Hemispheric symmetry in duration of visible persistence

Nine right-handed subjects performed a visual task requiring perceptual integration of a pattern whose parts were displayed sequentially in time. Correct performance on the task depended critically on the simultaneous visibility of all parts of the pattern; duration of visible persistence could therefore be gauged by varying the duration of the temporal interval between successive portions of the display. The pattern was displayed either foveally or parafoveally in either visual field. Analysis of overall performance and of distribution of errors at each temporal interval revealed more accurate performance for foveal displays but no hemispheric asymmetries in duration of visible persistence. These and other results reported in the literature are interpreted in terms of Moscovitch’s (1979) information-processing model of hemispheric functioning.     

Duration of visible persistence in relation to range of spatial frequencies

Five experiments examined the relationship between range of spatial frequencies contained in a visual display and duration of visible persistence. The high spatial frequency contents of the display were reduced by defocusing the image at the retina. Duration of visible persistence was measured by a task that required perceptual integration of a pattern whose parts were displayed sequentially in time. Experiments 1 and 2 showed that progressive reductions in the high-frequency contents of the display produced corresponding decrements in the duration of visible persistence. Experiments 3, 4, 5 showed that decrements in the duration of visible persistence could not be attributed to changes in the apparent size or in the brightness of the display brought about by defocusing. The results were interpreted in terms of the temporal response properties of perceptual mechanisms attuned to separate ranges of spatial frequencies. Strong parallels were drawn with the multichannel theory of visual information processing proposed by Breitmeyer and Ganz.     

Sentence processing: Evidence against the serial,independent stage assumption

The assumption that the processing stages involved in sentence comprehension are serially and independently executed was tested in two separate experiments using two new sentence types. One experiment was a sentence-picture verification task, the other was not. In Experiment I, subjects viewed sentences such as It's false that the dots are red and indicated, by pressing the appropriate response key, which of two colors would make the sentence true. In Experiment II, subjects verified sentences such as It isn't true that the dots aren't red against pictures of colored dots. On the strength of Sternberg's additive factor method, present findings challenge the validity of the serial, independent stage assumption, and results are alternatively discussed in terms of a capacity sharing model.This research was supported by PHS research grant MH 23401 to Sam Glucksberg, principal investigator.     

Forest lights: Notes on the conceptualization of the unconscious

Using the metaphor of lights appearing unexplained in the night, the author argues for a conceptualization of the unconscious based on a posture of trust and acceptance rather than one of fear and explanation.His last book,Idea and Experience, dealt with Husserl's project of phenomenology inIdeas I. He has recently completed another book,The Embers and the Stars: A Philosophical Inquiry into the Moral Sense of Nature.     

Perception of emotions by accepted and rejected children

The purpose of this study was to assess the perceptions of emotions by accepted and rejected children. Peer ratings and peer sociometrics were used to identify accepted and rejected children. All children were administered a task specifically designed to measure their ability to perceive emotions. This task consisted of a series of videotaped interactions involving two individuals—either two adults or two children—portraying one of three affective states: happiness, sadness, and anger. After viewing each interaction, children were asked to identify what the person was feeling. In addition, teachers and peers rated the children on their ability to perceive emotions in others. The results indicated that accepted children obtained significantly higher scores than rejected children on the identification of emotions in the interactions. Teachers and peers also rated accepted children as better perceivers of emotions than rejected children. Implications of the results are discussed.     

Zur Geschichte und gegenwärtigen Lage der Philosophie in der ČSR

Official Czech philosophy has been dominated by a mix of Engelsian philosophy of science and positivism, a combination explained in part by the survival of positivism in Czechoslovakia and the failure of analytic philosophy to make inroads into Czech thinking. However, due to Jan Patoka's influence in espousing the works of Husserl and Heidegger, there was an anthropologically oriented Marxism (K. Kosik) although its successes were greater abroad than in Czechoslovakia. A more neopositivistic variant (L. Tondl) of Marxism also appeared, but it was a short-lived phenomenon without purchase on mainstream philosophy.A certain renewal of Czech philosophy was evident before 1968, once again largely due to Patoka's influence. Foreign guests who took part in informally organized, often secret, seminars and discussion groups were very instrumental in spreading new ideas. Despite these positive occurrences, Czech philosophy is experiencing a crisis at the level of the middle generation of non-academic, philosophically competent intellectuals among whom sceptical and nihilist attitudes prevail. A rebirth of spirit may be in the offing if the recovery of the specific sense of the Czech Reformation's idea of truth is pursued.     

Sensorimotor synchronization: Motor responses to regular auditory patterns

Subjects (N = 32) were asked to synchronize a motor response with tones in auditory patterns. These patterns were created from six tones and six intertone intervals of equal duration. The pitch of the first tone differed from the others. It was found that subjects used three types of timing in their motor response: (1) the first intertone interval was prolonged and the second interval was shortened, (2) the second intertone interval was prolonged and the first interval was shortened, and/or (3) the first interval and the second interval were of approximately the same length. The prolongation of the fifth interval was observed during all three types of timing. The results are explained using the concept of suprasegmental control of timing, which explains a prolongation of intervals at critical control point of the patterns. The occurrence of three different strategies of timing is discussed in connection with similar principles in musical performance.     

Age-related changes in rate of visual information processing

Each of four groups of 12 subjects performed four psychophysical tasks. The age ranges of the four groups were 19-31, 45-57, 58-70, and 71-83 years, respectively. All four tasks required some form of visual information processing: Two were backward-masking tasks; two were temporal-integration tasks. In all four tasks increasing temporal functions over age were obtained, suggesting slower processing rates as age increased. The results support an active processing model of visual perception that interprets duration of visible persistence and duration of interval in which backward masking is effective as indices of the time course of early stages in the processing of stimulus features. The evidences also suggests that backward masking and visible persistence may be mediated by distinct mechanisms that are affected differently by aging processes. A model that conceptualizes the visual system as a multichannel processor is proposed as an explanation for some of the findings.