Lateral asymmetry in the perceived sequence of speech and nonspeech stimuli

The task was to estimate the position where a click had been superimposed in a spoken sentence. Experiment 1 confirmed Fodor and Bever’s observation of an ear-asymmetry effect: the click is located earlier when it is presented to the left ear and the sentence to the right ear than with the opposite arrangement. In Experiment 2, combinations of monaural and binaural presentations were considered. They made it possible to eliminate interpretations which link the laterality effect to the fact of reaching or not reaching a particular ear and showed that the relevant factor is the relative position of the stimuli in acoustic space. Experiments 3 and 4 explored the relation between spatial separation and perceived sequence in greater detail. The relation involves a plateau: when the click comes to the left of the speech, it is preposed to a degree which depends on the amount of spatial separation; but, when it comes to the right of the speech, separation is irrelevant and the mean error is of the same order of magnitude as in a control condition without separation.     

Perceiving the sequence of speech and non-speech stimuli

The task is to estimate on which syllable of a spoken sentence a click was superimposed. Experiment I confirms Ladefoged and Broadbent's finding of a systematic tendency to prepose the click (negative displacement), but shows also that the tendency is decreased when prior knowledge of the sentence is provided. Experiment II shows that acoustic prior knowledge is not necessary to produce the decrease and that it occurs also with textual prior knowledge. Experiment III shows that the negative displacement is not eliminated by short-term practice on the task, as Fodor and Bever contended. The effect of prior knowledge is inconsistent with the explanation of negative displacement in terms of attention demands suggested by Ladefoged and Broadbent. It is argued that this explanation was unnecessary, and that negative displacement can be expected in a system which analyses speech by discrete units.     

The time-course of preparation with regular and irregular foreperiods

A previous experiment (Bertelson, 1967) had shown that the temporal information brought by a warning signal affected RT even after very short foreperiods (FPs). The present experiment was carried out to examine whether this result was contingent on the predictability of the FP. After a 5 sec. waiting delay, the subject heard a warning click which was followed after a predictable (regular procedure) or unpredictable FP (irregular procedure) by the visual signal calling for a choice reaction. The range of FPs was 0-300 msec, again. The time course of the adjustments triggered by the click was found to be similar under both procedures. The main conclusion is that a shift from preparation to reaction can occur at any time and need not be programmed before preparation is started.     

Psychology experiments: Spiritism at the sorbonne

During the years which followed World War I, psychologists of the Sorbonne organized “control experiments” to question the reality of parapsychological phenomena. They worked with well-known mediums and the results of their investigations were published in widely-read French and American newspapers. Despite the melodramatic and somewhat humorous character of these episodes, the researchers involved were engaged in efforts toward genuinely scientific psychology. Henri Pieron and Henri Laugier, both positivists and militant rationalists, were leaders in the institutionalized development of psychology in France.