A three-component analysis of the modality effect in single-trial free recall

Johann-Wolfgang-Goethe Unversität, Frankfurt am Main, West-Germany In single-trial free recall a superiority of acoustical over visual presentation has been observed in the recency part of the serial position curve. The rehearsal-buffer model by Atkinson and Shiffrin (1968) was modified to distinguish between three different explanations that are discussed in the literature. The application of the model allowed some of the parameters to vary across modes of presentation while other parameters were held constant. A model assuming either a precategorical acoustical storage or additional processing for visually presented items gives a better account of the results than does a model derived from a two-store hypothesis.     

Prior context and the perception of lexically ambiguous sentences

The perceptual complexity of lexically ambiguous and unambiguous sentences was compared in three experiments. In Experiment 1, the report of ambiguous words from rapidly presented ambiguous sentences was worse than the report of corresponding unambiguous words from unambiguous sentences. Results of Experiment 2 showed that the effect was not reduced by the presence of prior biasing context within the sentence. Experiment 3 repeated the finding with a sentence meaning classification task. It was concluded that both meanings of a lexically ambiguous sentence must be computed, even when prior context makes one meaning more plausible than the other.     

SKED-controlled experimentation in an undergraduate instructional laboratory

A SKED-based facility for undergraduate instructional research has been operating for over a year. The two-computer approach, with one machine for programming and the other for running experiments, is used. Criteria for computerized undergraduate research laboratories, benefits of SKED, and the two-computer approach are discussed.     

What do you do after you say hello? Observing,coding, and analyzing parent-infant interactions

Procedures for observing, coding, and analyzing parent-infant interactions are described. Sample data are presented to illustrate the outcome of these procedures and the manner in which developmental issues can be addressed using the hardware and software systems described.     

Using computer conferencing to formulate a computer simulation of transitive behavior

The activities of a group engaged in simulation modeling via computer conferencing are described, and the model which resulted from those activities is briefly outlined. The phenomena which were modeled were initially described in a series of studies by Trabasso and his colleagues. These studies centered upon exhibition of transitive choices by children and adults, and supported the hypothesis that the choices were guided by formation of “linear arrays“ of the choice objects.     

Evaluation of a continuing computer conference on simulation

A 20-day computer conference was held in preparation for a face-to-face meeting to produce a computer simulation. The conferencing resulted in the generation of seven different models and was excellent preparation for the subsequent meeting. Computer conferencing appears to hold great value for faculty development in a period of reduced faculty mobility.     

Development of an on-line problem-oriented system for the evaluation of mental health treatment services

Current on-line assessment applications are limited to mimicking instruments designed for paper and pencil. The development of an instrument designed specifically for on-line technology is described. The instrument provides research data on treatment effectiveness, clinical information for treatment planning, and management information for resource allocation.     

Vowel recognition: Inferences from studies of forward and backward masking

The recognition of brief vowels was studied in forward and backward masking tasks. In a series of experiments in which both target and mask parameters were systematically varied, two populations of subjects were identified. The majority (Nonmaskers) evidenced little masking at any interstimulus interval, while relatively fewer subjects (Maskers) evidenced backward masking (but not forward masking) over a 100-200 ms interval. Increasing target set size systematically increased masking for the Maskers but not for the Nonmaskers. Adding white noise to the targets increased the extent of masking for both groups. These results suggest (1) that masking does not impose a substantive constraint on vowel perception in running speech, and (2) that multiple strategies may exist for vowel recognition.     

Book reviews

Wyer, Robert S., Jr. Cognitive Organization and Change : an Information Processing Approach. Potomac, Maryland: Lawrence Erlbaum Associates. 1974. Pp. 502. £10.50.

Egan, J. P. Signal Detection Theory and ROC Analysis. New York: Academic Press. 1975. Pp. 277. £9.75. ISBN

Aldis, O. Play-Fighting. New York: Academic Press. 1975. Pp. 319. £8.75.

Warburton, D. M. Brain Behaviour and Drugs. London: John Wiley. 1975. Pp. 280. £6.95. ISBN 0471 91991 8.

Grieve, D. W., Miller, D., Mitchelson, D., Paul, J. and Smith, A. J. Techniques for the Analysis of Human Movement. London: Lepus Books. 1975. Pp. 177. £5.50.     

Discrimination of time intervals marked by brief acoustic pulses of various intensities and spectra

Experienced observers were asked to identify, in a four-level 2AFC situation, the longer of two unfilled time intervals, each of which was marked by a pair of 20-msec acoustic pulses. When all the markers were identical, high-level (186-dB SPL) bursts of coherently gated sinusoids or bursts of band-limited Gaussian noise, a change in the spectrum of the markers generally did not affect performance. On the other hand, for 1-kHz tone-burst markers, intensity decreases below 25 dB SL were accompanied by sizable deterioration of the discrimination performance, especially at short (25-msec) base intervals. Similarly large changes in performance were observed also when the two tonal markers of each interval were made very dissimilar from each other, either in frequency (frequency difference larger than 1 octave) or in intensity (level of the first marker at least 45 dB below the level of the second marker). Time-difference thresholds in these two latter cases were found to be nonmonotonically related to the base interval, the minima occurring between 40- and 80-msec onset separations.