Brain and Language 95 (2005) 46–47 www.elsevier.com/locate/b&l

Facilitation and interference in phonological blocked-cyclic naming Catherine Hodgson

a,*

, Myrna F. Schwartz b, Tatiana T. Schnur b

b,c

, Adelyn Brecher

b

a University of Manchester, UK Moss Rehabilitation Research Institute, USA c University of Pennsylvania, USA

Accepted 8 July 2005 Available online 29 August 2005

Introduction

Procedure

The semantic blocking effect refers to the detrimental effect on naming latencies (nonaphasic speakers; e.g., Damian, Vigliococco, & Levelt, 2001) and accuracy (aphasic speakers) when targets are blocked by semantic category, compared with mixed-category presentation. The effect is most reliable when blocked sets are repeated multiple times in succession (i.e., for multiple ‘‘cycles’’). Schnur, Brecher, Rossi, and Schwartz (2004) recently showed that anterior aphasics are particularly vulnerable to the semantic blocking effect, as indexed by error rate in blocked-cyclic naming. They argued that the increased difficulty exhibited by their Broca’s group, compared to a matched group of fluent aphasic speakers, NonBroca’s, is consistent with the theory that the left inferior frontal lobe subserves selection during high competition (Thompson-Schill, et al., 1998). Less well understood is the effect of phonological blocking. For nonaphasic speakers, naming sets of phonologically related words generally facilitates latencies (e.g., Damian, 2003), but sometimes it has the opposite effect (O’Seaghdha & Marin, 2000). Phonemic cueing paradigms used with aphasic patients have also produced mixed results, with some patients responding favourably, whereas others do not (Croot, Patterson, & Hodges, 1999). The present study investigated phonological blocking in aphasic and nonaphasic speakers, using the blocked-cyclic naming paradigm.

Stimuli were 72 pictured objects with monosyllabic names beginning with one of 12 different phonemes. In the experiment, items were named successively in sets of 6, with each set presented randomly 4 times, before a new set began. In the ‘‘blocked’’ condition, setmates began with the same phoneme; in the ‘‘mixed’’ condition, all setmates had different onsets. All items were named in blocked and mixed contexts; and the entire experiment was run at two response-stimulus intervals (RSIs)—1 and 5 s.

Methods Participants Eighteen individuals with chronic aphasia secondary to left hemisphere stroke participated. Eight had Broca’s aphasia; the 11 NonBroca’s had variants of fluent aphasia. The two groups were matched on WAB AQ scores (t (17) = )1.545; p = .141). Twelve age and education matched nonaphasic controls were also studied.

*

Corresponding author. E-mail address: [email protected] (C. Hodgson).

0093-934X/$ - see front matter Ó 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.bandl.2005.07.017

Results A mixed model analysis of the control participants’ RTs yielded the following significant effects (a < .05): (1) Condition (F (1, 11) = 9.38)— faster latencies in the Blocked (773 ms) compared to Mixed (794 ms) condition; (2) Cycle (F (1, 33) = 99.32)—latencies decreasing across repetitions 1–4 (886, 765, 749, and 733 ms); (3) RSI (F (1, 11) = 153.89)—faster RTs at the 1 s RSI. Analysis of the control participants’ errors resulted in a significant effect of Cycle (F (1, 33) = 18.54)—errors decreasing across repetitions 1–4 (8.5, 5.9, 4.8, and 4.8%). A repeated measures ANOVA using the errors produced by the aphasic participants yielded the following significant effects (a < .05): (1) Condition (F (1, 17) = 12.398)—more errors produced in the Blocked (26.2%) than the Mixed (22.9%) condition; and (2) RSI (F (1, 17) = 15.226)—more errors at the 1 s (27.3%) compared to the 5 s RSI (21.8%). No other effects were significant. Table 1 shows, surprisingly, that the blocking effect (blocked–mixed errors) correlated negatively with phonological-word errors (formals) in naming.

Discussion The control participants were faster and produced fewer errors in the Blocked condition, indicating that phonological blocking was facilitatory. This follows previous research and highlights the difference between phonological blocking, which is facilitatory in nonaphasic speakers, and semantic blocking, which produces interference. The aphasic participants differed from the controls in that phonological blocking was inhibitory not facilitatory. It has been

Abstract / Brain and Language 95 (2005) 46–47

47

Table 1 Correlations between the size of the blocking effect in the aphasic speakers and background measures (parentheses = p values) Philadelphia Naming Test Errors

Blocking effect size

Total

Form

Non

Sem

).613 (.005)

).672 (.002)

).167 (.493)

.372 (.117)

PPT

SynTrip

WABAQ

QPAWpM

).031 (.900)

.611 (.005)

.210 (.389)

).506 (.027)

Form, Non, Sem, proportion of Formal, Nonword, and Semantic errors, respectively, relative to total errors. PPT, pyramids and palm trees (pictures); SynTrips, number correct on Synonymy Triplets—Philadelphia Comprehension Battery; WABAQ, Western Aphasia Battery Aphasia Quotient; QPAWpM, Qualitative Production Analysis, Words/Minute.

proposed that nonaphasic speakers derive a strategic benefit from phonological blocking (Damian, 2003); aphasics, it seems, do not. Instead, their naming is impaired by phonological blocking, more so in patients with fewer formal errors in naming, indicative of stronger lexical–phonological connections (Dell, Schwartz, Martin, Saffran, & Gagnon, 1997). In these patients, the phonological trace of past namings may persist just long enough to interfere with the current production, and not enough to generate the awareness that could lead to self-cuing. In aphasics with weaker lexical–phonological connections, the phonological trace decays too quickly to have much impact on the current production. From this, one can argue that the phonological blocking effect seen in aphasic speakers is different from the interference they experience during semantic blocking tasks. In the latter case, Broca’s patients are more vulnerable due to their frontal lesions (Schnur et al., 2004). Vulnerability to phonological blocking on the other hand is due to the relative strength of the lexical–phonological system and not to frontal lesions per se.

Acknowledgments This research was supported by NIH Grant #2RO1DC00191-23. We thank Nick Rossi for his help in collecting the data.

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