Publications

Abstract

Moores, Laiti, and Chelazzi (2003) found semantic interference from associate competitors during visual object search, demonstrating the existence of top-down semantic influences on the deployment of attention to objects. We examined whether effects of semantically related competitors (same-category members or associates) interacted with the effects of perceptual or cognitive load. We failed to find any interaction between competitor effects and perceptual load. However, the competitor effects increased significantly when participants were asked to retain one or five digits in memory throughout the search task. Analyses of eye movements and viewing times showed that a cognitive load did not affect the initial allocation of attention but rather the time it took participants to accept or reject an object as the target. We discuss the implications of our findings for theories of conceptual short-term memory and visual attention.

Abstract

Three dual-task experiments investigated the capacity demands of phoneme selection in picture naming. On each trial, participants named a target picture (Task 1) and carried out a tone discrimination task (Task 2). To vary the time required for phoneme selection, the authors combined the targets with phonologically related or unrelated distractor pictures (Experiment 1) or words, which were clearly visible (Experiment 2) or masked (Experiment 3). When pictures or masked words were presented, the tone discrimination and picture naming latencies were shorter in the related condition than in the unrelated condition, which indicates that phoneme selection requires central processing capacity. However, when the distractor words were clearly visible, the facilitatory effect was confined to the picture naming latencies. This pattern arose because the visible related distractor words facilitated phoneme selection but slowed down speech monitoring processes that had to be completed before the response to the tone could be selected.

Abstract

The authors investigated whether speakers who named several objects processed them sequentially or in parallel. Speakers named object triplets, arranged in a triangle, in the order left, right, and bottom object. The left object was easy or difficult to identify and name. During the saccade from the left to the right object, the right object shown at trial onset (the interloper) was replaced by a new object (the target), which the speakers named. Interloper and target were identical or unrelated objects, or they were conceptually unrelated objects with the same name (e.g., bat [animal] and [baseball] bat). The mean duration of the gazes to the target was shorter when interloper and target were identical or had the same name than when they were unrelated. The facilitatory effects of identical and homophonous interlopers were significantly larger when the left object was easy to process than when it was difficult to process. This interaction demonstrates that the speakers processed the left and right objects in parallel.

Abstract

In two experiments, we investigated the processing of extrafoveal objects in a double-object naming task. On most trials, participants named two objects; but on some trials, the objects were replaced shortly after trial onset by a written word probe, which participants had to name instead of the objects. In Experiment 1, the word was presented in the same location as the left object either 150 or 350 msec after trial onset and was either phonologically related or unrelated to that object name. Phonological facilitation was observed at the later but not at the earlier SOA. In Experiment 2, the word was either phonologically related or unrelated to the right object and was presented 150 msec after the speaker had begun to inspect that object. In contrast with Experiment 1, phonological facilitation was found at this early SOA, demonstrating that the speakers had begun to process the right object prior to fixation.

Abstract

Two experiments were conducted with younger and older speakers. In Experiment 1, participants named single objects that were intact or visually degraded, while hearing distractor words that were phonologically related or unrelated to the object name. In both younger and older participants naming latencies were shorter for intact than for degraded objects and shorter when related than when unrelated distractors were presented. In Experiment 2, the single objects were replaced by object triplets, with the distractors being phonologically related to the first object's name. Naming latencies and gaze durations for the first object showed degradation and relatedness effects that were similar to those in single-object naming. Older participants were slower than younger participants when naming single objects and slower and less fluent on the second but not the first object when naming object triplets. The results of these experiments indicate that both younger and older speakers plan object names sequentially, but that older speakers use this planning strategy less efficiently.

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.