Publications

Abstract

We compared the performance of young (college-aged) and older (50+years) speakers in a single object and a multiple object naming task and assessed their susceptibility to semantic and phonological context effects when producing words amidst semantically or phonologically similar or dissimilar words. In single object naming, there were no performance differences between the age groups. In multiple object naming, we observed significant age-related slowing, expressed in longer gazes to the objects and slower speech. In addition, the direction of the phonological context effects differed for the two groups. The results of a supplementary experiment showed that young speakers, when adopting a slow speech rate, coordinated their eye movements and speech differently from the older speakers. Our results imply that age-related slowing in connected speech is not a direct consequence of a slowing of lexical retrieval processes. Instead, older speakers might allocate more processing capacity to speech monitoring processes, which would slow down their concurrent speech planning processes

Abstract

The use of language is a fundamental component of much of our day-to-day life. Language often co-occurs with other activities with which it must be coordinated. This raises the question of whether the cognitive processes involved in planning spoken utterances and in understanding them are autonomous or whether they are affected by, and perhaps affect, non-linguistic cognitive processes, with which they might share processing resources. This question is the central concern of Automaticity and Control in Language Processing. The chapters address key issues concerning the relationship between linguistic and non-linguistic processes, including: * How can the degree of automaticity of a component be defined? * Which linguistic processes are truly automatic, and which require processing capacity? * Through which mechanisms can control processes affect linguistic performance? How might these mechanisms be represented in the brain? * How do limitations in working memory and executive control capacity affect linguistic performance and language re-learning in persons with brain damage? This important collection from leading international researchers will be of great interest to researchers and students in the area.

Abstract

In four experiments, participants named target pictures that were accompanied by distractor pictures with phonologically related or unrelated names. Across experiments, the type of phonological relationship between the targets and the related distractors was varied: They were homophones (e.g., bat [animal/baseball]), or they shared word-initial segments (e.g., dog-doll) or word-final segments (e.g., ball-wall). The participants either named the objects after an extensive familiarization and practice phase or without any familiarization or practice. In all of the experiments, the mean target-naming latency was shorter in the related than in the unrelated condition, demonstrating that the phonological form of the name of the distractor picture became activated. These results are best explained within a cascaded model of lexical access—that is, under the assumption that the recognition of an object leads to the activation of its name.

Abstract

In a visual search experiment, participants had to decide whether or not a target object was present in a four-object search array. One of these objects could be a semantically related competitor (e.g., shirt for the target trousers) or a conceptually unrelated object with the same name as the target-for example, bat (baseball) for the target bat (animal). In the control condition, the related competitor was replaced by an unrelated object. The participants' response latencies and eye movements demonstrated that the two types of related competitors had similar effects: Competitors attracted the participants' visual attention and thereby delayed positive and negative decisions. The results imply that semantic and name information associated with the objects becomes rapidly available and affects the allocation of visual attention.

Abstract

Griffin [Griffin, Z. M. (2003). A reversed length effect in coordinating the preparation and articulation of words in speaking. Psychonomic Bulletin & Review, 10, 603-609.] found that speakers naming object pairs spent more time before utterance onset looking at the second object when the first object name was short than when it was long. She proposed that this reversed length effect arose because the speakers' decision when to initiate an utterance was based, in part, on their estimate of the spoken duration of the first object name and the time available during its articulation to plan the second object name. In Experiment I of the present study, participants named object pairs. They spent more time looking at the first object when its name was monosyllabic than when it was trisyllabic, and, as in Griffin's study, the average gaze-speech lag (the time between the end of the gaze to the first object and onset of its name, which corresponds closely to the pre-speech inspection time for the second object) showed a reversed length effect. Experiments 2 and 3 showed that this effect was not due to a trade-off between the time speakers spent looking at the first and second object before speech onset. Experiment 4 yielded a reversed length effect when the second object was replaced by a symbol (x or +), which the participants had to categorise. We propose a novel account of the reversed length effect, which links it to the incremental nature of phonological encoding and articulatory planning rather than the speaker's estimate of the length of the first object name.

Abstract

We investigated the time course of conjunctive ''same''-''different'' judgements for visually presented object pairs by means of combined reaction time and on-line eye movement measurements. The analyses of viewing patterns, viewing times, and reaction times showed that participants engaged in a parallel self-terminating search for differences. In addition, the results obtained for objects differing in only one dimension suggest that processing times may depend on the relative codability of the stimulus dimensions. The results are reviewed in a broader framework in view of higher-order processes. We propose that overspecifications of colour, often found in object descriptions, may have an ''early'' visual rather than a ''late'' linguistic origin. In a parallel assessment of the detection materials, participants overspecified the objects' colour substantially more often than their size. We argue that referential overspecifications of colour are largely attributable to mechanisms of visual discrimination.

