Feature overlap slows lexical selection: evidence from the picture-word interference paradigm

The unseen, the seen, and the spoken: Latent and overt priming in cyclic picture naming

Language production entails selecting words in the face of internally, and sometimes externally, driven competition that influences the long-term accessibility of both selected words and competitors. Because both endogenous and externally presented competitors usually result in semantic interference, it is often assumed that they engage the same underlying processes. We question this assumption. Specifically, we propose that latent primes may more naturally commingle with endogenous lexical activation whereas overt primes elicit strong control processes. Two experiments examined the effects of latent (masked) and overt (picture-word) priming in combination with cyclic picture naming of small sets of taxonomically or thematically related or unrelated pictures. A subsequent continuous picture naming phase was designed to assess enduring effects of service as a prime or target. Only taxonomic relations showed substantial interference in cyclic naming. Latent priming tended to increase interference for taxonomic relations, but it produced facilitation for thematic relations. In contrast, overt priming induced interference for both types of relation, indicating exertion of cognitive control. In the continuous picture naming phases, accessibility was hindered for previously presented latent primes (Experiment 1) but enhanced for previously overt primes (Experiment 2). Surprisingly, interference in cyclic naming did not carry forward to the continuous phase. These findings suggest that masked priming may be a viable intervention in the internal dynamics of lexical selection. In contrast, they also add to the body of evidence questioning the validity of using picture-word procedures to study inherent semantic interference.

Cumulative semantic interference is blind to morphological complexity and originates at the conceptual level

When naming a sequence of pictures of the same semantic category (e.g., furniture), response latencies systematically increase with each named category member. This cumulative semantic interference effect has become a popular tool to investigate the cognitive architecture of language production. However, not all processes underlying the effect itself are fully understood, including the question where the effect originates from. While some researchers assume the interface of the conceptual and lexical level as its origin, others suggest the conceptual-semantic level. The latter assumption follows from the observation that cumulative effects, namely cumulative facilitation, can also be observed in purely conceptual-semantic tasks. Another unanswered question is whether cumulative interference is affected by the morphological complexity of the experimental targets. In two experiments with the same participants and the same material, we investigated both of these issues. Experiment 1, a continuous picture naming task, investigated whether morphologically complex nouns (e.g., kitchen table) elicit identical levels of cumulative interference to morphologically simple nouns (e.g., table). Our results show this to be the case, indicating that cumulative interference is unaffected by lexical information such as morphological complexity. In Experiment 2, participants classified the same target objects as either man-made or natural. As expected, we observed cumulative facilitation. A separate analysis showed that this facilitation effect can be predicted by the individuals’ effect sizes of cumulative interference, suggesting a strong functional link between the two effects. Our results thus point to a conceptual-semantic origin of cumulative semantic interference.

Language proficiency moderates the effect of L2 semantically related distractors in L2 spoken word production

Bilinguals differ substantially in their second language (L2) proficiency, but it remains unclear whether language proficiency modulates the effect of L2 semantically related distractors in L2 spoken word production. In the present study, two groups of high proficiency and low proficiency Chinese-English bilinguals named target pictures in their L2 accompanied by visually superimposed L2 distractor words while electroencephalogram signals were recorded. Distractor names were semantically related or unrelated to target names. Variables of L2 proficiency (high proficiency or low proficiency) and semantic relatedness (related or unrelated) were manipulated in the experiment. Behavioral results demonstrated an interaction between L2 proficiency and semantic relatedness, with a semantic interference effect appearing only in high proficiency bilinguals. Waveform analysis indicated that semantic relatedness only exerted significant effects on event-related potentials in high proficiency bilinguals around 300-500 ms post picture presentation. Source localization analysis revealed that semantically related distractors induced higher brain activations in the left middle and superior temporal regions among high proficiency bilinguals, while higher brain activations were found in the right prefrontal cortex among low proficiency bilinguals. Taken together, these findings substantiate the role of language proficiency in determining whether L2 semantically related distractors are sufficiently activated to exceed the competition threshold and interfere with L2 picture naming.

Semantic interference in the picture-word interference task: Is there a pre-lexical, conceptual contribution to the effect?

