Eva Belke

Early activation of object names in visual search

In a visual search experiment, participants had to decide whether or not a target object was present in a fourobject search array. One of these objects could be a semantically related competitor (e.g.,shirt for the targettrousers) or a conceptually unrelated object with the same name as the target—for example,bat (baseball) for the targetbat (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.

Top-down effects of semantic knowledge in visual search are modulated by cognitive but not perceptual load.

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.

Effects of working memory load on lexical-semantic encoding in language production

Some models of lexical access in language production postulate that lexical-semantic encoding is driven bottom-up, by the conceptual input, and top-down, by a representation of the task. In the cyclic semantic blocking paradigm, participants repeatedly name sets of objects that are either semantically related or unrelated. Whereas the manipulation of semantic relatedness affects lexical-semantic encoding in a bottom-up fashion, the cyclic presentation of small object sets allows participants to bias the corresponding lexical-semantic representations top-down for selection. The role of working memory (WM) in this top-down modulation was investigated by crossing the cyclic semantic blocking paradigm with a manipulation of WM load. Participants’ naming latencies displayed significant effects of semantic context, WM load, and their interaction. A word-naming task using the same materials yielded a main effect of WM load but no significant effects of semantic context or of its interaction with WM load. These and related results are discussed with regard to their implications for models of language production.

Cumulative and non-cumulative semantic interference in object naming: Evidence from blocked and continuous manipulations of semantic context

Experiments involving blocked and continuous manipulations of the semantic naming context demonstrate that, when speakers name several taxonomically related objects in close succession, they display persistent interference effects. A review of studies using the blocked paradigm shows that, unlike the continuous paradigm, it typically does not induce cumulative interference effects in healthy speakers. This contrasts with the simulation results obtained from a model of semantic context effects recently put forward by Oppenheim and colleagues [Oppenheim, G. M., Dell, G. S., & Schwartz, M. F. (2010). The dark side of incremental learning: A model of cumulative semantic interference during lexical access in speech production. Cognition, 114, 227–262], which generates cumulative effects in both paradigms. We propose that the effects are non-cumulative in the blocked paradigm, because it allows participants to bias top-down the levels of activation of lexical-semantic representations, thereby curtailing the accumulating interference. Indeed, prior research has shown that the interference effects in the blocked paradigm are exacerbated when participants carry out a concurrent digit-retention task, loading on working memory and reducing their capacity to exert a top-down bias. In Experiment 1, combining the continuous paradigm with a digit-retention task, we demonstrate that this does not exacerbate cumulative context effects, corroborating the selective role of working memory and the associated top-down biasing mechanism in the blocked paradigm. A review of neuropsychological and neuroimaging studies demonstrates that left inferior frontal regions may play a critical role in controlling semantic interference top-down. We discuss the implications of these findings for language production research and for models of lexical-semantic encoding.

Single and multiple object naming in healthy ageing

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.

Strategic origins of early semantic facilitation in the blocked-cyclic naming paradigm

In the blocked-cyclic naming paradigm, participants repeatedly name small sets of objects that do or do not belong to the same semantic category. A standard finding is that, after a first presentation cycle where one might find semantic facilitation, naming is slower in related (homogeneous) than in unrelated (heterogeneous) sets. According to competitive theories of lexical selection, this is because the lexical representations of the object names compete more vigorously in homogeneous than in heterogeneous sets. However, Navarrete, del Prato, Peressotti, and Mahon (2014) argued that this pattern of results was not due to increased lexical competition but to weaker repetition priming in homogeneous compared to heterogeneous sets. They demonstrated that when homogeneous sets were not repeated immediately but interleaved with unrelated sets, semantic relatedness induced facilitation rather than interference. We replicate this finding but also show that the facilitation effect has a strategic origin: It is substantial when sets are separated by pauses, making it easy for participants to notice the relatedness within some sets and use it to predict upcoming items. However, the effect is much reduced when these pauses are eliminated. In our view, the semantic facilitation effect does not constitute evidence against competitive theories of lexical selection. It can be accounted for within any framework that acknowledges strategic influences on the speed of object naming in the blocked-cyclic naming paradigm.

