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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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How it's known that scintillating scotomas are caused by cortical spreading depression? Is this a type of migraine?

I have just read about a visual effect called a scintillating scotoma. Many variations occur, but scintillating scotoma usually begins as a spot of flickering light near or in the center of the ...
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1answer
26 views

Unilateral vision in split brain subjects

I am just beginning to learn psychology and came across concept of split brain. I was wondering if a person has only left eye working and has their corpus callosum cut, would they be effectively blind ...
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1answer
19 views

Fit a psychometric function when the maximum is not 100% (not because of lapse)

I found that currently the form of psychometric function assumes that the proportion correct lies between 0.5-1 given the range of stimulus level, but how to fit a psychometric function when the ...
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2answers
72 views

If the optic nerve transmits to both hemispheres, how do split-brain experiments work?

From what I understand, the optic nerve of each eye transmits information to both hemispheres of the brain. This is unlike other sensory and motor information, where (for example) the right hand is ...
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Is the perception of drawings an acquired skill?

Most descriptions of visual perception explain how our brains interpret incoming visual stimuli (via feature detection, monocular depth cues, etc.). They then assume that the same process works for ...
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1answer
41 views

Visual field testing: Choose between Yes/No, 2AFC, and 2IFC task?

As a newbie to psychophysics experiment, I have a small project to do visual field testing on healthy, adult, naive subjects. The experiment stimulus is a small sine grating (0.3 degree, 6 cycles/...
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1answer
115 views

Finding largest level of imperceptible noise in an image

Suppose that we want to find the "largest level" of a random noise that can safely be added to an image such that the resultant noisy image cannot be distinguishable from the original noise-free image....
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1answer
39 views

Why do we see shadows in the following black-and-white optical illusion?

How does neuroscience explain the following optical illusion? Look at tiles. You will see spots of shadow near all corners. The shadow will be missing from some corners very near the center of your ...
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1answer
65 views

Why do views make you happy?

Why does having a nice view from your window make you happy? (As in people ask for a hotel room with a nice view). Could this be replicated by simply having a large TV screen showing a view? What ...
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1answer
32 views

How do I interpret an effect of electrode position in ERP research?

The example I have in my research is that both conditions show greater amplitude and latency in the parietal electrode sites than in the occipital ones. I'm not sure how meaningful this is for my ...
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1answer
38 views

Human vision detection of faint blinking or moving point of light, guidelines for sensitivity versus frequency

This question is in the neurology/neuroscience rather than the psychology aspect of this site. I'd like to check the limits of visibility of a (presumably green) LED at large (kilometer) distance, ...
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Crossed-eyes on non-stereo-scopic image

There are a lot of dual image stereoscopic depth images, and most "Magic Eye" images have the same structure. Some Examples: Example 1 Example 2 Example 3 (CG'd) Example 4 (Magic Eye) These are ...
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Convolutional Operations in the Visual Cortex

One of the fundamental operations in image neural networks is the operation of convolution, where a filter slides across the receptive field, activating on particular features. This is incredibly ...
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1answer
59 views

When your two eyes disagree sharply

Now and then, the image from each eye is so different from the other that it seems the brain has trouble combining them into a coherent image. You can create this situation by putting a hand or sheet ...
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53 views

Why watching heavy rain is calming?

Recently, I watched a heavy rain closely from window, with huge breeze. It felt enthusiastic. Calmed my anxiety. I felt like some magic happening. Are there any studies explaining this? I haven't ...
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26 views

Ability to identify an “average” vs a maximum (or minimum)?

I have a hypothesis that humans are better able to identify the largest (or smallest) in a set of objects, compared to their ability to identify an average object, i.e. the one closest to the mean. ...
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151 views

Proportion of cortex dedicated for vision and hearing

I have read in some websites that the percentage of the cortex devoted to processing visual information is from 30-66% with some claiming even 90%. And compared to that, only about 3% is dedicated to ...
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2answers
551 views

Due to Gestalt Psychology, is the face an illusion?

Gestalt Psychology maintains that we perceive a whole from parts, and that we fill in missing gaps. The "whole" we perceive is more than the sum of parts we perceive - it also involves what our minds ...
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3answers
531 views

The interactions between hallucinations and reality in people with schizophrenia

A person with schizophrenia sees a door become open, while in reality it's closed. What would he see when he tries to pass through the door? Bumps into an invisible obstacle. He sees the door become ...
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How do different emotional intensity ratings within a condition influence the comparison across different conditions in an event-related fMRI task?

I'm planning an event-related fMRI-experiment to investigate the difference in processing natural and computer-generated expressions. For this, we recorded videos of 4 different actors posing fearful ...
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61 views

To what extent is face-detection achieved in peripheral vision?

I'm trying to find out to what extent mere detection of faces (i.e. determining that something is a face, as opposed to recognition of specific individuals) is favored in the central vision vs ...
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1answer
101 views

Mental rotation test in a virtual environment

Parsons et al. (2004) found that the widely reported sex difference in performance in the pen-and-paper mental rotation test could not be reproduced in a virtual environment: The visuospatial ...
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1answer
101 views

Is V1 involved in visual imagery?

It's well known that mental imagery shares the neural substrates of its respective modality, despite dissociable multivariate patterns. For example, visual imagery can be decoded across the ventral ...
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1answer
142 views

How do I stream SMI glasses eye tracker data into MATLAB?

