Eyeblinking during autokinetic movement observed by a subject living in the up-down inverted visual world

Eyeblinking during autokinetic movement observed by one subject living in the up-down inverted visual world, was investigated. The subject wore frame-spectacles (without prisms) for the first two days and then wore up-down inverting spectacles (with prisms) for the next four days, followed by the resumption of the former frame-spectacles for one day. Eyeblinks during autokinetic movement were measured by using vertical EOG. Analysis showed (1) the occurrence of eyeblinking during autokinetic movement was not influenced by living in the up-down inverted visual world; (2) the frequency of eyeblinking during autokinetic movement significantly decreased with successive days of observation.     

Effects of living in the up-down inverted visual world on apparent movement

The purpose of this study was to examine whether a change of perceptual framework may affect the occurrence of apparent movement. Apparent movement was observed by one subject living over four days in the prismatically inverted visual world, because this situation was considered as the operation in which the subject was forced to change the perceptual framework to adapt himself to the novel environment. Apparent movement with two points was measured in vertical and horizontal configurations before wearing and after removing the prism as well as while wearing it. Analysis showed significant effects of prism-wearing on the occurrence of apparent movement in both vertical and horizontal configurations. Although further elaboration is required, an hypothesis was suggested from the viewpoint of the loss of visual position constancy.     

The origin of the autokinetic effect

The effects of unbalanced fatigue of the ocular and neck musculature on the auto- kinetic effect are described. It is shown that after deviation of the eyes to an extreme position, fixation of a small light source with the eye in the central position gives rise to an immediate and pronounced autokinetic effect. This apparent movement is typically in the same meridian as that of the ocular deviation and is often, at all events at first, in the opposite direction. Similar, though less clear-cut, results are obtained after induction of unbalanced fatigue in the neck musculature. It is argued that the autokinetic effect observed under these conditions warrants treatment as a primary illusion of movement and does not involve a “framework” or standard of reference. In an appendix, a speculative model of the ocular control system and some preliminary observations are presented. It is concluded that the autokinetic effect is principally due to spontaneous minor fluctuations in the neural system which monitors the outward signals controlling eye movement.     

A PHENOMENOLOGICAL APPROACH TO AUTOKINESIS

Analysis has shown that autokinesis constitutes a complex group of phenomena. Certain autokinetic movements ('paradoxical', i.e. experienced displacement without movement or vice versa) could not be adequately recorded by the 'tracing method', very often employed, or by other forms of purely physical registration. Autokinesis ought to be divided into a 'free' type (which may be 'paradoxical') and a 'restricted' type (always 'non-paradoxical'). 'Free' movements were experienced either in a plane perpendicular to the line of vision or as 'ad-ab' movements. 'Restricted' movements were described as either 'swinging' or 'undulating'.     

Autokinesis and some conditions of fatigue

Effects of physical, mental, and vigilance fatigue on the autokinetic reports of 48 undergraduate students are described. Eight response measures were taken of the subjects with an apparatus that permitted recording of the apparent motion of the autokinetic stimulus in the same plane as the light source. Presence of the fatigue states was verified by independent measurements. Fatigue conditions facilitated quick and continuous perception of the autokinetic movements. The most perceptual complexity in the patterns of apparent motion was observed under mental fatigue followed by physical and vigilance fatigue, with least in the neutral condition.     

Autokinetic movement in geometric illusions: a note.

Four static geometrical illusions were presented in an autokinetic movement situation. 50 Ss saw each form four times. Of the total responses, 36% were no-movement responses while 37% of the time the total figure was seen as moving. The meaning 27% of the responses involved apparent movement in only a part of the figure. In general, the elements seen as moving are the parts misperceived in the static geometrical illusion.     

The position of random autokinetic movement and the physiological position of rest are frequently stable and identical

Both the autokinetic illusion (AKI) and involuntary eye movements when a fixation point goes off have been attributed to unmonitored drift eye movements which result from constant features of the oculomotor system. Pilot studies confirmed that the visual directions where these effects had no directional bias, the position of random autokinetic movement (PRAKM) and the physiological position of rest (PPR), were highly correlated and reliable. The more precise main experiment showed that they were usually, but not always, stable and identical. Drifts are therefore not totally due to stable features of the oculomotor system but are a compound of several slow responses which can differ with both stimulus conditions and time. They are not all equally unmonitored.     

Profile of perceptual-cognitive traits and personality style of possible relevance to creative productivity.

The amount of illusory movement perceived on the autokinetic test, manifestations of primary process expression on the Rorschach, and creative productivity as measured by the Torrance Tests of Creative Thinking, were collected from 47 volunteer college students. Those individuals who expressed primary process thinking as blatant affect and the fusion of images, and elaborated on a stimulus pictorially, had extensive movement on the autokinetic test (P less than .05). We further delineated certain personality characteristics of these individuals employing a 26-item bipolar questionnaire. They are among other things, active, striving, assertive, in touch with and free to express emotion, rebellious, incautious, self-determing, productive, motivated to influence others, and excelling in producing objects or ideas which are unique.     

Autokinetic movement as a function of symbolic meaning of target shape.

