Eduardo Navarrete

ERP evidence for ultra-fast semantic processing in the picture-word interference paradigm

We used the event-related potential (ERP) approach combined with a subtraction technique to explore the timecourse of activation of semantic and phonological representations in the picture–word interference paradigm. Subjects were exposed to to-be-named pictures superimposed on to-be-ignored semantically related, phonologically related, or unrelated words, and distinct ERP waveforms were generated time-locked to these different classes of stimuli. Difference ERP waveforms were generated in the semantic condition and in the phonological condition by subtracting ERP activity associated with unrelated picture–word stimuli from ERP activity associated with related picture–word stimuli. We measured both latency and amplitude of these difference ERP waveforms in a pre-articulatory time-window. The behavioral results showed standard interference effects in the semantic condition, and facilitatory effects in the phonological condition. The ERP results indicated a bimodal distribution of semantic effects, characterized by the extremely rapid onset (at about 100u2009ms) of a primary component followed by a later, distinct, component. Phonological effects in ERPs were characterized by components with later onsets and distinct scalp topography of ERP sources relative to semantic ERP components. Regression analyses revealed a covariation between semantic and phonological behavioral effect sizes and ERP component amplitudes, and no covariation between the behavioral effects and ERP component latency. The early effect of semantic distractors is thought to reflect very fast access to semantic representations from picture stimuli modulating on-going orthographic processing of distractor words.

Factors determining semantic facilitation and interference in the cyclic naming paradigm.

The cyclic naming paradigm, in which participants are slower to name pictures blocked by semantic category than pictures in an unrelated context, offers a window into the dynamics of the mapping between lexical concepts and words. Here we provide evidence for the view that incremental adjustments to the connection weights from semantics to lexical items provides an elegant explanation of a range of observations within the cyclic naming paradigm. Our principal experimental manipulation is to vary the within-category semantic distance among items that must be named together in a block. In the first set of experiments we find that naming latencies are, if anything, faster for within-category semantically close blocks compared to within-category semantically far blocks, for the first presentation of items. This effect can be explained by the fact that there will be more spreading activation, and thus greater priming at the lexical level, for within-category semantically close blocks than within-category semantically far blocks. We test this explanation by inserting intervening filler items (geometric shapes), and show as predicted, that while intervening unrelated trials abolish short-lived semantic priming effects, the long-lag interference effect that is characteristic of this paradigm is unaffected. These data place new constraints on explanations of the cyclic naming effect, and related phenomena, within a model of language production.

Picture-word interference and the response-exclusion hypothesis: a response to Mulatti and Coltheart.

Mulatti and Coltheart (2011, this issue) review and summarize several findings from the picture-word interference paradigm that the authors argue challenge the Response Exclusion Hypothesis. However, the hypothesis they take to be the Response Exclusion Hypothesis is not that theory—it is an account developed by Mulatti and Coltheart that holds that target naming latencies in the picture-word paradigm are affected only by the process of excluding the distractor word (and by nothing else). We consider some of the background assumptions implicit in Mulatti and Coltheart’s discussion that may have led to this misattribution. Finally, we report a replication of an effect originally described by Dalrymple-Alford (1972) that serves as an empirical basis for reiterating the main points of our proposal and outlining the challenges that lie ahead.

Specifying the role of the left prefrontal cortex in word selection

Word selection allows us to choose words during language production. This is often viewed as a competitive process wherein a lexical representation is retrieved among semantically-related alternatives. The left prefrontal cortex (LPFC) is thought to help overcome competition for word selection through top-down control. However, whether the LPFC is always necessary for word selection remains unclear. We tested 6 LPFC-injured patients and controls in two picture naming paradigms varying in terms of item repetition. Both paradigms elicited the expected semantic interference effects (SIE), reflecting interference caused by semantically-related representations in word selection. However, LPFC patients as a group showed a larger SIE than controls only in the paradigm involving item repetition. We argue that item repetition increases interference caused by semantically-related alternatives, resulting in increased LPFC-dependent cognitive control demands. The remaining network of brain regions associated with word selection appears to be sufficient when items are not repeated.

Age-of-Acquisition Effects in Delayed Picture-Naming Tasks

We report two experiments that explored the linguistic locus of age-of-acquisition effects in picture naming by using a delayed naming task that involved only a low proportion of trials (25xa0%) while, for the large majority of the trials (75xa0%), participants performed another task—that is, the prevalent task. The prevalent tasks were semantic categorization in Experiment 1a and grammatical-gender decision in Experiments 1b and 2. In Experiment 1a, in which participants were biased to retrieve semantic information in order to perform the semantic categorization task, delayed naming times were affected by age of acquisition, reflecting a postsemantic locus of the effect. In Experiments 1b and 2, in which participants were biased to retrieve lexical information in order to perform the grammatical gender decision task, there was also an age-of-acquisition effect. These results suggest that part of the age-of-acquisition effect in picture naming occurs at the level at which the phonological properties of words are retrieved.

