contrasts thought to better independently measure response and semantic conflict and we presented the trial types in pure blocks to maximize response conflict and therefore better distinguish between the conflict types. Our data indicate that the left inferior PFC plays an important role in the processing of both response and semantic (or stimulus) conflict, whilst regions of the left parietal cortex (BA40) play an accompanying role in response, but not semantic, conflict processing. Moreover, our study reports a role for the right mediodorsal thalamus in processing semantic, but not response, conflict. In none of our comparisons did we observe activity in the anterior cingulate cortex (ACC), a finding we ascribe to the use of blocked trial type presentation and one that has implications for theories of ACC function.

Further investigation of distinct components of Stroop interference and of their reduction by short response-stimulus intervals.

The aim of this paper is to extend the so-called semantic Stroop paradigm (Neely & Kahan, 2001) - which already successfully distinguishes between the contribution of the semantic vs. response conflict to Stroop interference - so that it can take account of and capture the separate contribution of task conflict. In line with this idea, the Stroop interference observed using the aforementioned paradigm with both short and long RSIs (500 vs. 2000ms) did indeed reflect the specific contribution of the task, semantic and response conflicts. However, the contribution of task conflict (as opposed to the semantic and response conflicts) failed to reach significance when the semantic Stroop paradigm was administered with manual (Experiment 1) as opposed to vocal responses (Experiment 2). These experiments further tested the extent to which the specific contribution of the different conflicts can be influenced by the increased cognitive control induced by a short (vs. long) RSI. The corresponding empirical evidence runs contrary to the assumption that the reduction of overall Stroop interference by a short (vs. long) RSI is due to the reduced contribution of the task (Parris, 2014) and/or semantic (De Jong, Berendsen, & Cools, 1999) conflicts. Indeed, in neither experiment was the contribution of these conflicts reduced by a short RSI. In both experiments, this manipulation only reduced the contribution of the response conflict to the overall Stroop interference (e.g., Augustinova & Ferrand, 2014b). Thus these different results clearly indicate that Stroop interference is a composite phenomenon involving both automatic and controlled processes. The somewhat obvious conclusion of this paper is that these processes are more successfully integrated within multi-stage accounts than within the historically favored single-stage response competition accounts that still dominate current psychological research and practice.

Modulation of conflicts in the Stroop effect.

The purpose of the current study was to evaluate the unique contribution of task conflict, semantic conflict and response conflict to the Stroop effect and to test how these conflicts are modulated by manipulating the proportion of neutral trials, known to affect the magnitude of the Stroop effect. In the first experiment, we employed the two-to-one paradigm (De Houwer, 2003) while adding neutral illegible stimuli, and in the second experiment, we employed two colors and four word colors. In both experiments, we created four congruency conditions (neutral, congruent and two kind of incongruent conditions-those that include response conflict and those that do not), which allowed decomposing the Stroop effect into three orthogonal conflicts. In both experiments, we also manipulated the proportion of neutral trials. Task conflict was defined by the contrast between illegible neutrals and color words, semantic conflict by the contrast between congruent and incongruent stimuli, and response conflict by contrasting the two kinds of incongruent stimuli. Our results showed that all conflicts contributed to the Stroop effect. Task conflict and semantic conflict were modulated by the proportion of neutrals but response conflict was not. These findings imply that task conflict and semantic conflict are part of the control loop of the Stroop effect, as conceptualized by Botvinick et al.'s (2001) conflict monitoring model. There is no clear evidence of the response conflict being part of the loop. To complete the picture, we also analyzed the conflicts in the Stroop task using the traditional dependent contrasts approach and found the basic pattern of results was similar. Thus, the main advantage of the orthogonal comparisons approach is the possibility to estimate the unique contribution of the conflicts contributing to the Stroop effect and their modulation of the Stroop phenomenon.

Some further clarifications on age-related differences in Stroop interference.