The autokinetic movement responses of 10 American, 10 Chinese, and 10 Iranian students to religious symbols and control stimuli were measured. The hypothesis of differential direction response as a function of the target shapes was supported. Iranian students did show a pattern of responding significantly different from the American and Chinese.     

The role of vision in the temporal and spatial control of handwriting.

The general observation that handwriting is not noticeably impaired by the withdrawal of vision can be explained in two ways. One might argue that vision is not needed during the act of writing. Micro-analyses should then reveal that spatial as well as temporal writing features are identical in conditions of vision and no vision. Alternatively, it is possible that vision is needed during the act of writing, but that without vision possible errors and inaccuracies have to be prevented. Assuming that the latter would place an extra demand on movement control, this should be revealed by an increase in processing time. We have found evidence for the latter view in the present study in which 12 subjects wrote a nonsense letter sequence with and without vision. Close examination showed that writing shapes remained equally invariant under both vision conditions, suggesting that spatial control was unaffected by withdrawing vision. The prediction that invariance of shapes is preserved in the absence of vision at the expense of processing time increments was confirmed. The increase of reaction time observed when visual guidance was withdrawn suggests that more processing time was needed prior to the movement start. Moreover, the RT increment was larger when a short writing duration was instructed. The present findings will be discussed in light of the remarkable flexibility of writing as a motor skill in which writers appear to be able to employ specific strategies to preserve shape in the absence of visual guidance.     

The lability of the tactile-kinaesthetic framework

This paper is concerned with the ability to recognize settings of a rod (pivoted at the centre) at various angles of tilt without the use of vision. Five angles of tilt, all within the upper right quadrant, were used and 80 subjects took part in the experiments. It is shown that tactile-kinaesthetic recognition of a given angle of tilt is decidedly poor, subjects commonly reporting that the position of the rod had been changed. The direction of these subjective shifts was found to be in general towards the centre of the quadrant. If, following the recognition experiments, the subjects were required to judge settings of the rod in fact vertical and horizontal, errors made tended to be in a direction opposite to that normally found in making these judgements. It was further found that attempts to reinstate the original settings led to mean judgements equivalent to those given on the recognition tests, but with signs reversed. These various phenomena are ascribed to lability and disorganization of the tactile-kinaesthetic framework. An analogy with the autokinetic phenomenon is adduced.     

Outflow theory and autokinetic movement: color, viewing angle, and dark adaptation.

The number of reported changes in direction of autokinetic movement was assessed as a function of color of the light that served as stimulus, viewing angle (0, 30, or 60 deg of displacement from straight ahead), and dark adaptation. Color and dark adaptation had no significant main effect on the number of reported changes in direction for the red and yellow lights, but viewing angle was inversely related to the number of reported changes. For the blue-green light, atypical effects of viewing angle and dark adaptation were found.     

Expectation and autokinesis

The reported direction of autokinesis for naive observers is not biased by gaze deviations of 22.5 deg of arc. However, instructions to expect either “inward” or “outward” movement produce reports of autokinetic movement that are progressively biased in the expected direction. Instructions to expect “more” or “less” movement resulted in a decrease in the reported duration of apparent movement for the “less” group but no change for the “more” group. Response bias is not considered to play a role in these results. The results are discussed in terms of fixational bias and selective attention mechanisms of autokinesis.     

MOVEMENT AND DISTORTION IN VISUAL PATTERNS DURING PROLONGED FIXATION

H onisett , J., and O ldfield , R. C. Movement and distortion in visual patterns during prolonged fixation. Scand. J. Psychol ., 1960, 2 , 49–55.—Observations are reported from which it appears that if fixation upon a single point in a complex visual field is maintained for periods of half a minute or more a proportion of normal individuals experience movement of the whole field or of parts of it. Changing distortions of form and pattern can result. Some types of this movement are, it is thought, improbably due to intrinsic or extrinsic ocular changes, and more resemble the autokinetic phenomenon. It is suggested that eye-movements and their visual consequences are indispensable to the maintenance of a stable coordinate system in the visual world.     

Movement segmentation and visual perturbation increase developmental differences in motor control and learning

We examined the developmental differences in motor control and learning of a two‐segment movement. One hundred and five participants (53 female) were divided into three age groups (7–8 years, 9–10 years and 19–27 years). They performed a two‐segment movement task in four conditions (full vision, fully disturbed vision, disturbed vision in the first movement segment and disturbed vision in the second movement segment). The results for movement accuracy and overall movement time show that children, especially younger children, are more susceptible to visual perturbations than adults. The adults’ movement time in one of the movement segments could be increased by disturbing the vision of the other movement segment. The children's movement time for the second movement segment increased when their vision of the first movement segment was disturbed. Disturbing the vision of the first movement segment decreased the percentage of central control of the second movement in younger children, but not in the other two age groups. The children's normalized jerk was more easily increased by visual perturbations. The children showed greater improvement after practice in the conditions of partial vision disturbance. As the participants’ age increased, practice tended to improve their feedforward motor control rather than their feedback motor control. These results suggest that children's central movement control improves with age and practice. We discuss the theoretical implications and practical significance of the differential effects of visual perturbation and movement segmentation upon motor control and learning from a developmental viewpoint.     

