David A. Balota

The English Lexicon Project.

The English Lexicon Project is a multiuniversity effort to provide a standardized behavioral and descriptive data set for 40,481 words and 40,481 nonwords. It is available via the Internet at elexicon.wustl.edu. Data from 816 participants across six universities were collected in a lexical decision task (approximately 3400 responses per participant), and data from 444 participants were collected in a speeded naming task (approximately 2500 responses per participant). The present paper describes the motivation for this project, the methods used to collect the data, and the search engine that affords access to the behavioral measures and descriptive lexical statistics for these stimuli.

Are lexical decisions a good measure of lexical access? The role of word frequency in the neglected decision stage.

Three experiments investigated the impact of five lexical variables (instance dominance, category dominance, word frequency, word length in letters, and word length in syllables) on performance in three different tasks involving word recognition: category verification, lexical decision, and pronunciation. Although the same set of words was used in each task, the relationship of the lexical variables to reaction time varied significantly with the task within which the words were embedded. In particular, the effect of word frequency was minimal in the category verification task, whereas it was significantly larger in the pronunciation task and significantly larger yet in the lexical decision task. It is argued that decision processes having little to do with lexical access accentuate the word-frequency effect in the lexical decision task and that results from this task have questionable value in testing the assumption that word frequency orders the lexicon, thereby affecting time to access the mental lexicon. A simple two-stage model is outlined to account for the role of word frequency and other variables in lexical decision. The model is applied to the results of the reported experiments and some of the most important findings in other studies of lexical decision and pronunciation.

Visual Word Recognition of Single-Syllable Words

Speeded visual word naming and lexical decision performance are reported for 2428 words for young adults and healthy older adults. Hierarchical regression techniques were used to investigate the unique predictive variance of phonological features in the onsets, lexical variables (e.g., measures of consistency, frequency, familiarity, neighborhood size, and length), and semantic variables (e.g. imageahility and semantic connectivity). The influence of most variables was highly task dependent, with the results shedding light on recent empirical controversies in the available word recognition literature. Semantic-level variables accounted for unique variance in both speeded naming and lexical decision performance, level with the latter task producing the largest semantic-level effects. Discussion focuses on the utility of large-scale regression studies in providing a complementary approach to the standard factorial designs to investigate visual word recognition.

Stroop performance in healthy younger and older adults and in individuals with dementia of the Alzheimer's type.

Components of the Stroop task were examined to investigate the role that inhibitory processes play in cognitive changes in healthy older adults and in individuals with dementia of the Alzheimers type (DAT). Inhibitory breakdowns should result in an increase in Stroop interference. The results indicate that older adults show a disproportionate increase in interference compared with younger adults. DAT individuals show interference proportionate to older adults but a disproportionate increase in facilitation for congruent color-word trials, and an increased intrusion of word naming on incongruent color naming trials. An ex-Gaussian analysis of response time distributions indicated that the increased interference observed in older adults was due to an increase in the tail of the distribution. Application of the process dissociation analysis of the Stroop task (D.S. Lindsay & L.L. Jacoby, 1994) indicated that older adults showed increased word process estimates, whereas DAT individuals showed differences in both color and word process estimates. Taken together, the results are consistent with an inhibitory breakdown in normal aging and an accelerated breakdown in inhibition in DAT individuals.

Individual differences in information-processing rate and amount: Implications for group differences in response latency.

Research on group differences in response latency often has as its goal the detection of Group x Treatment interactions. However, accumulating evidence suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditive interactions in which the slower group produces a larger treatment effect. The authors propose a rate-amount model that predicts linear relationships between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global processing parameters may be used to linearly transform response latencies from different individuals to a common information-processing scale so that small-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may be used to augment traditional analyses of raw response latencies.

