Put your right hand on your head. Unless you are near a mirror, you can no longer see your hand, but you know where it is, right? You know what position it is in. You know how far away it is from most of the other things around you. I’m using the word “know,” but that’s just for convenience, because you don’t actually know those things. That is, you can’t be 100 percent certain your hand is on your head. You assume it is, and that’s as good as it is going to get – a best guess. We’ll come back to that. You can put your hand down now.

I once interviewed the great neuroscientist V.S. Ramachandran, and asked him about a condition known as anosognosia. This is the term for a disorder that causes the sufferer to deny another disorder. Blind people will sometimes believe they are not, for example. I asked him about this because I had learned that he once treated a patient with paralysis of one arm who denied that the arm was paralyzed even though she couldn’t move it when asked. She could no longer make an emotional connection to her arm. She denied that the arm was even a part of her. That biological connection, that feeling of ownership, was missing from her mind, and when asked whose arm it was she would say it was her mother’s or her brother’s. She said someone was playing a prank on her from under the table. Patients like this will explain away obvious things, but never seem to come out and say something like “it is my arm but I can’t feel ownership of it.” If she looked at her arm she could see the facts of the matter, but facts couldn’t alter her narrative. This is a form of anosognosia, and in these cases family and friends who are on one side of reality have a difficult time understanding how those on the other can continue to believe as they do. Inside the head of the sufferer, it’s not an easy thing to realize they are wrong. One of the defining features of anosognosia is that facts often don’t work on those who suffer under its terrible spell. I asked Ramachandran how that could that be possible.

One of my favorite tropes in fiction is the idea of the perfect thinker – the person who has shed all the baggage of being an emotional human being and could enjoy the freedom and glory of pure logic, if only he or she could feel joy.

Spock, Data, Seven of Nine, Sherlock Holmes, Mordin Solus, Austin James, The T-1000 – there are so many variations of the idea. In each fictional world, these beings accomplish amazing feats thanks to possessing cold reason devoid of all those squishy feelings. Not being very good at telling jokes or hanging out at parties are among their only weaknesses.

It’s a nice fantasy, to imagine without emotions one could become super-rational and thus achieve things other people could not. It suggests that we often see emotion as a weakness, that many people wish they could be more Spockish. But the work of neuroscientists like Antonio Damasio suggests that such a thing would be a nightmare. In his book, “Decarte’s Error” he describes patients who, because of an accident or a disorder, are no longer able to feel silly or annoyed or hateful or anything else. If they can, those feelings just graze them, never taking hold. Damasio explains that these patients, emotionally barren, are rendered powerless to choose a path in life. They can’t ascribe value to anything. Their world is flat. Despite remaining very intelligent and able to carry on conversations, they no longer make good decisions. Former business owners will lose all their money on bad investments. People who used to work from home will become lost in constantly reorganizing their shelves. Not only are their decisions flawed, but reaching conclusions becomes an excruciating process. When Damasio handed one of these patients two pens, one red and one blue, and asked him to fill out a questionnaire, the man was lost. To choose red over blue using logic alone took about half an hour. Every pro and con was listed, every branching possibility of future outcomes considered. Damasio wrote that “when emotion is entirely left out of the reasoning picture, as happens in certain neurological conditions, reason turns out to be even more flawed than when emotion plays bad tricks on our decisions.” Judgments and decisions corrupted by bias and passion are the only way we ever get anything done.

Why do you so often fail at removing bad habits from your life?

You try to diet, to exercise, to stop smoking, to stop staying up until 2 a.m. stuck in a hamster wheel of internet diversions, and right when you seem to be doing well, right when it seems like your bad habit is dead, you lose control. It seems all too easy for one transgression, one tiny cheating bite of pizza or puff of smoke, and then it’s all over. You binge, calm down, and the habit returns, reanimated and stronger than ever.

You ask yourself, how is it possible I can be so good at so many things, so clever in so many ways, and still fail at outsmarting my own vice-ridden brain? The answer has to do with conditioning, classical like Pavlov and operant like Skinner, and a psychological phenomenon that’s waiting in the future for every person who tries to twist shut the spigot of reward and pleasure – the extinction burst, and in this episode we explore how it works, why it happens, and how you can overcome it.

You live in the past.

You don’t know this because your brain lies to you and then covers up the lies, which is a good thing. If your brain didn’t fudge reality, you wouldn’t be able to hit a baseball, drive a car, or even carry on a conversation.

You may have already noticed this through its absence. Sounds that come from very far away don’t get edited. Maybe you’ve been high in the bleachers at a sporting event and saw the crack of a bat or the crunch of a tackle, but the sound seemed to arrive in your head just a tiny bit later than when it should have. Sometimes there is a delay, like reality is out of sync. You can see this in videos too. If you see a big explosion or a gun shot from far away, the sound will arrive after the camera has already recorded the images so that there is gap between seeing the boom and hearing it.

The reason this occurs, of course, is because sound waves travel much more slowly than light waves. But if that’s true, why isn’t there always a lag between seeing and hearing? How come you can carry on a conversation with someone at the end of a long hallway even though the light that’s allowing you to see her mouth is arriving well before the sound of her voice?

I did something this week that I’m sure many people secretly do every day. I stopped, talked to myself for a moment, and checked to see how much slack was in the leash I keep on my tongue.

I was reminded that I need to do that from time to time, or at least I believe that I do, by a bit of news that was passed around for a few days this week. The reports said that one of the government’s most prestigious energy laboratories was working to eradicate the Southern accent – not from the planet, mind you, just from employees who had requested the service.