Additivity of factor effects in reading tasks is still a challenge for computational models: Reply to Ziegler, Perry, and Zorzi (2009).

J. C. Ziegler, C. Perry, and M. Zorzi (2009) have claimed that their connectionist dual process model (CDP+) can simulate the data reported by S. O'Malley and D. Besner. Most centrally, they have claimed that the model simulates additive effects of stimulus quality and word frequency on the time to read aloud when words and nonwords are randomly intermixed. This work represents an important attempt given that computational models of reading processes have to date largely ignored the issue of whether it is possible to simulate additive effects. Despite CDP+'s success at capturing many other phenomena, it is clear that CDP+ fails to capture the full pattern seen with skilled readers in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neighbourhood Density, Word Frequency, and Spelling-Sound Regularity Effects in Naming: Similarities and Differences Between Skilled Readers and the Dual Route Cascaded Computational Model.

An experiment with skilled readers and a series of simulations with the Dual Route Cascaded model (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001) investigated the joint effects of stimulus quality and Neighbourhood Density (N) in nonword naming. Neighbourhood Density and stimulus quality yielded additive effects on reaction time (RT) for skilled readers whereas the model produced an interaction between these factors. A further set of simulations show that DRC also produces an interaction between stimulus quality and (1) word frequency, (2) spelling-sound regularity, and, (3) nonword letter length. None of these three factors interact with stimulus quality in performance by skilled readers. It is suggested that DRC's assumption of cascaded processing throughout represents a central problem. A proposal as to how the model can be modified to accommodate these and other problematic data is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading aloud: Qualitative differences in the relation between stimulus quality and word frequency as a function of context.

Virtually all theories of visual word recognition assume (typically implicitly) that when a pathway is used, processing within that pathway always unfolds in the same way. This view is challenged by the observation that simple variations in list composition are associated with qualitative changes in performance. The present experiments demonstrate that when reading aloud, the joint effects of stimulus quality and word frequency on response time are driven by the presence/absence of nonwords in the list. Interacting effects of these factors are seen when only words appear in the experiment, whereas additive effects are seen when words and nonwords are randomly intermixed. One way to explain these and other data appeals to the distinction between cascaded processing (or interactive activation) on the one hand versus a thresholded mode of processing on the other, with contextual factors determining which mode of processing dominates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the additive effects of stimulus quality and word frequency in lexical decision: Evidence for opposing interactive influences revealed by RT distributional analyses.

The joint effects of stimulus quality and word frequency in lexical decision were examined in 4 experiments as a function of nonword type (legal nonwords, e.g., BRONE, vs. pseudohomophones, e.g., BRANE). When familiarity was a viable dimension for word-nonword discrimination, as when legal nonwords were used, additive effects of stimulus quality and word frequency were observed in both means and distributional characteristics of the response-time distributions. In contrast, when the utility of familiarity was undermined by using pseudohomophones, additivity was observed in the means but not in distributional characteristics. Specifically, opposing interactive effects in the underlying distribution were observed, producing apparent additivity in means. These findings are consistent with the suggestion that, when familiarity is deemphasized in lexical decision, cascaded processing between letter and word levels is in play, whereas, when familiarity is a viable dimension for word-nonword discrimination, processing is discrete. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

“Additive and interactive effects of stimulus degradation: No challenge for CDP+”: Correction to Ziegler et al. (2009).

Reports an error in "Additive and interactive effects of stimulus degradation: No challenge for CDP+" by Johannes C. Ziegler, Conrad Perry and Marco Zorzi (Journal of Experimental Psychology: Learning, Memory, and Cognition, 2009[Jan], Vol 35[1], 306-311). The URL for the supplemental material was incomplete. The complete URL is http:dx.doi.org/10.1037/a0013738.supp. (The following abstract of the original article appeared in record 2008-18581-023.) S. O'Malley and D. Besner (2008) showed that additive effects of stimulus degradation and word frequency in reading aloud occur in the presence of nonwords but not in pure word lists. They argued that this dissociation presents a major challenge to interactive computational models of reading aloud and claimed that no currently implemented model is able to simulate additive effects in these conditions. In the current article, it is shown that the connectionist dual process model (CDP+) can simulate these effects because its nonlexical route is thresholded. The authors present a series of simulations showing that CDP+ can not only simulate the precise dissociation observed by O'Malley and Besner but more generally can produce additive effects for a wide range of parameter combinations and different sets of items. The nonlexical route of CDP+ was not modified post hoc to deal with the effects of stimulus quality, but it had been thresholded for principled reasons before it was known that these effects existed. Together, the effects of stimulus quality on word frequency do not challenge CDP+ but rather provide unexpected support for its architecture and processing dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additive and interactive effects of stimulus degradation: No challenge for CDP+.

