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Biomedical subjects

D W Massaro

Publications and source records attributed to D W Massaro.

18 recordsLinked to original sources
PubMed1979

Similarity effects in backward recognition masking.

Auditory backward recognition masking refers to the ability of a masking sound to terminate further perceptual resolution of a test sound presented slightly earlier in time. The present experiments were conducted to determine whether mask/test tone similarity effects in backward recognition masking could be reliably demonstrated. Although similarity effects were found in Experiments 1 and 2, only about 60% of the subjects demonstrated these effects. Experiment 3 was designed to isolate which stage of information processing is responsible for similarity effects. It was hypothesized that similarity effects are due to mask interference with the synthesized auditory memory of the test tone rather than to selective overwriting of a preperceptual auditory store: previous research has shown that interference in synthesized auditory memory depends on the similarity of the interfering stimulus to the items held in memory. By independently varying the backward masking interval and the interfering effect of the mask on the test tone memory, it was possible to demonstrate that similarity effects are indeed caused by mask interference in synthesized memory. The implications of these results are considered in the framework of auditory and visual masking.

Auditory Perception↗
PubMed1979

Letter information and orthographic context in word perception.

Theories of word perception in reading can be categorized in terms of the assumption made about whether or not a word context modifies the feature analysis of its component letters. Independence theories assume that the visual information passed on by feature analysis is independent of word context. Nonindependence theories assume that a word context directly influences visual analysis. Some nonindependence theories have assumed that word context enhances feature analysis of letters, others have assumed that word context overrides feature analysis of letters, and some have assumed that word context directs which letters are analyzed. The present experiment provided a critical test between the two classes of theories by independently varying orthographic context and visual letter information in a letter recognition task. The results contradict the qualitative predictions of the class of nonindependence theories and are accurately described by a quantification of independence theory.

Discrimination Learning↗
PubMed1979

Orthographic regularity, positional frequency, and visual processing of letter strings.

Previous research has demonstrated that familiarity with the orthographic structure within a letter string can facilitate the processing of the component letters. The current research was directed at discovering the psychologically relevant properties of this structure. Two fundamental descriptions were independently varied in the construction of six-letter nonword strings. A probabilistic description based on the frequency of occurrence of letters in each position was factorially combined with a rule-governed description defined in terms of graphemic and phonological constraints. College sophomores and sixth-grade readers were asked to indicate whether or not a predesignated target letter was present in these strings. For both groups of readers, orthographic regularity and summed positional frequency were found to have only a small facilitative effect on reaction time (RT). In contrast, RTs to say "no" increased dramatically with increases in the number of letters in the catch string that were physically similar to the target letter. In another experiment, the letter string was presented for a short duration, followed immediately by masking stimulus and then the target letter. College students indicated whether or not the target was present in the test string. Accuracy of performance was critically dependent on the orthographic regularity and summed positional frequencies of the letters in the test string. No effect of letter similarity was observed. The large differences that were observed between these two tasks were accounted for in terms of the stages of processing that are critical for performance in the tasks.

Adult↗
PubMed1978

Temporal course of perceived vowel duration.

The current study explored the temporal course of the perception of vowel duration. A backward recognition masking paradigm was employed in which the subject was to determine which of two target vowels, differing only in duration, was presented on a given trial. The target was followed, after a variable silent intervowel interval, by a masking vowel having one of three possible durations. Subjects were instructed either to identify the long vowel as /i/ and the short vowel as /I/, or were told that the targets were nonsense sounds they were to identify as long or short. For both instruction conditions, identification of the long target improved consistently with increases in the intervowel interval, whereas identification of the short target was equally accurate at the long and the short intervals. Identification of the long target vowel was most accurate when followed by a long masking vowel, whereas identification of the short target vowel was most accurate when followed by a short masking vowel. An information-processing model provided a good description of the quantitative results.

Auditory Perception↗
PubMed1977

Perceptual grouping in audition.

The present experiments evaluated the effect of relative frequency as a determinant of the figure-ground organization of sequences of auditory tones. Observers counted sequences of 20 ms tones that were presented at the same frequency or that alternated between two different frequencies. The alternating tones differed in frequency by one whole tone, seven tones, or nineteen tones. Counting accuracy increased with increases in the silent interval between the tones. When the alternating tones differed by seven or nineteen tones, counting was disrupted at rates of presentation of eight tones per second or slower. In contrast to this decrement in the counting of tones that alternated by over an octave, very little decrement was observed when the tones alternated by just one whole tone. The best subjects counted these alternating tones more accurately than the tones presented at the same frequency. The poorest subjects showed a small decrement even when the tones alternated by just one whole tone. The results were discussed in terms of determinants of figure-ground organization in auditory information processing.

Auditory Perception↗
PubMed1977

Backward recognition masking in relative pitch judgments.

Backward recognition masking refers to interference of a second masking tone with recognition of a target tone presented earlier in time. The degree of interference has been found to decrease as the length of the silent interval separating the two tones increases. These results have been interpreted as representing interference of the masking tone upon the preperceptual storage and perceptual resolution of the target. It is logically possible, however, that the masking tone does not interfere with perceptual resolution but interferes with comparison of the target to a long-term memory representation. The current research was designed to provide a critical test of this alternative hypothesis by modifying the backward recognition masking task. Subjects determined whether the masking tone was higher or lower in pitch than the target tone. The frequencies of the target and masking tones varied randomly across trials. This ensured that the task could not be performed by comparing the target to a representation in long-term memory. Nevertheless, masking was obtained in this task, arguing against the comparison argument and in favor of the perceptual resolution interpretation. Given that masking was obtained under both ipsilateral and contralateral presentation of the tones, the results argue for a central preperceptual auditory storage that holds information after the inputs from the two ears are combined in the auditory system.

Functional Laterality↗
PubMed1976

Perceiving and counting sounds.

Observers counted sequences of 20-msec tones that were presented to the same spatial location or alternated between spatial locations. Counting accuracy increased with increases in the silent interval between tones and increased at a faster rate when the tones were presented to the same location. In the second study, subjects monitored the same sequences of tones for a probe tone that was either higher or lower than the other tones. Probe recognition improved with increases in the silent interval between tones, and there was no significant decrement in monitoring tones alternated between spatial locations. In the next two studies, observers processed a sequence of tones presented at the same spatial location, but the tones could alternate in frequency by slightly more than an octave. Counting accuracy was poorer when the tones alternated in frequency. When subjects monitored these sequences of tones for the duration of a probe tone, recognition leveled off at a lower asymptote for sequences of tones alternating in frequency. The deficit in counting sounds alternating between spatial locations or frequencies appears to be due to a process that has difficulty integrating successive tones that are perceived at different spatial locations or pitch levels.

Aptitude↗