Scientists believe to have at long last figured out what makes us humans. Thus, they say that what sets us apart from other creatures of no mean intelligence is one very specific area of our brain that allows us to process abstract information of different types.

To identify the brain area in question, researchers carried out a series of experiments during which they presented human volunteers and macaque monkeys to different stimuli and monitored their brains to see how they responded to them.

As detailed in a report in the journal Current Biology, the human volunteers and the macaque monkeys were made to listen to several simple sequence of tones while in a lying position inside a functional magnetic resonance imaging (fMRI) scanner.

The scanner kept tabs on blood flow inside the test subjects' brains, revealing which regions were activated by the auditory cues, i.e. the sequences of tones, and which remained at rest.

The human volunteers responded differently to the stimuli

While some of the sequences of tones that were played for the monkeys and the human volunteers to hear were identical, others differed in terms of pattern and the total number of sounds.

The researchers say that both species successfully registered shifts in the number of tones and in the pattern of the sequences they were made to listen to. Still, only the human brain proved capable of integrating both these types of abstract information.

“It is like the monkey recognizes a pattern but does not realize it is interesting and take it no further - only humans take it on to the next level of analysis. This gives us a powerful clue about what is special about our minds,” says New York University specialist Gary Marcus.

One brain region turned out to be of special importance

The one brain area that lit up in the human test subjects but not in the macaque monkeys during this series of experiments was the so-called inferior frontal gyrus. This brain region displayed a unique response in changes in both tone number and sequence, Nature informs.

Interestingly, the inferior frontal gyrus was previously shown to be involved in making sense of numbers and in processing language. Hence, it might, in fact, be what distinguishes us from other animal species that, although smart, cannot work with abstract information.

“We had expected that humans have brain areas that put together information. This type of computation may turn out to be relevant to other characteristics that make humans unique, like music appreciation,” explains University of Vienna scientist Tecumseh Fitch.