Abstract

The study investigated the neuronal basis of the retrieval of words from the mental lexicon. The semantic category interference effect was used to locate lexical retrieval processes in time and space. This effect reflects the finding that, for overt naming, volunteers are slower when naming pictures out of a sequence of items from the same semantic category than from different categories. Participants named pictures blockwise either in the context of same- or mixedcategory items while the brain response was registered using magnetoencephalography (MEG). Fifteen out of 20 participants showed longer response latencies in the same-category compared to the mixed-category condition. Event-related MEG signals for the participants demonstrating the interference effect were submitted to a current source density (CSD) analysis. As a new approach, a principal component analysis was applied to decompose the grand average CSD distribution into spatial subcomponents (factors). The spatial factor indicating left temporal activity revealed significantly different activation for the same-category compared to the mixedcategory condition in the time window between 150 and 225 msec post picture onset. These findings indicate a major involvement of the left temporal cortex in the semantic interference effect. As this effect has been shown to take place at the level of lexical selection, the data suggest that the left temporal cortex supports processes of lexical retrieval during production.

Abstract

The purpose of this study was to relate a psycholinguistic processing model of picture naming to the dynamics of cortical activation during picture naming. The activation was recorded from eight Dutch subjects with a whole-head neuromagnetometer. The processing model, based on extensive naming latency studies, is a stage model. In preparing a picture's name, the speaker performs a chain of specific operations. They are, in this order, computing the visual percept, activating an appropriate lexical concept, selecting the target word from the mental lexicon, phonological encoding, phonetic encoding, and initiation of articulation. The time windows for each of these operations are reasonably well known and could be related to the peak activity of dipole sources in the individual magnetic response patterns. The analyses showed a clear progression over these time windows from early occipital activation, via parietal and temporal to frontal activation. The major specific findings were that (1) a region in the left posterior temporal lobe, agreeing with the location of Wernicke's area, showed prominent activation starting about 200 msec after picture onset and peaking at about 350 msec, (i.e., within the stage of phonological encoding), and (2) a consistent activation was found in the right parietal cortex, peaking at about 230 msec after picture onset, thus preceding and partly overlapping with the left temporal response. An interpretation in terms of the management of visual attention is proposed.

Abstract

Eye movements have been shown to reflect word recognition and language comprehension processes occurring during reading and auditory language comprehension. The present study examines whether the eye movements speakers make during object naming similarly reflect speech planning processes. In Experiment 1, speakers named object pairs saying, for instance, 'scooter and hat'. The objects were presented as ordinary line drawings or with partly dele:ed contours and had high or low frequency names. Contour type and frequency both significantly affected the mean naming latencies and the mean time spent looking at the objects. The frequency effects disappeared in Experiment 2, in which the participants categorized the objects instead of naming them. This suggests that the frequency effects of Experiment 1 arose during lexical retrieval. We conclude that eye movements during object naming indeed reflect linguistic planning processes and that the speakers' decision to move their eyes from one object to the next is contingent upon the retrieval of the phonological form of the object names.

Abstract

In a recent series of papers, Caramazza and Miozzo [Caramazza, A., 1997. How many levels of processing are there in lexical access? Cognitive Neuropsychology 14, 177-208; Caramazza, A., Miozzo, M., 1997. The relation between syntactic and phonological knowledge in lexical access: evidence from the 'tip-of-the-tongue' phenomenon. Cognition 64, 309-343; Miozzo, M., Caramazza, A., 1997. On knowing the auxiliary of a verb that cannot be named: evidence for the independence of grammatical and phonological aspects of lexical knowledge. Journal of Cognitive Neuropsychology 9, 160-166] argued against the lemma/lexeme distinction made in many models of lexical access in speaking, including our network model [Roelofs, A., 1992. A spreading-activation theory of lemma retrieval in speaking. Cognition 42, 107-142; Levelt, W.J.M., Roelofs, A., Meyer, A.S., 1998. A theory of lexical access in speech production. Behavioral and Brain Sciences, (in press)]. Their case was based on the observations that grammatical class deficits of brain-damaged patients and semantic errors may be restricted to either spoken or written forms and that the grammatical gender of a word and information about its form can be independently available in tip-of-the-tongue stales (TOTs). In this paper, we argue that though our model is about speaking, not taking position on writing, extensions to writing are possible that are compatible with the evidence from aphasia and speech errors. Furthermore, our model does not predict a dependency between gender and form retrieval in TOTs. Finally, we argue that Caramazza and Miozzo have not accounted for important parts of the evidence motivating the lemma/lexeme distinction, such as word frequency effects in homophone production, the strict ordering of gender and pho neme access in LRP data, and the chronometric and speech error evidence for the production of complex morphology.

Abstract

According to most models of speech production, the planning of spoken words involves the independent retrieval of segments and metrical frames followed by segment-to-frame association. In some models, the metrical frame includes a specification of the number and ordering of consonants and vowels, but in the word-form encoding by activation and verification (WEAVER) model (A. Roelofs, 1997), the frame specifies only the stress pattern across syllables. In 6 implicit priming experiments, on each trial, participants produced 1 word out of a small set as quickly as possible. In homogeneous sets, the response words shared word-initial segments, whereas in heterogeneous sets, they did not. Priming effects from shared segments depended on all response words having the same number of syllables and stress pattern, but not on their having the same number of consonants and vowels. No priming occurred when the response words had only the same metrical frame but shared no segments. Computer simulations demonstrated that WEAVER accounts for the findings.