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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42
votes
6answers
45k views

Why would the brain flip the images perceived by your eyes?

The following is a common scientific statement, which you don't have to google long for to find: The eye views images upside-down in the manner of a camera lens, but our brains reinterpret this ...
28
votes
1answer
841 views

The effects of bilingualism on colour perception

Peltola et al. (2012) showed that there are two types of bilinguals. Balanced bilinguals mix their two languages and are effected by linguistic categories from both. Dominant bilinguals seem to ...
26
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3answers
681 views

Why does the human visual system produce a bright patch after staring at a bright light source and looking away?

If a person looks at a bright light source, such as a light bulb or perhaps the sun for a period of time, and then looks away and closes their eyes, they typically see a bright patch in the shape of ...
23
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1answer
3k views

Why is white on black considered higher contrast than black on white?

While researching to answer Why are "Inverted Colors" considered an accessibility feature? I noticed the puzzling claim that "White text on a black background is a higher contrast to the opposite, so ...
22
votes
5answers
1k views

Why do we prefer visually aligned objects?

We all know visual alignment is one of the foundations of design. Everything must be aligned with everything else. We also know that when things are aligned it is easier to process information. My ...
18
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3answers
962 views

Is it possible for certain people to perceive colors differently?

What if someone perceives a color as 'red' when it is actually 'green'? Since different people have preferences for different colors, and colors are perhaps constructed in the mind, is it possible ...
16
votes
3answers
2k views

Is it possible to improve reading speed and visual comprehension by doing exercises?

Background I'm trying to capture detailed information from the images in my visual memory, mainly text. My daily life requires reading many documents on varying topics. I want to increase my reading ...
15
votes
1answer
191 views

How is the size of a video related to its perceived quality?

Video is often presented at different sizes. On the Internet, many websites provide quite a few size settings. In the store, you can buy TVs of many different sizes. In both cases, it's the same ...
15
votes
2answers
385 views

What concepts of perception should designers be aware of when designing?

Visual perception is a huge topic, much of which is relevant to the work of a designer. I have identified topics in visual memory, visual cognition and colour perception that are relevant, and I'm ...
13
votes
1answer
293 views

How do humans control saccades?

I've gathered the standard rational for a visual system utilizing saccades from perception textbooks: the neural cost of processing an entire scene at a high level of detail would be prohibitive, but ...
12
votes
4answers
5k 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 ...
12
votes
3answers
1k views

What is the “static” in human vision called?

Sort of like a cheap digital Camera, the human eye has certain feedback that's perceived but doesn't actually exist in the real world; a little layer of Static that's especially noticeable in pitch ...
12
votes
1answer
1k views

How do the blind dream?

Lately, a friend of mine has been telling me that he's been having recurring dreams involving a certain rabbi, who died around a hundred years ago. Since there's been some controversy surrounding the ...
12
votes
1answer
4k 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 ...
11
votes
3answers
346 views

What neural mechanism explains the tendency to visually attend to the whole scene before attending to details?

I have the intuition that human vision first attends to large-scale objects and then small-scale details. Is there any mechanism in the visual cortex that will explain this phenomenon? Is there a ...
11
votes
2answers
267 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 ...
11
votes
1answer
805 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 ...
11
votes
1answer
599 views

Under what conditions does 60hz video produce visual artifacts?

There are some important thresholds of frame rate in video playback that effect whether or not animation appears fluid. This wikipedia page about Visible Frame Rate suggests that a framerate of 60 ...
11
votes
3answers
8k views

Why is it easier to see black text on a white background?

I'm wondering why it's easier to see black text on a white background than it is to see white text on a black background. I say that it's harder based on life experience (Hate webpages with black ...
11
votes
2answers
1k views

Origin of the SEEV Model of visual attention distribution

What's the original source of the SEEV (Salience Effort Expectancy Value) Model for predicting the distribution of visual attention? I've seen it mentioned in many papers and presentations but ...
11
votes
1answer
536 views

What is the current status of tetrachromacy in humans?

Tetrachromacy is a condition of having four colour channels. There is a hypothesis that some women posses 4 different types of cone cells (each with different opsin responsible for different ...
10
votes
2answers
2k views

Does perception have a “frame rate”?

Are the objects of visual perception processes divisible into individual, still frames, like video is? If so: Are the perceptions from different senses synced to the same frequency? Are these "stills"...
10
votes
2answers
523 views

How does the brain act on the information gained via eye saccades?

I've often heard that the process of saccading can be described as a statistical sampling technique. Specifically, the standard textbook definition of the function of saccades seems to be that the ...
10
votes
2answers
2k views

What's the explanation of this optical illusion where many coloured arcs radiate from a central point?

I saw the image below on facebook. At first, I thought it's a GIF animation since it doesn't appear static but it turned out to be a static JPEG image and the apparent motion is caused by the brain. ...
10
votes
2answers
291 views

How does this illusion - that I just inadvertently created - work?

As I was working on a basic chess application for Android, I loaded some chess clip art into my imageviews. Then this happened. Look closely at the top two rows. At first I was startled. My ...
10
votes
1answer
567 views

Is there an effect of visual expertise on eye movements when examining an image?