Picture naming takes longer in the presence of a semantic-categorically related distractor word compared to an unrelated distractor word. This semantic interference effect in the picture-word interference (PWI) task is an empirical cornerstone in speech production research and of central importance in theory development and evaluation. Prominent models locate the effect at an abstract lexical level, yet only few studies have tested for a possible pre-lexical, conceptual contribution. Moreover, those studies that did are not conclusive. We re-explored the locus of semantic interference by contrasting two task versions that were implemented in as parallel a fashion as possible, but differed with respect to the processing stages involved: naming pictures (requiring conceptual processing and lexical processing) and deciding on their natural size (requiring conceptual processing only). We predicted semantic interference in naming, replicating the standard effect. If part of the effect is localized at the conceptual level, we predicted interference in size decision, too. We found semantic effects in both tasks but with different polarity - interference in naming and facilitation in size decision. This pattern supports the view that semantic interference in PWI has its locus at the lexical level and its origin at the conceptual level.

The Effect of Lexical Cohort Size Is Independent of Semantic Context Effects in a Picture-Word Interference Task: A Combined ERP and sLORETA Study

Lexical cohort size is known to play an important role in the magnitude of semantic interference during picture naming in continuous and blocking naming tasks. Nevertheless, whether and how lexical cohort size influences semantic context effects in a picture-word interference (PWI) task remains unclear. To address this issue, participants were required to name pictures, which were paired with both semantically related and unrelated distractors, from both large and small lexical cohorts while electroencephalogram (EEG) signals were recorded. Behavior results showed a semantic interference effect but no interaction between semantic relatedness and lexical cohort size in naming latencies. ERPs and correlation analyses revealed that semantic interference effects occurred at the lexical level in the time windows of 200-400 and 400-600 ms, and lexical cohort size effects occurred at the conceptual level in the time window of 100-200 ms and at the lexical level in the time windows of 200-400 ms. Critically, no interaction between two variables was found, reflecting that lexical cohort size is independent of semantic interference for categorical relations in the PWI. sLORETA results found stronger brain activations for large lexical cohorts at the left superior temporal gyrus and inferior frontal gyrus in the time interval of 250-300 ms, which may relate to lexical selection and self-monitoring. Our findings provide evidence for the swinging lexical network rather than the response exclusion hypothesis in spoken production.

Reduced competition between tool action neighbors in left hemisphere stroke

When pantomiming the use of tools, patients with limb apraxia after left hemisphere stroke (LCVA) produce more spatiotemporal hand action errors with tools associated with conflicting actions for use versus grasp-to-pick-up (e.g., corkscrew) than tools having a single action for both use and grasp (e.g., hammer). There are two possible accounts for this pattern of results. Reduced performance with 'conflict' tools may simply reflect weakened automaticity of use action activation, which is evident only when the use and grasp actions are not redundant. Alternatively, poor use performance may reflect a reduced ability of appropriate tool use actions to compete with task-inappropriate action representations. To address this issue, we developed a Stroop-like experiment in which 21 LCVA and 8 neurotypical participants performed pantomime actions in blocks containing two tools that were similar ("neighbors") in terms of hand action or function, or were unrelated on either dimension. In a congruent condition, they pantomimed the use action associated with the visually presented tool, whereas in an incongruent condition, they pantomimed the use action for the other tool in the block. Relative to controls and other task conditions, LCVA participants showed reductions in hand action errors in incongruent relative to congruent action trials; furthermore, the degree of reduction in this incongruence effect was related to the participants' susceptibility to grasp-on-use conflict in a separate test of pantomime to the sight of tools. Support vector regression lesion-symptom mapping analyses identified the left inferior frontal gyrus, supramarginal gyrus, and superior longitudinal fasciculus as core neuroanatomical sites associated with abnormal performance. Collectively, the results indicate that weakened activation of tool use actions in limb apraxia gives rise to reduced ability of these actions to compete for task-appropriate selection when competition arises within single tools (grasp-on-use conflict) as well as between two tools (reduced neighborhood effects).

