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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 & ...


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

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

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

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

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 ...


7

The bouba/kiki effect is the phenomenon that about 95% of subjects assign the name bouba to a blobby form, and the name kiki to a pointy shape (Fig. 1). Fig. 1. Kiki and bouba, at least in 95% of the people. source: Synesthesia Test It is thought that the reason behind the strong preference is that the sharp changes in visual direction of the lines in the ...


7

Short Answer It appears that stimulation of the thalamus would invoke feeling of pain: Direct deep brain stimulation (DBS) in the VP thalamus from patients without pain typically evoked nonpainful, paraesthetic sensation. DBS at the core and posterior inferior region of the VP thalamus can evoke pain sensation without specific topographic distribution. ...


7

Some of those pop science articles might be simplifying a bit by saying the stimuli are provided to the left or right eyes. In fact, they are actually presented to the left or right visual field which is an important distinction. The left visual field, from both eyes, goes to the right hemisphere, and vice versa. The experimental paradigm is illustrated in ...


6

Wickens et al. (2003) is the earliest I'm aware of: Wickens, C. D., Goh, J., Helleberg, J., Horrey, W. J., & Talleur, D. A. (2003). Attentional models of multitask pilot performance using advanced display technology. Human Factors: The Journal of the Human Factors and Ergonomics Society, 45(3), 360-380. Actually, in that paper he cites Wickens et al. (...


6

This paper was written in 2010: Perceptual shift in bilingualism: brain potentials reveal plasticity in pre-attentive colour perception. In this paper, we test whether in Greek speakers exposure to a new cultural environment (UK) with contrasting colour terminology from their native language affects early perceptual processing as indexed by an ...


6

Jay's answer is correct, this occurs as a result of Gestalt processing. I will address your comment that: No response actually brings light on why we prefer things to be aligned, only the realization of such fact (for example, Gestalt principle). But first I will say that I believe this assumption is wrong: Nothing in nature is "aligned". Many ...


6

From personal observation, the consensus seems to be that the two streams hypothesis is an oversimplification of the truth, albeit a useful one. The primary reason that this hypothesis is seen as an oversimplification is because there is a lot of cross-talk between the two streams. For example, Zanon et al. (2010) provides evidence for functional ...


6

It has been theorized that it has to do with "visualizing" dreams, but the movements themselves are by virtue of the pattern of electrical activity as the waves travel between the Pons (in the brainstem), Geniculate nuclei (in the thalamus), and Occipital lobe. From PGO Waves PGO waves and REM sleep PGO waves are an integral part of rapid eye ...


6

From Stevens & Galanter (1957) Although an extensive investigation of the subjective scale of brightness is still in progress in this laboratory, enough has been learned to show that, for patches of white light viewed in a dark room, subjective brightness is a power function of luminance. Moreover, the exponent is of the order of one-third ...


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