Making Sense of It All

A summary of the first chapter of You Don't Know What You're M ss ng

“The senses deceive from time to time, and it is prudent never to trust wholly those who have deceived us even once.” - Rene Descartes

Over the next few weeks, I’m running a series of posts summarising the chapters of my new book, You Don’t Know What You’re M ss ng, ahead of publication on 4th June. The aim is to give you a feel for the shape of the book, the kinds of stories I use to illustrate the concepts, and the ideas I hope will stick with you long after you’ve finished reading it.

In this post I’m going to summarise Chapter 1, Making sense of it all.

Late in the evening of 22nd December 1978, routine Alitalia flight 4128 took off from Rome, ferrying passengers home to Sicily for Christmas. Past midnight, on final approach to Palermo, the runway lights appeared as a thin strip against otherwise total darkness. The pilots descended a little more, held steady, waiting until they were above the runway - and then hit the sea. It is suspected they fell victim to a trick of the mind known as the “black hole illusion”. 108 of the 129 people on board lost their lives.

That story is extreme, but it illustrates the fundamental idea of the chapter: that the mind can be tricked and the consequences can be huge. More importantly, it’s not just pilots who suffer misconceptions and it’s not just extreme events that trigger them. We are all subject to intrinsic missingness - the way our own minds and bodies filter, compress, and sometimes simply drop information. Our senses can seem to make things disappear.

When you look around you, it’s easy to believe you are experiencing an objective reality. You can see the texture of the ground beneath you, you can feel the rough pages of a book, you can hear birds or traffic. It feels unmediated, as if the world is simply arriving in your mind fully labelled and correctly sorted.

But the compressions and rarefactions of the air that hit your eardrums do not arrive with tags saying “blackbird” or “car engine”. The electromagnetic waves entering your eye don’t say “green” or “blue”, much less “grass” or “sky”. It is your brain’s job to interpret the signals it is constantly bombarded with and to figure out what they mean. This is the perception problem.

Perception is not simply the narration of a pre-written story. It is an inventive and creative act: the brain attempts to weave the threads of the signals it receives into a coherent narrative. Most of the time the working rules it uses are good enough for everyday life, which is precisely why we so readily assume they must be accurate. But “good enough to get by” and “true” are not the same thing.

Natural selection is driven by fitness - survival and reproduction - not by a commitment to metaphysical accuracy. Our sensory systems have evolved towards mechanisms that allow us to complete tasks efficiently. They spare us the world’s excruciating detail and present us with something closer to a usable interface than a perfect representation.

That interface comes with a cost. In taking shortcuts that subjectify reality, in conjunction with our senses, our brains select which information we see and which we don’t. Information is filtered without us necessarily being able to see the mesh through which it is being strained. And because the system is designed to be seamless, the absences often don’t feel like absences. They feel like the world.

Much of the chapter is focussed then on the ways in which this filtering happens.

Sometimes it’s because our brains rely on implicit rules that usually work. These rules are so deeply embedded that we barely notice them - until they misfire. We can learn to compensate in familiar situations, but that doesn’t mean we literally “see” correctly. It means we’ve learned that our perception can be misleading, and we’ve learned how to behave accordingly.

Sometimes it’s because our senses conflate different properties of the world, so the signal doesn’t uniquely determine what’s out there. A simple example is touch. Metal cutlery can feel colder than a wooden spoon sitting in the same kitchen, even when both objects are at the same ambient temperature. What we “feel” as cold depends on heat transfer and material properties, not just temperature. So even something as basic as “how cold is this?” isn’t as straightforward to answer with our fallible sense as we might hope.

For me, the most practically relevant part of intrinsic missingness is the set of mechanisms that make us miss things even when they’re present.

Adaptation is one mechanism which causes things to go missing. It’s the reason smells fade. It’s why background noise can melt away. It’s why constant stimuli stop clamouring for attention. Adaptation is often beneficial because it stops us being overwhelmed, leaving us sensitive to change. And yet it can be disastrous when it makes us tune out the very thing we most needed to notice.

Here’s a pertinent example. Natural gas is odourless, so an unpleasant smell is added to make leaks detectable. But if you’re exposed to that smell over time you can become acclimatised, and then the warning signal stops feeling like a warning signal. In 2009 the Conagra food production plant was having new boiler fitted. Relying on smell rather than detectors, the workers fitting the boiler unknowingly allowed the room they were working in to fill gas which eventually ignited, resulting in multiple deaths and many injuries. The brain’s capacity to “get used to” a stimulus did exactly what it evolved to do - and in that context it was catastrophic.

Habituation is another filtering mechnism. Unlike adaptation, habituation isn’t that you stop perceiving the stimulus. It’s that you stop responding to it because experience has taught you it isn’t important. That can be sensible, but it can also be deadly. Alarm fatigue is the most obvious example: if an alarm goes off repeatedly and nothing happens, people learn that the alarm can be ignored. Expected alarms don’t provoke the same automatic responses as unexpected ones, which means that when the real emergency finally arrives, the system is already biased towards complacency.

Then there’s attention. We like to think we take everything in, but attention behaves more like a spotlight than a floodlight. When attention is engaged, we miss stimuli we are not expecting to perceive that fall outside of the narrow cone of the spotlight. This is the territory of inattentional blindness. It’s also why phone conversations can be dangerous in cars even when your eyes are on the road and your hands are on the wheel: the issue isn’t physical control, it’s the allocation of cognitive capacity.

Finally, there’s the extra twist that makes all of this so difficult to manage: metacognitive errors – errors in what we think about the way we think. We are not just prone to missing things. We are prone to being overconfident about our ability to notice. Even when people are told how common and substantial these misses can be, they still massively overestimate their own detection abilities. That overconfidence is part of the problem. It makes intrinsic missingness feel like something that happens to other people.

The aim here isn’t to encourage paranoia, or to suggest we should doubt every piece of information that comes through our senses. The key is not to doubt or question everything, but to be more conscious of our blind spots, and more alert to the situations in which we might be missing information without even realising it. Once you start seeing intrinsic missingness for what it is - a feature of the system, not an occasional glitch - you begin to understand why illusions work, why errors can feel impossible in retrospect, and why “I would definitely have noticed” is such a dangerous sentence.

A favour: pre-order the book

If you’ve enjoyed this summary, you’ll find much more detail in the book itself, with the stories, the science and the slightly uncomfortable implications.

If the book sounds like your sort of thing, please consider pre-ordering it. Pre-orders matter far more than most readers realise. They’re one of the strongest early signals that a book has an audience, which influences everything from how many copies are stocked to how widely it’s recommended.

Amazon: https://www.amazon.co.uk/Dont-Know-What-Youre-Missing/dp/1529438039

Bookshop.org (supports independent bookshops): https://uk.bookshop.org/p/books/you-don-t-know-what-you-re-missing-the-science-of-what-s-lost-and-how-to-find-it-kit-yates/497ab9dcf971763a

Thanks, Kit