Distance perception under binocular and monocular viewing conditions

First, third, and fifth graders and college adults made judgments of absolute distance in a binocular (full-information) condition and in one of three monocular conditions: redundant texture gradient, compression gradient, and control (no texture). No age-related differences in accuracy of judgment were observed in any of the conditions. Substantial differences in the effectiveness of different kinds of information were found, however. The results indicate that the ability to register information for distance is well developed by first grade, but that substantial limitations exist on the visual system’s ability to process various forms of redundant information.     

The acquisition of catching under monocular and binocular conditions

The effects of binocular and monocular viewing on spatial and temporal errors in one-handed catching were investigated in two experiments. The first experiment-using expert catchers-recorded more spatial errors under the monocular than under the binocular condition. No significant differences in the number of temporal errors were apparent. In a second experiment, which paradigm, relatively poor catchers were trained under both vision conditions. Its objective was to investigate whether the superior results obtained under the binocular condition in the first experiment, for the number of catches and number of spatial errors, could be attributed simply to the fact that subjects had more experience with binocular than monocular viewing. The following results occurred after a period of training (a) a significant reduction in the number of spatial errors under the monocular condition, reaching a level similar to that under the binocular condition; (b) no significant reduction in the number of spatial errors when subjects transferred from monocular to binocular viewing, and significantly more spatial errors when subjects transferred from binocular to monocular viewing; and (c) a training-sequence effect. The latter effect indicates that subjects had more benefit from training in the sequence monocular-binocular than vice versa. These findings are discussed in the context of the strategies of specificity of learning and use of multisources.     

Critical flicker frequency and intelligence

Tests of verbal intelligence (Concept Mastery Test) and nonverbal intelligence (Raven's Advanced Progressive Matrices) showed nonsignificant zero-order correlations and a nonsignificant multiple correlation with critical flicker frequency (CFF), in 100 university students. Age-partialled correlations were even lower, and corrections for attenuation and restriction of range yielded unimpressive results. It was concluded that CFF has a negligible relationship to psychometric intelligence and is probably a poor tool in the investigation of the nature of g.     

Combining binocular and monocular curvature features.

A study is reported of the perception of visual surfaces in wire-frame stimuli generated by combinations of monocular surface contours and binocular disparity that provide differing information about 3-D relief. Observers vary considerably in the relative contribution made by the binocular and monocular cues to the perception of overall 3-D form. Without training, many observers may entirely fail to perceive surface curvature from the binocular disparity patterns, interpreting the form of the surface only according to the monocular information. For other observers, both cues contribute to the end percept, with the monocular interpretation dominating where the disparity information indicates planarity and with disparity dominating where disparity information suggests curvature and the monocular interpretation suggests planarity. Where stereo and monocular interpretations indicate inconsistent surface curvature features at a common location, more complex resolution strategies are suggested.     

Three- to eight-month-old infants' catching under monocular and binocular vision

We report a cross-sectional and a longitudinal experiment that examined developmental changes in the relative contribution of monocular and binocular variables in the guidance of interceptive arm movements. Three- to eight-month-old infants were observed while presented with differently sized balls that approached frontally with a constant velocity under both monocular and binocular viewing conditions. Movement onset indicated that with age infants increasingly came to rely on binocular variables in controlling the timing of the interceptive arm movements. That is, from 7 to 8 months of age movement onset was independent from object size under binocular but not under monocular viewing. In contrast, binocular viewing enhanced the spatial accuracy of the interceptive arm movements at all ages. We concluded that attunement to binocular information is a key process in infants' gaining adaptive control of goal-directed arm movements. However, interceptive arm movements entail the formation of multiple on-line couplings between optic and movement variables, each of which appears to develop at its own pace.     

Depth of monocular elements in a binocular scene: the conditions for da Vinci stereopsis

Quantitative depth based on binocular resolution of visibility constraints is demonstrated in a novel stereogram representing an object, visible to 1 eye only, and seen through an aperture or camouflaged against a background. The monocular region in the display is attached to the binocular region, so that the stereogram represents an object which is only partially visible to the eye that sees it. The results show that this feature is necessary for quantitative depth, which is not found for a fully visible monocular object in the same location, and that depth in these displays, although very precise, is not based on fusional Stereopsis. The findings provide clear support for the existence of a process of da Vinci Stereopsis, but one more sophisticated than the one proposed by K. Nakayama and S. Shimojo (1990).     

Sociability/impulsivity and caffeine-induced arousal: Critical flicker/fusion frequency and procedural learning

The influence of sociability/impulsivity in caffeine-induced arousal effects was investigated in two separate experiments: Experiment 1 examined critical flicker/fusion frequency change scores (ΔCFFT) in 60 subjects; and Experiment 2 investigated procedural learning in 30 subjects. In the two experiments, subjects received either caffeine citrate (500 mg) or placebo. The pattern of results was consistent across both studies:(1) a strong interactive effect of sociability (as measured by the EPQ extraversion scale) by caffeine/placebo which showed that (a) subjects low in sociability showed the greatest increase in ACFFT and learned most under placebo, while the reverse was true under caffeine; (b) subjects high in sociability, showed no increase in ΔCFFT and learned least under placebo, while the reverse was true under caffeine; and (2) in neither experiment did impulsivity (as measured by the EPS impulsiveness scale) significantly interact with caffeine/placebo. The results are consistent with Eysenck's (The Biological Basis of Personality, 1967) theory of personality in suggesting that subjects low in sociability are highly arousable under low-arousal (placebo) but over-aroused under high-arousal (caffeine), with the reverse pattern of effects holding for subjects high in sociability. The implications of these data for the respective roles of sociability and impulsivity components of extraversion in arousal-mediated performance are discussed.     

Possible monocular predictors of binocular rivalry of contours

An analysis of contour disappearances in conflicting patterned stereograms is made from the knowledge of two monocular events: contrast effects associated with contours and phasic local adaptation. It is argued that the percepts resulting from these monocular processes are combined simply by some more central process and that a suppression mechanism may not be necessary to account for contour rivalry. Predictions were tested in three experiments and the results tend to support the argument given.     

A simple device for producing synchronous and asynchronous binocular flicker

Many studies on binocular integration have compared in-phase and out-of-phase flicker stimulation. A new method of producing such stimulation is described. It differs from previous designs in that a combination of polarizers is used rather than mechanical light choppers or electronic flashers. The arrangement produces sinusoidal luminance pulses that can be presented with any degree of asynchrony between the two eyes.