Researchers Discover the Brain Uses One Mechanism to Assess All Five Senses

Metacognitive Mechanism

Scientists at EFPL in Switzerland have found conclusive evidence that the brain uses a lone mechanism, known as a supramodality, to determine its confidence in all the senses.

Metacognition is a term that refers to the ability to assess or analyze our mental state. One component of this faculty is determining how confident we are that what we're seeing, hearing, touching, smelling, or tasting is accurate.

Often, we need to combine information being delivered via more than one of our senses to ensure that the information we're receiving is right— like using both audio and visual cues to recognize a musical instrument that's being played.

In a Sense

The EFPL research team wanted to know whether the brain used the same rules to determine its confidence in all senses, or whether it assessed each input differently. To find out, they performed three experiments on volunteers.

The first was based around behavioral psychophysics, and it found that participants who excelled in terms of metacognitive performance for one sense were likely to do well for others, too. The second, computational modelling, established a parallel between confidence estimates for things we see and things we hear. The final experiment used electrophysiological recordings to determine that subjects shared similar characteristics when they expressed confidence in responses to audio and audiovisual prompts.

"These results make a strong case in favor of the supramodality hypothesis," commented lead researcher Nathan Faivre in a press release. "They show that there is a common currency for confidence in different sensory domains – in other words, that confidence in a signal is encoded with the same format in the brain no matter where the signal comes from."

The team hopes that these findings could offer up new methods of diagnosis and treatment for neurological and psychological disorders that affect metacognition.