A rose by any other name is still a rose: A reinterpretation of Hantsch and Mädebach

The Response Exclusion Hypothesis localises the semantic interference effect as observed in the picture–word paradigm at a postlexical level of processing. An important aspect of this proposal is that the ease with which distractor words can be excluded from production at the response level is determined by the degree to which they satisfy criteria demanded of a correct response. This proposal predicts that naming a picture of a “rose” with the response “flower” will be slower with the distractor “rose” than a distractor word that would not be appropriate for the picture (e.g., “tulip”). Hantsch and Mädebach report evidence consistent with this expectation; however, the authors argue that the results are problematic for the Response Exclusion Hypothesis. Here we unpack Hantsch and Mädebachs arguments about why their finding is (putatively) problematic for the Response Exclusion Hypothesis. We conclude that the pattern of effects that the authors report are not only in line with what would be expected by the Response Exclusion Hypothesis, but are difficult to reconcile with Hantsch and Mädebachs preferred theoretical position.

The CRITICAL DIFFERENCE in models of speech production: A response to Roelofs and Piai

In our original article (Mahon, Garcea, & Navarrete, 2012), we replicated Dalrymple-Alford’s (1972) observation of semantic facilitation at zero SOA when participants name the ink color (e.g., ‘red’) of semantically related non-color words (e.g., ‘fire’) compared to semantically unrelated non-color word distractors (e.g., ‘lawn’; see also Glaser & Glaser, 1989). We replicated this classic finding to draw attention to the implications of this semantic facilitation effect, and semantic facilitation effects generally, for a model of word selection in speech production. The implication is straightforward: The theory of lexical selection by competition predicts that the distractor ‘fire’ should interferemorewith saying ‘red’ than thedistractor ‘lawn’. This (and other) observation(s) of semantic facilitation are incompatible with the theory of lexical selection by competition. WEAVERþþ (Roelofs, 1992, 2003) is the most developed model that implements lexical selection by competition, and as itmakes both qualitative and quantitative predictions, its ability to simulate response time effects has been taken as a litmus test of the viability of the hypothesis of lexical selection by competition. As Roelofs and Piai (2013) write of the original (i.e., Roelofs, 2003) WEAVERþþ simulations, “.facilitation of 41 msec or more was obtained at preexposure SOAs and no effect at zero SOA” (p. 1768). In other words, the previously published simulations of WEAVERþþ did not resemble, in relevant ways, the empirical data. On that

Distributional analyses in the picture-word interference paradigm: Exploring the semantic interference and the distractor frequency effects.

The present study explores the distributional features of two important effects within the picture–word interference paradigm: the semantic interference and the distractor frequency effects. These two effects display different and specific distributional profiles. Semantic interference appears greatly reduced in faster response times, while it reaches its full magnitude only in slower responses. This can be interpreted as a sign of fluctuant attentional efficiency in resolving response conflict. In contrast, the distractor frequency effect is mediated mainly by a distributional shift, with low-frequency distractors uniformly shifting reaction time distribution towards a slower range of latencies. This finding fits with the idea that distractor frequency exerts its effect by modulating the point in time in which operations required to discard the distractor can start. Taken together, these results are congruent with current theoretical accounts of both the semantic interference and distractor frequency effects. Critically, distributional analyses highlight and further describe the different cognitive dynamics underlying these two effects, suggesting that this analytical tool is able to offer important insights about lexical access during speech production.

With or Without Semantic Mediation: Retrieval of Lexical Representations in Sign Production

How are lexical representations retrieved during sign production? Similar to spoken languages, lexical representation in sign language must be accessed through semantics when naming pictures. However, it remains an open issue whether lexical representations in sign language can be accessed via routes that bypass semantics when retrieval is elicited by written words. Here we address this issue by exploring under which circumstances sign retrieval is sensitive to semantic context. To this end we replicate in sign language production the cumulative semantic cost: The observation that naming latencies increase monotonically with each additional within-category item that is named in a sequence of pictures. In the experiment reported here, deaf participants signed sequences of pictures or signed sequences of Italian written words using Italian Sign Language. The results showed a cumulative semantic cost in picture naming but, strikingly, not in word naming. This suggests that only picture naming required access to semantics, whereas deaf signers accessed the sign language lexicon directly (i.e., bypassing semantics) when naming written words. The implications of these findings for the architecture of the sign production system are discussed in the context of current models of lexical access in spoken language production.

What can Written-Words Tell us About Lexical Retrieval in Speech Production?

In recent decades, researchers have exploited semantic context effects in picture naming tasks in order to investigate the mechanisms involved in the retrieval of words from the mental lexicon. In the blocked naming paradigm, participants name target pictures that are either blocked or not blocked by semantic category. In the continuous naming task, participants name a sequence of target pictures that are drawn from multiple semantic categories. Semantic context effects in both tasks are a highly reliable phenomenon. The empirical evidence is, however, sparse and inconsistent when the target stimuli are printed-words instead of pictures. In the first part of the present study we review the empirical evidence regarding semantic context effects with written-word stimuli in the blocked and continuous naming tasks. In the second part, we empirically test whether semantic context effects are transferred from picture naming trials to word reading trials, and from word reading trials to picture naming trials. The results indicate a transfer of semantic context effects from picture naming to subsequently read within-category words. There is no transfer of semantic effects from target words that were read to subsequently named within-category pictures. These results replicate previous findings (Navarrete et al., 2010) and are contrary to predictions from a recent theoretical analysis by Belke (2013). The empirical evidence reported in the literature together with the present results, are discussed in relation to current accounts of semantic context effects in speech production.