Questions tagged [vision]

For questions regarding the visual system, which serves to transduce light energy into neural impulses, or regarding visual perception, how we interpret such incoming visual information.

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4
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2answers
169 views

Do we perceive contrast colour patterns easily because of adaptation?

I can understand that colours are just manipulation of our brain to light rays of different wavelength and energy. We perceive patterns better at higher contrast. Do we perceive patterns better at ...
3
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2answers
78 views

How do mammals estimate the speed of moving objects?

Has there been any research on how mammals predict the speed of moving objects? In particular, how do they integrate top-down information? For instance, do they have greater difficulty estimating the ...
4
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1answer
783 views

Are we able to simulate pain through the brain?

I have like 0 experience or knowledge about brain signals and all that stuff but I'm curious about how much we know about the brain in terms of like tricking your brain that with simulation of pain. ...
5
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1answer
272 views

What do you call sensations without stimuli?

Sometimes, when you close your eyes in the dark, you see what looks like sparks or flashes. Sometimes when you are tired, your vision seems to shift sideways and realign, like someone bumped into a ...
2
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1answer
207 views

Do direct cortical pathways exist in the visual system, or do they all go via the thalamus?

Do visual cortical signals always go back and forth between the thalamus, or other subcortical structures, or can they travel directly from one region in the cortex to another?
4
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1answer
4k views

What is the difference between apparent motion and apparent movement?

A definition for apparent movement is: The perception of movement produced by stimuli that are stationary but are presented first at one position and then, at an appropriate time interval, presented ...
4
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1answer
270 views

What is the optimal contrast ratio for best readability?

I have asked the same question half a year ago on Graphic Design but received no useful answer. According to the W3C (and another question on this site), the contrast ratio between body text and text ...
4
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3answers
538 views

Does the strength of the simultaneous contrast illusion vary with the length of time it is viewed?

I have done several searches without finding any papers addressing this question.. I'd like to know if there is any evidence to suggest that the strength of the simultaneous contrast illusion (or any ...
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0answers
40 views

Model of human estimation of correlation tasks

I am looking for a model (bayesian or not) on how people would estimate the correlation between two variables from a given scatter plot. Any one knows of such model?
8
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2answers
546 views

What does the visual feed from the retina look like before it is processed by the visual cortex?

I was recently at the ACM Symposium on Applied Perception, where I saw a keynote on visual attention. The speaker (Laurent Itti) showed an animation that blew my mind. It showed a video of fish ...
6
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1answer
152 views

How is the focal point determined when looking into a clear sky?

When looking into a clear blue sky, no cloud, birds, trees or any object to give a frame of reference. When a person is actively looking, as opposed to day dreaming or gazing. The sky goes for a long ...
5
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1answer
124 views

How common is it for twins conjoined at the head to share thoughts and visual stimuli?

I've always been interested in the possibility of a pair of conjoined twins, joined at the head, being able to read each other's thoughts, react to stimuli that one of them can't see/hear/feel, and ...
5
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1answer
153 views

What are the effects of visual deprivation on mental health and the other senses?

How do blind people who haven't always been visually impaired deal with their day-to-day lives? I've heard rumors (very, very unreliable rumors) that once you stay in the dark for too long you'll ...
2
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2answers
113 views

How image orientation influences perception

Im a painter for many years. When I paint, I usually walk around and look at my painting for many hours. When painting session is long, it harder and harder to maintain a "fresh look". By fresh look; ...
2
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1answer
478 views

What is the difference between 'stereoscopic depth' and 'crossed/uncrossed disparity'?

What is the difference between stereoscopic depth and crossed/uncrossed disparity, and specifically in terms of their use in the methods to manipulate visual stimuli to investigate depth-perception?
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3answers
430 views

Is prior experience necessary to perceive the Kanizsa triangle illusion?

We know the Kanizsa Triangle. Kanizsa Triangle I was socialized in a "western" world, where I learned mathematics for about 13 years; I have designed products surrounding me using geometric forms ...
5
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1answer
159 views

Why can't hemineglect patients be trained to actively pay attention to their neglected side?