Language production in a shared task: Cumulative semantic interference from self- and other-produced context words

This study assessed the effects of semantic context in the form of self-produced and other-produced words on subsequent language production. Pairs of participants performed a joint picture naming task, taking turns while naming a continuous series of pictures. In the single-speaker version of this paradigm, naming latencies have been found to increase for successive presentations of exemplars from the same category, a phenomenon known as Cumulative Semantic Interference (CSI). As expected, the joint-naming task showed a within-speaker CSI effect, such that naming latencies increased as a function of the number of category exemplars named previously by the participant (self-produced items). Crucially, we also observed an across-speaker CSI effect, such that naming latencies slowed as a function of the number of category members named by the participants task partner (other-produced items). The magnitude of the across-speaker CSI effect did not vary as a function of whether or not the listening participant could see the pictures their partner was naming. The observation of across-speaker CSI suggests that the effect originates at the conceptual level of the language system, as proposed by Belkes (2013) Conceptual Accumulation account. Whereas self-produced and other-produced words both resulted in a CSI effect on naming latencies, post-experiment free recall rates were higher for self-produced than other-produced items. Together, these results suggest that both speaking and listening result in implicit learning at the conceptual level of the language system but that these effects are independent of explicit learning as indicated by item recall.

The Role of Task-Specific Response Strategies in Blocked-Cyclic Naming

In word retrieval, speakers need to select a lexical entry among several co-activated candidates for lexicalization. How a target entry is selected is a matter of ongoing debate. Semantic context effects on naming times, as seen in the blocked-cyclic naming paradigm, are of specific interest to this debate. In the standard version of this paradigm, participants name lists of objects compiled from several repetitions (cycles) of a small set of semantically related objects (homogeneous context) or unrelated objects (heterogeneous context). In the first cycle, participants typically show either no context effect or semantic facilitation. From cycle two onward, they display a stable semantic interference effect that does not increase over cycles. In this review, I demonstrate that the early semantic facilitation effect is only observed consistently in studies that present homogeneous and heterogeneous lists in a blocked fashion. With this design, participants can easily pick up on the categorical relatedness of the items in semantically related contexts and apply this knowledge strategically. In principle, such response strategies can be easily tied in with existing models of lexical selection, but they are incompatible with accounts of semantic context effects that take the semantic facilitation effect in cycle 1 to be a consequence of processes inherent to the lexicalization process. Users of the blocked-cyclic naming paradigm should review their experimental designs carefully regarding potential response strategies. Once these are taken into account, the paradigm can be used to study lexical-semantic encoding in different populations of healthy and also impaired speakers.

Language play facilitates language learning: Optimizing the input for gender-like category induction

Gender induction has been claimed to be virtually impossible unless nouns provide reliable semantic or phonological gender-relevant cues. However, learners might exploit syntactic cues, such as definite articles, to infer the gender of gender-unmarked nouns. In children’s poems and songs, such syntactic cues are presented in a highly structured fashion. We assessed gender-like category induction in an artificial language that provided exclusively syntactic cues for its gender-like subclasses. We trained participants with structured or unstructured input presented in a prose, a rhyming, a melodic, or a rhyming and melodic fashion. Input structuring significantly facilitated gender-like category induction. Participants trained in the Rhyme-and-Melody mode significantly outperformed participants trained in the Prose mode, especially when the input was structured. The Rhyme-only and Melody-only modes yielded intermediate results. Thus, a highly structured rhyming and melodic input substantially facilitates gender-like category induction, making a case for the use of children’s songs in language teaching.

Effects of lesions to the left lateral prefrontal cortex on task-specific top-down biases and response strategies in blocked-cyclic naming

ABSTRACT Anders, Riès, van Maanen and Alario put forward evidence accumulation modelling of object naming times as an alternative to neural network models of lexical retrieval. The authors exemplify their approach using data from the blocked-cyclic naming paradigm, requiring speakers to repeatedly name small sets of related or unrelated objects. The effects observed with this paradigm are understood reasonably well within the tradition of neural network modelling. However, implemented neural network models do not specify interfaces for task-specific top-down influences and response strategies that are likely to play a role in the blocked-cyclic naming paradigm, distinguishing it from continuous, non-cyclic manipulations of the naming context. I argue that the evidence accumulation approach falls short on this account as well, as it does not specify the potential contribution of task-specific top-down processes and strategic facilitation effects to the response time distributions. Future endeavours to model or fit data from blocked-cyclic naming experiments should strive to do so by simultaneously considering data from continuous context manipulations.