[Correction Notice: An erratum for this article was reported in Vol 35(2) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2009-02753-020). The URL for the supplemental material was incomplete. The complete URL is http:dx.doi.org/10.1037/a0013738.supp.] S. O'Malley and D. Besner (2008) showed that additive effects of stimulus degradation and word frequency in reading aloud occur in the presence of nonwords but not in pure word lists. They argued that this dissociation presents a major challenge to interactive computational models of reading aloud and claimed that no currently implemented model is able to simulate additive effects in these conditions. In the current article, it is shown that the connectionist dual process model (CDP+) can simulate these effects because its nonlexical route is thresholded. The authors present a series of simulations showing that CDP+ can not only simulate the precise dissociation observed by O'Malley and Besner but more generally can produce additive effects for a wide range of parameter combinations and different sets of items. The nonlexical route of CDP+ was not modified post hoc to deal with the effects of stimulus quality, but it had been thresholded for principled reasons before it was known that these effects existed. Together, the effects of stimulus quality on word frequency do not challenge CDP+ but rather provide unexpected support for its architecture and processing dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning to read and spell in Persian: A cross-sectional study from Grades 1 to 4.

We investigated the reading and spelling development of 140 Persian children attending Grades 1–4 in Iran. Persian has very consistent letter–sound correspondences, but it varies in transparency because 3 of its 6 vowel phonemes are not marked with letters. Persian also varies in spelling consistency because 6 phonemes have more than one orthographic representation. We tested whether lexicality effects—an advantage of words over nonwords—would be affected be reading transparency and spelling consistency. We found that children became more efficient readers and spellers across grades, with the greatest growth occurring between Grades 1 and 2. For reading, lexicality effects were present with transparent words starting in Grade 2, but lexicality effects with opaque words were not yet present in Grade 4. As expected, the size of transparency effects for reading decreased across grades. For spelling, however, there was no lexicality effect for either consistent or inconsistent words. Moreover, consistency effects were large and did not decrease systematically across grades. Most interesting from a developmental perspective was the finding that both reading transparency and spelling polygraphy affected reading as well as spelling in Grades 1 and 2, but the word characteristics had differential effects as a function of literacy task in Grades 3 and 4. This pattern highlights the vulnerability of children's representations and processes during the early phases of acquisition as well as the rapidity with which representations and processes become specialized as a function of the literacy task at hand. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Establishing a time-line of word recognition: evidence from eye movements and event-related potentials

The average duration of eye fixations in reading places constraints on the time for lexical processing. Data from event related potential (ERP) studies of word recognition can illuminate stages of processing within a single fixation on a word. In the present study, high and low frequency regular and exception words were used as targets in an eye movement reading experiment and a high-density electrode ERP lexical decision experiment. Effects of lexicality (words vs pseudowords vs consonant strings), word frequency (high vs low frequency) and word regularity (regular vs exception spelling-sound correspondence) were examined. Results suggest a very early time-course for these aspects of lexical processing within the context of a single eye fixation.     

Reading aloud: Spelling-sound translation uses central attention.

Contrary to the received view that reading aloud reflects processes that are "automatic," recent evidence suggests that some of these processes require a form of attention. This issue was investigated further by examining the effect of a prior presentation of exception words (words whose spelling-sound translation are atypical, such as pint as compared with mint, hint, or lint) and pseudohomophones (nonwords that sound identical to words, such as brane from brain) on reading aloud in the context of the psychological refractory period paradigm. For exception words, the joint effects of repetition and stimulus onset asynchrony (SOA) yielded an underadditive interaction on the time to read aloud, replicating previous work--a short SOA between Task 1 and Task 2 increased reaction time (RT) and reduced the magnitude of the repetition effect relative to the long SOA. For pseudohomophones, in contrast, the joint effects of repetition and SOA were additive on RT. These results provide converging evidence for the conclusion that (a) processing up to and including the orthographic input lexicon does not require central attention when reading aloud, whereas (b) translating lexical and sublexical spelling to sound requires the use of central attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Two routes or one in reading aloud? A connectionist dual-process model.

