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43 votes
Accepted

Are drugs made bitter artificially to prevent being mistaken for candy?

Short answer A bittering agent may be applied to therapeuticals to prevent pediatric poisonings, but many drugs inherently taste bitter by themselves. Background Bitter taste is thought to have ...
AliceD's user avatar
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35 votes
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Why does my room suddenly look 'reddish'? My eyes seem to adapt to color

Short answer The phenomenon you describe can be explained by the negative afterimage effect, which indeed is elicited by adaptive processes in the retinae. Background In the retina there are three ...
AliceD's user avatar
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33 votes
Accepted

Can one see flickering of a light bulb at 50 Hz?

Short answer Yes, the flickering of a light bulb may be noticeable, and yes, that's directly related to the mains frequency. However, since the flickering of a bulb is about two times higher than the ...
AliceD's user avatar
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30 votes
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Why do mints make your mouth feel cold?

The feeling of cold from mints is caused by menthol. Menthol affects the TRPM8 receptor on skin and also in the mouth. TRPM8 is also a general cold receptor: so if you are in contact with menthol the ...
AlexDeLarge's user avatar
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12 votes

Why do I still see a bright light after looking directly at it?

Short answer The effect you describe is called a negative after image. It can be explained by adaptation effects of the photoreceptors in the eye. Background source: Dresden University Steadily ...
AliceD's user avatar
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10 votes

Best colour for a dog to track an object against green background

Dogs are a dichromatic species, featuring only a long wavelength (L) and a short wavelength (S) cone (source: Smithsonian). As such, they are thought to perceive mainly blues and yellowish hues (Fig. ...
AliceD's user avatar
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10 votes
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What is the smallest touch sensation that a human can feel?

Short answer The detection threshold of static indentation stimuli on the palm of the hand is approximately 10 to 40 micrometers, dependent on the exact location under investigation. Background The ...
AliceD's user avatar
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9 votes
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Is brain plasticity such that we can train ourself to see with our ears?

Short answer Yes, we can see with our ears. Background Bach-y-Rita famously stated "We see with our brains, not our eyes". Bach-y-Rita worked for decades on sensory substitution. Sensory substitution ...
AliceD's user avatar
  • 52.5k
8 votes

Can one see flickering of a light bulb at 50 Hz?

A lamp flickers at 2x the mains frequency, i.e. 100 or 120 Hz, and that is typically not noticeable to human eyes. It is visible to chicken and insects. That being said, a low quality lamp or a lamp ...
StessenJ's user avatar
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6 votes
Accepted

How exactly does sensory substitution work?

Tot start of with your definition: Sensory substitution, when one of sensory modality changes into another sensory modality to help someone restore the ability to perceive defective sensory using a ...
AliceD's user avatar
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5 votes
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Is synesthesia caused by crossing the circuitry of different sensory inputs?

Short Answer Synesthesia happens at a point during processing where we are not dealing with "raw visual input" or "raw auditory input" anymore, but already with more abstract ...
Oosaka's user avatar
  • 3,245
5 votes

Understanding the "Waterfall Illusion"

The motion after-effect (MAE) is believed to be primarily due to adaptation of direction sensitive cells in the middle temporal area (MT) (Fig. 1.). The directional cells in this area of the cortex ...
AliceD's user avatar
  • 52.5k
4 votes

Can low temperatures induce a withdrawal reflex?

The withdrawal reflex is a nociceptive flexor reflex and is a spinal reflex intended to protect the body from damaging stimuli. In other words, activation of heat receptors is not the trigger of the ...
AliceD's user avatar
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4 votes
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How do we perceive weight?

This would most likely come under the category of Proprioception - the sense of how our bodies are arranged in the world, and how much effort each part of our body is expending. From Wikipedia, 'In ...
Jay Moore's user avatar
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4 votes

Does the nature of nervous impulses give us a finite number of things we can perceive?