We are planning to use the SMI glasses eye tracker. This eye tracker obtains gaze data and we will use it for pupillometry as a measure of cognitive load. The only thing I'd like to accomplish is ...
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27 views

Region of Interest Proposal in Vision

In machine learning, Region of Interest (ROI) proposal is a method for subsampling an image to identify "interesting" subregions. A canonical example is from Region Convolutional Neural Networks, ...
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2answers
91 views

What electrical stimuli do brain implants use?

I was reading about artificial eyes and came to think about how the brain works. More specifically, what "signals" it uses in the case of cortical visual prosthetics in blind people? Cortical ...
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1answer
51 views

Learning In Retina

Most of the sources studying retina seem to suggest that retinal connectome is hardwired and species dependent (like specialized vertical movement detector in small rodents). I couldn't find a single ...
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1answer
103 views

What are the definitions of 'multi-channel coding' and 'opponent channel coding'?

I am looking for the definitions of Multi-channel coding Opponent-channel coding And specifically in the context of visual adaptation. I have searched for information on the web and in books, but ...
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1answer
87 views

What is the cause of differences that are too small to see?

Consider two identical pieces of paper. Scenario 1: On both something is drawn in black ink. If the difference between the areas covered in black ink is sufficiently small, I cannot see the ...
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1answer
53 views

Is there a waterfall visual after-effect with discrete inputs?

If you watch a waterfall for several seconds and then suddenly change your gaze to a fixed object it appears to briefly move upward. But if instead you're looking at a scrolling LED marquee sign, ...
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1answer
35 views

Are the receptive fields of bipolar and retinal ganglion cells directly stimulated by light?

I know this is a basic question, but I can't find the answer anywhere. How can a cell that is not photoreceptive (eg LGN and retinal gangion cells) have a receptive field that is stimulated by "light" ...
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69 views

Use of the visual cortex in mathematical thinking?

In modern computers (and programming) one makes alienated use of the high powers of graphical processing units (GPU) for non-graphics-related tasks, enhancing drastically the power of the general ...
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0answers
41 views

How bright must a light bulb to be noticed in a room?

If one has say an 800 lumen bulb, how many lux are necessary in order for a human to detect when it's suddenly turned on in a room with brightness levels of 30 Lux 50 Lux 100 Lux 1.-How many Lux ...
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0answers
77 views

Random-dot kinematograms implementation in javascript/HTML

I am looking for a "random-dot kinematograms" implementation in javascript/HTML that I can use in web-based experiments. Something like this, where the user can specify the direction using a mouse or ...
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19 views

What is the frame-rate of an average person's perception for fast objects? [duplicate]

When things move really fast, you might notice that it looks broken down into discrete images at a fast enough speed, even though the object isn't actually teleporting. Or, in the case of staring at a ...
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3answers
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How to use a QUEST staircase in 2-AFC?

Firstly, I need to declare that I am not psychologyst, however I am currently working on visual recognition research. To be precise, I working on face recognition deficits in Autism Spectrum Disorder. ...
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1answer
373 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 ...
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1answer
63 views

Is habituation responsible for inaccurate airport security screenings?

The U.S. Transportation Security Administration has "red teams" who try to sneak dangerous items through airport security. The security personnel often fail up to 95% of these tests. Is this high ...
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1answer
73 views

What happens in my retina if I press on my eyeballs?

If I press my eyes I can "see" all kind of things: sparkling blue dots (which sometimes seem random and sometimes there seems to be a pattern in them), growing or diminishing rings of all kinds of ...
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What timing of visual emphasis paired with a spoken word provides the best cognition? [closed]

I am working on an animation in which there are three somewhat small font words (Environmental, Social, and Economic) together with three colored horizontal histogram bars on each side of the labels ...
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1answer
581 views

Can color blindness be treated with image filtering technology?

Using image color-filtering techniques we can simulate the way colorblind people see: The aim of this question is to know whether the opposite process could be possible, namely can a colorblind ...
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1answer
64 views

What is the neural adaptation underlying the habituation to reversed visual images? [closed]

When a person wears glasses that reverse the image upside-down, it is possible to adjust your vision in a matter of days. What are the suggestions behind the neurological process?
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1answer
19 views

Can we learn to adapt to image-reversal when being intermittently exposed to them?

I know that human vision can get accustomed to reverse vision when wearing reverse glasses for several days. But does it work when we see the reverse image just in certain moments throughout the day? ...
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1answer
287 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. ...
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2answers
189 views

How is the biological error signal in predictive coding computed?

I am quite inspired by the results obtained by PredNet, which implements a predictive coding model using artificial neural networks. They compute the prediction error as a simple subtraction, and then ...
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1answer
320 views

How does a person who wears prism glasses through which the the world is perceived upside-down experience the transition back to normal?

If someone wears prism glasses that turn the visual field upside down, this person will eventually adapt and see the world in its normal orientation again. Now my question is, how does the person ...
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1answer
156 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 ...
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1answer
112 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 ...
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1answer
111 views

Do non-human primates exhibit the Kiki/Bouba effect?

After understanding that cats cannot experience the Kiki/Bouba effect, I wonder if smart non-human primates can experience it. There is evidence suggesting that Chimpanzees associate high pitch with ...
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3answers
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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 ...