The effects of the illusion on reflexive saccades are not subject to endogenous control, nor are they modulated by the strength of an exogenous target signal. Since the perceptual effects of these reversed comparisons were quite similar to the effects computed here, we decided to omit the presentation of these effects. Subjects were instructed to carry out a saccade to the other end of the horizontal shaft right after the appearance of the figure. This action effect did not differ from the perceptual effect. A related possibility is that the seeming effect of the M-L illusion on reflexive saccade amplitudes might actually have resulted from voluntary movements occasionally produced in response to a visual go-signal. The participants were asked to explore the display made of two arrowheads fixed at the end of rod which pointed to their left.
The figure illustrates how the perceptual effects are determined for the direct and indirect comparison see the 1 for a tabular account of results. To test these possibilities, Experiment 2 employed a reflexive saccade task similar to that of Experiment 1, but manipulated target location probabilities to induce observers to prepare movements prior to onset of the go-signal. Effects of visual illusions on grasping. This means that the fact that half of the subjects viewed the display before performing the haptic task had no significant effect on the haptic error. In the study conducted by Bernardis et al.
oiterature First, all trials used visual go-signals. Psychological Science14, — The stimulus figure for that trial appeared immediately thereafter, with the vertex of the middle wing centered on the fixation mark.
Literature review on muller lyer illusion
Motion of a surrounding frame was used to induce illusory changes in the target step. As can be seen in Figure 3amplitudes for both reflexive and voluntary saccades were modulated by the M-L illusion; for both classes of movement, the difference in amplitude for near and far targets was smaller within the M-L configurations than within control figures.
Vision Research9, — Journal of Neuroscience18, yler This suggests that in the current reflexive saccade task, contrast of the go-signal should do little to modulate the effects of the M-L illusion. We were interested here not only in the absolute values of the response times in each modality, but also in their possible correlation with perceptual error in both modalities.
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Neuropsychologia34, — One press on either key resulted in an increase or decrease of 1 mm. Journal of Experimental Psychology: According to another interpretation of Ginsburgreviiew illusion may be caused by spatial filtering mechanisms, leading to size distortions in the filtered images that are similar to the perceived sizes.
Effects on 2D Oculomotor Behavior. Reflexive top and voluntary bottom saccade amplitudes for Experiment 1. It refers to the finding that the endpoints of saccades can be diverted from the target point in the direction of the center of gravity of a stimulus configuration. A Novel [Alain de Botton] on Amazon.
An alternative possibility, as noted in literatrue preceding paragraph, is that the higher level spatial representation involved in reflexive saccade programming is not perfectly matched to a subjective frame of reference.
To draw conclusions about the effects of cue contrast and location probability on saccade amplitudes, it is first necessary to examine saccade latency data for independent evidence that manipulations of these litegature were effective. For statistical analysis, latency data were submitted to a within-subjects ANOVA with signal strength weak vs.
Literature review on muller lyer illusion
Another explanation is that the common ability underlying the illusion in both modalities is the capability to inhibit the irrelevant information i. Orthogonal influences alter the direction of saccades and therefore involve other neurophysiological mechanisms change of the muscular activation pattern, recruitment of other mullef eye muscles. A related possibility is that the seeming effect of the M-L illusion on reflexive saccade amplitudes might actually have resulted from voluntary movements occasionally produced in response to a visual go-signal.
Observers were eight young adults recruited from the community mullfr the University of Illinois at Urbana-Champaign.
O second experiment was conducted to further investigate the effects of the M-L illusion on reflexive saccade programming. Together, this indicates the existence of the COGE. Finally, it is useful to consider the apparent contradiction between the current results and those of Wong and Mackwho found no effect of an induced motion illusion on reflexive saccade targeting.
The results of Experiment 2 indicate that the influence of the illusion on reflexive saccades is not modulated by endogenous saccade preparation or by strength of the transient signal marking the target location. From these adjustments, the perceptual effect can be obtained in two ways Franz et al. Consistent with a weak separate representation model, some findings suggest that illusion affects some aspects of visually guided movement e.
For methodical mkller on how the effects are computed, see Figure 3 and the description in the Results section. While the amplitudes of the saccades along the shafts of the Brentano figure oriented vertically were similar to the perceptual effect, the horizontal saccades perpendicular to the shaft from outside the figure to the midpoints of the Brentano figure did not show deviations in the direction of the expected COGE.
Perceptual and Motor Skills Vision Research24, —