Dual-route Account Research Articles

Partial overlap between holistic processing of words and Gestalt line stimuli at an early perceptual stage.

A dual-route account of holistic processing has been proposed, which includes a stimulus-based and experience-based approach to holistic processing. The bottom-up route was suggested by the observation of holistic processing for novel Gestalt line patterns in the absence of expertise. For words, there is mainly evidence for a late, lexical, experience-based locus of holistic processing with scarce evidence for an early, stimulus-based locus. However, salient early Gestalt information (i.e., connectedness, closure, and continuity between parts) are important for letter and word identification. Thus, there might be an overlap at an early, perceptual processing stage, between Gestalt stimulus-based holistic processing and word holistic processing. In the task we used, words and Gestalt line patterns were superimposed, and we evaluated whether one class of stimuli was processed less holistically when an aligned other class pattern (processed holistically) was superimposed. There was some evidence supporting an early locus for the influence of word processing on Gestalt line patterns, but the interaction between the two stimuli was not reciprocal, which needs further clarification. When an aligned word (processed holistically) was overlaid on a line pattern, the line pattern was processed less holistically. However, when an aligned line pattern (processed holistically) was overlaid on a word, the word was not processed less holistically. This pattern might result from the higher cohesiveness of words and their automaticity and feedback from the lexicon.

The Dual-route Account of Writing-to-Dictation in Chinese: A Short Report.

This is a short report of an experiment conducted to investigate the effects of phonology-to-orthography (P-O) consistency, lexical frequency, imageability, and the number of strokes on writing-to-dictation in Chinese. Thirty-two undergraduates were tested using a writing-to-dictation task consisting of 60 Chinese characters without homophones (i.e., P-O consistent) and 60 Chinese characters with at least two homophones (i.e., P-O inconsistent), the responses of which were recorded on an Android tablet. Linear mixed-effect modelling was used to investigate the significance of the different effects on three measures-accuracy, response time (RT), and total writing time. The results indicated that imageability was significant in predicting accuracy and RT; P-O consistency was significant in predicting RT and total writing time; the number of strokes was significant in predicting accuracy and total writing time; and the lexical frequency effect was significant in predicting all three measures. In general, the results supported the dual-route account of writing-to-dictation in Chinese and confirmed that both the lexical-semantic and lexical non-semantic pathways are needed to explain writing-to-dictation in Chinese. The significance of the different effects observed in the three measures also indicated the need to include different measures when studying writing-to-dictation to better understand the time course of the writing process.

Similarity Effects on the Emergence of Default Inflection in Jordanian Arabic

This study investigates the similarity effects that determine the default inflection in the nominal system of Jordanian Arabic (JA). Unlike the single route hypothesis (e.g. Rumelhart and McClelland 1986), the dual-route account assumes that regular and irregular forms are stored and processed in two autonomous systems (e.g. Kim et al. 1994; Pinker 1999, Pinker and Prince 1998, Pinker and Ullman 2002, Clahsen et al. 2015). A Paired Sample t-test was used to measure the effects of similarity on agreement between the inflected forms and the base forms. We used 40 triplicate words designed by analogy to 20 pairs of existing JA nouns (base nouns) given to 20 JA native speakers. The results showed that JA speakers manifested tight matching of inflection among irregular forms which was not observed with regularly inflected forms. The results of the study support the idea that the regular inflection is a default; such observation indicates that the regular inflection applies regardless of the similarity of the target to existing regular tokens. The default inflection is triggered by an ‘elsewhere condition’ upon the failure to activate a similar irregular token in associative memory (Kiparsky 1973). This research also provides evidence on the regular inflection application to non-word targets that show phonological distance from their base nouns. Keywords: Jordanian Arabic, default, similarity, sound feminine, regular inflection.

