Physiological Mechanisms Underlying Motion-Induced Blindness

Visual disappearance illusions - such as motion-induced blindness (MIB) - are commonly used to study the neural underpinnings of visual perception. In such illusions a salient visual target becomes perceptually invisible. Previous studies are inconsistent regarding the role of primary visual cortex (V1) in these illusions. Here we provide physiological and psychophysical evidence supporting a role for V1 in generating MIB

Visual illusions: An interesting tool to investigate developmental dyslexia and autism spectrum disorder

A visual illusion refers to a percept that is different in some aspect from the physical stimulus. Illusions are a powerful non-invasive tool for understanding the neurobiology of vision, telling us, indirectly, how the brain processes visual stimuli. There are some neurodevelopmental disorders characterized by visual deficits. Surprisingly, just a few studies investigated illusory perception in clinical populations. Our aim is to review the literature supporting a possible role for visual illusions in helping us understand the visual deficits in developmental dyslexia and autism spectrum disorder. Future studies could develop new tools – based on visual illusions – to identify an early risk for neurodevelopmental disorders

Modularist explanations of experience and other illusions

Debates about modularity invariably involve a crucial premise about how visual illusions are experienced. This paper argues that these debates are wrongheaded, and that experience of illusions is orthogonal to the core issue of the modularity hypothesis: informational encapsulation

Visual illusions of movement

Visual illusions related to involuntary eye movemen

Visually Perceiving the Intentions of Others

I argue that we sometimes visually perceive the intentions of others. Just as we can see something as blue or as moving to the left, so too can we see someone as intending to evade detection or as aiming to traverse a physical obstacle. I consider the typical subject presented with the Heider and Simmel movie, a widely studied ‘animacy’ stimulus, and I argue that this subject mentally attributes proximal intentions to some of the objects in the movie. I further argue that these attributions are unrevisable in a certain sense and that this result can be used to as part of an argument that these attributions are not post-perceptual thoughts. Finally, I suggest that if these attributions are visual experiences, and more particularly visual illusions, their unrevisability can be satisfyingly explained, by appealing to the mechanisms which underlie visual illusions more generally

T-Visual Approach Slope Indicator System (T-VASIS) versus Precision Approach Path Indicator (PAPI) – the debate revisited

Two visual approach slope indicator lighting systems are in use in Australasia. These systems are designed to ameliorate and overcome the visual illusions associated with the approach and landing manoeuvre of aircraft. Using a flight simulator, 14 student pilot candidates, with little actual flying experience, ‘flew’ 10 approaches using PAPI and 10 approaches using T-VASIS. The approaches were ‘flown’ in various flight conditions including low visibility. The visual approach slope indicator lighting system was randomly assigned to each experimental condition. Results indicated that overall, there was less deviation from a correct glidepath when the approaches were ‘flown’ using T-VASIS. A post-flight survey indicated that participants found T-VASIS to be more intuitive. The results are discussed with reference to the prevailing preference of PAPI over T-VASIS by aviation authorities

Fooling the eyes: the influence of a sound-induced visual motion illusion on eye movements

The question of whether perceptual illusions influence eye movements is critical for the long-standing debate regarding the separation between action and perception. To test the role of auditory context on a visual illusion and on eye movements, we took advantage of the fact that the presence of an auditory cue can successfully modulate illusory motion perception of an otherwise static flickering object (sound-induced visual motion effect). We found that illusory motion perception modulated by an auditory context consistently affected saccadic eye movements. Specifically, the landing positions of saccades performed towards flickering static bars in the periphery were biased in the direction of illusory motion. Moreover, the magnitude of this bias was strongly correlated with the effect size of the perceptual illusion. These results show that both an audio-visual and a purely visual illusion can significantly affect visuo-motor behavior. Our findings are consistent with arguments for a tight link between perception and action in localization tasks

Affording illusions? Natural Information and the Problem of Misperception

There are two related points at which J.J. Gibson’s ecological theory of visual perception remains remarkably underspecified: Firstly, the notion of information for perception is not explicated in much detail beyond the claim that it “specifies” the environment for perception, and, thus being an objective affair, enables an organism to perceive action possibilities or “affordances.” Secondly, misperceptions of affordances and perceptual illusions are not clearly distinguished from each other. Although the first claim seems to suggest that any perceptual illusion amounts to the misperception of affordances, there might be some relevant differences between various ways of getting things wrong. In this essay, Gibson’s notion of “specifying” information shall be reconstructed along the lines of Fred Dretske’s relational theory of information. This refined notion of information for perception will then be used to carve out the distinction between perceptual illusions and the misperception of affordances, with some help from the “Empirical Strategy” (developed by Purves et al.). It will be maintained that there are cases where perceptual illusions actually help an organism to correctly perceive an affordance. In such cases, the prima facie misrendered informational relations involved are kept intact by a set of appropriate transformation rules. Two of Gibson’s intuitions shall thus be preserved: the objectivity of informational relations and the empowerment of the organism as an active perceiver who uses those objective relations to his specific ends

Sensation and perception

One of the oldest and most difficult questions in science is how we are able to develop an awareness of the world around us from our senses. Topics covered under the title of, 'Sensation and perception' address this very question. Sensation encompasses the processes by which our sense organs (e.g. eyes, ears etc.) receive information from our environment, whereas perception refers to the processes through which the brain selects, integrates, organises and interprets those sensations. The sorts of questions dealt with by psychologists interested in this area include: 'how does visual information get processed by the brain?', 'how is it that I am able to recognise one face out of many many thousands?', and 'what causes visual illusions to occur?: Within New Zealand there are a number of researchers studying visual perception specifically and their research interests range from understanding the biologica