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17

Your question is referring to display polarity. A positive polar display consists of dark letters on a light background, a negative polar display consists of light letters on a dark background. Polarity by itself is independent of text-to-background contrast, as you rightly state. Generally, positive polarity facilitates performance (e.g. Buchner & ...


16

At least for images (I don't know of such a result tested on videos) for a given resolution, there is an optimal display size (assuming constant viewing distance. otherwise, display size should be measured in angles from the viewers point of view). In a paper from 1989, Peter Barten provided a formula to compute this effect [1]. The gist can be seen in the ...


16

One of the main reasons related to the 'Gestalt principles' Law of Proximity Objects near each other tend to be grouped together. Law of Similarity Similar items tend to be grouped together. Law of Closure Objects grouped together are seen as a whole. Law of Continuity Lines are seen as following the smoothest path. Law of Common Region Items in similar ...


15

I think you are succumbing to the homunculus argument, the fallacy that there is some sort of image in the brain for someone to view. There is no magical theater in your head where what is incident on your retina is projected. All you have in your brain is complicated patterns of neural activity, there are no images and nothing to view. However, these ...


13

There are two related reasons, I believe for this: Relationship and connection. When things are aligned, we see then as connected and related. Nature does give us the guidance for things that are related and connected in other ways, but often by a degree of alignment or similarity. In UX terms, we indicate the relationships between items by positioning and ...


13

As @Gray mentioned, the philosophical problem you are interested in is known as the inverted spectrum. Unfortunately, @Gray's claim about no empirical difference is not exactly true. As @ChuckSherrington pointed out, we can have differences in color perception due to brain lesions, but this is cheating in way. We don't have to go this far, we already have ...


13

Yes, this scenario is possible, occurring with certain cases of brain lesions in specific areas of the visual cortex, the fusiform, lingual and posterior parahippocampal gyri. These areas are analogous to what is referred to in primates as V4, or the 4th visual cortex, and are known to be involved (at least partly) in the perception of color (though see ...


13

First, it is not only your intuition - there are many experimental results showing that we first perceive the gist of scenes (for example, is it outdoors or indoors?), then the major parts of it (was there an animal, or a human figure in it?) then more and more details (is that figure male or female? what is her expression?) [1] [2]. Note, however, that it ...


13

Usually, for something to be 'real', we want it in some reasonable manner to be objective or (because that is extremely vague) at least very consistent across subjective observers. Unfortunately, colour does not satisfy this. Physical basis. As explained very well by @Stop_forgetting_my_account: Physics does not have colour, it just has a continuous ...


13

I basically agree with @Nick Stauner, but I want to add another important aspect, namely the gradient of photoreceptor densities in the human retina: In the fovea there is a sharp peak in cone density compared to more eccentric regions, as described in Curcio et al. (1990) and see the following graph obtained from Web Vision: The cones have a different ...


13

You may want to read Meaidi et al (2014). They obtained dream reports from congenitally blind, late blind, and matched sighted controls. To quote the abstract, they found: All blind participants had fewer visual dream impressions compared to sighted control participants. In late blind participants, duration of blindness was negatively correlated with ...


12

The fact that the image does not appears upside-down has to do with the way visual information is processed in the brain. In his book, Jeff Hawkins argues that the low-level visual features on the retina (being upside down, distorted, and changing rapidly) are lost in the process of forming invariant representation. And it's those representations that we ...


11

Basically, the retina contains two different kinds of receptors: rods and cones. Cones are concentrated in the fovea and activate ganglion cells more discretely than rods. Rods are more interconnected by horizontal cells (if I'm not mistaken...), so multiple rods can often activate the same ganglion cell, whereas each cone is more likely to have its own ...


11

The source I have quoted below gives an example of the following stenographic image:- Is this perception a particular trick that my eye performs or is it processing the visual data in an alternative way? Stereograms can be viewed as three-dimensional images by providing two side-by-side views of a three-dimensional scene, rendered from slightly ...


10

It's essentially shot noise. In optics, shot noise describes the fluctuations of the number of photons detected (or simply counted in the abstract) due to their occurrence independent of each other. This is therefore another consequence of discretization, in this case of the energy in the electromagnetic field in terms of photons. In the case of photon ...