I'm still having a hard time understanding the symptoms of hemineglect, mainly because perception and attention has been two peas of a pod for most of my experiences. A Scholarpedia article states ...
4
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1answer
434 views

What is the relationship between visual attention network and visual stream (Two-streams hypothesis)?

There are two visual attention networks proposed by Maurizio Corbetta and Gordon L. Shulman (2002). These are top-down and bottom-up attention networks. One system, which includes parts of the ...
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1answer
87 views

What is the maximum time difference to still associate an acoustic and visual event?

I am developing a game where the music needs to be synchronized to the actual game logic. That means that some objects in the game react to events in the music. Of course, the music will never be ...
6
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1answer
186 views

How long does it take to learn to cane travel?

How long does it take the average person (either sighted or blind) to learn to use the guide cane successfully for mobility purposes? Source: Lions. Because required training times will depend on ...
2
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1answer
141 views

What is the relation of visual quality and distance from the central field of view?

I have read somewhere that Our visual perception degrades non-linearly with distance from the fovea. However, it was not referenced. I was wondering if there is a reference talking about this? ...
7
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1answer
86 views

Find the panda among snowmen!

I just saw this picture puzzle, and found it easily by doing a row-by-row scan, but it seems harder to find it just by looking around. I was thinking that the puzzle was intentionally designed to draw ...
3
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1answer
378 views

What is the location of the center-surround receptive fields of retinal ganglion cells?

I have read wikipedia article about receptive fields of visual system and it states the following: The receptive field is often identified as the region of the retina where the action of light ...
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4answers
6k views

Simulate colorblindness in non-colorblind individuals

Is there any way by which individuals with normal color vision could "see" the effects of Deuteranopia or any of the common colorblindness types, say by using special lenses or anything? Color ...
6
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1answer
154 views

If I think of a checkerboard, is there a similar structure to see in my visual cortex?

When I´m imagining a checkerboard in my mind, can one find, with all kinds of fancy equipment, a corresponding figure in the area of my visual cortex? For example, the neurons firing in such a way as ...
4
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1answer
337 views

Does the human visual system implement (adaptive) histogram equalization?

The human visual system is very good at 'cancelling out' shadows and other lightning effects, and focusing on the contrast in images. A famous example of this is Adelson's checker shadow illusion: In ...
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0answers
14 views

Searching for literature on cognition of flyover animations

I'm rewriting a journal article on flyover animations: the virtual camera moves in a 3D map environment (e.g. a flyover of the Grand Canyon showing off the topography). The paper describes our user ...
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0answers
23 views

Conscious versus Visual Representation Update

In their paper "A cortical network that marks the moment when conscious representations are updated" Stottinger et al claim that there is a network in the anterior insula, medial and inferior frontal ...
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2answers
104 views

How much our visual limitations are instrument(eye)-based, and how much are they brain-based?

Are the limitations to our vision like the field of view and singular focus entirely based on the limitations of the eye? It seems like it's possible to feed an artificial signal into the brain ...
2
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1answer
59 views

Toolbox for modelling visual search performance

I'm looking for a toolbox to model visual search performance in a singleton search task based on line orientations (you need to find a line that is most different from all others in it's orientation). ...
11
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2answers
273 views

To what extent do individuals vary in their ability to mentally visualise?

Background: Yesterday I was shocked when a friend of mine told me that he can see only "completely black darkness" when he closes he eyes. When I close my eyes, I can see some images or "movies" of ...
2
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1answer
61 views

What are the estimates in total neurons and average connections per neuron for each of the processing areas of the visual cortex?

I am trying to find ballpark estimates for the number of neurons in each functional area of the visual cortex (V1, V2, V3, etc). While nice if known, the numbers themselves are not as important to me ...
4
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1answer
743 views

Is there terminology for perceptual illusions at the moment that figure-ground reversal occurs?

