Masked Priming From Orthographic Neighbors: An ERP Investigation

More documents

Recommendations

Info

MASKED PRIMING FROM ORTHOGRAPHIC NEIGHBORS171Figure 9. ERPs time locked to target onset in two conditions (solid line: nonword neighbor prime, dashed line:unrelated) in Experiment 2.the N400 time window, on the other hand, priming from wordneighbors differed significantly from the priming effects found withnonword neighbors. As in Experiment 1, word neighbor primes producedlittle or no priming in this epoch. Nonword neighbor primes, onthe other hand, showed the standard effect of priming on the N400with reduced negativities in the related prime condition.Finally, a direct comparison of the two related prime conditionsand the two unrelated conditions revealed that it is indeed the relatedFigure 10. Voltage maps centered on the two epochs used in the statisticalanalyses. The maps represent voltage differences at each electrode sitecalculated by subtracting the voltage values in the related prime conditionfrom the voltage values in the corresponding unrelated prime condition inExperiment 2.conditions that are driving the differences between word and nonwordneighbor primes seen in the behavioral results and ERPs in the N400epoch. This analysis also revealed an effect of prime lexicality in theearlier time window, suggesting that whether the prime is a word ornot (independently of its relation to the target) influences ERPs duringthe early phases of target word processing.General DiscussionThe present study combined the masked priming paradigm withelectrophysiological recordings to provide a more fine-grainedtemporal analysis of the effect of primes that are high-frequencyorthographic neighbors of target words. According to one prominentaccount of the inhibitory effects of orthographic neighborpriming found in behavioral studies, it is lateral inhibitory connectionsbetween whole-word orthographic representations that arethe source of the inhibitory priming effect (Davis & Lupker, 2006;Grainger & Jacobs, 1996; Jacobs & Grainger, 1992). Based on thisaccount and our prior work combining ERPs and masked priming,we predicted a very specific pattern of priming effects from suchword neighbor primes compared with the effects of repetitionpriming (Experiment 1) and nonword neighbor priming (Experiment2). According to Holcomb and Grainger (2006, 2007;Grainger & Holcomb, 2009), the N250 and N400 components,found to be modulated by masked priming, are thought to reflectthe transition from form-level processing (orthographic and phonological)to semantic-level processing during visual word recognition.The N250 component is thought to reflect the mapping ofprelexical form representations onto whole-word form representations,whereas the N400 would reflect the mapping of whole-wordform representations onto semantics. Furthermore, the N250 ishypothesized to reflect stabilization of activation in prelexical
172 MASSOL ET AL.Figure 11. Left: Voltage maps centered on the two epochs used in the statistical analyses. The maps representvoltage differences at each electrode site calculated by subtracting the voltage values in the word prime conditionfrom the voltage values in the corresponding nonword prime condition in Experiment 2, for related primes(upper) and unrelated primes (lower). Right: Blowup of site Cz showing effects of prime lexicality for relatedprimes (upper) and unrelated primes (lower).representations as well as the initial build-up of activation inwhole-word form representations, whereas the N400 would reflectstabilization in activation at the level of whole-word form representations.Therefore, it was argued that if the effects of wordneighbor primes reflect competitive interactions between wholewordform representations, then these effects should become evidentin the ERP signal somewhere in between the N250 and N400components, and remains effective throughout the N400.The effects of word neighbor primes were compared with effectsof repetition priming in Experiment 1 and effects of nonwordneighbor primes in Experiment 2. As argued above, we expected tosee similar patterns of priming effects for repetition primes andnonword neighbor primes in both the N250 and N400 ERP components,and both of these priming effects were expected to line-upwith the effects of word neighbor primes in the N250 componentbut differ in the N400 component. Therefore, we predicted maineffects of priming and no interaction with type of prime in theN250 component, and an interaction between priming and type ofprime in the N400. The results of the present study are in line withthese predictions. All types of prime showed similar primingeffects in the N250 component, whereas in the N400 componentthe word neighbor prime condition produced a distinct pattern ofeffects in both experiments. This pattern was particularly clear inExperiment 2 where the only difference between the two types ofprime was their lexicality.The results of the present study therefore provide support for thehypothesis that the inhibitory effects of word neighbor primesfound in behavioral responses reflect competitive interactions betweenwhole-word representations that influence the final phase ofhoming in on a unique interpretation of the target word. The resultsare also supportive of the interpretative framework proposed byHolcomb and Grainger (Grainger & Holcomb, 2009; Holcomb &Grainger, 2006, 2007), according to which the shift from formlevelprocessing to semantic-level processing during visual wordrecognition is reflected in the transition between the N250 and theN400 ERP components. As noted in the introduction, this analysismay only be applicable to results obtained with masked priming,and some clarification is still in order with respect to how such aframework could accommodate reports of lexical and semanticinfluences arising earlier in the course of visual word recognition(e.g., Hauk et al., 2006; Hauk & Pulvermüller, 2004).The priming effects found with word neighbor primes in thepresent study are in line with the findings of Holcomb, Grainger,and O’Rourke (2002) in a study manipulating the number oforthographic neighbors of word targets (in the absence of priming).Words with many orthographic neighbors were found to generatesignificantly more negative-going waveforms in the region of theN400 than words with small numbers of orthographic neighbors(see Debruille, 1998, for an earlier report of a similar finding). Thisincreased negativity for words with more orthographic neighborswas found in both a lexical decision and a semantic categorizationexperiment.In the present study, word neighbor primes did not generatesignificantly greater negativity than unrelated primes. Instead, inthe N400 time window, these primes did not significantly affecttarget word processing relative to unrelated word primes. Weinterpret this null effect as the combined influence of an underlyingfacilitatory component, as reflected in the reduced negativityfound with nonword neighbor primes, plus an inhibitory influenceof word neighbor primes via competitive interactions acrosswhole-word representations. This account predicts that a directcomparison of the related word and related nonword prime conditionstested in Experiment 2 should reveal significantly greaternegativity in the word prime condition in the N400 time window.This was found to be the case.Finally, the pattern of priming effects in the N400 component iscompatible with the knowledge inhibition account of variations inN400 amplitude proposed by Debruille (2007). Within this theoreticalcontext, orthographic neighbors of a given target wordrepresent activated but inappropriate knowledge that must be in-
Page 1 and 2: Journal of Experimental Psychology:
Page 3 and 4: 164 MASSOL ET AL.Figure 1. ERP mask
Page 5 and 6: 166 MASSOL ET AL.in each of three p
Page 7 and 8: 168 MASSOL ET AL.300-550 ms target
Page 9: 170 MASSOL ET AL.Figure 8. ERPs tim
Page 13: 174 MASSOL ET AL.Grainger, J., & Fe

Masked Priming From Orthographic Neighbors: An ERP Investigation

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?