Visual imagery and evoked-responses

Summary Two experiments were performed to determine whether a physiological correlate of visual imagery could be measured from visually-evoked-responses (VERs). High and Low imagery groups were used. There was no direct effect of imagery, although some differences between the groups emerged. These differences are thought to be due to factors associated with imaging, but not imagery per se.     

Parafoveal word perception: A case against semantic preprocessing

The present experiment investigated semantic information extraction in parafoveal word perception. An ambiguous word (bank) was presented in foveal vision, and simultaneously a disambiguating word (water, money) was presented in the parafovea. Subjects were required to make a forced choice between two phrases, and the task was constructed so that a correct choice could be made if semantic information about both the foveal and parafoveal word had been obtained. However, the results indicated that the forced-choice results could be explained by two factors: identification of the parafoveal word and correct guessing. Hence, it was concluded that those models of reading which rely on unconscious semantic preprocessing of parafoveal words were not supported.     

Proportionality,linearity, and parameter constancy: Messick and Sentis reconsidered

Messick and Sentis found greater support for weak proportionality in subjects' outcome allocations (suggesting that subjects wish to maintain a constant ratio between outcomes across situations when inputs are held constant) than for constant differences between outcomes. They claimed that their data thus provided stronger support for Adams' ratio definition of equity than for Harris' linear formula. A dialogue between the two sets of authors establishes that (1) so far as their specification of fair outcomes is concerned, Adams' formula is a special case of the linear formula; (2) weak proportionality does not necessarily follow from Adams' formula and can be derived from the linear formula; (3) Adams' formula applied to subjective (rather than experimenter-defined) inputs nevertheless provides a more natural base from which to derive weak proportionality than does the linear formula in its general form; (4) excellent fits to several sets of data, including much better fit to Messick and Sentis' data than that provided by weak proportionality, are obtained if we assume that subjects use allocations which are a weighted average of those implied by Adams' formula, the Equality principle, and Komorita and Kravitz' Equal Excess Norm; and (5) a fit to Messick and Sentis' data that is almost as good as that provided by the weighted solutions model is obtained by assuming that subjects apply Adams' formula to subjective inputs and subjective outcomes that are different from the corresponding experimenter-defined values. It is agreed that the delineation of the relationships among observable properties of outcome distributions, alternative equity formulae, and different psychological processes is as important as it can be devious.     

Asymmetries in the perceptual span for Israeli readers

Native Israeli readers read Hebrew and English text as their eye movements were monitored. A window of text moved in synchrony with their eye movements and the window was either symmetrical about the fixation point or offset to the left or right. When subjects were reading Hebrew, the perceptual span was asymmetric to the left and when they were reading English it was asymmetric to the right. The results point out the importance of attentional factors in reading.     

Is visual information integrated across saccades?

After subjects established fixation on a target cross, 12 dots were presented parafoveally. When the dots were presented, the subjects made an eye movement to the location of the dots, and during the saccade the 12 initially presented dots were replaced by 12 other dots. The 24 dots were part of a 5 × 5 matrix, and the task of the subject was to report which dot was missing. The data were consistent with other recent studies: subjects could successfully report the location of the missing dot far above chance (54%), whereas performance in a control condition (in which the two sets of dots were presented to different spatial and retinal locations) was almost at chance level (10%). However, a number of control conditions demonstrated that the effect was due primarily to persistence from the phosphor of the cathode ray tube used for stimulus presentation and that little of the visual information integrated was across two fixations. Implications of the results for a theory of integration across saccades are discussed.     

Sexual activity and contraceptive use among low-income urban black adolescent females.

A modified form of Nathanson and Becker's (1983) Health Belief Model Questionnaire and other measures designed to assess cognitive processing were administered to low-income black adolescent female clients of an inner-city comprehensive health care clinic. The purpose of the study was to explore determinants of sexual activity and contraceptive use. Subjects were classified as not sexually active (n = 50), sexually active/noncontracepting (n = 20), or sexually active/contracepting (n = 72). Not sexually active subjects tended to be younger, more career motivated, to have a father at home, to be more influenced by family values, and to have more conservative attitudes regarding adolescent sexuality than did sexually active subjects. Sexually active/noncontracepting subjects tended to report fewer benefits and more barriers to the use of contraception. Level of cognitive processing did not differ among the three groups, but was at a lower-than-expected level for age. Finally, inconsistent contraceptive use was common to both sexually active groups.     

Making and correcting errors during sentence comprehension: Eye movements in the analysis of structurally ambiguous sentences

Eye movements were recorded as subjects read sentences containing temporary structural ambiguities. In accord with the garden-path theory of sentence comprehension, shorter reading times were found for sentences conforming to certain independently motivated parsing strategies (late closure and minimal attachment) than for comparable sentences which violate these strategies. Further, longer fixation durations were associated with the very first fixation in the region of the sentence which disambiguated the sentence, suggesting that the human sentence-parsing mechanism operates in a rather systematic fashion, immediately computing the structural consequences of fixated material for the analysis of preceding material. The pattern of regressive eye movements did not conform to the view that the parsing mechanism automatically returns to the beginning of the sentence to revise an incorrect analysis of linguistic material nor did it support the view that the parsing mechanism systematically backtracks through the sentence until the source of the erroneous analysis is located. Rather, the pattern of regressions indicated that the parsing mechanism typically engages in selective reanalysis, exploiting whatever information it has available about the type of error it has committed to guide its reanalysis attempts. Finally, it is emphasized that an understanding of the parser's revision procedures is essential to an explanation of why certain linguistic structures cannot be successfully parsed by humans.     

Information flow in the brain: Computer requirements (A tutorial)

This paper covers mathematical, statistical, and experimental design considerations needed to design a computer system for EEG data acquisition, spectrum, and cross-spectrum analyses. A tutorial approach is used in which no formal proofs are offered. Conclusions are stated simply and in summary fashion, without justifying arguments. References to formal works are given. Conclusions about system design are discussed. Frequently encountered design issues are mentioned with various alternatives.