YouTube: | https://youtube.com/watch?v=zjTCbL2wbRk |
Previous: | Life Inside a Dead Whale |
Next: | How to Forget Things on Purpose |
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Statistics
View count: | 443,890 |
Likes: | 10,430 |
Comments: | 752 |
Duration: | 02:29 |
Uploaded: | 2015-12-01 |
Last sync: | 2024-08-19 19:45 |
Citation
Citation formatting is not guaranteed to be accurate. | |
MLA Full: | "Why Do We Have Blind Spots?" YouTube, uploaded by SciShow, 1 December 2015, www.youtube.com/watch?v=zjTCbL2wbRk. |
MLA Inline: | (SciShow, 2015) |
APA Full: | SciShow. (2015, December 1). Why Do We Have Blind Spots? [Video]. YouTube. https://youtube.com/watch?v=zjTCbL2wbRk |
APA Inline: | (SciShow, 2015) |
Chicago Full: |
SciShow, "Why Do We Have Blind Spots?", December 1, 2015, YouTube, 02:29, https://youtube.com/watch?v=zjTCbL2wbRk. |
Your brain is lying to you about what you see-- find out why in this Quick Question!
Hosted by: Hank Green
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Sources:
http://www.livescience.com/52033-human-blind-spot-can-shrink.html
http://io9.com/5804116/why-every-human-has-a-blind-spot---and-how-to-find-yours
https://visionaryeyecare.wordpress.com/2008/08/04/eye-test-find-your-blind-spot-in-each-eye/
http://serendip.brynmawr.edu/bb/blindspot1.html
https://en.wikipedia.org/wiki/Blind_spot_(vision)
http://www.britannica.com/science/blind-spot
http://www.sciencedirect.com/science/article/pii/S0960982215008295
Hosted by: Hank Green
----------
Dooblydoo thanks go to the following Patreon supporters -- we couldn't make SciShow without them! Shout out to Justin Ove, David Campos, Chris Peters, Philippe von Bergen, Lilly Grainger, Happy Birthday!!, Fatima Iqbal, and Justin Lentz.
----------
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records: http://dftba.com/scishow
Or help support us by becoming our patron on Patreon:
https://www.patreon.com/scishow
----------
Looking for SciShow elsewhere on the internet?
Facebook: http://www.facebook.com/scishow
Twitter: http://www.twitter.com/scishow
Tumblr: http://scishow.tumblr.com
Instagram: http://instagram.com/thescishow
Sources:
http://www.livescience.com/52033-human-blind-spot-can-shrink.html
http://io9.com/5804116/why-every-human-has-a-blind-spot---and-how-to-find-yours
https://visionaryeyecare.wordpress.com/2008/08/04/eye-test-find-your-blind-spot-in-each-eye/
http://serendip.brynmawr.edu/bb/blindspot1.html
https://en.wikipedia.org/wiki/Blind_spot_(vision)
http://www.britannica.com/science/blind-spot
http://www.sciencedirect.com/science/article/pii/S0960982215008295
[intro plays]
[text: QQs: "Why do we have blind spots?"]
Hank: We're gonna do a little experiment. Make sure you watch this part of the video in full screen, close or cover your left eye, look at the plus sign. Be aware of the circle but don't focus on it, keep looking at the plus. You may need to move your head back and forth a bit or move your thing closer to your face, but at some point the circle is gonna disappear. Now close your right eye and look at the circle, move your head back and forth until the plus sign disappears.
You've just found your naturally occurring blind spot in each eye and of course daily practice we do not notice this. The human eye has what you might call a fundamental flaw. Light sensing cells in your retina send signals to your brain via nerves and those nerves are in front of the light sensing cells. Eventually, those nerves have to pass through the back of your eye to get to your brain and in the part of your retina where they pass through, there aren't any light sensing cells. That's your blind spot.
Now this isn't normally a problem because the blind spots are located at slightly different points in each eye and each of your eyes work together to fill in a complete picture. But even with one eye closed, you're not seeing a big black hole. Instead, your brain fills in what it figures ought to be there, that's why when the circle disappears you see the color of the background. Your brain is guessing, and it's guessing wrong.
Although at least one very small study found you might be able to shrink you blind spot with practice, researchers showed ten participants an image that fell within the margins of their blind spots and asked them to describe it. By the end of the experiment, people got a little better at describing those images. The researchers think it's because the light-sensing cells right around the edges of the blind spot became more sensitive, better at picking up and passing on light signals. That's the kind of skill that's probably not gonna ever make any kind of difference in a life or death situation and humans have had blind spots in their eyes for as long as we've had eyes. But it's a neat way to try and hone your brain if you're into that kind of thing.
There is a different kind of creature though that just completely avoids this problem. Cephalopods like octopuses and squids have their nerves behind their light sensing cells so there's no need for them to have a blind spot. Why did we not do it that way? Evolution. I for one welcome our tentacled overlords.
Thank you for asking and thank you especially to all of our patrons on Patreon who keep these answers coming. If you'd like to submit questions to be answered or get these quick questions a few days before everyone else, you can go to patreon.com/scishow and if you want to keep getting smarter with us, you can go to youtube.com/scishow and subscribe. Just do it.
[text: QQs: "Why do we have blind spots?"]
Hank: We're gonna do a little experiment. Make sure you watch this part of the video in full screen, close or cover your left eye, look at the plus sign. Be aware of the circle but don't focus on it, keep looking at the plus. You may need to move your head back and forth a bit or move your thing closer to your face, but at some point the circle is gonna disappear. Now close your right eye and look at the circle, move your head back and forth until the plus sign disappears.
You've just found your naturally occurring blind spot in each eye and of course daily practice we do not notice this. The human eye has what you might call a fundamental flaw. Light sensing cells in your retina send signals to your brain via nerves and those nerves are in front of the light sensing cells. Eventually, those nerves have to pass through the back of your eye to get to your brain and in the part of your retina where they pass through, there aren't any light sensing cells. That's your blind spot.
Now this isn't normally a problem because the blind spots are located at slightly different points in each eye and each of your eyes work together to fill in a complete picture. But even with one eye closed, you're not seeing a big black hole. Instead, your brain fills in what it figures ought to be there, that's why when the circle disappears you see the color of the background. Your brain is guessing, and it's guessing wrong.
Although at least one very small study found you might be able to shrink you blind spot with practice, researchers showed ten participants an image that fell within the margins of their blind spots and asked them to describe it. By the end of the experiment, people got a little better at describing those images. The researchers think it's because the light-sensing cells right around the edges of the blind spot became more sensitive, better at picking up and passing on light signals. That's the kind of skill that's probably not gonna ever make any kind of difference in a life or death situation and humans have had blind spots in their eyes for as long as we've had eyes. But it's a neat way to try and hone your brain if you're into that kind of thing.
There is a different kind of creature though that just completely avoids this problem. Cephalopods like octopuses and squids have their nerves behind their light sensing cells so there's no need for them to have a blind spot. Why did we not do it that way? Evolution. I for one welcome our tentacled overlords.
Thank you for asking and thank you especially to all of our patrons on Patreon who keep these answers coming. If you'd like to submit questions to be answered or get these quick questions a few days before everyone else, you can go to patreon.com/scishow and if you want to keep getting smarter with us, you can go to youtube.com/scishow and subscribe. Just do it.