The time course of colour congruency effects in picture naming

In our interactions with people and objects in the world around us, as well as in communicating our thoughts, we rely on the use of conceptual knowledge stored in long-term memory. From a frame-theoretic point of view, a concept is represented by a central node and recursive attribute-value structures further specifying the concept. The present study explores whether and how the activation of an attribute within a frame might influence access to the concept's name in language production, focussing on the colour attribute. Colour has been shown to contribute to object recognition, naming, and memory retrieval, and there is evidence that colour plays a different role in naming objects that have a typical colour (high colour-diagnostic objects such as tomatoes) than in naming objects without a typical colour (low colour-diagnostic objects such as bicycles). We report two behavioural experiments designed to reveal potential effects of the activation of an object's typical colour on naming the object in a picture-word interference paradigm. This paradigm was used to investigate whether naming is facilitated when typical colours are presented alongside the to-be-named picture (e.g., the word "red" superimposed on the picture of a tomato), compared to atypical colours (such as "brown"), unrelated adjectives (such as "fast"), or random letter strings. To further explore the time course of these potential effects, the words were presented at different time points relative to the to-be-named picture (Exp. 1: -400 ms, Exp. 2: -200 ms, 0 ms, and + 200 ms). By including both high and low colour-diagnostic objects, it was possible to explore whether the activation of a colour differentially affects naming of objects that have a strong association with a typical colour. The results showed that (pre-)activation of the appropriate colour attribute facilitated naming compared to an inappropriate colour. This was only the case for objects closely connected with a typical colour. Consequences of these findings for frame-theoretic accounts of conceptual representation are discussed.

Semantic similarity: normative ratings for 185 Spanish noun triplets

The present study introduces the first Spanish database with normative ratings of semantic similarity for 185 word triplets. Each word triplet is constituted by a target word (e.g., guisante [pea]) and two semantically related and nonassociatively related words: a word highly related in meaning to the target (e.g., judía [bean]), and a word less related in meaning to the target (e.g., patata [potato]). The degree of meaning similarity was assessed by 332 participants by using a semantic similarity rating task on a 9-point scale. Pairs having a value of semantic similarity ranging from 5 to 9 were classified as being more semantically related, whereas those with values ranging from 2 to 4.99 were considered as being less semantically related. The relative distance between the two pairs for the same target ranged from 0.48 to 5.07 points. Mean comparisons revealed that participants rated the more similar words as being significantly more similar in meaning to the target word than were the less similar words. In addition to the semantic similarity norms, values of concreteness and familiarity of each word in a triplet are provided. The present database can be a very useful tool for scientists interested in designing experiments to examine the role of semantics in language processing. Since the variable of semantic similarity includes a wide range of values, it can be used as either a continuous or a dichotomous variable. The full database is available in the supplementary materials.

The roles of shared vs. distinctive conceptual features in lexical access

Contemporary models of spoken word production assume conceptual feature sharing determines the speed with which objects are named in categorically-related contexts. However, statistical models of concept representation have also identified a role for feature distinctiveness, i.e., features that identify a single concept and serve to distinguish it quickly from other similar concepts. In three experiments we investigated whether distinctive features might explain reports of counter-intuitive semantic facilitation effects in the picture word interference (PWI) paradigm. In Experiment 1, categorically-related distractors matched in terms of semantic similarity ratings (e.g., zebra and pony) and manipulated with respect to feature distinctiveness (e.g., a zebra has stripes unlike other equine species) elicited interference effects of comparable magnitude. Experiments 2 and 3 investigated the role of feature distinctiveness with respect to reports of facilitated naming with part-whole distractor-target relations (e.g., a hump is a distinguishing part of a CAMEL, whereas knee is not, vs. an unrelated part such as plug). Related part distractors did not influence target picture naming latencies significantly when the part denoted by the related distractor was not visible in the target picture (whether distinctive or not; Experiment 2). When the part denoted by the related distractor was visible in the target picture, non-distinctive part distractors slowed target naming significantly at SOA of -150 ms (Experiment 3). Thus, our results show that semantic interference does occur for part-whole distractor-target relations in PWI, but only when distractors denote features shared with the target and other category exemplars. We discuss the implications of these results for some recently developed, novel accounts of lexical access in spoken word production.