Andrew W. Ellis

Age of Acquisition Norms for a Large Set of Object Names and Their Relation to Adult Estimates and Other Variables

Studies of lexical processing have relied heavily on adult ratings of word learning age or age of acquisition, which have been shown to be strongly predictive of processing speed. This study reports a set of objective norms derived in a large-scale study of British childrens naming of 297 pictured objects (including 232 from the Snodgrass & Vanderwart, 1980, set). In addition, data were obtained on measures of rated age of acquisition, rated frequency, imageability, object familiarity, picture-name agreement, and name agreement. We discuss the relationship between the objective measure and adult ratings of word learning age. Objective measures should be used when available, but where not, our data suggest that adult ratings provide a reliable and valid measure of real word learning age.

Naming the Snodgrass and Vanderwart Pictures: Effects of Age of Acquisition, Frequency, and Name Agreement

Independent measures of age of acquisition (AoA), name agreement, and rated object familiarity were obtained from groups of British subjects for all items in the Snodgrass and Vanderwart (1980) picture set with single names. Word frequency measures, both written and spoken, were taken from the Celex database (Centre for Lexical Information, 1993). The line drawings were presented to a separate group of participants in an object naming task, and vocal naming latencies were recorded. A subset of 195 items was selected for analysis after excluding items with, for example, low name agreement. The major determinants of picture naming speed were the frequency of the name, the interaction between AoA and frequency, and name agreement. (The main effect of the AoA of the name and the effect of the rated image agreement of the picture were also significant on one-tailed tests.) Spoken name frequency affects object naming times mainly for items with later-acquired names.

Matching Familiar and Unfamiliar Faces on Internal and External Features

Two experiments are reported in which subjects were asked to match a photograph of a complete face and a simultaneously presented photograph of internal or external features of a face, deciding whether or not the two photographs were pictures of the same person. In experiment 1 ‘same’ pairs were derived from different pictures of the same face, so that subjects had to match the faces and not the particular photographs used. Matches based on internal features were found to be faster for familiar than for unfamiliar faces, whereas there was no difference in reaction time between matches based on the external features of familiar and unfamiliar faces. Faster matching of internal features of familiar faces was found to hold equally for pairs of photographs that differed in orientation of the face or in facial expression. In experiment 2 ‘same’ pairs were derived from the same photograph, which gave subjects the choice of matching on the basis of the features of the depicted faces or matching the photographs. Reaction times were faster than in experiment 1, and there were no differences between familiar and unfamiliar faces. The study confirms reports of differential saliency of the internal features of familiar faces, and shows that this only holds when stimuli are treated as faces. The finding thus reflects properties of structural rather than pictorial codes.

Age of acquisition effects in adult lexical processing reflect loss of plasticity in maturing systems : Insights from connectionist networks

Early learned words are recognized and produced faster than later learned words. The authors showed that such age of acquisition effects are a natural property of connectionist models trained by back-propagation when patterns are introduced at different points into training and learning of early and late patterns is cumulative and interleaved. Analysis of hidden unit activations indicated that the age of acquisition effect reflects a gradual reduction in network plasticity and a consequent failure to differentiate late items as effectively as early ones. Further simulations examined the effects of vocabulary size, learning rate, sparseness of coding, use of a modified learning algorithm, loss of early items, acquisition of very late items, and lesioning the network. The relationship between age of acquisition and word frequency was explored, including analyses of how the relative influence of these factors is modulated by introducing weight decay.

Age of acquisition, not word frequency, affects object naming, not object recognition

Word frequency is widely believed to affect object naming speed, despite several studies in which it has been reported that frequency effects may be redundant upon age of acquisition. We report, first, a reanalysis of data from the study by Oldfield and Wingfield (1965), which is standardly cited as evidence for a word frequency effect in object naming; then we report two new experiments. The reanalysis of Oldfield and Wingfield shows that age of acquisition is the major determinant of naming speed, and that frequency plays no independent role when its-correlation with other variables is taken into account. In Experiment 1, age of acquisition and phoneme length proved to be the primary determinants of object naming speed. Frequency, prototypicality, and imageability had no independent effect. In Experiment 2, subjects classified objects into two semantic categories (natural or man-made). Prototypicality and semantic category were the only variables to have a significant effect on reaction time, with no effect of age of acquisition, frequency, imageability, or word length. We conclude that age of acquisition, not word frequency, affects the retrieval andlor execution of object names, not the process of object recognition. The locus of this effect is discussed, along with the possibility that words learned in early childhood may be more resistant to the effects of brain injury in at least some adult aphasics than words learned somewhat later.

