The Müller-Lyer illusion through mental imagery (original) (raw)
Related papers
Structural and cognitive components in the Müller-Lyer illusion assessed via Cyclopean presentation
Perception & Psychophysics, 1984
Several levels of visual information processing contribute to the formation of visual geometric illusions. The present experiment attempted to separate the relative contributions of structural (physiologically based) and strategy (cognitively based) mechanisms in the formation of the MUller-Lyer illusion. A novel experimental procedure that combined Cyclopean stimulus presentation and illusion decrement was employed. The results indicated that approximately 47% of the observed illusion magnitude can be attributed to the involvement of structural factors, a result consistent with other studies that have used different experimental techniques to explore the same issue.
The role of context in Müller-Lyer illusion: The case of negative Müller-Lyer illusion
2013
The Müller-Lyer illusion is one of the most prominent geometrical-optical illusions that have been the subjectof experimental investigation throughout a century. Like most optical illusions the Müller-Lyer illusion is causedby an appropriate context - inward or outward fins that act in a specific manner. These fins either prolong or shortenthe central line placed between the fins. In this study, we manipulated the context by varying the presentation ofthe illusion parts, which led to the negative effect of Müller-Lyer illusion. Here we disassociated the context, i.e.,the fins that create the illusion, from the lines the length of which needed to be assessed. Firstly, the fins were presentedalone for 10 seconds, than the line would appear alone for 100 ms. In such situations the phenomenon ofillusion emerges in an opposite direction: the line that temporally succeeded the inward fins seemed longer, whilethe line succeeding the outward fins seemed shorter. An experiment with three experimental situations was carried out. Twenty participants took part in the experiment, in three different experimental situations. The size of the illusion was measured using the method of constant stimuli, which was also used to determine the point of subjective equality. The analysis confirmed the described effect which was found to be significant when compared to two other situations: the control situation and the standard Müller-Lyer illusion situation. The negative Müller-Lyer illusions possibly caused by a kind of after effect, which occurred by prolonged gazing at the fins and/or by fatigue of the appropriate selective angle sensitive cells. Such findings implicate that angle sensitive cells might be active in the emergence of the standard Müller-Lyer illusion.
Grasping the Müller–Lyer illusion: not a change in perceived length
2007
Abstract Peak grip aperture has often been used to quantify the influence of illusions on judgments of size for action. However, a larger peak grip aperture need not mean that the object looks larger. It could also mean that it was grasped more carefully. These two possibilities can be distinguished on the basis of the velocity of grip closure just before contact. We let people grasp a bar that was placed on the shaft of a Mller–Lyer figure. The Mller–Lyer figure influenced the peak grip aperture.
2007
Arrows terminating a line can distort the perceived line length. This so-called Müller-Lyer illusion can be used in healthy human subjects to mimic the performance of neglect patients in visuospatial judgments (e.g., in the landmark task). In this study, we investigated the neural mechanisms underlying the Müller-Lyer illusion, the landmark task, and their interaction. This was achieved by parametrically manipulating the magnitude of the Müller-Lyer illusion both in a landmark and in a luminance (control) task. As expected, the landmark task activated right posterior parietal cortex and right temporo-occipital cortex. In contrast, the neural processes associated with the strength of the Müller-Lyer illusion were located bilaterally in the lateral occipital cortex as well as the right superior parietal cortex. The data not only converge with but also extend neuropsychological data that indicate maintained linelength illusion in neglect patients. In addition, our results support the size-constancy scaling hypothesis as a putative mechanism underlying line-length illusions. Furthermore, activation that was driven by both the task and the strength of the Müller-Lyer illusion was observed in right intraparietal sulcus, thus arguing in favor of an interaction of illusory information with the top--down processes underlying visuospatial judgments in right parietal cortex.
Grasping the Müller-Lyer illusion: The contributions of vision for perception in action
Neuropsychologia, 2007
The present study examines the contributions of vision for perception processes in action. To this end, the influence of allocentric information on different action components (i.e., the selection of an appropriate mode of action, the pre-planning and online control of movement kinematics) is assessed. Participants (n = 10) were presented with a shaft of various lengths (i.e., 13-20 cm) that was embedded in a Müller-Lyer figure. Picking up the shaft would, dependent on its length, either require a one-or a two-handed grasp. In different conditions participants were instructed to give a verbal judgement on the size of the shaft (VSJ); to make a manual estimation of the shaft's length (MLE); to indicate verbally whether they would grasp the shaft with one-or two hands (VAE); to actually grasp the shaft (G). We found that the Müller-Lyer figure affected the choice between using a one-or two-handed grasp, both when the participants actually grasped (G) the object and when they made a verbal estimation (VAE). The illusionary bias was of a similar magnitude as the one found in the verbal (VSJ) and manual perception task (MLE). The illusion had only a minor influence on the movement kinematics, and appears to be restricted to participants in which the grasping condition was immediately preceded by the VSJ-condition. We conclude that vision for perception contributes to the selection of an action mode, and that its contributions beyond that stage are dependent on the particular (experimental) circumstances.
The Müller-Lyer illusion explained by the statistics of image–source relationships
Proceedings of the National Academy of Sciences, 2005
The Müller-Lyer effect, the apparent difference in the length of a line as the result of its adornment with arrowheads or arrow tails, is the best known and most controversial of the classical geometrical illusions. By sampling a range-image database of natural scenes, we show that the perceptual effects elicited by the MüllerLyer stimulus and its major variants are correctly predicted by the probability distributions of the possible physical sources underlying the relevant retinal images. These results support the conclusion that the Müller-Lyer illusion is a manifestation of the probabilistic strategy of visual processing that has evolved to contend with the uncertain provenance of retinal stimuli.
Müller-Lyer and Oppel-Kundt illusions compared
2017
The modified Muller-Lyer and Oppel-Kundt stimuli possessing three spatial intervals were taken for psychophysical experiments in which subjects adjusted the length of the test interval (the middle one with inward wings or just empty) to be equal perceptually to that of the references (two lateral intervals with outward wings or fillings of spots, line segment, or stripes). The data obtained from thirty subjects showed the two well-known illusions being similar in their manifestation stiles.
Geometrical illusions: study and modelling
Biological Cybernetics, 1997
The phenomena of geometrical illusions of extent suggest that the metric of a perceived field is different from the metric of a physical stimulus. The present study investigated the Müller-Lyer and Oppel-Kundt illusions as functions of spatial parameters of the figures, and constructed a neurophysiological model. The main idea of the modelling is based on the uncertainty principle, according to which distortions of size relations of certain parts of the stimulus, socalled geometrical illusions, are determined by processes of spatial filtering in the visual system. Qualitative and quantitative agreement was obtained between psychophysical measurement of the strength value of the illusions and the predictions of our model.