Donders Wonders

Neuroscience is not mind-reading

This post is also available in Dutch.

These days, people seem to be afraid that neuroscientists might be able to read their minds. In reality, that’s not quite possible, yet.

In recent years, there’s been a lot of talk about how brain scanners allow neuroscientists to read people’s minds. The rumor is that when you go into an fMRI machine, scientist can apparently tell what you’re thinking. The truth is, neuroscientists can’t do this: neuroscience is not mind-reading.

It’s true that some of the methods they use sound similar to mind reading, but in practice they can’t just read anything that pops up in someone’s mind. Neural decoding is a popular method of this type (read this Donders Wonders blog post on decoding) where scientists create a computer program that learns to recognize certain patterns of brain activity. Different patterns can be based on distinct images, e.g., a cat or a dog.

Illustration by Pim Mostert.
Brain image by Bertyhell (CC BY-SA 3.0). Head image by Mouagip (Public Domain).

When you hear about a method like this, you might think that neural decoding is similar to reading your mind. True, if a program can recognize the pattern of your thoughts, then it can know what you’re thinking! However, there’s a catch: the computer program needs to learn and train considerably before it can read your brain and recognize the pattern of your potential thoughts.

For neural decoding to work, the program needs to receive information about your brain activity across many, many different occasions. For it to recognize that you’re thinking of, for instance, a cat, it needs to first observe you seeing a cat hundreds of times, in hundreds of different settings.

This kind of program is also not that accurate. Often, scientists consider the program good enough when the program is around 60% – 70% accurate when reading out what a person sees. This is far from 100%.

On top of that, in order to decode neural activity, the computer program needs to learn each person’s individual neural pattern. If it learns about my brain activity, it may not be able to decode your brain activity because our neural patterns are different. So if scientists want to “read your mind” with neural decoding, they first need to train the program on your unique brain, using countless examples of the ‘thing’ they want to read out.

At this point, neuroscience is quite far from being able to simply read your mind. So, someone (i.e., a neuroscientist) wanting to know where you were last night, is unrealistic and far from reach. So don’t worry! Neuroscience cannot read your thoughts…

At least not yet.

Written by Marisha. Edited by Marpessa.

Featured image: Image from Uki_71 (CCO Public Domain)

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