In the following linked image, you can see the eye movement traces of a subject examining a bust of Nefertiti (I came across this image while reading the following blog). When I was in grade school, ...
10
votes
1answer
173 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 ...
10
votes
3answers
151 views

Images on personal computers - Which aspect of size to keep constant?

For various reasons we're doing a reaction time study involving images that runs on unstandardized equipment: patients' personal computers (unless they don't meet certain requirements). It's not about ...
10
votes
1answer
165 views

Is cortical magnification in the visual system related to synaptic pruning, or is it a separate developmental or learning process?

I'm primarily interested in learning about current computational models that explain cortical magnification in the visual system. With this in mind, my specific questions are: (1) Is this phenomenon ...
9
votes
2answers
408 views

Why can we not see around our point of focus of our eyes?

Why do we have to strictly focus on something to really see what it looks like? Is everything else around blurred, or is our brain trained only to see in the center of the image projected on the ...
9
votes
3answers
1k views

Why is sensory substitution not that successful?

By successful, I mean made it out to the large world market or being massively funded. After looking online it seems that the most relevant research is the one done by Bach-y-Rita about the seeing ...
9
votes
1answer
659 views

Are some facial features more important than others in human facial recognition?

I'm often surprised by the human ability to correctly identify other individuals despite significant modifications due to ageing, hairstyle, injury etc. But, sometimes the addition of a beard and a ...
9
votes
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,...
9
votes
1answer
94 views

Source for turning cone cell opponent process diagram into equations

There is a diagram on wikipedia that is part of the article on the opponent process. I assume practical equations have been developed, at least reasonable approximations, but they appear to be missing ...
8
votes
3answers
2k views

Are colors real?

We know that we distinguish colors when they fall on our photo receptors in our eyes and neurons pass its signals to our brain to recognise them as the specific colors. How accurate is it? For ...
8
votes
2answers
150 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 ...
8
votes
2answers
499 views

Is the concept of neuroplasticity applicable to visual cortex and how does it affect visual perception?

I've been searching about this but all I found was this presentation, which is a bit too technical for me to understand, e.g: Visual Cortical Plasticity In what way does neuroplasticity affect the ...
8
votes
2answers
449 views

What is the difference between spike-triggered averaging and reverse correlation?

I'm interested in the difference between spike-triggered averaging and reverse correlation. In some papers (i.e., Schwartz, Odelia, et al) I see the term 'Spike Triggered Averaging'. In others, (ie ...
8
votes
2answers
151 views

Any models that act using both streams of visual processing?

The Two-Stream Hypothesis, where object properties are processed independently from spatial information, remains the most well established theory of visual processing. However, it concerns me that ...
8
votes
1answer
138 views

Are there shapes defined by 3 (or more) generative parameters whose mapping to psychological similarity space is known?

I am trying to generate 4 shapes that are equidistant in psychological similarity space - meaning that they are all equally discriminable from one another - which differ in 3 parameters, such that ...
8
votes
1answer
158 views

What is the meaning of “little efferent input” to retina?

Gollisch & Meister (2010) state that "the retina receives little efferent input from the brain" (p. 157). Could anyone describe what exactly this "little efferent input" (where it originates, ...
8
votes
1answer
504 views

Are there any rules about masking?

I am currently programming an experiment where participants have to do a divided visual field task. In a paper about the correct methodology about these tasks, it is said that you should use a ...
8
votes
1answer
65 views

Rated model of driving-related processes and objects

The Salience, Effort, Effort and Value (SEEV) model for predicting the distribution of visual attention contains a parameter called 'value' which represents the importance of a certain area of the ...
8
votes
1answer
244 views

How to set up a binocular rivalry experiment which splits a single image in two separately controlled ones?

The question is about the actual physical setup and steps needed to take in order to experiment with the phenomena. I found a tutorial on jove.com, "How to Create and Use Binocular Rivalry", and it ...
8
votes
1answer
550 views

How do people visually recognize their own reflection?

I'm interested in how the brain processes and recognizes the image of the person's own face. A bit of background: A while ago I've developed an overlay-camera like app for iPhone that allows me to ...
8
votes
1answer
875 views

What explains the characteristics of the receptive fields of simple cells in V1?

Here is a YouTube video of a Hubel & Wiesel experiment from 1965 in the visual cortex. The video shows the experimenters outlining the receptive field of a simple cell in the first part of the ...
8
votes
2answers
480 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 ...
8
votes
1answer
75 views

What are biologically plausible ways to model binocular disparity?

I figure there is a vast body of literature on stereovision, both neurophysiological and computational studies. Computer Vision also provides some algorithmic insight on implementing binocular ...
8
votes
1answer
101 views

Number of presynaptic inputs per cell in primary visual cortex

I have been digging in the literature lately, but I haven't found a nice answer with clear cut numbers (avg +- std) to this question: How many presynaptic inputs receives a pyramidal cell in primary ...
8
votes
2answers
218 views

Are there physical techniques to relieve eye strain? [closed]

I asked a question about eye strain Does looking into a mirror relieve eye strain in a similar way to looking at distant objects?. Are there any physical exercises or techniques that can help to ...

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