Biomedical subjects

A F Healy

Publications and source records attributed to A F Healy.

15 recordsLinked to original sources

PubMed1992

A developmental evaluation of the role of word shape in word recognition.

Fourth- and seventh-grade children and college-age adults proofread passages typed either in lowercase or in all capital letters. Words were misspelled by deleting one of four letters, s, c, k, or p, that have similar features in lowercase and uppercase. Proofreading errors decreased with age and increasing reading ability, but all of the subjects were sensitive to changes in word shape--they missed more words with deletions of s or c than k or p in the lowercase passage but not in the all-capitals passage. These findings indicate that word shape is an important variable in recognizing familiar words, even for young readers.

Adolescent↗

PubMed1992

Output and retrieval interference in the missing-number task.

Three experiments are reported that represent a reexamination of the missing-number method (Buschke, 1963b) of estimating short-term memory span. The missing-number task involved presenting a random sequence of all but one of the numbers of a known reference set and asking subjects to identify the missing number. Experiment 1 introduced a modified missing-number task that included two missing items and two choices made by the subject. With a large decline in performance for the second choice relative to the first, it is possible that only the second choice was subject to output or retrieval interference. An alternative explanation is that subjects output the number with the weakest memory representation as their first response. By postcuing subjects to report their two choices in a forward or backward sequence, Experiment 2 provided evidence against the importance of output interference and support either for the importance of retrieval interference or for the "weakest-first" hypothesis. However, with a paradigm that replaced only correctly identified missing numbers, a prediction that subjects would select the number with the weakest memory representation as their first response was not confirmed in Experiment 3. Instead, retrieval interference was implicated to explain the first-choice superiority found in Experiments 1 and 3. The results were interpreted in terms of the TODAM model of Murdock (1982, 1987, in press).

Attention↗

PubMed1991

Syllable-internal structure and the sonority hierarchy: differential evidence from lexical decision, naming, and reading.

Treiman (1983) and others have argued that spoken syllables are best characterized not as linear strings of phonemes, but as hierarchically organized units consisting of an onset (initial consonant or consonant cluster) and a rime (the vowel and any following consonants) and that the rime is further divided into a peak or nucleus (the vowel) and a coda (the final consonants). It has also been argued that the sonority (or vowel-likeness) of the consonant closest to the peak, which is a function of its phonetic class, may have an effect on the strength of boundaries determined by the hierarchical division of the syllable (e.g., Treiman, 1984). We examined the evidence for syllable-internal structure and for sonority in two experiments that employed visually presented stimuli and lexical decision, naming, and reading tasks. Our results provide support for the breakdown of the rime into a peak and a coda and for an effect of the sonority of the postvocalic consonant on that break. This pattern occurred only in our lexical decision tasks, so the effect is assumed to be postlexical. We did not find an effect of the onset-rime boundary, perhaps because of an unanticipated effect of word frequency. Our results are discussed in terms of phonological coding in short-term memory.

Adult↗

PubMed1991

Long-term repetition effects for motoric and perceptual procedures.

Two experiments examined the relationship between implicit and explicit measures of memory for information encoded in a motoric task, called data entry. In both experiments, subjects entered lists of digit sequences with a computer keypad. They were retested on the same task after a delay of up to 1 month. At retention, implicit memory for the digit lists was evidenced by faster entry of old relative to new lists in both experiments. In Experiment 1, subjects were able to discriminate old from new lists. Recognition memory of old lists was better after than before entering the lists. In Experiment 2, perceptual and motoric contributions to the old/new difference in typing speed were isolated by means of a transfer paradigm. The results showed that the entry-speed advantage for the old lists was due to the separate reinstatement at the retention test of both perceptual and motoric procedures encoded earlier. Implicit and explicit measures of memory were found to be dependent rather than independent. The findings from this study are interpreted within a framework of memory based on procedural reinstatement.

Adult↗

PubMed1991

Same-different judgments of multiletter strings: insensitivity to positional bias and spacing.

Several recent studies of multiletter matching have included pairs of strings that have the same letters in different positions (rearranged pairs). The task can be defined such that these rearranged pairs are correctly classified as different (i.e., subjects respond "same" only if the strings have the same letters in the same positions--the order task) or as same (i.e., subjects respond "same" if the strings have the same letters regardless of their positions--the item task). The order task produces left-to-right serial-position effects, whereas the item task produces U-shaped serial-position effects. Because these differences suggest that subjects may be able to exert strategic control over the comparison process, two sets of experiments were designed to test whether or not subjects can change the relative weightings devoted to the respective serial positions. In Experiments 1 and 2, the probability that a mismatch occurred in the different positions was manipulated. In Experiments 3 and 4, the physical spacing between letters, as well as whether or not the spaces were filled with neutral noise characters, was varied. None of the manipulations had much influence on the serial-position effects. Thus, the distinct serial-position effects for the order and item tasks apparently are mandatory and not due to any voluntary comparison strategy.

Attention↗

PubMed1990

Acquisition and retention of a letter-detection skill.

In two experiments, we examined the acquisition and retention of a letter-detection skill with a consistent-mapping procedure. In Experiment 1, subjects were trained from 0 to 4 sessions at detecting the letter H in displays containing random letters, and retesting occurred after a 1-month delay. Performance improved and in some cases became more automatic, and the performance level was maintained over the retention interval. When tested with a prose passage, the high error rate on the word THE was eliminated after training and after the retention interval, regardless of the amount of training. In Experiment 2, two subjects were given 12 sessions of training followed by a retention test 6 months later. For 1 subject there was also a retention test 15 months after acquisition. Performance improved dramatically with training, and substantial but not complete automaticity was achieved. Performance on the retention tests was close to the final acquisition level. The surprising lack of forgetting in this study was contrasted with the substantial forgetting typically found in studies of verbal learning.

Form Perception↗

PubMed1990

Identification of letters in the predesignated target paradigm: a word superiority effect for the common word the.

The size of the perceptual unit used in reading was addressed using the predesignated target paradigm. Sixteen subjects viewed the following stimuli in random order: the words tee, the, tie, and toe; the nonwords eet, eht, eit, and eot; and the letters e, h, i, and o. Subjects fixated on the location of the center letter and identified the letter as e, h, i, or o, alternatives which were known to them at the onset. A word superiority effect was obtained for the common word the but not for the less common words tee, tie, and toe. The word superiority effect was attributable to bias rather than discriminability: Subjects exhibited a bias to perceive the words in this experiment as the (i.e., there was a bias to perceive h in the t e stimulus presentations). These results suggest that the common word the is processed in reading units that are larger than the letter, and that the system is biased to perceive common rather than uncommon words in data-limited conditions.

Adult↗

PubMed1989

Facilitating text memory with additional processing opportunities in rapid sequential reading.

Previous research indicates that during conventional reading, readers pause at particular loci within a text, presumably for the purpose of higher level processing and integration. If such pausing is necessary for efficient text comprehension and memory, then providing readers with equivalent processing opportunities with strategically placed pauses in rapid sequential visual presentation (RSVP) text displays should facilitate comprehension and memory. Three experiments are reported in which various time parameters of RSVP displays are manipulated. The results indicate that memory for specific text is facilitated when additional processing time is provided. However, how and where the additional time is distributed within a text, over broad limits, is not important. We use a method of text memory assessment that is not typically used in RSVP research and that is more sensitive to text presentation manipulations than the commonly used multiple-choice questions. This fill-in-the-blank technique also provides evidence that memory representations for texts are structured as meaningful subsentence units.

Adult↗

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↗

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↗