A nonverbal route to conceptual knowledge involving the right anterior temporal lobe

The semantic variant of primary progressive aphasia (PPA-S) is diagnosed based on impaired single-word comprehension, but nonverbal impairments in face and object recognition can also be present, particularly in later disease stages. PPA-S is associated with focal atrophy in the left anterior temporal lobe (ATL), often accompanied by a lesser degree of atrophy in the right ATL. According to a dual-route account, the left ATL is critical for verbal access to conceptual knowledge while nonverbal access to conceptual knowledge depends upon the integrity of right ATL. Consistent with this view, single-word comprehension deficits in PPA-S have consistently been linked to the degree of atrophy in left ATL. In the current study we examined object processing and cortical thickness in 19 patients diagnosed with PPA-S, to evaluate the hypothesis that nonverbal object impairments would instead be determined by the amount of atrophy in the right ATL. All patients demonstrated inability to access conceptual knowledge on standardized tests with word stimuli: they were unable to match spoken words with their corresponding pictures on the Peabody Picture Vocabulary Test. Only a minority of patients, however, performed abnormally on an experimental thematic verification task, which requires judgments as to whether pairs of object pictures are thematically-associated, and does not rely on auditory or visual word input. The entire PPA-S group showed cortical thinning in left ATL, but atrophy in right ATL was more prominent in the subgroup with low verification scores. Thematic verification scores were correlated with cortical thickness in the right rather than left ATL, an asymmetric mapping which persisted when controlling for the degree of atrophy in the contralateral hemisphere. These results are consistent with a dual-route account of conceptual knowledge: breakdown of the verbal left hemispheric route produces an aphasic syndrome, which is only accompanied by visual object processing impairments when the nonverbal right hemispheric route is also compromised.

Evidence for salience-guided search in a fine-localization task

When is search for a target interrupted by unusual distractors? Recent work on this question is equivocal, with some studies finding distraction for both task-relevant and task-irrelevant stimulus dimensions, and other studies finding distraction effects only for task-relevant dimensions. The present study seeks to clarify this discrepancy by utilizing a novel point-and-click task asking participants to indicate the precise location of a target (an oblique line amongst vertical lines) using a computer mouse. Using spatial accuracy as a dependent variable, and displaying stimuli for only short durations, results from Experiment 1 show that accuracy is disrupted significantly more when a unique distractor is defined by a feature in a task-relevant (horizontal line) rather than task irrelevant (red vertical line) dimension. Experiments 2 and 3 looked at the effect of vertical red-line distractors when modulated in terms of frequency and salience, respectively, and found no effect of these modulations, but a significant effect of unique distractor presence versus absence. On the face of it, these results are irreconcilable with a dual-route account that assumes selection of a single dimension prior to search, and instead support an attention-contingent search guided by target salience (a la Wolfe's Guided Search Theory). In other words, it appears that fine localization not only requires focal attention but occurs through a summed activation map which takes input from multiple feature dimensions. Meeting abstract presented at VSS 2016

Effects of paired-object affordance in search tasks across the adult lifespan

The study investigated the processes underlying the retrieval of action information about functional object pairs, focusing on the contribution of procedural and semantic knowledge. We further assessed whether the retrieval of action knowledge is affected by task demands and age. The contribution of procedural knowledge was examined by the way objects were selected, specifically whether active objects were selected before passive objects. The contribution of semantic knowledge was examined by manipulating the relation between targets and distracters. A touchscreen-based search task was used testing young, middle-aged, and elderly participants. Participants had to select by touching two targets among distracters using two search tasks. In an explicit action search task, participants had to select two objects which afforded a mutual action (e.g., functional pair: hammer–nail). Implicit affordance perception was tested using a visual color-matching search task; participants had to select two objects with the same colored frame. In both tasks, half of the colored targets also afforded an action. Overall, middle-aged participants performed better than young and elderly participants, specifically in the action task. Across participants in the action task, accuracy was increased when the distracters were semantically unrelated to the functional pair, while the opposite pattern was observed in the color task. This effect was enhanced with increased age. In the action task all participants utilized procedural knowledge, i.e., selected the active object before the passive object. This result supports the dual-route account from vision to action. Semantic knowledge contributed to both the action and the color task, but procedural knowledge associated with the direct route was primarily retrieved when the task was action-relevant. Across the adulthood lifespan, the data show inverted U-shaped effects of age on the retrieval of action knowledge. Age also linearly increased the involvement of the indirect (semantic) route and the integration of information of the direct and the indirect routes in selection processes.

The locus of serial processing in reading aloud: orthography-to-phonology computation or speech planning?

