Teenagers’ brains and their ideas

Teenage brains can’t tell what’s important and what isn’t claims an article in New Scientist. There are lots of articles and books like this one claiming that behaviour X is a result of a person’s brain. This kind of argument is primarily an excuse for denigrating people.

Any human brain is a universal computer – it is capable of computing anything that can be computed. And since the information processing done by a person’s brain can be computed, this means that any human brain is capable of computing anything that another human brain can compute. As such, the difference between the brains of different people is how they are programmed. It is not a hardware difference.

In addition, human beings are capable of creating new explanatory knowledge. Even a person learning stuff that other people know has to recreate that knowledge in his own mind by the same kind of process that somebody creating completely novel knowledge would use. He guesses and criticises those guesses. Saying that there is some knowledge teenagers can’t create implies that there is some limit to what sort of explanations they could guess and criticise short of what an adult could do. No such limit has been explained. Nor does any such limit make sense. A child learns language, which includes all of the explanatory knowledge that is common enough for people to coin words to refer to it. For example, the word “fall” involves the idea of motion, a distinction between higher and lower, the idea of interactions that can raise objects and oppose falling motion, the idea of objects that you can fall off and so on. People had to discover this knowledge and come up with new words to describe it. So there is no hard and fast distinction between knowledge that lots of people happen to know now and knowledge that is not common in terms of the process of creating that knowledge. If you can learn English well enough to communicate at all then you can learn anything. There are examples of young children knowing more than their teachers or other adults, e.g. – Gauss.

A person can look for an explanation of his current ideas and priorities and change them if that explanation has flaws. This is true of all human beings, including teenagers and young children. Both teenagers and children can and do change their ideas and priorities in the light of new information. So if you want to explain the behaviour of any human being, including a child or teenager, you need to understand what explanations that person had adopted.

So trying to explain a person’s behaviour by referring to his brain is irrelevant and unhelpful. It’s like trying to explain why a character in a computer game has particular dialogue by talking about electrons in circuits. The reason why a character has particular dialogue is that somebody wrote that dialogue. The dialogue writer chose particular words in light of his knowledge about the computer game, cultural context etc. The explanation of the dialogue has to refer to the relevant context.

So why do people refer to brains when they talk about behaviour? Part of the explanation may be confusion, but that can’t be the whole explanation. Anyone capable of writing an article can read. Anyone who can read can learn about the theory of computation and the theory of how people create knowledge. So a writer could think about such ideas and refrain from writing false stuff about the brain. People actually write about the behaviour of teenagers in terms of brain because of a reckless disregard for the truth, and a desire to denigrate teenagers.

Consider the first paragraph of the article:

Teenagers may know full well how important final exams are – but that won’t stop some putting in minimal effort. This may be because their brains aren’t developed enough to properly assess how high the stakes are, and adapt their behaviour accordingly.

Some teenagers don’t put a lot of effort into exams. Instead of asking those teenagers about their priorities the writer attributes this behaviour to their brains. So then the writer doesn’t have to ask questions like the following. Do exams actually matter? Why might a person value some other activity over passing an exam?

The article continues:

Catherine Insel, at Harvard University, and her team asked adolescents between the ages of 13 and 20 to play a game while lying in an fMRI brain scanner. In some rounds of the game, participants could earn 20 cents for a correct response, while an incorrect one would cost them 10 cents. But in rounds with higher stakes, correct responses were worth a dollar, and wrong answers lost the participants 50 cents.

…

The team found that while the older volunteers performed better in the high stakes rounds, the younger ones didn’t – their performance didn’t change in line with whether the stakes were low or high. And the older the volunteers were, the more improved their performance was. “Interestingly, the ability to adjust performance according to the stakes at play emerged gradually across adolescence,” says Insel.

When the team looked at the brain activity of the volunteers, they found that their ability to improve their performance was linked to how developed their brains were. A region called the corticostriatal network seemed to be particularly important. This is known to connect areas involved in reward to those that control behaviour, and continues to develop until we are at least 25 years old.

A person’s priorities and ideas will in general change how he uses his brain and so would change patterns of brain activation. So studies like this don’t imply that a teenager’s brain explains his behaviour and ideas.

There are other explanations to consider. For example, parents will often take property and money away from children and teenagers. So teenagers and children may value money less since they think they won’t be allowed to use it to fulfil their own preferences.

This sort of “study” is careless junk science.