Publications

Abstract

Introduction to the special issue 'The Effects of Literacy on Cognition and Brain Functioning'

Abstract

The cause of developmental dyslexia is still unknown despite decades of intense research. Many causal explanations have been proposed, based on the range of impairments displayed by affected individuals. Here we draw attention to the fact that many of these impairments are also shown by illiterate individuals who have not received any or very little reading instruction. We suggest that this fact may not be coincidental and that the performance differences of both illiterates and individuals with dyslexia compared to literate controls are, to a substantial extent, secondary consequences of either reduced or suboptimal reading experience or a combination of both. The search for the primary causes of reading impairments will make progress if the consequences of quantitative and qualitative differences in reading experience are better taken into account and not mistaken for the causes of reading disorders. We close by providing four recommendations for future research.

Abstract

Do people routinely pre-activate the meaning and even the phonological form of upcoming words? The most acclaimed evidence for phonological prediction comes from a 2005 Nature Neuroscience publication by DeLong, Urbach and Kutas, who observed a graded modulation of electrical brain potentials (N400) to nouns and preceding articles by the probability that people use a word to continue the sentence fragment (‘cloze’). In our direct replication study spanning 9 laboratories (N=334), pre-registered replication-analyses and exploratory Bayes factor analyses successfully replicated the noun-results but, crucially, not the article-results. Pre-registered single-trial analyses also yielded a statistically significant effect for the nouns but not the articles. Exploratory Bayesian single-trial analyses showed that the article-effect may be non-zero but is likely far smaller than originally reported and too small to observe without very large sample sizes. Our results do not support the view that readers routinely pre-activate the phonological form of predictable words.

Abstract

Implicit up/down words, such as bird and foot, systematically influence performance on visual tasks involving immediately following targets in compatible vs. incompatible locations. Recent studies have observed that the semantic relation between prime words and target pictures can strongly influence the size and even the direction of the effect: Semantically related targets are processed faster in congruent vs. incongruent locations (location-specific priming), whereas unrelated targets are processed slower in congruent locations. Here, we used eye-tracking to investigate the moment-to-moment processes underlying this pattern. Our reaction time results for related targets replicated the location-specific priming effect and showed a trend towards interference for unrelated targets. We then used growth curve analysis to test how up/down words and their match vs. mismatch with immediately following targets in terms of semantics and vertical location influences concurrent saccadic eye movements. There was a strong main effect of spatial association on linear growth with up words biasing changes in y-coordinates over time upwards relative to down words (and vice versa). Similar to the RT data, this effect was strongest for semantically related targets and reversed for unrelated targets. Intriguingly, all conditions showed a bias in the congruent direction in the initial stage of the saccade. Then, at around halfway into the saccade the effect kept increasing in the semantically related condition, and reversed in the unrelated condition. These results suggest that online processing of up/down words triggers direction-specific oculomotor processes that are dynamically modulated by the semantic relation between prime words and targets.

Abstract

Visual attention is biased by both visual and semantic representations activated by words. We investigated to what extent language-induced visual and semantic biases are subject to task demands. Participants memorized a spoken word for a verbal recognition task, and performed a visual search task during the retention period. Crucially, while the word had to be remembered in all conditions, it was either relevant for the search (as it also indicated the target) or irrelevant (as it only served the memory test afterwards). On critical trials, displays contained objects that were visually or semantically related to the memorized word. When the word was relevant for the search, eye movement biases towards visually related objects arose earlier and more strongly than biases towards semantically related objects. When the word was irrelevant, there was still evidence for visual and semantic biases, but these biases were substantially weaker, and similar in strength and temporal dynamics, without a visual advantage. We conclude that language-induced attentional biases are subject to task requirements.

Abstract

Many studies have demonstrated that listeners use information extracted from verbs to guide anticipatory eye movements to objects in the visual context that satisfy the selection restrictions of the verb. An important question is what underlies such verb-mediated anticipatory eye gaze. Based on empirical and theoretical suggestions, we investigated the influence of five potential predictors of this behavior: functional associations and general associations between verb and target object, as well as the listeners’ production fluency, receptive vocabulary knowledge, and non-verbal intelligence. In three eye-tracking experiments, participants looked at sets of four objects and listened to sentences where the final word was predictable or not predictable (e.g., “The man peels/draws an apple”). On predictable trials only the target object, but not the distractors, were functionally and associatively related to the verb. In Experiments 1 and 2, objects were presented before the verb was heard. In Experiment 3, participants were given a short preview of the display after the verb was heard. Functional associations and receptive vocabulary were found to be important predictors of verb-mediated anticipatory eye gaze independent of the amount of contextual visual input. General word associations did not and non-verbal intelligence was only a very weak predictor of anticipatory eye movements. Participants’ production fluency correlated positively with the likelihood of anticipatory eye movements when participants were given the long but not the short visual display preview. These findings fit best with a pluralistic approach to predictive language processing in which multiple mechanisms, mediating factors, and situational context dynamically interact. 

Abstract

Using real-time eye-movement measures, we asked how a fantastical discourse context competes with stored representations of semantic and world knowledge to influence children's and adults' moment-by-moment interpretation of a story. Seven-year- olds were less effective at bypassing stored semantic and world knowledge during real-time interpretation than adults. Nevertheless, an effect of discourse context on comprehension was still apparent.