Dual-route theories of reading posit that a sublexical reading mechanism that operates serially and from left to right is involved in the orthography-to-phonology computation. These theories attribute the masked onset priming effect (MOPE) and the phonological Stroop effect (PSE) to the serial left-to-right operation of this mechanism. However, both effects may arise during speech planning, in the phonological encoding process, which also occurs serially and from left to right. In the present paper, we sought to determine the locus of serial processing in reading aloud by testing the contrasting predictions that the dual-route and speech planning accounts make in relation to the MOPE and the PSE. The results from three experiments that used the MOPE and the PSE paradigms in English are inconsistent with the idea that these effects arise during speech planning, and consistent with the claim that a sublexical serially operating reading mechanism is involved in the print-to-sound translation. Simulations of the empirical data on the MOPE with the dual route cascaded (DRC) and connectionist dual process (CDP++) models, which are computational implementations of the dual-route theory of reading, provide further support for the dual-route account.

Selecting object pairs for action: Is the active object always first?

Perception is linked to action via two routes: a direct route based on affordance information in the environment and an indirect route based on semantic knowledge about objects. The present study explored the factors modulating the recruitment of the two routes, in particular which factors affecting the selection of paired objects. In Experiment 1, we presented real objects among semantically related or unrelated distracters. Participants had to select two objects that can interact. The presence of distracters affected selection times, but not the semantic relations of the objects with the distracters. Furthermore, participants first selected the active object (e.g. teaspoon) with their right hand, followed by the passive object (e.g. mug), often with their left hand. In Experiment 2, we presented pictures of the same objects with no hand grip, congruent or incongruent hand grip. Participants had to decide whether the two objects can interact. Action decisions were faster when the presentation of the active object preceded the presentation of the passive object, and when the grip was congruent. Interestingly, participants were slower when the objects were semantically but not functionally related; this effect increased with congruently gripped objects. Our data showed that action decisions in the presence of strong affordance cues (real objects, pictures of congruently gripped objects) relied on sensory-motor representation, supporting the direct route from perception-to-action that bypasses semantic knowledge. However, in the case of weak affordance cues (pictures), semantic information interfered with action decisions, indicating that semantic knowledge impacts action decisions. The data support the dual-route account from perception-to-action.

Selecting a phoneme-to-grapheme mapping: Random or weighted selection?

Selecting a phoneme-to-grapheme mapping: Random or weighted selection?

No attentional capture for simple visual search: evidence for a dual-route account.

An enduring question in visual attention research is whether unattended objects are subject to perceptual processing. The traditional view suggests that, whereas focal attention is required for the processing of complex features or for individuating objects, it is not required for detecting basic features. However, other models suggest that detecting basic features may be no different from object identification and also require focal attention. In the present study, we approach this problem by measuring the effect of attentional capture in simple and compound visual search tasks. To make sure measurements did not reflect strategic components of the tasks, we measured accuracy with brief displays. Results show that attentional capture influenced only compound but not basic feature searches, suggestive of a distinction between attentional requirements of the 2 tasks. We discuss our findings, together with recent results of top-down word cue effects and dimension-specific intertrial effects, in terms of the dual-route account for visual search, which suggests that the task that is being completed determines whether search is based on attentive or preattentive mechanisms.

Multiple routes for compound word processing in the brain: Evidence from EEG

Are compound words represented as unitary lexical units, or as individual constituents that are processed combinatorially? We investigated the neuro-cognitive processing of compounds using EEG and a passive-listening oddball design in which lexical access and combinatorial processing elicit dissociating Mismatch Negativity (MMN) brain-response patterns. MMN amplitude varied with compound frequency and semantic transparency (the clarity of the relationship between compound and constituent meanings). Opaque compounds elicited an enhanced ‘lexical’ MMN, reflecting stronger lexical representations, to high- vs. low-frequency compounds. Transparent compounds showed no frequency effect, nor differed to pseudo-compounds, reflecting the combination of a reduced ‘syntactic’ MMN indexing combinatorial links, and an enhanced ‘lexical’ MMN for real-word compounds compared to pseudo-compounds. We argue that transparent compounds are processed combinatorially alongside parallel lexical access of the whole-form representation, but whole-form access is the dominant mechanism for opaque compounds, particularly those of high-frequency. Results support a flexible dual-route account of compound processing.