A connectionist study of word reading is described that emphasizes the computational demands of the spelling–sound mapping in determining the properties of the reading system. It is shown that the phonological assembly process can be implemented by a two-layer network, which easily extracts the regularities in the spelling–sound mapping for English from training data containing many exception words. It is argued that productive knowledge about spelling–sound relationships is more easily acquired and used if it is separated from case-specific knowledge of the pronunciation of known words. It is then shown how the interaction of assembled and retrieved phonologies can account for the combined effects of frequency and regularity–consistency and for the reading performance of dyslexic patients. It is concluded that the organization of the reading system reflects the demands of the task and that the pronunciations of nonwords and exception words are computed by different processes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Orthography, familiarity, and meaningfulness reconsidered: Attentional strategies may affect the lexical sensitivity of visual code formation.

Three same–different matching experiments used strings of letters as stimuli to explore the influence of orthography, familiarity, and lexical meaningfulness on visual code formation for words. In Experiment 1, larger effects of lexical meaningfulness occurred under conditions of visual stimulus degradation than when stimuli were bright and easy to resolve. Experiments 2 and 3 included diagnostics of two strategies (selective or divided attention) and showed that either could occur, but that only one produced the interaction. In the selective or visual, pattern of results which was observed in Experiment 2, lexicality interacted with the visual quality of the stimulus display, and there was no influence of phonological confusability between the strings being matched. In the divided attention, or multicode, pattern, observed in Experiment 3, lexicality and visual quality produced additive effects, while phonological confusability interfered with different decisions. This suggests that decisions were based on multiple, potentially redundant codes—visual and phonological—and that in such a situation the facilitatory influence of lexicality on visual code formation does not occur. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Written spelling to dictation: Sound-to-spelling regularity affects both writing latencies and durations.

The authors examined the effect of sound-to-spelling regularity on written spelling latencies and writing durations in a dictation task in which participants had to write each target word 3 times in succession. The authors found that irregular words (i.e., those containing low-probability phoneme-to-grapheme mappings) were slower both to initially produce and to execute in writing than were regular words. The regularity effect was found both when participants could and could not see their writing (Experiments 1 and 2) and was larger for low- than for high-frequency words (Experiment 3). These results suggest that central processing of the conflict generated by lexically specific and assembled spelling information for irregular words is not entirely resolved when the more peripheral processes controlling handwriting begin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Similar attentional, frequency, and associative effects for pseudohomophones and words

Between the presentation and recall of 1 or 5 digits, Ss performed a secondary task of naming a visually presented letter string--a pseudohomophone (e.g., FOLE, HOAP) or its real-word counterpart (FOAL, HOPE). Memory load interacted with frequency (HOPE vs. FOAL, HOAP vs. FOLE) but not with lexicality (HOPE vs. HOAP, FOAL vs. FOLE). This outcome counters models in which nonwords are named by a slow (resource-expensive) process that assembles phonology and words are named by a fast (resource-inexpensive) process that accesses lexical phonology. When the associative priming-of-naming task was secondary to the memory task, pseudohomophone associative priming (HOAP-DESPAIR, FOLE-HORSE) equaled associative priming (HOPE-DESPAIR, FOAL-HORSE) and was affected in the same way by memory load. Assembled phonology seems to underlie the naming of both words and nonwords.     

Loci of signal probability effects and of the attentional blink bottleneck.

To investigate the locus of signal probability effects and the influence of stimulus quality on this locus, the authors manipulated probability in Task 2 of a psychological refractory period (PRP) paradigm. The effect was additive with stimulus onset asynchrony (SOA) when the target was not masked but underadditive with decreasing SOA when the target was masked. Even with masking, however, a range of probabilities had effects additive with SOA. The results suggest loci of stimulus probability before the PRP bottleneck as well as at or after the bottleneck. A second issue addressed was the locus of interference in the attentional blink (AB). The AB was larger when the probability of the first of 2 targets was lower. The results lead to the conclusion that one cause of the AB effect is a locus at least as late as the PRP bottleneck. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategic effects in word naming: Examining the route-emphasis versus time-criterion accounts.

