Biomedical subjects

Derek Besner

Publications and source records attributed to Derek Besner.

27 records · Page 2Linked to original sources

PubMed2004

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 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.

Humans↗

PubMed2004

On the control of visual word recognition: changing routes versus changing deadlines.

Two different accounts have been proposed to explain the fact that (1) an effect of word frequency is present when readers of transparent orthographies read only words aloud and (2) the effect of word frequency is eliminated when subjects name words and nonwords mixed together in a single block. In the route-shifting account, subjects shift from using a lexical route that can read only words to using a nonlexical route that can read both words and nonwords via the use of sublexical spelling-sound correspondences (hence, no word frequency effect). The essence of the second, time criterion account is that the elimination of the word frequency effect is determined by the speed with which the nonwords are processed, because subjects attempt to homogenize the point in time at which they release an articulation. These two different accounts are pitted against each other in a series of naming experiments utilizing the transparent Turkish orthography. A word frequency effect persists even when words and nonwords are mixed together, provided that nonword sets are matched so as to be named as quickly as the high-frequency words and as slowly as the low-frequency words, respectively. This result is argued to be consistent with the time criterion account, but not with the unadorned route-shifting account.

Humans↗

PubMed2004

Single letter coloring and spatial cuing eliminates a semantic contribution to the Stroop effect.

Previous work has shown that the Stroop effect is reduced in size when a single letter is colored and spatially precued. The present experiment addresses a number of criticisms of this work by (1) providing a direct measure of semantic processing, (2) using a vocal response instead of a manual one, and (3) using a more appropriate baseline. A semantically based Stroop effect (slower color naming for color-associated words than for color-neutral words) is observed when all letters in the display are precued and appear in a homogeneous color. This Stroop effect is statistically eliminated when a single letter is precued and is the "odd man out" in terms of its color. Two explanations are considered. In one, single-letter coloring and cuing serve to curtail semantic processing. In the other, single-letter coloring and cuing help to keep the informational sources (i.e, color, word) separate and hence reduce interference, but semantic analysis is not curtailed. The latter account provides a more complete account of existing data.

Color Perception↗

PubMed2003

A paradigm for exploring what the mind does while deciding what it should do.

One widespread belief about automatic mental processes is that, among other characteristics, they are involuntary. No initial conscious intent is necessary because such processing is stimulus initiated. This claim was studied in the context of a novel task-choice procedure in which subjects were informed as to which of two tasks they should perform on a letter string either well in advance of a target, or when the target appeared. The hypothesis that initial processing of the target occurs without intent predicts that the effect of contrast reduction will be absent when the task cue appears synchronously with the target. This is because initial processing of the target should be completed during the time taken to decode the task cue. The results are inconsistent with this account. Instead, they support an account in which functional target processing is delayed until the subject knows what the task is. Some directions for future investigations are noted.

Attention↗

PubMed2003

Reading nonwords aloud: results requiring change in the dual route cascaded model.

The time to name a nonword increases monotonically as letter length increases. The leading computational model of basic processes in reading (Coltheart, Rastle, Perry, Langdon & Ziegler's dual route cascaded model) simulates this, because its nonlexical route assigns phonemes to letters serially, left to right, and arguably, this corresponds to what humans do. New simulation work shows that (1) this letter length effect interacts with the effect of slowing the rate of early processing, and (2) the model produces a qualitatively different pattern from that observed with university-level readers. The contrast between simulation and human performance thus illuminates a problem with how the nonlexical route operates in the model, and constrains accounts that can be provided for the human data. Consideration is given to thresholding the output of the letter-level module as a way to modify the model so as to make it possible to simulate the human data.

Humans↗

PubMed2003

When parallel processing in visual word recognition is not enough: new evidence from naming.

Low-frequency irregular words are named more slowly and are more error prone than low-frequency regular words (the regularity effect). Rastle and Coltheart (1999) reported that this irregularity cost is modulated by the serial position of the irregular grapheme-phoneme correspondence, such that words with early irregularities exhibit a larger cost than words with late ones. They argued that these data implicate rule-based serial processing, and they also reported a successful simulation with a model that has a rule-based serial component--the DRC model of reading aloud (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). However, Zorzi (2000) also simulated these data with a model that operates solely in parallel. Furthermore, Kwantes and Mewhort (1999) simulated these data with a serial processing model that has no rules for converting orthography to phonology. The human data reported by Rastle and Coltheart therefore neither require a serial processing account, nor successfully discriminate among a number of computational models of reading aloud. New data are presented wherein an interaction between the effects of regularity and serial position of irregularity is again reported for human readers. The DRC model simulated this interaction; no other implemented computational model does so. The present results are thus consistent with rule-based serial processing in reading aloud.

Humans↗

PubMed2002

Semantic priming: on the role of awareness in visual word recognition in the absence of an expectancy.

By hypothesis, awareness is involved in the modulation of feedback from semantics to the lexical level in the visual word recognition system. When subjects are aware of the fact that there are many related prime-target pairs in a semantic priming experiment, this knowledge is used to configure the system to feed activation back from semantics to the lexical level so as to facilitate processing. When subjects are unaware of this fact, the default set is maintained in which activation is not fed back from semantics to the lexical level so as to conserve limited resources. Qualitative differences in the pattern of data from two lexical decision experiments that employ masked priming are consistent with this hypothesis. Semantic context and stimulus quality interact when the prime is processed with awareness whereas these same two factors produce additive effects on RT when the prime is unlikely to have been processed with awareness. These experiments thus illustrate one way in which awareness (or lack thereof) affects the dynamics of visual word recognition.

Adult↗

PubMed2002

When are morphemic and semantic priming observed in visual word recognition?

J. Stolz and D. Besner (1998) reported a dissociation between morphemic and semantic priming in the context of lexical decision. Morphemic priming was observed following letter search on the prime display, but semantic priming was not. Participants in the present experiment identified the colour of a single letter in the prime display before making a lexical decision to the target. Both morphemic and semantic priming were observed. These results are discussed in relation to the observation that identifying the colour of a single letter of a word in the Stroop task is associated with a reduction in the size of the Stroop effect as compared to when all letters are coloured.

Analysis of Variance↗

PubMed2002

Neighbourhood density effects in reading aloud: new insights from simulations with the DRC model.

A series of nine simulations with the Dual Route Cascaded (DRC) model (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001) investigated neighbourhood density (N) effects in nonword and word naming. Two main finding emerged from this work. First, when naming nonwords there are two loci for the effect of N in the model, contrary to Coltheart et al.'s single locus explanation of what the model is doing. The early N effect involves interactive activation between the orthographic lexicon and the letter units such that high N facilitates letter identification, which in turn affects the nonlexical route. The late N effect arises from activation in the orthographic lexicon that feeds forward to the phonological lexicon and primes phonemes in the phoneme system. Second, when naming words the presence/absence of an effect of N on the Letter Units through feedback from the lexical level depends on the parameter settings. Implications and suggestions for future directions are made.

Computer Simulation↗