Abstract

While structural priming makes a valuable contribution to psycholinguistics, it does not allow direct observation of representation, nor escape “source ambiguity.” Structural priming taps into implicit memory representations and processes that may differ from what is used online. We question whether implicit memory for language can and should be equated with linguistic representation or with language processing.

Abstract

The notion that processing spoken (object) words involves activation of category-specific representations in visual cortex is a key prediction of modality-specific theories of representation that contrasts with theories assuming dedicated conceptual representational systems abstracted away from sensorimotor systems. In the present study, we investigated whether participants can detect otherwise invisible pictures of objects when they are presented with the corresponding spoken word shortly before the picture appears. Our results showed facilitated detection for congruent ("bottle" -> picture of a bottle) vs. incongruent ("bottle" -> picture of a banana) trials. A second experiment investigated the time-course of the effect by manipulating the timing of picture presentation relative to word onset and revealed that it arises as soon as 200-400ms after word onset and decays at 600ms after word onset. Together, these data strongly suggest that spoken words can rapidly activate low-level category-specific visual representations that affect the mere detection of a stimulus, i.e. what we see. More generally our findings fit best with the notion that spoken words activate modality-specific visual representations that are low-level enough to provide information related to a given token and at the same time abstract enough to be relevant not only for previously seen tokens but also for generalizing to novel exemplars one has never seen before.

Abstract

It is well established that the comprehension of spoken words referring to object concepts relies on high-level visual areas in the ventral stream that build increasingly abstract representations. It is much less clear whether basic low-level visual representations are also involved. Here we asked in what task situations low-level visual representations contribute functionally to concrete word comprehension using an interference paradigm. We interfered with basic visual processing while participants performed a concreteness task (Experiment 1), a lexical decision task (Experiment 2), and a word class judgment task (Experiment 3). We found that visual noise interfered more with concrete vs. abstract word processing, but only when the task required visual information to be accessed. This suggests that basic visual processes can be causally involved in language comprehension, but that their recruitment is not automatic and rather depends on the type of information that is required in a given task situation.

Abstract

Learning to read is known to result in a reorganization of the developing cerebral cortex. In this longitudinal resting-state functional magnetic resonance imaging study in illiterate adults we show that only 6 months of literacy training can lead to neuroplastic changes in the mature brain. We observed that literacy-induced neuroplasticity is not confined to the cortex but increases the functional connectivity between the occipital lobe and subcortical areas in the midbrain and
the thalamus. Individual rates of connectivity increase were significantly related to the individualdecoding skill gains. These findings crucially complement current neurobiological concepts ofnormal and impaired literacy acquisition.

Abstract

Ambiguity in natural language is ubiquitous, yet spoken communication is effective due to integration of information carried in the speech signal with information available in the surrounding multimodal landscape. Language mediated visual attention requires visual and linguistic information integration and has thus been used to examine properties of the architecture supporting multimodal processing during spoken language comprehension. In this paper we test predictions generated by alternative models of this multimodal system. A model (TRACE) in which multimodal information is combined at the point of the lexical representations of words generated predictions of a stronger effect of phonological rhyme relative to semantic and visual information on gaze behaviour, whereas a model in which sub-lexical information can interact across modalities (MIM) predicted a greater influence of visual and semantic information, compared to phonological rhyme. Two visual world experiments designed to test these predictions offer support for sub-lexical multimodal interaction during online language processing.

Abstract

Experiments 1 and 2 examined the time-course of retrieval of phonological, visual-shape and semantic knowledge as Dutch participants listened to sentences and looked at displays of four pictures. Given a sentence with beker, `beaker', for example, the display contained phonological (a beaver, bever), shape (a bobbin, klos), and semantic (a fork, vork) competitors. When the display appeared at sentence onset, fixations to phonological competitors preceded fixations to shape and semantic competitors. When display onset was 200 ms before (e.g.) beker, fixations were directed to shape and then semantic competitors, but not phonological competitors. In Experiments 3 and 4, displays contained the printed names of the previously-pictured entities; only phonological competitors were fixated preferentially. These findings suggest that retrieval of phonological, shape and semantic knowledge in the spoken-word and picture-recognition systems is cascaded, and that visual attention shifts are co-determined by the time-course of retrieval of all three knowledge types and by the nature of the information in the visual environment.

Abstract

Visual attention can be directed immediately, as a spoken word unfolds, towards conceptually related but nonassociated objects, even if they mismatch on other dimensions that would normally determine which objects in the scene were appropriate referents for the unfolding word (Huettig & Altmann, 2005). Here we demonstrate that the mapping between language and concurrent visual objects can also be mediated by visual-shape relations. On hearing "snake", participants directed overt attention immediately, within a visual display depicting four objects, to a picture of an electric cable, although participants had viewed the visual display with four objects for approximately 5 s before hearing the target word - sufficient time to recognize the objects for what they were. The time spent fixating the cable correlated significantly with ratings of the visual similarity between snakes in general and this particular cable. Importantly, with sentences contextually biased towards the concept snake, participants looked at the snake well before the onset of "snake", but they did not look at the visually similar cable until hearing "snake". Finally, we demonstrate that such activation can, under certain circumstances (e.g., during the processing of dominant meanings of homonyms), constrain the direction of visual attention even when it is clearly contextually inappropriate. We conclude that language-mediated attention can be guided by a visual match between spoken words and visual objects, but that such a match is based on lexical input and may not be modulated by contextual appropriateness.