K. Rastle and M. Coltheart (1999) demonstrated that both nonwords and low-frequency regular words are named more slowly when mixed with first-phoneme irregular word fillers (e.g., CHEF) than when mixed with third-phoneme irregular word fillers (e.g., GLOW). Those authors suggested that their effects were due to a strategic de-emphasis of the nonlexical route when first-phoneme irregular fillers were used. An alternative explanation is that these results simply reflect a more lax position of a time criterion (S. J. Lupker, P. Brown, and L. Colombo, 1997) in the first-phoneme irregular filler condition. We contrasted these 2 accounts in 4 experiments. In all experiments, target naming latencies were longer when the fillers were harder to name, regardless of whether the fillers were nonwords or exception words. These results strongly favor a time-criterion account of K. Rastle and M. Coltheart's effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Think before you speak: Pauses, memory search, and trace redintegration processes in verbal memory span.

Immediate memory span and speed of memory search were assessed for words and nonwords of short and long spoken duration. Memory span was substantially greater for words than for nonwords and for short than for long items, though speed of memory search was unaffected by either length or lexicality. An analysis of the temporal pattern of responses in the memory span task indicated that inter-item pauses were longer between nonwords than words but that these pause durations were unaffected by item length. A model of verbal short-term memory span is described in which trace selection from a short-term store and the redintegration (restoration) of degraded phonological traces both occur in the pauses between saying successive items. Both trace selection and trace redintegration appear to play important roles in accounting for individual differences in memory span. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additive and interactive effects on response time distributions in visual word recognition.

Across 3 different word recognition tasks, distributional analyses were used to examine the joint effects of stimulus quality and word frequency on underlying response time distributions. Consistent with the extant literature, stimulus quality and word frequency produced additive effects in lexical decision, not only in the means but also in the shape of the response time distributions, supporting an early normalization process that is separate from processes influenced by word frequency. In contrast, speeded pronunciation and semantic classification produced interactive influences of word frequency and stimulus quality, which is a fundamental prediction from interactive activation models of lexical processing. These findings suggest that stimulus normalization is specific to lexical decision and is driven by the task's emphasis on familiarity-based information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nonword naming: Further exploration of the pseudohomophone effect in terms of orthographic neighborhood size, graphemic changes, spelling-sound consistency, and reader accuracy.

Five experiments examined nonword pronunciation. As reported by R. S. McCann and D. Besner (1987), accurate, regular pronunciation increased as the number of orthographic neighbors (N) increased. Adults read pseudohomophones (nonwords that sound like a word) more accurately than other nonwords only when the nonwords were low n, shared the consonants with the words on which they were based, and overall accuracy was lower. Children showed a pseudohomophone advantage even when N was high. Adults pronounced nonwords comprised of inconsistent endings (with existing regular and irregular pronunciations) in an irregular fashion when this resulted in a word; this applied to relatively high-N items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phonological priming in the lexical decision task: regularity effects are not necessary evidence for assembly

The contribution of assembled phonology in reading English was examined in the lexical decision task by comparing two markers: regularity effects and phonological priming. Strategic control was assessed by manipulating the phonological lexicality of the foils: Experiment 1 used legal nonwords, whereas Experiment 2 used pseudohomophones. Replicating existing findings, null regularity effects were obtained in the presence of legal nonwords. Modest regularity effects, in accuracy only, were observed with pseudohomophone foils. In contrast, phonological priming effects emerged in each of the experiments, regardless of the presence of regularity effects. Assembled phonology thus constrains reading under conditions that strongly discourage its use. However, regularity effects are not necessary evidence for its presence. The dissociation of regularity and phonological priming effects is discussed in terms of the two-cycles model.     

Dissociative effects of stimulus quality on semantic and morphological contexts in visual word recognition.

Semantic and morphological contexts were manipulated jointly with stimulus quality under conditions where there were few related prime-target pairs (i.e., low relatedness proportion) in a lexical decision experiment. Additive effects of semantic context and stimulus quality on RT were observed, replicating previous work. In contrast, morphological context interacted with stimulus quality. This dissociation is discussed in the context of Besner and colleagues' evolving multistage framework. The essence of the account is that 1) stimulus quality affects feature and letter levels, but not later levels, 2) feedback from semantics to the lexical level is inoperative under low relatedness proportion conditions (hence stimulus quality and semantic context yield additive effects), whereas 3) feedback from the lexical level to the letter level is intact, hence stimulus quality and morphological context produce an interaction by virtue of them affecting a common stage of processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)