Publications

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

Four eye-tracking experiments examined whether semantic and visual-shape representations are routinely retrieved from printed-word displays and used during language-mediated visual search. Participants listened to sentences containing target words which were similar semantically or in shape to concepts invoked by concurrently-displayed printed words. In Experiment 1 the displays contained semantic and shape competitors of the targets, and two unrelated words. There were significant shifts in eye gaze as targets were heard towards semantic but not shape competitors. In Experiments 2-4, semantic competitors were replaced with unrelated words, semantically richer sentences were presented to encourage visual imagery, or participants rated the shape similarity of the stimuli before doing the eye-tracking task. In all cases there were no immediate shifts in eye gaze to shape competitors, even though, in response to the Experiment 1 spoken materials, participants looked to these competitors when they were presented as pictures (Huettig & McQueen, 2007). There was a late shape-competitor bias (more than 2500 ms after target onset) in all experiments. These data show that shape information is not used in online search of printed-word displays (whereas it is used with picture displays). The nature of the visual environment appears to induce implicit biases towards particular modes of processing during language-mediated visual search.

Abstract

We describe the key features of the visual world paradigm and review the main research areas where it has been used. In our discussion we highlight that the paradigm provides information about the way language users integrate linguistic information with information derived from the visual environment. Therefore the paradigm is well suited to study one of the key issues of current cognitive psychology, namely the interplay between linguistic and visual information processing. However, conclusions about linguistic processing (e.g., about activation, competition, and timing of access of linguistic representations) in the absence of relevant visual information must be drawn with caution.

Abstract

Three eye-tracking experiments investigated the influence of stored colour knowledge, perceived surface colour, and conceptual category of visual objects on language-mediated overt attention. Participants heard spoken target words whose concepts are associated with a diagnostic colour (e.g., "spinach"; spinach is typically green) while their eye movements were monitored to (a) objects associated with a diagnostic colour but presented in black and white (e.g., a black-and-white line drawing of a frog), (b) objects associated with a diagnostic colour but presented in an appropriate but atypical colour (e.g., a colour photograph of a yellow frog), and (c) objects not associated with a diagnostic colour but presented in the diagnostic colour of the target concept (e.g., a green blouse; blouses are not typically green). We observed that colour-mediated shifts in overt attention are primarily due to the perceived surface attributes of the visual objects rather than stored knowledge about the typical colour of the object. In addition our data reveal that conceptual category information is the primary determinant of overt attention if both conceptual category and surface colour competitors are copresent in the visual environment.

Abstract

In the visual world paradigm as used in psycholinguistics, eye gaze (i.e. visual orienting) is measured in order to draw conclusions about linguistic processing. However, current theories are underspecified with respect to how visual attention is guided on the basis of linguistic representations. In the visual search paradigm as used within the area of visual attention research, investigators have become more and more interested in how visual orienting is affected by higher order representations, such as those involved in memory and language. Within this area more specific models of orienting on the basis of visual information exist, but they need to be extended with mechanisms that allow for language-mediated orienting. In the present paper we review the evidence from these two different – but highly related – research areas. We arrive at a model in which working memory serves as the nexus in which long-term visual as well as linguistic representations (i.e. types) are bound to specific locations (i.e. tokens or indices). The model predicts that the interaction between language and visual attention is subject to a number of conditions, such as the presence of the guiding representation in working memory, capacity limitations, and cognitive control mechanisms.

Abstract

The influence of formal literacy on spoken language-mediated visual orienting was investigated by using a simple look and listen task (cf. Huettig & Altmann, 2005) which resembles every day behavior. In Experiment 1, high and low literates listened to spoken sentences containing a target word (e.g., 'magar', crocodile) while at the same time looking at a visual display of four objects (a phonological competitor of the target word, e.g., 'matar', peas; a semantic competitor, e.g., 'kachuwa', turtle, and two unrelated distractors). In Experiment 2 the semantic competitor was replaced with another unrelated distractor. Both groups of participants shifted their eye gaze to the semantic competitors (Experiment 1). In both experiments high literates shifted their eye gaze towards phonological competitors as soon as phonological information became available and moved their eyes away as soon as the acoustic information mismatched. Low literates in contrast only used phonological information when semantic matches between spoken word and visual referent were impossible (Experiment 2) but in contrast to high literates these phonologically-mediated shifts in eye gaze were not closely time-locked to the speech input. We conclude that in high literates language-mediated shifts in overt attention are co-determined by the type of information in the visual environment, the timing of cascaded processing in the word- and object-recognition systems, and the temporal unfolding of the spoken language. Our findings indicate that low literates exhibit a similar cognitive behavior but instead of participating in a tug-of-war among multiple types of cognitive representations, word-object mapping is achieved primarily at the semantic level. If forced, for instance by a situation in which semantic matches are not present (Experiment 2), low literates may on occasion have to rely on phonological information but do so in a much less proficient manner than their highly literate counterparts.

Abstract

Eye movements made by listeners during language-mediated visual search reveal a strong link between
visual processing and conceptual processing. For example, upon hearing the word for a missing referent
with a characteristic colour (e.g., “strawberry”), listeners tend to fixate a colour-matched distractor (e.g.,
a red plane) more than a colour-mismatched distractor (e.g., a yellow plane). We ask whether these
shifts in visual attention are mediated by the retrieval of lexically stored colour labels. Do children
who do not yet possess verbal labels for the colour attribute that spoken and viewed objects have in
common exhibit language-mediated eye movements like those made by older children and adults?
That is, do toddlers look at a red plane when hearing “strawberry”? We observed that 24-montholds
lacking colour term knowledge nonetheless recognized the perceptual–conceptual commonality
between named and seen objects. This indicates that language-mediated visual search need not
depend on stored labels for concepts.

Abstract

The nature of children’s early lexical processing was investigated by asking what information 36-month-olds access and use when instructed to find a known but absent referent. Children readily retrieved stored knowledge about characteristic color, i.e. when asked to find an object with a typical color (e.g. strawberry), children tended to fixate more upon an object that had the same (e.g. red plane) as opposed to a different (e.g. yellow plane) color. They did so regardless of the fact that they have had plenty of time to recognize the pictures for what they are, i.e. planes not strawberries. These data represent the first demonstration that language-mediated shifts of overt attention in young children can be driven by individual stored visual attributes of known words that mismatch on most other dimensions. The finding suggests that lexical processing and overt attention are strongly linked from an early age.