Symbol complexity and symbol identification with rotated symbols

Previous studies of the identification of rotated symbols have been restricted to either alphanumeric characters or symbols designed to be similar in complexity and type to alphanumerics. These researches have found identification response times to be independent of the magnitude of a symbol's angular displacement from a standard upright position, such findings being typically interpreted as supporting a feature extraction model of identification. In the present experiment complex Japanese characters were used to assess whether such a feature extraction interpretation could be generalized to identifying complex rotated symbols. Identification response times were also found to be constant across all non-standard orientations of the characters, supporting a feature extraction interpretation, but quicker times for standard cases suggested that some qualifications might be necessary.     

Towards a model of stress and human performance

An outline is presented of a model that aims to relate energetical and structural mechanisms of human information processing and to incorporate an interactionally defined stress notion in performance research. The first section summarizes objections to unidimensional notions of arousal and stress. It is concluded that further progress requires the analysis of joint cognitive-energetical processing structures. In the second section two current performance models - in terms of linear stages and resources - are briefly reviewed. Despite a number of problems and objections, it is decided to base the model upon linear stage notions of information processing. This is further elaborated in the third section. In accord with Pribram and McGuinness (1975) three energetical supply systems are proposed which are selectively related to specific cognitive processing mechanisms. Stress is defined as a state of imbalance in the energetical supply which is difficult to restore or to compensate. The final section is devoted to the discussion of some lines of evidence and to suggestions for future research.     

What is educational theory and how to make it?

An analysis is provided detailing the conditions for the appropriate theoretical study of the object of educational science: pedagogy.     

Performance of humans in concurrent avoidance/positive-reinforcement schedules

Performance maintained under concurrent schedules consisting of a variable-interval avoidance component and a variable-interval positive-reinforcement component was studied in three human subjects using points exchangeable for money as the reinforcer. The rate of responding in the avoidance component increased, and the rate of responding in the positive-reinforcement component declined, as a function of the frequency of point-losses avoided in the avoidance component. The performance of all three subjects conformed to equations proposed by Herrnstein to describe behavior in concurrent schedules. The logarithms of the ratios of the response rates in the two components, and the logarithms of the ratios of the times spent in the two components, were linearly related to the logarithms of the ratios of the frequency of loss avoidance in the avoidance component to the frequency of reinforcement in the positive-reinforcement component. When a changeover delay of 5.0 sec was imposed, the slopes of the linear functions were close to 1.0 in the case of two subjects, whereas the third subject exhibited significant undermatching. For two subjects the changeover delay was then reduced to 2.0 sec; in both cases the slopes of the linear functions were lower than under the 5.0-sec condition. One subject participated in a third phase, in which no changeover delay was imposed; there was a further reduction in the slopes of the linear functions.     

Structural models for the mediation of salience effects on attribution

Previous research has demonstrated that salient information is overrepresented in causal attributions. Two experiments were conducted to investigate potential mediators for this effect and to make a case for the use of structural models in explanations of process. Two mediators were considered: enhanced visual recall of salient stimuli and exaggerated schema-relevant recall of salient stimuli. Although analyses of variance supported the visual recall model, structural analyses demonstrated its implausibility. Analyses of variance and structural models revealed that schema-relevant recall, that is, information seen as representative of causal influence, is a plausible mediator; this was particularly true of relevant visual information. Results suggest that salience effects (S. E. Taylor & S. T. Fiske in L. Berkowitz (Ed.), Advances in experimental social psychology (Vol. 11). New York: Academic Press, 1978) are due to: (a) the attentional advantage of inherently salient visual events and (b) the influence of stored visual and nonvisual schema-relevant information on causal judgments.     

Counting eliminates the repetition effect in judgments of temporal duration.

College student subjects estimated the duration of time intervals (8–54 sec) by counting or not (N=35 per group). Counting eliminated the repetition effect (a decline in the magnitude of estimations across trials), and resulted in a truncation of the psychophysical function. The former result was interpreted as contrary to Treisman's (1963) model. The latter result was attributed to the effortfulness of counting, which was established in a subsequent experiment.     

Adaptation of the category boundary between speech and nonspeech: A case against feature detectors

Two experiments were performed employing acoustic continua which change from speech to nonspeech. The members of one continuum, synthesized on the Pattern Playback, varied in the bandwidths of the first three formants in equal steps of change, from the vowel /α/ to a nonspeech buzz. The other continuum, achieved through digital synthesis, varied in the bandwidths of the first five formants, from the vowel /æ/ to a buzz. Identification and discrimination tests were carried out to establish that these continua were perceived categorically. Perceptual adaptation of these continua revealed shifts in the category boundaries comparable to those previously reported for speech sounds. The results were interpreted as suggesting that neither phonetic nor auditory feature detectors are responsible for perceptual adaptation of speech sounds, and that feature detector accounts of speech perception should therefore be reconsidered.     

Semantic focus and sentence comprehension.

Reaction time to detect a phoneme target in a sentence was found to be faster when the word in which the target occurred formed part of the semantic focus of the sentence. Focus was determined by asking a question before the sentence; that part of the sentence which comprised the answer to the sentence was assumed to be focussed. This procedure made it possible to vary position of focus within the sentence while holding all acoustic aspects of the sentence itself constant. It is argued that sentence understanding is facilitated by rapid identification of focussed information. Since focussed words are usually accented, it is further argued that the active search for accented words demonstrated in previous research should be interpreted as a search for semantic focus.