Real age-of-acquisition effects in lexical retrieval.

Previous research on the effects of age of acquisition on lexical processing has relied on adult estimates of the age at which children learn words. The authors report 2 experiments in which effects of age of acquisition on lexical retrieval are demonstrated using real age-of-acquisition norms. In Experiment 1, real age of acquisition emerged as a powerful predictor of adult object-naming speed. There were also significant effects of visual complexity, word frequency, and name agreement. Similar results were obtained in reanalyses of data from 2 other studies of object naming. In Experiment 2, real age of acquisition affected immediate but not delayed object-naming speed. The authors conclude that age-of-acquisition effects are real and suggest that age of acquisition influences the speed with which spoken word forms can be retrieved from the phonological lexicon.

“Neglect dyslexia” and the early visual processing of letters in words and nonwords

Abstract We report the case of a nonphasic patient, VB, who suffered a left-sided neglect which affected her reading (a condition known as “neglect dyslexia”). In text reading she often read only the right halves of lines, and in single-word reading she made errors which affected the initial letters (e.g. RIVER misread as “liver” or YELLOW as “pillow”). Neglect errors to both words and nonwords typically involved the substitution of initial letters rather than deletion or addition, resulting in errors of the same length as the target words. Comprehension of misread words matched the error rather than the target. We propose, following Shallice (1981), that “neglect dyslexia” affects the early visual analysis of letters in both words and nonwords. More particularly we propose that although VBs neglect sometimes prevented the encoding of leftmost letters for identity, processes which assign positions to letters in strings on a left-right spatial basis still responded to the existence of those letters. This ...

Different methods of lexical access for words presented in the left and right visual hemifields.

Right-handed adults were asked to identify by name bilaterally presented words and pronounceable nonwords. For words in the normal horizontal format, word length (number of letters) affected left visual hemifield (LVF) but not right visual hemifield (RVF) performance in Experiments 1, 2, 3, 5, and 6. This finding was made for words of high and low frequency (Experiment 6) and imageability (Experiment 5). It also held across markedly different levels of overall performance (Experiments 1 and 2), and across different relative positionings of short and long words in the LVF and RVF (Experiment 3). Experiment 4 demonstrated that the variable affecting LVF performance is the number of letters in a word, not its phonological length. For pronounceable nonwords (Experiment 7) and words in unusual formats (Experiment 8), however, length affected both LVF and RVF performance. The characteristics identified for RVF performance in these experiments also hold for the normal reading system. In this (normal) system the absence of length effects for horizontally formatted words is generally taken to reflect the processes involved in lexical access. Length effects in the normal reading system are thought to arise when lexical access for unusually formatted words and for the pronunciation of nonwords requires the short-term storage of information at a graphemic level of analysis. The characteristics of LVF performance indicate that horizontally formatted words presented to the right cerebral hemisphere can only achieve lexical access by a method that requires the short-term storage of graphemic information. This qualitative difference in methods of lexical access applies regardless of whether the right hemisphere is seen as accessing words in the left hemispheres lexicon or words in a lexicon of its own.

Real age of acquisition effects in word naming and lexical decision

Age of acquisition (AoA) has been reported to be a predictor of the speed of reading words aloud (word naming) and lexical decision, with early-acquired words being responded to faster than later-acquired words in both tasks. All previous studies of AoA effects have, however, relied upon adult estimates of word learning age the validity of which it is easy to cast doubt upon. Using objective age of acquisition norms derived from childrens naming data, this study shows that AoA effects do not depend upon the use of adult ratings. In addition to effects of real AoA, influences of word frequency and orthographic neighbourhood size were obtained in both word naming and lexical decision. Imageability affected lexical decision but not word naming, while the characteristics of the words initial phoneme affected word naming but not lexical decision.

Naming times for the Snodgrass and Vanderwart pictures in Spanish.

We present new Spanish norms for object familiarity and rated age of acquisition for 140 pictures taken from Snodgrass and Vanderwart (1980), together with data on visual complexity, image agreement, name agreement, word length (in syllables and phonemes), and five measures of word frequency. The pictures were presented to a group of 64 Spanish subjects, and oral naming latencies were recorded. In a multiple regression analysis, age of acquisition, object familiarity, name agreement, word frequency, and word length made significant independent contributions to predicting naming latency.