The basic neurobiology behind the 12-dot illusion

Interesting idea about the eye-tracking for VR: offloading computation to the brain!

I'll make a correction that while minor, makes a world of difference: filling in the blank is more accurately understood as the brain making bayesian inferences or predictions or best guesses about what's missing or uncertain. The top down interaction occurring there is much more interesting than the term caching implies.

Without the lines... there is much higher contrast.

I'm all for hearing an alternative hypothesis, but right now this article's seems pretty good at covering whta is happening.

Very interesting, thanks! Especially that second link.

Interestingly, I seem to have a little different effect than they did in the second illusion they present. First of all, I find there are three distinct perceptions, the left-right and up-down that they mention plus spinning (fan motion). I actually didn't see the left-right form at all until getting to the page with the larger star, although when I went back I could see it in earlier pages. On the page with rows of red x and green o with alternating color positions between rows, I see the top row as spinning and the other rows as up-down; after looking at it a bit longer than for the other pages to change it changes to all spinning, then can change back to just the top row spinning. Now when I go back to the similar colored dots page I see the same thing, although I didn't the first time.

Also interesting how you can affect what you see in that illusion - not reliably at first, but with increasing accuracy over a few minutes. Or at least affect what most of them do - that top row on some of them still does its own thing sometimes. I wonder if more complex perception changes would be possible with more practice. Very interesting stuff!

The worst trait I see when domain experts try to write "introductory" material is a depressingly-common amnesia toward what it was like to not already know their subject matter. This article is so badly written, so overly and needlessly wordy, that I'm honestly considering deconstructing it line-by-line as a case study in how not to write articles for the layman.

Here's a brief example, using the most jarring line I've been derailed by so far (I still haven't finished reading this article, getting hung up on runs like this):

> So what is the purpose of lateral inhibition in the retina? Let’s consider what kind of stimuli are optimal for activating this bipolar cell.

"What is the purpose of lateral inhibition in the retina?" Uh, hi - I just got here. We are zero lines from the place where we were first introduced to any of these terms (the last two words of the preceding illustration's detail are literally the first place the phrase "lateral inhibition" even appears).

We've just been shown this concept, at all, for the first time - in a literally microscopic illustration, with some concepts so unexplained they were just left for us to hunt for ("Notice that a single neuron pools information" - notice what? Notice how?) - and now we're supposed to be considering the ultimate purpose for this obliquely-introduced phenomenon? Not only that - we're supposed to be pondering this now using a neurologist's lexicon?

If we were actually supposed to be following what the author is saying here, we'd be given some time to reiterate this concept we were just presented from one angle, to consider it in different approaches, with descriptions we don't immediately understand reinforcing a model we could build with other descriptions we could better understand.

Instead of reinforcing its subject, the article spends time on aside paragraphs mocking what a non-neurological model of human vision might be (talking about Dennett's Cartesian Theatre), despite the way that nobody reading this would have that misconception, and introducing it only adds a concept so unrelated that it actively impedes understanding of the material. Passages like this are just thrown in, like the author wants to say "I know more than you, and I want you to know that I don't just know neurology, I also took a philosophy course."

The line I excerpted doesn't even have to spend more time describing the concept. Indeed - it's actually more effective if you make it less wordy, because a high-level general description tells us which things we don't strictly have to understand to follow the next part. Here's how I'd write that whole paragraph - note how much less I hang meaning on unexplained jargon:

> So, when a wide area of photoreceptors see the same signal, they actually reduce the signal seen by the tight cluster in the center. Why reduce the signal like this? Because this way, when we see a small detail - one that isn't surrounded by a big area of the same kind of light - that wider group of photoreceptors (connected to the horizontal cell) doesn't inhibit the signal. Getting stronger signals for just the smaller details is what makes stuff like dots and edges visually obvious to our human eyes.

It's not perfectly clear - it still needs a round or two of editing to be truly smooth to read - but, even as a rough draft, that's smoother than anything in the linked publication, which reads like didactic sandpaper.

It's terrifying that you can innocently trigger bugs in your visual cortex that will take lots of time to fix.

A terrible idea would be to make a video game (or a short movie maybe) which triggered the effect. Imagine if the background in (e.g.) Super Hexagon were designed for this purpose...