The production and fading of entoptic images

A new apparatus, suitable for obtaining reliable reports of entoptic images, was developed. Basically, this apparatus moved a small light across the S’s eyelid (transcleral illumination). While the light was moving, Ss reported the appearance of the three entoptic phenomena of interest-retinal blood vessels, foveal images, and background illumination. After initial training with this apparatus, 12 Ss were tested for the differential disappearance (fading) of the entoptic images after the light source stopped moving but continued its transcleral illumination of the retina. Results indicated that although the background image did fade to a dark field, this background fade time ( \(\bar X\) = 1.3 sec) is faster than that reported for externally stabilized images, which may take 2 to 4 sec to fade, and was significantly slower than the very rapid fade times for blood vessels and foveal images. Furthermore, there was no reappearance of these entoptic images.     

Temporal and spatial factors in the fading of diffuse visual images

Pattern vision breaks down after a period of inspecting a diffusely contoured dark figure upon a ground of uniform brightness and texture. When the field is illuminated with flickering light it is found that the persistence of pattern vision is inversely related to flicker frequency up to the region of fusion. At low flicker frequencies complex figures persist longer than less complex ones of equivalent area, but the reverse applies at frequencies above fusion. These findings are consistent with data obtained from experiments using stabilized retinal images     

Management of extended-wear contact lenses in infant rhesus monkeys

Infant rhesus monkeys were fitted with extended-wear contact lenses (EWCLs) to correct surgically induced aphakia. The protocol that produced the most favorable experimental outcome, including good lens-wear compliance, involved: (1) custom-made EWCLs with parameters adjusted for each animal, (2) selection for study of neonates who seemed to tolerate EWCLs most naturally, (3) individual housing of monkeys, (4) lens check at 2-h intervals around the clock by trained personnel, (5) a large inventory of EWCLs for each animal, (6) periodic ophthalmologic examinations, and (7) darkroom housing of monkeys during treatment of lens-wear-related incidents. The EWCL is a new tool for studies of the visual system and is a useful complement to existing experimental techniques.     

The fading of stabilized images: Eye movements and information processing

Two experiments are reported which indicate that neural and photochemical satiation processes are inadequate to explain the fading of the stabilized retinal image. When eye movements are attempted over the stimulus, fading occurs more rapidly, indicating an information processing component in the disappearance of the image.     

Foundations of spatial vision: from retinal images to perceived shapes

Vision is based on spatial correspondences between physically different structures--in environment, retina, brain, and perception. An examination of the correspondence between environmental surfaces and their retinal images showed that this consists of 2-dimensional 2nd-order differential structure (effectively 4th-order) associated with local surface shape, suggesting that this might be a primitive form of spatial information. Next, experiments on hyperacuities for detecting relative motion and binocular disparity among separated image features showed that spatial positions are visually specified by the surrounding optical pattern rather than by retinal coordinates, minimally affected by random image perturbations produced by 3-D object motions. Retinal image space, therefore, involves 4th-order differential structure. This primitive spatial structure constitutes information about local surface shape.     

Development of planning and its relation to other cognitive processes

The purpose of this study was to (a) delineate the course of development of children's planning skills during school years, (b) examine whether different levels of planning exist, and (c) explore the role of other cognitive processes as cognitive correlates of planning. The participants were 250 students, 50 from each of the five targeted grades (3, 5, 7, 9, and 11). They each completed a battery of planning, attention, and simultaneous and successive processing tasks. MANOVA indicated that the main effect of grade was significant, whereas gender had no significant effect on planning. Pairwise comparisons of performance means between grades indicated that developmental trajectories were not uniform across planning tasks. Correlation and regression analyses showed that the relationship between planning tasks and attention, and simultaneous and successive processing scores varied as a function of the planning task and the grade level. Furthermore, two planning factors were found and cluster analyses of variables indicated that one of the tasks, Crack-the-Code, may represent a different kind of planning than the other planning tasks used.     

The relationship between sighting dominance and the fading of a stabilized retinal image

The fading of a stabilized retinal image in the sighting and the nonsighting dominant eye was studied using the Haidinger’s brush target. Reaction time to the complete disappearance of the stabilized image was significantly longer when the target was input to the sighting eye. The greater persistence of stabilized targets in the sighting eye suggests possible differences in the neural channels from the two eyes or processing differences in the two monocular channels that are related behaviorally to eye dominance.     

Speed choice in relation to speed limit and influences from other drivers

Speeding is a general problem in traffic and exploring factors underlying the choice of speed is an important task. In the present paper, based on data from Swedish drivers on 90 km/h roads, drivers’ attitudes towards speeding and influences from other road users on the drivers’ speed choice were investigated. Unobtrusively recorded vehicle speeds were compared with drivers’ responses to questions concerning their speed choice (N=533). The present investigation replicates a previous study on 50 km/h roads, where a model including measures of attitudes and perceptions about others’ behaviour could explain about 15% of observed behaviour. In the present study, where a majority of the drivers observed exceeded the speed limit, a similar model could explain 41% of the variance in observed speed. Theoretical and practical implications of the results are discussed.     

The relation of multiserial eta to other measures of correlation

Ordinary product-moment correlation and regression methods are frequently not immediately applicable to qualitative data, whereas multiserialr, point-multiserialr, and multiserial eta can be easily applied. The multiserialr is rejected for prediction since it tells us only what the correlationmight be if certain assumptionswere true and if wecould measure what isnot now measured. The point-multiserialr and multiserial eta are identical when the number of categories is two but differ when it is three or greater. The multiserial eta is identical with the product-momentr when categories are assigned scale values equal to their means on the continuous variable. With three or more categories, the point-multiserialr, whichassumes linearity withequal step intervals, is always lower than the multiserial eta, whichforces linearity by adoption ofunequal step intervals based upon difference in criterion attainment. While the multiserial eta expends one degree of freedom with the weighting of each category, this is known and correctable, whereas the vague partial loss of degrees of freedom due to the ordering of categories in the point-multiserial is not correctable.Personnel Research Section, A.G.O.     

Effects of framed spectacles and contact lenses on self-ratings of facial attractiveness.

15 females with glasses tended to defend against relatively low self-perceptions of attractiveness by de-emphasizing the influence of their eyes on facial beauty.     

Iconic memory and its relation to perceptual processing and other memory mechanisms

Research on iconic memory is reviewed. Specific issues discussed include the duration of the icon, effects of stimulus variables, types of information lost, selection, processing capacity, and scanning. More general issues include the level of encoding in the icon and its relation to short-term memory. It is also argued that a number of experiments do not show what they were intended to show because of possible methodological problems. The view is developed that iconic memory is postretinal but uncoded; nor is it influenced directly by strategies or subsequent mechanisms.     

The use of contact lenses for the lateralisation of visual input in man.

This research demonstrates the use of a new method of investigating lateralised hemisphere functions. Specially designed contact lenses were used, which directed visual input to either the left or the right cerebral hemisphere. These lenses are an advance on previous methods used in investigating hemisphere function in that they enable the subject to react to stimuli without restrictions on movement and without time limitations on the exposure of stimuli. Investigations of language and visual-spatial functions showed that the lenses appeared to be very effective in lateralising verbal and spatial information.