Coding processes in preselected and constrained movements: effect of vision

Three experiments were conducted in which visual information was manipulated either at the endpoint or during preselected, subject defined and constrained, experimenter-defined movements. In Experiments 1 and 2 the subject's task was to reproduce the movement in the absence of vision. Augmenting the terminal location of the criterion movement with vision had no differential effect on reproduction in Experiment 1, although preselected movement accuracy was significantly superior to constrained. Providing vision throughout the criterion movement in Experiment 2 not only failed to improve the accuracy of constrained movements but decreased reproduction performance in preselected movements. In Experiment 3 procedures were adopted to control the allocation of the subjects' attention during the criterion movement. The subjects reproduced by vision alone, movement alone, or with both visual and movement information available. When subjects were informed of the modality of reproduction prior to criterion presentation, they were able to ignore concurrent input from vision and attend to movement information. In the absence of precues visual information was spontaneously attended. The data were interpreted as contrary to closed-loop assumptions that additional information necessarily enhances the strength of a motor memory representation. Rather, they can be accommodated in terms of Posner, Nissen and Klein's (1976) theoretical account of visual dominance and serve to illustrate the importance of selective attention effects in movement coding.     

Development of Multiple Movement Representations With Practice: Specificity Versus Flexibility

The question addressed in the present experiment was whether an individual who practices a task under different conditions of afferent information develops different movement representations, each of which is based on the most accurate source of afferent information for movement control. In Experiment 1, participants (N = 23) performed a manual aiming movement in a target-only condition for 520 trials before performing in a normal vision condition for an equivalent amount of practice. Control groups performed all practice trials in either a normal vision or a target-only condition. The results revealed that the movement representation developed in the initial (target-only) practice phase remained accessible for movement planning and control. The results of Experiment 2 indicated, however, that participants did not maintain such a representation when their initial practice in the target-only condition was reduced (40 or 160 trials) before they had extensive practice in normal vision. Those results indicate that extensive practice in a target-only and then in a normal vision condition enables an individual to plan and control his or her movement on the basis of the most efficient source of available afferent information. Because visual afferent information provides optimal information for ensuring movement accuracy, however, if initial practice in the target-only condition is only modest or moderate it is likely that that information source will progressively dominate all other sources of afferent information for movement planning and control.     

Development of multiple movement representations with practice: specificity versus flexibility

The question addressed in the present experiment was whether an individual who practices a task under different conditions of afferent information develops different movement representations, each of which is based on the most accurate source of afferent information for movement control. In Experiment 1, participants (N = 23) performed a manual aiming movement in a target-only condition for 520 trials before performing in a normal vision condition for an equivalent amount of practice. Control groups performed all practice trials in either a normal vision or a target-only condition. The results revealed that the movement representation developed in the initial (target-only) practice phase remained accessible for movement planning and control. The results of Experiment 2 indicated, however, that participants did not maintain such a representation when their initial practice in the target-only condition was reduced (40 or 160 trials) before they had extensive practice in normal vision. Those results indicate that extensive practice in a target-only and then in a normal vision condition enables an individual to plan and control his or her movement on the basis of the most efficient source of available afferent information. Because visual afferent information provides optimal information for ensuring movement accuracy, however, if initial practice in the target-only condition is only modest or moderate it is likely that that information source will progressively dominate all other sources of afferent information for movement planning and control.     

Effects of target-background luminance ratios upon the autokinetic illusion

This study investigated effects of the target-background luminance ratios upon the autokinetic illusion, with special emphasis on manipulation of the background intensity. Exp. 1, in which the effects of four levels of target luminance were examined against the completely dark background, showed that the target luminance did not affect the illusion as long as the target was small enough in size (0.17 degrees in visual angle). This result confirmed the suggestion by Edwards in 1954. In Exp. II effects of the target-background luminance ratios were examined by varying the luminance of target and background independently. Dominant illusory patterns at the luminance ratio 1 were "pendulum-like" and "bobbing"; these differed from those at higher ratios ("winding"). On the other hand, latency and duration were not affected by the ratios. These findings suggest that the movement pattern is effective in specifying the autokinetic illusion, if it is appropriately categorized and represented.     

Tye-dyed teleology and the inverted spectrum

Michael Tye’s considered position on visual experience combines representationalism with externalism about color, so when considering spectrum inversion, he needs a principled reason to claim that a person with inverted color vision is seeing things incorrectly. Tye’s responses to the problem of the inverted spectrum (2000, in: Consciousness, color, and content, The MIT Press, Cambridge, MA and 2002a, in: Chalmers (ed.) Philosophy of mind: classical and contemporary readings, Oxford University Press, Oxford) rely on a teleological approach to the evolution of vision to secure the grounds upon which people with normal color vision can be justly called ‘right’ and those with inverted color vision can be called ‘wrong’. I demonstrate that since the inverted spectrum thought experiment requires that both sorts of vision be behaviorally indistinguishable, no biologically acceptable concept of teleology will allow Tye to draw the distinction he needs.