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Biomedical subjects

A F Healy

Publications and source records attributed to A F Healy.

At least 37 records · Page 2Linked to original sources
PubMed1988

Investigating the boundaries of reading units across ages and reading levels.

In Experiments 1 and 2 first-, third-, and seventh-grade children and college subjects circled the letter a while reading passages constructed of words familiar to first graders. First graders made more errors on the letter a embedded in a word than on the word a, whereas the converse was true of the other age groups. In Experiments 3 and 4 first-, second-, fourth-, and seventh-grade children and college students read passages and circled the letter t, making more errors on the common word the than on other words and on correctly spelled than on misspelled words. The effect of misspelling the other words increased with age and reading skill. Our combined results suggest that reading unit size increases with age and reading ability and that, whereas younger children, like adults, unitize common words, the unitization of less common words increases as word configurations become more familiar.

Adolescent↗
PubMed1988

Semantic, phonological, and mediated priming in reading and lexical decisions.

Four experiments were conducted to investigate whether semantic activation of a concept spreads to phonologically and graphemically related concepts. In lexical decision or self-paced reading tasks, subjects responded to pairs of words that were semantically related (e.g., light-lamp), that rhymed (e.g., lamp-damp), or that combined both of these relations through a mediating word (e.g., light-damp). In one version of each task, test lists contained word-word pairs (e.g., light-lamp) as well as nonword-word (e.g., pown-table) and word-nonword pairs (e.g., month-poad); in another version, test lists contained only word-word pairs. The lexical decision and self-paced reading tasks were facilitated by semantic and rhyming relations regardless of the presence or absence of nonwords on the test lists. The effect of the mediated relation, however, depended on the presence of nonwords among the stimuli. When only words were included, there was no effect of the mediated relation, but when nonwords were included, lexical decision and self-paced reading responses were inhibited by the mediated relation. These inhibitory effects are attributed to processes occurring after lexical access, and the relative advantages of the self-paced reading task are discussed.

Adult↗
PubMed1987

Detecting letters in continuous text: effects of display size.

In three letter detection experiments, subjects responded to each instance of the letter t in continuous text typed in a standard paragraph, typed with one to four words per line, or shown for a fixed duration on a computer screen either one or four words at a time. In the multiword and the standard paragraph conditions, errors were greatest and latencies longest on the word the when it was correctly spelled. This effect was diminished or reversed in the one-word conditions. These findings support a set of unitization hypotheses about the reading process, according to which subjects do not process the constituent letters of a word once that word has been identified unless no other word is in view.

Attention↗
PubMed1987

Effects of cuing on short-term retention of order information.

In two experiments, subjects recalled one of two letter sequences following a digit-filled retention interval. Recall performance was increased by precues informing subjects which letter sequence would be tested, and the cuing advantage remained throughout 60-digit retention intervals. No improvement was found, however, for cues occurring after the letters but before the digits. The cuing effects were attributed to encoding, not rehearsal, processes and were explained by a version of the Estes perturbation model, which included a long-term storage component and a fixed perturbation probability.

Cues↗
PubMed1985

A secondary-task analysis of a word familiarity effect.

In three experiments we examined aspects of the word inferiority effect and word frequency disadvantage for letter detection. In Experiment 1 we tested a prediction derived from a hypothesis based solely on attentional factors. Adult subjects performed one of two secondary detection tasks while reading for comprehension. The inferiority effects were obtained only when the secondary task was letter detection, not when nonletter targets were used in the secondary task. This finding is inconsistent with the attentional hypothesis, but is consistent with the unitization hypothesis of Healy and Drewnowski (1983). In Experiments 2 and 3 we found that manipulation of the need to read for comprehension had little influence on the letter-detection inferiority effects, but a strong influence on the effects involving the detection of nonletter targets. These results are discussed in terms of their implications concerning processing system flexibility.

Attention↗
PubMed1985

Order-relevant and order-irrelevant decision rules in multiletter matching.

Two experiments examined order effects in multiletter matching. In each experiment, subjects used one of two decision rules that differed in whether pairs of letter strings that contained the same letters, but in different orders (rearranged pairs), were classified as same or different. Method of presentation also was varied, with the two strings in each pair being presented either simultaneously or successively in one experiment, and with the exposure duration of the second of two successively presented strings being either short or long in the other. Latency and accuracy of responding to the rearranged pairs varied as a function of the amount of positional displacement, with the two tasks showing similar, but mirror image, patterns. This outcome suggests that most of the order effects are attributable to processes common to both tasks, although there was some evidence for a contribution from task-specific processes as well. Both method-of-presentation manipulations had little influence on the order effects, suggesting that the effects are attributable to perceptual and decision processes, rather than to memory processes. The results are most consistent with a model that assumes position-sensitive comparisons, with the same-different decision based on pooled information.