I'm looking for a term in the perception / cognition area of research. I recently saw this visual illusion that 'flips' what is negative-space and what is positive-space. This is known in the arts ...
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2answers
118 views

Why vision cannot count things instantly?

If vision can instantly "see" 30x30 grid, why does the brain often need to count rows and columns for understand there is 30 rows and 30 columns? Why does the brain fail to instantly count?
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1answer
213 views

What is forward masking

I am trying to understand what is visual masking (or more specificaly forward masking). I have read the explanation here, but still.. I understand that a background can interfere with a frontal ...
3
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2answers
68 views

Color and shape arriving together in visual system

I know that in the visual cortex there are separate visual pathways for both color and shape. Do these separate pathways imply that human beings become consciously aware of these features separately ...
5
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1answer
7k views

Why do humans' eyes enter an unfocused gaze when recalling a memory or imagining something?

The question is self-explanatory (I hope). Is this trait unique to humans? Does the direction of the unfocused gaze indicate anything about which physical part of the brain is being utilized? Is ...
8
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2answers
153 views

How is saccadic movement managed in the brain?

I haven't been able to find any decent articles on this specific topic. So I have three (hopefully quick) questions: What part of the brain is actively controlling saccadic movement? If this part ...
12
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1answer
5k views

Is our attention attracted by bright lights?

Bright lights are often used to attract human attention. For example, brightly lit signs, despite often being too bright to look at directly are often used for information and/or advertisement. Why ...
9
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1answer
4k views

Are there gender differences in color discrimination ability?

There appears to be a prevalent stereotype that girls seem to have "heightened" color perception. By this term, I mean that they can identify the salient features of different shades of color. However,...
6
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1answer
405 views

In psychophysics, why are log luminance rather than absolute luminance values reported?

Are there any papers which justify converting into log luminance? For example papers showing humans being sensitive to changes in log luminance rather than luminance per se?
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1answer
90 views

Pupillometry: how long needs the pupil to respond towards an cognitive stimuli?

I would like to know if somebody could give me some references on the latency of the pupil response after a cognitive stimulus. I know that the light reflex is quite fast compared to cognitive ...
11
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1answer
911 views

What happens in your brain when you see a dinosaur in this stenographic image?

You might have come across stereographic Images like the one shown below (found here): What happens in your brain when you observe the dinosaur? (as you put your face on the image by touching your ...
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0answers
349 views

Optical illusions : human universal vs environmental influences [closed]

It's well known today that the susceptibility to optical illusions are influenced by the environment: multiple studies with the Müller-Lyer illusion conducted in Zambia proved this environmental ...
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0answers
29 views

Why does video footage of walking look unnatural when viewed upside down? [closed]

I noticed this whilst lying on the floor to stretch my back and the TV happened to be on. People look like they're walking in a very unnatural way.
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1answer
4k views

How to train our brain to see everything in slow motion? [duplicate]

People who had near death experience often found that they were able to see everything in slow motion and capture every details in their surrounding at that particular period. Because the brain ...
8
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1answer
130 views

Are there any models of the human visual field of view taking into account head, neck and eye movements and calculating likelihood of fixation?

I would like to know if there are studies that (1) model the field of view taking into account all degrees of freedom of the head, neck and eyes and (2) if there is any probabilistic model assigned to ...
7
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1answer
187 views

How come we see a line when there isn't one in this picture?

I got this picture I generated myself and I don't understand how come we can see two diagonal lines when, I think, there is no actual lines. Zooming in: Center: Just another 2px wide square… After ...
10
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1answer
174 views

Are the center surround receptive fields learnt or inherited?

I know that neurons higher in visual pathways can learn their receptive fields after birth, but what about the connections between bipolar cells and Amacarine cells which form center/surround on/off ...
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0answers
61 views

Why do I see those static pictures as they are moving [duplicate]

Have a look at the following static pictures: There are more of them here. On the same website this PDF describes findings.However I could not find any explanation why this phenomenon happening. Is ...