Carnegie Mellon University scientists have devised a way of using brain activation patterns to identify complex thoughts.

The latest research uncovered that the mind processes complex thoughts by activating parts of the brain that give a sentence its meaning, so for a sentence like “the witness shouted during the trial,” 42 meaning components are activated including person, setting, size, social interaction and physical action included in the sentence.

“One of the big advances of the human brain was the ability to combine individual concepts into complex thoughts, to think not just of ‘bananas,’ but ‘I like to eat bananas in evening with my friends,'” said Marcel Just, Carnegie Mellon University Professor of Psychology.

“We have finally developed a way to see thoughts of that complexity. The discovery of this correspondence between thoughts and brain activation patterns tells us what the thoughts are built of.”

Previously, Just and his team had showed that when we think about a single object, like a banana for example, we evoke the neural systems that deal with our interactions with those objects.

So when you think about a banana the neural systems concerned with how you hold it, how you bite it and what it looks like are stimulated.

The new study built on this knowledge and demonstrated how the brain deals with 240 complex sentences.

Working with seven participants, the researchers used a computational model to assess the different brain activation patterns for 239 sentences.

Using the patterns they saw in the original 239 sentences, the researchers were then able to predict the features of a 240th complex sentence, with 87% accuracy, despite never being exposed to it or its features before.

The researchers were also able to work in the other direction and predict what was activated in the brain when the sentence was being interpreted.

“This advance makes it possible for the first time to decode thoughts containing several concepts. That’s what most human thoughts are composed of,” Just said.

“A next step might be to decode the general type of topic a person is thinking about, such as geology or skateboarding. We are on the way to making a map of all the types of knowledge in the brain.”