Both the locus and processes underlying the age-related differences in Stroop interference are usually inferred from changes in magnitudes of standard (i.e., overall) Stroop interference. Therefore, this study addressed these still-open issues directly. To this end, a sample of younger (18-26 years old) and healthy older (72-97 years old) was administered the semantic Stroop paradigm (that assesses the relative contribution of semantic compared to response conflict both of which contribute to overall Stroop interference) combined with a single-letter coloring and cuing (SLCC) procedure. Independently of an increased attentional focus on the relevant color dimension of Stroop words induced by SLCC (as compared to all letters colored and cued, ALCC), greater magnitudes of standard Stroop interference were observed in older (as compared to younger) adults. These differences were due to greater magnitudes of response conflict whereas magnitudes of semantic conflict remained significant and unchanged by healthy aging and SLCC. Thus, this direct evidence places the locus of age-related differences in Stroop interference at the level of response conflict (as opposed to semantic and/or both conflicts). In terms of processes underlying these differences, the reported evidence shows that both age-groups are equally (in)efficient in (a) focusing on the relevant color dimension and (b) suppressing the meaning of the irrelevant word-dimension of Stroop words. Healthy older adults are simply less efficient in suppressing the (pre-)response activity primed by the fully processed meaning of the irrelevant word-dimension. Standard interpretations of age-related differences in Stroop interference and a more general issue of how attentional selectivity actually operates in the Stroop task are therefore reconsidered in this paper.

Neural correlates of bilingual language control during interlingual homograph processing in a logogram writing system.

Bilingual studies using alphabetic languages have shown parallel activation of two languages during word recognition. However, little is known about the brain mechanisms of language control during word comprehension with a logogram writing system. We manipulated the types of words (interlingual homographs (IH), cognates, and language-specific words) and the types of participants (Chinese (L1)-Japanese (L2) bilinguals vs. Japanese monolinguals). Greater activation was found in the bilateral inferior frontal gyri, supplementary motor area, caudate nucleus and left fusiform gyrus, when the bilinguals processed IH, as compared to cognates. These areas were also commonly activated when the bilinguals processed L2 control words during an L1 lexical decision task. The areas function as the task/decision system that plays a role in cognitive control for resolving response conflict. Furthermore, the anterior cingulate cortex, left thalamus, and left middle temporal gyrus were activated during IH processing, suggesting resolution of the semantic conflict at the stimulus level (i.e., one logographic word having different meanings in the two languages).

Assessing stimulus-stimulus (semantic) conflict in the Stroop task using saccadic two-to-one color response mapping and preresponse pupillary measures.

Conflict in the Stroop task is thought to come from various stages of processing, including semantics. Two-to-one response mappings, in which two response-set colors share a common response location, have been used to isolate stimulus-stimulus (semantic) from stimulus-response conflict in the Stroop task. However, the use of congruent trials as a baseline means that the measured effects could be exaggerated by facilitation, and recent research using neutral, non-color-word trials as a baseline has supported this notion. In the present study, we sought to provide evidence for stimulus-stimulus conflict using an oculomotor Stroop task and an early, preresponse pupillometric measure of effort. The results provided strong (Bayesian) evidence for no statistical difference between two-to-one response-mapping trials and neutral trials in both saccadic response latencies and preresponse pupillometric measures, supporting the notion that the difference between same-response and congruent trials indexes facilitation in congruent trials, and not stimulus-stimulus conflict, thus providing evidence against the presence of semantic conflict in the Stroop task. We also demonstrated the utility of preresponse pupillometry in measuring Stroop interference, supporting the idea that pupillary effects are not simply a residue of making a response.

Inhibitory deficit in semantic conflict in obsessive-compulsive disorder: an event-related potential study.

The present study examines the inhibitory function of patients with obsessive-compulsive disorder (OCD) involved in semantic conflict using event-related potentials (ERPs). EPRs were recorded in a group of 18 medicine-free OCD patients and 18 normal controls using a modified Stroop paradigm in which the participants were asked to make a judgment of congruent or incongruent stimuli. The reaction time to color-word incongruent stimuli in the OCD group was significantly longer than the reaction time to congruent stimuli. In the OCD group, a significant negativity shift was discovered in P350 amplitude and N450 amplitude in response to incongruent stimuli, a shift not present in the control group. The amplitude of difference waveform was significantly higher for OCD than for control subjects. The findings probably revealed an inhibitory deficit in patients with OCD when performing semantic conflict tasks. The results suggest that this type of inhibitory deficit may be the cause of increased Stroop effects in patients with OCD, and one of contributors to the pathophysiology of OCD.