I know we have sensors in the form of hairs that trigger a nervous impulse to the brain when they are stimulated. But as I understand it, each one can only send that on/off binary signal when they ...
Charles E. Grant's user avatar
4 votes

Additive property of taste

I would classify the neurological phenomenon of "taste" or "tastyness" as an emergent property (1), and therefore synergistic (i.e. not adequately explained simply by additive effects). For example, ...
MikeyC's user avatar
  • 4,734
3 votes

Can one see flickering of a light bulb at 50 Hz?

Let's say there is a point source of light (it could be a lamp or a highly reflective object) that undergoes large, rapid intensity changes, say 50-100 times a second. If you quickly move your eyes ...
Artelius's user avatar
  • 191
3 votes

How we can localize sound vertically (up-down) and front-to-back?

The Wikipedia article is quite good. In brief, as you state, the wave phase can be used only to localise sounds in the plane of the ears. To have an approximation of the position in the median plane (...
Joce's user avatar
  • 1,127
3 votes
Accepted

How we can localize sound vertically (up-down) and front-to-back?

Localization along the azimuth (horizontal left-right axis) is mediated by various processes: 1) First, there is the head shadow effect, which means that sounds from the left reach the right ear (AD) ...
AliceD's user avatar
  • 52.5k
3 votes

Nature of sight/ color perception?

The color you perceive is ultimately dependent on the relative contributions of the color photoreceptors in the retina, namely the red, green and blue cones. The sensation of color, therefore, is ...
AliceD's user avatar
  • 52.5k
3 votes

Are our ears more sensitive to low or high pitched sounds?

Short answer Our ears are most sensitive to the mid-frequencies. Background There are different ways of assessing sound level. The physical one simply determines the physical sound pressure level (...
AliceD's user avatar
  • 52.5k
3 votes

Are there gaps in what our ears can hear?

Short answer No, there are no between-hair cell induced tonotopical gaps in frequency perception. Background Young people are able to hear over a frequency range of about 10 octaves, with a ...
AliceD's user avatar
  • 52.5k
3 votes

Are there gaps in what our ears can hear?

To add to the good answer by @AliceD, take a look at some tuning curves for hair cells, the sound receptors in the cochlea (these happen to be fairly low frequencies and a turtle cochlea, though those ...
Bryan Krause's user avatar
  • 45.9k
3 votes

Are there people blind to touch?

Short answer In a way, yes. Background One prime example where the sense of touch is diminished is when peripheral sensory neurons degenerate, which is called sensory neuropathy. Diabetes is ...
AliceD's user avatar
  • 52.5k
2 votes

What is the smallest pressure differential that humans can detect?

Short answer The sensitivity to pressure differences highly depends on the study setup used. A paper resembling the conditions in your kitchen experiment concludes that the just noticeable difference ...
AliceD's user avatar
  • 52.5k
2 votes
Accepted

What causes a selective shift of colour perception after removing wavelength filtered glasses?

The short answer is you don't see light you see a reconstruction of your environment made by a learning organ, your brain adapts to changes in stimuli. Color in particular is tricky because there is ...
John's user avatar
  • 14.7k
2 votes

What is the essential benefit of center-surround organization of retinal ganglion cells?

You are assuming that light comes in perfectly in spots, and that the purpose of vision is to replicate a "bitmap" of the incoming light. This would actually be very inefficient computationally. In ...
Bryan Krause's user avatar
  • 45.9k
2 votes
Accepted

What is the term for awareness of or inclusion of real sounds within a dream?

I think I found a good expression : "sensory incorporation in dreams" https://www.psychologytoday.com/blog/dream-factory/201409/sensory-incorporation-in-dreams It doesn't seem reflected in a Google ...
Oosaka's user avatar
  • 3,245
2 votes
Accepted

Is the masking effect of sound related to action potentials or to mechanical aspects of hearing?

Short answer Both - masking occurs through neural effects, as well as via mechanical effects in the inner ear. Background First off, there are basically three types of masking, namely simultaneous, ...
AliceD's user avatar
  • 52.5k
2 votes
Accepted

Is arachnophobia connected to lower immunity against spider toxins?

This is an interesting question and may stem from the fact that spider phobias tend to run in families and thus have a genetic link - assuming susceptibility to toxin levels can be passed from parent ...
wanderweeer's user avatar
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