And now, I take a auick #NeuroThursday break from this grant-writing to draw you deeper into the rabbit-hole of how we perceive so much less than we think, all the time.
This is a follow-on from last week, where I explained how our precise/color vision is only good right at the center of our gaze.
But it doesn't feel like that, amirite? Big wide world out there, in full color and high definition!

Don't believe it. As my long-time readers know: your brain is full of lies.
Thanks to the fortuitous intervention of @mattdoveywriter and @KatanaPen this morning, I found a perfect example of how your brain makes stuff up and never lets you notice.
This here gray grid contains 12 black dots… but most people can only see 1-3 of them at a time. Move your eyes around, and different ones will slip in and out of view.
One reason I love optical illusions is because they aren't just signs of your brain messing up. They're signs of your brain *succeeding*. Every optical illusion is reveals a clever hack your brain uses to make its life easier.
So how do those elusive black dots reveal your brain's secret ninja tricks? First you have to understand the limitations your brain is working under. For that, remember last week: peripheral vision is kinda bad.
Now, peripheral vision isn't bad at everything. In case you've forgotten, you have lots of "rod" cells out there, which are great at low-light vision.
(Heh heh rod cells)
Peripheral vision does a lot more – you have whole swathes of brainstem devoted to gleaning important information from it. Especially movement & other surprises that you need to point your eyes at ASAP.
But your peripheral vision is bad at color, and – relevantly for this illusion – bad at precision. Once you get a little ways out from Gaze Central, you just don't have enough precision to pick up one of those little black circles.
As I said last week, your brain fills in the gaps based on the information it has. And in this illusion, the structure of the image gives your brain a LOT of information. Grey lines of constant color, in a completely regular pattern!
So what does your brain do? It uses all that lovely available information and fills in the world with it!
But when you fill things in with the available structure, you miss little one-off bits. Like those dots.
The #NeuroThursday takeaway is that when your brain doesn't know what's going on (which is constantly), it gets clever and fills in the gaps. Which is super useful - but not perfect.
Next week I'll take this one step further and show how this fill-in-the-gaps goes all the way up to your sense of time-continuous experience.
If you want to see the original scientific paper behind this illusion, here it is:…
And that initial image was the classic Müller-Lyer illusion:üller-Ly…
If #NeuroThursday helped you fill in the gaps, share it around, join the discussion, or suggest a future topic!
And if you enjoy my neuroscience or my fiction, consider nominating me for the Best Fan Writer category in the #HugoAwards, or for the Campbell Award for Best New Writer!…
I also nominate the typo at the top of this thread for Best Nevella.

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More from @BenCKinney

Aug 13, 2018
Handedness comes in two groups, "right handed" and "not right handed." Most people use their right hands for almost all precision movement, but the other group is a broad spectrum from weakly-right to strongly-left.
The way we describe and define handedness creates the effect @CStuartHardwick rightly notices. Culture defines how we talk about it - but the behavior is mostly genetic. The % of righties has remained constant across continents and milennia.
Hand dominance is a more squirrelly thing than most people realize. For example, righties are better at *some* things with their left hand... and *some* of these asymmetries flip in lefties. Take a few minutes on #LeftHandersDay to learn more!
Read 4 tweets
Aug 8, 2018
Quick heads up on the #BlackSpecFic report: the story counts for @escapepodcast @Pseudopod_org and @PodCastle_org are incomplete, and revisions will be forthcoming.
But you should read and learn from the #BlackSpecFic report anyways! The missing data is due to idiosyncrasies of the @EAPodcasts model, and has no impact on any other magazine's numbers.
Long story short, we treat reprints very differently from other magazines. For @escapepodcast specifically, they were ~45% of our 2017 stories, and our editorial process has one unified pipeline for originals + reprints together.
Read 4 tweets
Jul 23, 2018
Regretting organizing my two Worldcon panels this year. It means I'm not free to throw up my hands in frustration and give up on programming. The last 24hrs have been the last worst icing on a bad cake that's long been baking.
I mean, my panels will be awesome. But if you're skipping programming because you don't trust the con, you've made a sensible choice.
There are always more people who want to be on programming than can fit. There's no way to make everyone happy. I get that. But this weekend's screwups come in the context of a long chain of trust-erosion.
Read 4 tweets
Jul 13, 2018
So glad this one came out! "After Midnight at the Zap Stop" by @ouranosaurus is an awesome story - full of late-night grease, and the luckless & the worthy. But also because it's a #neuroscience teaching opportunity. Might even be a #NeuroThursday!
One offhand line explains a technology as "stimulating a particular set of mirror neurons." Which works as a story element just fine. It sounds plausible and authoritative! But as a neuroscientist, I have strong opinions about #mirrorneurons. I don't think they're real.
To be clear, mine is a controversial opinion. Many neuroscientists would disagree. But it's a hill I'm willing to fight on, especially given how often "mirror neurons" crop up in popular science.
Read 14 tweets
Jul 8, 2018
This Lindsey Sterling + Evanescence concert has been going for 3 minutes and it is already amazing.
Update: she is simultaneously dancing, playing violin, and kicking skeletons.
P.S. She too is a skeleton. Hard to be sure at this distance but I believe she has glittery bones.
Read 14 tweets
Jul 4, 2018
This phenomenon - when you look away from a moving thing, and you briefly see illusory motion in the other direction - is the "Motion Aftereffect," and it comes from some very basic brain maneuvers. Who wants to join me on going full #NeuroThursday here?…
Most neurons in the brain (and elsewhere) do this thing called "adaptation," where they accept whatever's going on as the new normal. For example, if you sit down with your laptop on your lap, you'll soon stop noticing the weight.
This can arise from the crudest single-cell level: some ion channels in the cell membrane have negative feedback loops that self-dampen.
Read 14 tweets

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