The Interaction of Contextual Constraints and Parafoveal Visual Information in Reading

An experiment is reported which demonstrates that contextual constraints and parafoveal visual information interact during reading. As subjects read sentences, the parafoveal visual information available from a target area in the sentence was varied: the parafoveal information was either visually similar or dissimilar to a target word the subject would later fixate. The visual similarity of the parafoveal preview was factorially combined with the predictability of the target word based on the preceding sentence context. That is, as the subjects made a saccade to the target area, the parafoveal preview was replaced by either a target word that was highly predictable or one that was relatively less predictable from the sentence context. Eye movements and fixation durations were affected both by the visual similarity of the parafoveal information and the target predictability. Moreover, although the visual similarity of the parafoveal preview produced an effect even when the target was not predictable from the context, the effect of parafoveal information was greater when it was predictable. There was also evidence indicating that when the parafoveal information was highly predictable, subjects appeared to use more detailed parafoveal visual information. The results are interpreted within an interactive framework in which lexical representations accumulate activation via both contextual constraint and parafoveal information.

The locus of word-frequency effects in the pronunciation task: Lexical access and/or production? ☆

Abstract Three experiments were conducted to separate the influence of word frequency on lexical access from its influence on production stages in the pronunciation task. A delayed pronunciation task was used in which a word was presented and, after some delay, a cue was presented to pronounce the word aloud. Presumably, subjects should access the words lexical representation during the delay interval and any effect of frequency can be attributed to its influence on production rather than on lexical access. In the first two experiments frequency still had a significant effect with a delay interval of 900 milliseconds. At a delay interval of 400 milliseconds, where the subjects should have accessed the words lexical representation before the pronunciation cue, the word-frequency effect was 41 milliseconds, only 17 milliseconds less than the 58-millisecond effect obtained with the same words in a normal pronunciation task. A significant word-frequency effect at a delay interval of 2900 milliseconds was found in the third experiment where rehearsal during the delay interval was disrupted by requiring subjects to whisper the alphabet while waiting for the cue to respond.

The Relationship Between Working Memory Capacity and Executive Functioning: Evidence for a Common Executive Attention Construct

Attentional control has been conceptualized as executive functioning by neuropsychologists and as working memory capacity by experimental psychologists. We examined the relationship between these constructs using a factor analytic approach in an adult life span sample. Several tests of working memory capacity and executive function were administered to more than 200 subjects between 18 and 90 years of age, along with tests of processing speed and episodic memory. The correlation between working memory capacity and executive functioning constructs was very strong (r = .97), but correlations between these constructs and processing speed were considerably weaker (rs approximately .79). Controlling for working memory capacity and executive function eliminated age effects on episodic memory, and working memory capacity and executive function accounted for variance in episodic memory beyond that accounted for by processing speed. We conclude that tests of working memory capacity and executive function share a common underlying executive attention component that is strongly predictive of higher level cognition.

Effects of Lexicality, Frequency, and Spelling-to-Sound Consistency on the Functional Anatomy of Reading

Functional neuroimaging was used to investigate three factors that affect reading performance: first, whether a stimulus is a word or pronounceable non-word (lexicality), second, how often a word is encountered (frequency), and third, whether the pronunciation has a predictable spelling-to-sound correspondence (consistency). Comparisons between word naming (reading) and visual fixation scans revealed stimulus-related activation differences in seven regions. A left frontal region showed effects of consistency and lexicality, indicating a role in orthographic to phonological transformation. Motor cortex showed an effect of consistency bilaterally, suggesting that motoric processes beyond high-level representations of word phonology influence reading performance. Implications for the integration of these results into theoretical models of word reading are discussed.

VERIDICAL AND FALSE MEMORIES IN HEALTHY OLDER ADULTS AND IN DEMENTIA OF THE ALZHEIMER'S TYPE

Five groups of participants (young, healthy old, healthy old-old, very mild Dementia of the Alzheimers Type, Mild Dementia of the Alzheimers Type) studied and were tested on six 12-item lists of words selected from the DRM (Deese, 1959; Roediger & McDermott, 1995) materials. These lists of words strongly converged semantically on a nonpresented critical word. The results indicated that both veridical recall and recognition performance decreased both as a function of age of the participants and as a function of dementia severity. However, the recall and recognition of the highly related nonpresented items actually increased as a function of age, and only slightly decreased as a function of DAT. When false memory was considered as a proportion of veridical memory, there was a clear increase as a function of both age of the participants and as a function of disease severity. The results are discussed in terms of (a) age and DAT-related changes in attention and memory performance, and (b) the underlying mec...