Progressive aphasia presenting with deep dyslexia and dysgraphia

Primary progressive aphasia is clinically heterogeneous. We report a patient, alias Don, with a novel form of progressive aphasia, characterised by deep dyslexia and dysgraphia and dissociated access to phonological and orthographic word forms. The hallmarks of deep dyslexia and dysgraphia were present early in the course and persisted over time. Writing was initially poorer than reading, but this reversed over time. There was a lack of concordance between reading and writing errors. Don benefited from a semantic mediation strategy to learn letter sounds, involving associating letters with a country name (e.g., A=Afghanistan). Remarkably, he continued to be able to generate those phonologically complex country names when no longer able to name or sound letters. Don’s performance is compatible with a traditional dual-route account of deep dyslexia and dysgraphia. The findings have potential practical implications for speech and language therapy in progressive aphasia. Moreover, they illustrate both the remarkable specificity yet clinical diversity in presentation of progressive aphasia.

Working-memory load decreases mappings effects in spatial-compatibility tasks

The paper investigates the role of working memory for the translation of spatial stimuli into spatial responses. Performance is typically superior with compatible mapping between stimulus and response locations than with incompatible mapping (spatial-mapping effect). According to popular dual-route models, the spatial-mapping effect may arise from differences in the effectiveness of S-R translation, and/or from the effects of automatic response activation. Working-memory load should not affect the automatic route, but delay S-R translation in the incompatible condition, increasing the mapping effect under load. These predictions were tested in two dual-task experiments. Participants performed a spatial-compatibility task with compatible or incompatible S-R mapping, while memorizing different amounts of spatial (Experiment 1) or verbal (Experiment 2) information. In both experiments, working-memory load decreased the mapping effect, but did not eliminate it. Results are at odds with the dual-route account. An alternative explanation based on the response-discrimination account (Ansorge and Wühr in J Exp Psychol Hum Percept Perform 30:365-377, 2004) is proposed.

Decomposing infants’ object representations: A dual-route processing account

The capacity for infants to form mental representations of hidden or occluded objects can be decomposed into two tasks: one process that identifies salient objects and a second complementary process that identifies salient locations. This functional decomposition is supported by the distinction between dorsal and ventral extrastriate visual processing in the primate visual system. This approach is illustrated by presenting an eye-movement model that incorporates both dorsal and ventral processing streams and by using the model to simulate infants’ reactions to possible and impossible events from an infant looking-time study (R. Baillargeon, “Representing the existence and the location of hidden objects: object permanence in 6- and 8-month-old infants”, Cognition, 23, pp. 21–41, 1986.). As expected, the model highlights how the dorsal system is sensitive to the location of a key feature in these events (i.e. the location of an obstacle), whereas the ventral system responds equivalently to the possible and impossible events. These results are used to help explain infants’ reactions in looking-time studies.

Further Evidence that the SNARC Effect is Processed Along a Dual-Route Architecture

In a binary response setting, it has been frequently observed that small numbers are reacted to faster with the left hand and large numbers with the right hand (i. e., the SNARC-effect) which reflects the spatial left-right orientation of the mental number line (Dehaene, Bossini, & Giraux, 1993). In line with the work of Keus and Schwarz (in press), we investigated the locus of the conflict in the SNARC effect in a parity judgment task with the Arabic numerals 1, 2, 8, or 9. Differences between compatible (left-hand response to 1 or 2 and right-hand response to 8 and 9) and incompatible SNARC conditions (left-hand response to 8 or 9 and right-hand response to 1 or 2) were observed in the lateralized readiness potential (LRP) but not in the peak latency of the P300. In accordance with Keus and colleagues (Keus, Jenks, & Schwarz, 2005), we argue that the locus of the conflict is situated at intermediate response-related stages. However, instead of adopting a single-route processing architecture, a dual route account is proposed as the underlying processing architecture explaining the SNARC effect.