10

Short answer: there appears to be a whole range of ability at the task of mental visualization. Based on what I have found on the Web, your own level of ability is fairly unusual. Your friend's level of ability, by contrast, seems to be fairly common. Sources I found on this were fairly sparse, though, and my conclusions should not be relied on too heavily. ...


9

People who are unable to perceive stereoscopic depth typically only perceive information from the dominant eye. Failure to perceive stereoscopic depth is usually caused by conditions where the eyes do not converge properly (e.g., strabismus). If left untreated, it is not possible to develop the necessary correspondance between the two signals from either ...


9

There is no true frame rate of the eyes, but there are limitations. The brain uses blurring to simulate continuity. Films are shot at 24 frames per second; if you go too much lower than that, the film will seem choppy. This is because the motion blurring process is too fast and it finishes "blurring" before the frame changes, so you just see choppy frames....


9

This is a type of illusory motion (or motion illusion) called the Enigma Illusion. The cause of motion illusion in general is not well understood, but research suggests that there may be slightly different reasons for the different types of motion illusions. A common theory is that particularly high-contrast colours are perceived separately in the retina (...


9

Bach-y-Rita's Tactile Vision Substitution System (TVSS) project was initiated in 1963 and he has since been regarded as the founding father of sensory substitution. The concept of sensory substitution refers to the process of obtaining information about the world from a functional sensory system (e.g. touch) that would normally be obtained from a lost ...


9

Probably. What you mentioned in your question is called retinotopy. There is a mapping between locations on your retina and areas on your cortex. As you go further up the visual processing streams, the mapping gets more complex and the patterns would be less obvious. Here's an image of from a 1988 paper in the Journal of Neuroscience (Tootell, et al.). It ...


8

There is a substantial literature on eye tracking. Skill acquisition example One study that I am familiar with and is of some relevance is Study 2 in Lee and Anderson (2000, PDF). Specifically the study used eye tracking tools to examine how visual attention was allocated over time on an air traffic control simulator. The broad finding, consistent with ...


8

The nervous system, especially the cortex, is a distributed system. Asking "where" is not always a sensible question. In reality, different properties of the visual scene are assembled in different areas of cortex. There is no one area where everything is reassembled. All the information we know about a scene is stored all over the visual system. In ...


8

The Wikipedia article no longer makes reference to the phenomenon that you quote (to my inspection), so I'm not entirely sure if that assertion was edited out as an inaccuracy on someone's part. I did find some information on visual perception and high frequency flicker that might point to some of the significance of the 60 Hz refresh rate of a monitor. At ...


8

Well for one, the first neurons to decode this symbol are orientation neurons, in V1 of the primary visual cortex. So some neurons have enhanced firing for say a 45 degree angle, and neighboring neurons for a 46 degree angle, and so on. Higher up the processing stream groups of neurons respond to shapes, that are a conglomerate of the orientation lines. Then ...


8

Seems this is a newly discovered phenomenon! Tangen, Murphy, and Thompson (2011) describe this as a result of their method of presentation: alignment of the pupils and fast cycling through faces with different proportions. It is also important that the cycle of new images remain uninterrupted. They say "relative encoding seems to drive the effect," and list ...


8

The human visual processing system receives input from the eyes, and then passes it through a number of areas of the brain that break it down, process it in various different ways, recombine it, and break it down again several times. I'm assuming this question is only about the visual cortex, general theories about how information might be broken down for ...


7

Not surprisingly, there's a huge load of stuff you need to consider when designing things for users. Here's a good paper written by some perception and vision researchers on the topic that might give you a more detailed introduction that what you have seen so far: Healey, C.G. & Enns, J.T. (in press). Attention and visual memory in visualization and ...


7

It appears that throughout your question you are touching on multiple questions and topics. I will address them in a series of quotes and responses, beginning with the title: Are colors real? They are not physical things. Colors are a form of perception (an abstraction). They exist in your head. In physics the perception of colors is caused by light ...


7

Actually, black objects absorb light across visible frequencies indiscriminately, but not completely. So some light still reflects off them. This is described on this Q&A of the Department of Physics, University of Illinois at Urbana-Champaign. But even if there was a perfectly black objects which absorbs 100% of the light that falls on it, you could ...


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