Frequency-selective detection at three signal amplitudes

Using the probe-signal method, frequency-response characteristics were obtained for four Os detecting signals nominally of only 1000Hz under three signal-amplitude conditions: E/N_o=10.0, 12.6, and 15.8. Detection of 1000-Hz signals decreased systematically with signal-amplitude decreases, but signals at 850 Hz and at 1150 Hz were detected at or near the chance level during all signal-amplitude conditions. From the detection performance data, the detectability was inferred for four probe-signal frequencies relative to that of 1000-Hz signals for each of the amplitude conditions. From the curvesofrelative detectability, hal[-detectability bandwidths were estimated. Neither the relative detectability curves nor the half-detectability bandwidths indicate any systematic change in the frequencyselectivebehavior of the auditory O across the signal amplitudes used.     

Classical and bayesian inference in certain latency processes

Certain aspects of point estimation are treated for two kinds of exponential latency processes. The first unitary process is represented by a simple exponential density in which the rate parameter may be viewed as an unknown constant or as a random variable. If a second, slower exponential process is grafted onto the first, there results a postulated two-component latency between stimulus and response. Moments estimators are derived for the two parameters of this latter density, and the relevance of the second parameter to decision time is emphasized.This research was supported in part by National Institutes of Health Grant MH-04439-05. The author would like to express his appreciation to James Baker of Oregon Research Institute for certain helpful comments concerning aspects of this work.     

The role of stimulation in the delay of onset of crying in the newborn infant

Crying is said to result from stimulus need. An experiment was done in which infants were stimulated during quiet periods to see if this would postpone the onset of crying. The results were positive. An alternative explanation in terms of internal temperature control is considered.     

Internal consistency and reliability of alternate short forms of the college women's assertion sample: Clinical and research implications

Assertive behavior is most often assessed with self-report or role-play measures. The latter modality is preferred because it provides for the sampling of the structure of behavior and for the consideration of the situational context. MacDonald (1978) has developed such an assessment device but it is limited by the length of time for administration and scoring. Two studies were conducted to reconstruct reliable alternate short forms. The first study describes the selection of items and demonstrates the internal consistency of the alternate forms. The second study demonstrates the alternate form and retest reliability and provides normative statistics. We conclude that reliable alternate short forms have been constructed to be used in research in clinical applications.This research was supported by the Marie Wilson Howells Fund.Alternate short forms of the CWAS may be obtained from the first author.     

Evaluating a computational model of perceptual grouping by proximity

A formal approach to the phenomenon of perceptual grouping by proximity was investigated. Grouping judgments of random dot patterns were made by the CODE algorithm (van Oeffelen & Vos, 1982) and several related algorithms, and these judgments were compared with subjects’ grouping judgments for the same stimuli. Each algorithm predicted significantly more subject judgments than would be expected by chance. The more subjects agreed on how a given dot pattern should be grouped, the more successful was the algorithms’ ability to match the judgments for that pattern. CODE predicted significantly fewer subject judgments than did some of the other algorithms, largely because of its overemphasis on the extent of interactivity among dots as they are being grouped.     

Coming to terms with stress: Effects of stress location in sentence processing

The purpose of this research was to determine the role of syllabic stress in language processing during the early on-line processing of speech and later in the representation of a sentence in memory. Experiment 1 used a syllable monitoring task while Experiment 3 used a probe task in which subjects heard a sentence and then were asked to determine whether a probe syllable had occurred in the sentence. In the monitoring task, stressed syllables were detected more rapidly in word-initial position, but unstressed syllables were detected more rapidly in word-final position. Stress facilitation in initial syllables was strongly related to high relative F0, but not to changes in perceived vowel quality as assessed in Experiment 2. This pattern is interpreted as evidence that lexical stress is used on-line to guide lexical access and/or lexical segmentation. The probe task of Experiment 3 showed stress facilitation in both positions, indicating that stress is independently retained in the postperceptual representation of a sentence.The research reported in this paper was supported by grant 80-0416 to Harvard University (Peter C. Gordon, Principal Investigator) from the Air Force Office of Scientific Research Life Sciences Directorate. We thank Chris Thurber for his extensive and competent assistance in testing subjects and making acoustic measurements, and Jay Rueckl for comments on an earlier version of this paper