Current Awareness in NMR in Biomedicine

Current Awareness in NMR in Biomedicine

A dual-route account for access to grammatical gender: evidence from functional MRI

Research investigating the neural correlates of grammatical gender processing has provided contradictory evidence with respect to activation in the left inferior frontal gyrus (IFG). A possible account for these discrepancies is a dual-route model proposing explicit vs implicit access to the gender information. In this event-related fMRI experiment, we investigated this issue by taking into account different processing strategies reported by the subjects. The participants performed two tasks, a gender judgement of German nouns and a non-lexical baseline task (spacing of consonant letter strings). Depending on the reported strategy (silent production of the definite determiner or direct access to the gender information), different patterns of activation in the left IFG were observed. Direct access to gender information yielded activation in the inferior tip of BA 44, whereas the verbalisation strategy elicited activation in the superior portion of BA 44, BA 45/47, and the fronto-median wall. These results speak in favour of a dual-route account for modelling the access to grammatical gender information during language comprehension.

Getting to the Meaning of the Regular Past Tense: Evidence from Neuropsychology

Neuropsychological impairments of English past tense processing inform a key debate in cognitive neuroscience concerning the nature of mental mechanisms. Dual-route accounts claim that regular past tense comprehension deficits reflect a specific impairment of morphological decomposition (e.g., jump + ed), disrupting the automatic comprehension of word meaning accessed via the verb stem (e.g., jump). Single-mechanism accounts claim that the deficits reflect a general phonological impairment that affects perception of regular past tense offsets but which might preserve normal activation of verb semantics. We tested four patients with regular past tense deficits and matched controls, using a paired auditory semantic priming/lexical decision task with three conditions: uninflected verbs (hope/wish), regular past tense primes (blamed/accuse), and irregular past tense primes (shook/tremble). Both groups showed significant priming for verbs with simple morphophonology (uninflected verbs and irregular past tenses) but the patients showed no priming for verbs with complex morphophonology (regular past tenses) in contrast to controls. The findings suggest that the patients are delayed in activating the meaning of verbs if a regular past tense affix is appended, consistent with a dual-route account of their deficit.

The role of meaning in inflection: Why the past tense does not require a rule

How do we produce the past tenses of verbs? For the last 20 years this question has been the focal domain for conflicting theories of language, knowledge representation, and cognitive processing. On one side of the debate have been similarity-based or single-route approaches that propose that all past tenses are formed simply through phonological analogies to existing past tenses stored in memory. On the other side of the debate are rule-based or dual-route approaches which agree that phonological analogy is important for producing irregular past tenses (e.g., think→ thought), but argue that regular past tenses (e.g., walk→ walked) are generated via a + ed rule and that a principled account of regular inflection can only be given by recourse to explicit rules. This debate has become a crucial battleground for arguments concerning the necessity and importance of abstract mental rules, embracing not only language processing, but also the of nature cognition itself. However, in centering on the roles of phonological similarity and rules, the past tense debate has largely ignored the possible role of semantics in determining inflection. This paper presents five studies that demonstrate a striking and decisive role of semantic similarity in inflection. In fact, semantic factors appear to be more important in inflection than the grammatical considerations put forward by the dual-route account. Further, these new findings provide a new way of discriminating between the claims of single-route (similarity-based) and dual-route (rule-based) approaches. It appears that inflection is carried out through analogical reminding based on semantic and phonological similarity and that a rule-based route is not necessary to account for past tense inflection.

Imageability effects, phonological errors, and the relationship between auditory repetition and picture naming: Implications for models of auditory repetition

Hanley and Kay (1997) reported the case of a patient (PS) who showed effects of imageability on tests of auditory repetition, but whose errors were phonological rather than semantic. They argued that this pattern of performance could be explained in terms of a partial impairment to both lexical and nonlexical repetition routes so long as some interaction between the two routes was allowed, consistent with Hillis and Caramazza's (1991) "summation" hypothesis. The present paper investigates the performance of a new patient (MF) who also makes a large number of phonological errors when repeating words of low imageability. MF performs at a similar level to PS on tests of picture naming, but is less impaired than PS when repeating words and nonwords. It is argued that the pattern of performance that MF demonstrates on these and on a wide range of other tests of word production and comprehension can be readily accommodated in terms of the dual-route account of impaired auditory repetition that Hanley and Kay (1997) put forward. However, we argue that it is difficult to explain these patients' performance in terms of models of auditory word repetition that do not incorporate a separate nonlexical repetition route (Dell, Schwartz, Martin, Saffran, & Gagnon, 1997; Foygel & Dell, 2000).