Brain scans have allowed researchers to know exactly what a person was imagining after scientists used them to decode images directly from the brain.

Researchers have been able to put together what numbers people have seen, the memory a person is recalling, and even reconstruct videos of what a person has watched.

“We are trying to understand the physical mechanisms that allow us to have an inner world, and a part of that is how we represent other people in our mind,” said Cornell University cognitive neuroscientist Nathan Spreng.

Nathan Spreng’s team gave 19 volunteers descriptions of four imaginary people.

These characters had different personalities half being agreeable and cooperative and half being cold and aloof.

Half were described as outgoing and social and half were depicted as shy and inhibited.

Scientists matched the genders of these characters to each volunteer giving them names like Mike, Chris, Dave, or Nick, or Ashely, Sarah, Nicole, or Jenny for the women.

The volunteer’s brains were then scanned using functional magnetic resonance imaging. The technology measures brain activity by changes in blood flow.

Volunteers were then asked to picture how the characters might react in different scenarios, such as if they saw a homeless veteran asking for change or if they were at a bar and someone else spilled a drink.

“Humans are social creatures, and the social world is a complex place,” Nathan Spreng told Business Insider.

“A key aspect to navigating the social world is how we represent others.”

Brain scans allow researchers to know exactly what a person is imagining

Brain activity in picturing each personality was linked to a unique pattern of brain activity in the medial prefrontal cortex.

“This is the first study to show that we can decode what people are imagining,” Nathan Spreng said.

That area of the brain helps people deduce traits about others and the findings suggest it’s also the region where personality models are encoded, assembled, and updated.

“The scope of this is incredible when you think of all the people you meet over the course of your life and are able to remember. Each one probably has its own unique representation in the brain,” Nathan Spreng said.

“This representation can be modified as we share experiences and learn more about each other, and plays into how we imagine future events with others unfolding.”

The area is also linked to autism and disorders that inhibit people in social interactions.

People with these disorders may not be able to build accurate personality models of other people.

These advances could someday help treat these disorders.