Frequency response characteristics for sinusoidal movement in the fovea and periphery

Threshold sensitivity was measured for sinusoidal movement of bright 1-deg lines against a dark background as a function of oscillation frequency and retinal location. Sensitivity was greatest in the fovea and at a frequency of 1–2 Hz. Peripheral sensitivity was more narrowly tuned than foveal sensitivity. The presence of a stationary reference line affected mainly the foveal sensitivity. The results are interpreted as evidence for both position- and velocity-sensitive mechanisms in the movement detection system.     

Alterations of the phonetic coding of speech sounds during repetition

One aspect of the comprehension of speech is the assignment of a phonetic representation to the sounds being heard. However, if a person listens to a meaningless syllable that is continually repeated, over time he will hear the syllable undergo a variety of changes. These changes are very systematic in character and represent alterations in the phonetic coding assigned to an unchanging sound stimulus. When the restricted nature of the changes that occur is analyzed phonetically, these changes are found to invlove a reorganization of the phones constituting the syllables and changes in a small number of distinctive features.     

EMG waveform duration: A validation method for the surface electromyogram

The electromyogram (EMG) recorded with surface electrodes was examined using a triggered oscilloscope technique. When all but the high-amplitude waveforms in a given segment of activity were excluded from analysis, it was found that the duration of the remaining waveforms was specific to the muscle that produced them. That is, waveforms of a given duration were recorded whenever conventional indices-observable contraction, joint movement. needle recordings-showed activity in a specific muscle. This led to the suggestion that waveform duration might be used to validate the surface EMG. The suggestion. which is limited by the need to control posture and electrode placement, both of which may influence waveform duration, was illustrated in application to psychological research.     

NÉCESSITÉ ET SIGNIFICATION DES RECHERCHES COMPARATIVES EN PSYCHOLOGIE GÉNÉTIQUE

Need and meaning of comparative studies in genetic psychology. — The comparative studies in the field of genetic psychology are indispensable for Psychology in general and also for Sociology, because only such studies allow us to separate the effects of biological or mental factors from those of social and cultural influences on the formation and the socialization of individuals. Relevant to this discussion is the well-known issue between culturalistic psychoanalysts like Fromm, Horney, etc., and classical freudian psychoanalysts who reduce the whole individual development to an endogenous evolution of « instinct ». In the field of cognitive functions to which this paper is devoted, at least four kinds of various factors must be distinguished, the respective influences of which can be separated through comparative studies : I. Biological factors depending on the “epigenetic” system (maturation of nervous system, etc.). These factors probably explain the sequential aspects (constant and necessary order) of the stages in the development of operative intelligence. However, if only these factors were acting, the stages would not only appear in a sequence, but at the same ages, whereas in fact, the ages where a stage appears differ from one environment to another. 2. Equilibration or autoregulation factors, determining behavior and thought in their various specific activities. They correspond to the sequential forms in general coordination of the actions of individuals as interacting with their physical environment; such intervening regulations are probably at the origin of the mental operations themselves, especially logical - mathematical operations. 3. General socialization factors, which are identical for all societies : cooperations - discussions - oppositions - exchanges, etc., between children or between adults or between adults and children. These factors 3 are closely related with the factors 2, because the general coordination of actions concerns inter-individual as so as intra-individual actions. 4. Factors related to educational and cultural transmission, which differ from one society to another; they are those we usually have in mind when we say briefly “social factors”. To discuss the influence of these four factors, Mohseni's study on Teheran school children and illiterate rural children is given as an example. Three results were obtained : (1) For “conservation” tasks, the same stages of intellectual development are observed for urban and rural children, in Iran as well as in Europe. (2) For these same tasks, a systematic delay of two to three years is observed among rural children with respect to Teheran children. (3) For performance tests (i.e. Porteus, Goodenough, etc.) there is a delay of four and primarily five years. These data seem to show that there is some sequential order of the stages which depends partially on the factors I. But, the ages for each stage are not constant, showing the factors 2 and 3 are intervening in a probably inseparable way. On the other hand, the difference between the actual operative results and the performance tests seems to indicate that a distinction might be made between the factors of general coordination (factors 2 and 3) and the educational transmissions (factors 4). About these last factors, the three and four year delays observed by Canadian psychologists working in Martinique with school children (French curriculum) in operative tasks (like conservations) seem to indicate that the general operations depend less on school than on the activities themselves of children or in general on the adult stimulations in the environment. We must pay special attention to the problems raised by language. In some precise and systematic experiments in Geneva, Sinclair shows children on the “preoperative” level (i.e. with no conservation…) do not spontaneously use the same language as operative children : the former use chiefly “scale” words (“much” or “many”, “little” or “few”, “large”, “small”) and the latter use chiefly “vector” words (“more”, “less”). If the younger subjects are submitted to a verbal training, they do learn to use the older children's language, but it only results in very little operative improvement (about one case out of 10 subjects on the average). Therefore, replicating the same experiments in countries speaking different languages would be very interesting. For instance, in the Turkish language, there is only one “vector” word, i.e. “again”; so that the Turk says “again much, again many” to say “more”. Then, the question is to know whether a change will be observed for the stages of logical-mathematical operations or whether these operations will be found everywhere with their identical common background; it seems that this last conclusion has already been observed in Aden (Hyde), Hong Kong (Goodnow), South Africa (Price-Williams). In conclusion, the kind of psychology we develop in our social environments, remains conjectural as long as comparative extensive and systematical research is not available; a great effort is still to be made in this direction.     

Disruption of proofreading by irrelevant speech: Effects of attention,arousal or memory?

A series of five experiments examined the effects of irrelevant speech on proofreading and memory. Four of the experiments used a proofreading task and showed that the deleterious effects of irrelevant speech: (1) depend on the speech being meaningful, (2) are only present when the burden on short-term memory is low and (3) are manifested in a lower detection rate for non-contextual as opposed to contextual errors. Neither the spatial location of the speech (either in terms of spatial dispersion of sources or spatial movement of a single source) nor the intensity of the speech (in a range bounded by 50 dB(A) and 70 dB(A)) had any effect on proofreading. Late selection models of attention are favoured by the results in preference to models having arousal, short-term memory or early selection in attention as their basis. A final experiment showed serial recall for visual lists to be impaired by the presence of any speech-like sound (including reversed speech and speech in an unfamiliar language) which suggests a set of phenomena qualitatively different from those associated with proofreading. Throughout the article the practical consequences of the findings are emphasized.