Decision Making↗
PubMed1984

Effects of repetition on short-term retention of order information.

Two experiments examined the effects of repetition on the short-term retention of order information. A partial report procedure was coupled with the distractor paradigm to vary which one of two 4-letter sequences was tested after a digit-filled retention interval. Repeatedly presenting the stimulus but not its testing did not increase recall, but recall did increase when both presentation and testing were repeated. Recall was also improved by precues that informed subjects in advance which sequence was to be recalled. The perturbation model of Estes (1972; Lee & Estes, 1981) was able to account for the qualitative and quantitative aspects of the results by making an explicit distinction between two types of rehearsal: the reactivation process, which corresponds to a passive, automatic rehearsal process; and an active, conscious rehearsal process that crystallizes the memory structure and makes perturbations less likely.

Adult↗
PubMed1983

Investigating the boundaries of reading units: letter detection in misspelled words.

In two experiments, subjects searching for the letter t in passages that contained some misspellings made many more errors on the word the than on other correctly spelled words. Accuracy increased dramatically when the word the and the other words containing t were misspelled, even when the misspelled word was the same shape as the original. These findings define a word-inferiority effect, which stands in contrast to the superior perception of letters in words over nonwords commonly found in tachistoscopic studies. In a third experiment, subjects searched for the letter n in passages typed normally or typed with all interword spaces replaced by the symbol +. Detection errors on the word and were greatly reduced when the interword spaces were replaced by +s, but errors on other words, including those ending in the suffix morpheme -ing, were not affected by this manipulation. These results suggest that frequent function words are processed in terms of reading units that are larger than the letter and include the interword spaces.

Attention↗
PubMed1982

Context independence and phonetic mediation in categorical perception.

Categorical perception, as an ideal situation, is rarely if ever observed in the laboratory. Two separate requirements must be met for categorical perception: (a) Discrimination performance must be phonetically mediated (i.e., it should be predictable from labeling performance), (b) labeling responses must be independent of the stimulus context. To determine the extent to which departures from the ideal are due to failures to meet one or both of these requirements, we used four stimulus continua in same-different (AX) discrimination and labeling tasks: stop-consonant-vowel (CV) syllables, isolated vowels, isolated fricative noises, and nonspeech sounds varying in timbre. We found that perception of CV syllables fell short of the ideal only because of contextual influences on labeling. Neither criterion of categorical perception was met by vowels or fricative noises, but subjects were more prone to phonetic mediation with vowels than with fricative noises, and they showed more context independence with fricative noises than with vowels. Surprisingly, the nonspeech timbre stimuli satisfied both requirements better than either vowels or fricative noises. This findings was attributed to the short duration of our timbre stimuli, which prevented them from sounding vowel-like but at the same time may have prevented stable auditory memory traces.

Discrimination Learning↗
PubMed1979

Categories and context in the perception of isolated steady-state vowels.

The noncategorical perception of isolated vowels has been attributed to the availability of auditory memory in discrimination. In our first experiment, using vowels from an /i/-/I/epsilon) continuum in a same-different (AX) task and comparing the results with predictions derived from a separate identification test, we demonstrated that vowels are perceived more nearly categorically if auditory memory is degraded by extending the interstimulus interval and/or filling it with irrelevant vowel sounds. In a second experiment, we used a similar paradigm, but in addition to presenting a separate identification test, we elicited labeling responses to the AX pairs used in the discrimination task. We found that AX labeling responses predicted discrimination performance quite well, regardless of whether auditory memory was available, whereas the predictions from the separate identification test were more poorly matched by the obtained data. The AX labeling reponses showed large contrast effects (both proactive and retroactive) that were greatly reduced when auditory memory was interfered with. We conclude from the presence of these contrast effects that vowels are not perceived categorically (that is, absolutely). However, it seems that by taking the effects of context into account properly, discrimination performance can be quite accurately predicted from labeling data, suggesting that vowel discrimination, like consonant discrimination, may be mediated by phonetic labels.

Adult↗
PubMed1976

Detection errors on the word the: evidence for reading units larger than letters.

In four experiments, subjects read 100-word passages and circled instances of the letter t. Subjects missed a disproportionate number of ts in the word the. Evidence was provided against explanations of this effect involving the location and pronunciation of the t in the and against an explanation in terms of the redundancy of the. Rather the high frequency of the appeared to be critical, and it was suggested that high-frequency words are read in terms of units larger than the letter.

Auditory Perception↗