Final Thought: Perceptions of a dress

Do you remember the dress?

If you were online five years ago, you probably do. It was a terrible photograph of a dress that some people looked at and swore was black and blue, while others (like me) couldn’t see anything but white and gold. 

People argued about the dress long and hard on the Internet, while scientists saw something that they’d never seen before. A perfectly ambiguous image. 

Ambiguity is a fact of life. Indeed, our brains are nothing but machines designed to take input and try and disambiguate what is being seen. 

We see the world in three dimensions. Or so we think. But what is actually happening is we have two eyeballs that see in two dimensions, and we use visual cues from the world around us to construct a three dimensional reality, using all our past experiences in moving through the world to create this sense of three dimensions. 

We are taking two dimensional information and reconstructing that third dimension. 

Usually, we are pretty good at this, but every so often, our eyeballs fail us. 

I remember once, looking up while a passenger in a car, and seeing the road disappear over a hill, the sky a deep rich blue at the top of the road. It was like we were driving into the ocean. 

Then I saw the trees on the other edge of the “sky” and realized I was looking at a huge lake, mirror still. And my brain did this little flip as it took this new information, and used it to re-interpret what I was seeing. No longer were we driving uphill, but down. It was not the sky at the end of the road, but a lake.

There have been optical illusions before. Like the duck that, when you look at it for long enough, suddenly resolves itself as a rabbit. This is what’s known as a bistable image. Our mind will suddenly resolve the image as a duck, or a rabbit. And we can see both. 

But the dress was different. Because it was bistable, but across individuals. If you see the dress as blue and black, it is almost (but not quite) impossible to see it as white and gold. 

Turns out the reason we see the dress whatever way we see it is colour constancy. That’s where our brain interprets familiar objects as the colours they are, even under different lighting conditions. 

Take, for example, a strawberry. Researchers have been able to show a picture of a bowl of strawberries that appear to be red, but there is no red in the image. Instead, our brains interpret the image not by what is, but by what ought to be. You are not observing the strawberry—to paraphrase Bertrand Russell—you are observing the effect of the strawberry on you. 

The way the brain disambiguates information is by running it past all your previous experiences—your priors—and giving you its interpretation of reality. 

But every once in a while, there is something that is completely ambiguous. Like the dress. Which has a number of contradictory visual queues, and so the brain needs to interpret it based on past experiences. 

Some, mostly early risers, see the window behind the dress. Their brains think “oh, this is a picture shot in daylight,” and their minds, knowing that the sky gives the world a blue tint, therefore we must interpret the colour of the dress as white and gold. 

Whereas people who wake up later and spend more time under incandescent light look at the bottom half of the dress, and see that it is in a shop, and assume the dress is lit by artificial light which is a yellowish light. Their brains subtract the yellow light in the image, leaving the dress as blue and black. 

It is possible for you to see the dress as both, but it takes a lot of work. You need to effectively train your brain to see the world from a different perspective. 

How we perceive the world is not limited to how colour affects our vision. Our experiences—our priors—colour our experiences everyday, as our minds seek to interpret different input. And just like with the dress, there are ways we interpret the data that is fundamentally different than how someone else interprets the data. And just like the dress, we are almost hardwired to interpret the information differently. 

This goes a long way to explaining why some people—in the face of overwhelming evidence to the contrary—will argue things like the Coronavirus is a Chinese plot against the Americans, or a Bill Gate Plot to rule the world or that it was manufactured in a lab or that it is caused by 5G. 

And for most of us, we are left looking and scratching our heads, because our priors lead us to a completely different, far less insidious reason for the pandemic, or for the social distancing orders or for 5G. 

The same differences pepper our day to day interactions around topics like global warming and politics and bears. 

We used to live in much more enclosed sociatal groups, where priors were shared amongst most, if not all the people in the society. But now, we all have different shared priors and it affects the way we see the world. My next door neighbour might (and probably does) hold completely different political, economic, religious and musical priors than I do. Which means that when we talk about stuff, there’s a good chance that very quickly, we will disagree on the finer points of politics or whether Takehisa Kosugi’s Music for a Revolution is, indeed, actually music. (The score reads: Scoop out one of your eyes 5 years from now and do the same with the other eye 5 years later.)

Worse, as people begin to politicize a pandemic, they are forcing people into seeing a medical crisis through priors that don’t fit the situation, but which your brain is perfectly happy to use to disambiguate the situation and tell you this is, indeed a political situation. 

But to paraphrase the World Health Organization’s Director-General Tedros Adhanom Ghebreyesus: by turning it into a political issue, you run the risk of adding many more body bags to the death toll. It’s hard to listen sometimes, but they’re not telling you to stay home to gain control over your life. They’re telling you that to help save lives. 

Maybe even yours.

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