Research Published March 11 2016
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BRAIN’US was born at the Brain and Spine Institute. This mobile app, developped by Jean Daunizeau, Inserm researcher and co-director of the “Motivation, Brain and Behaviour” team at the Institut du Cerveau – ICM, had the ambition to gather knowledge on how the brain works. One year later, we look back on this ambitious participative science project.

One app, 8 games, 30 000 participants, a unique scientific experience conducted by Jean Daunizeau. The denominalized and confidential collected data, have been analyzed through mathematical models. In an exclusive interview, Jean Daunizeau, Institut du Cerveau – ICM researcher, delivers the first results where it is question of theory of mind, cognitive functions and links between both.


It is the capacity which enables us to represent other people’s mental states : what they think, what they feel, what they want, what they like…. This cognitive function plays a major role in our social interactions.

Through it, we can assign intentions, beliefs, desires, or mental representations to other people. Learning this ability is based, among other things, on the understanding that other people have mental states and a representation of the world which differ from ours. This ability lets us enter into relationship with others, communicate,  better handle conflicts, collaborate, and also understand metaphors or jokes.

In order to do this, we use all kinds of information called social signals, such as gaze direction, facial expression, body posture, language, explicit behaviour (language, gestures,…)… We integrate all these signals to make an internal representation of other people’s mental states in order to be able to predict their behaviour.


Two kinds of mechanisms may be involved in theory of mind.

The first kind is implicit, automatic, fast, efficient, and probably negligent. It is similar to instinct. It is, for example, the automatic capacity to read emotions on someone’s face without thinking about it, it is the “intuitive” understanding we have of other people.

The second kind of mechanism, explicit mechanisms, correspond to the conscious and controlled analysis of other people’s mental states. This kind of internal deliberation requires the involvement of “executive functions,” and more particularly :
– ” Working memory “, which content forms conscious thought, and stores (in the short-term) the necessary information to explicit reasoning. Its capacity is limited, and this limit varies from one individual to another.
– The “inhibiting control” is our ability to interrupt a thought or an action in preparation and/or currently executed, Among other things, it enables us to draw our attention from all details which are not relevant for reasoning.

Executive functions make explicit, controlled, slower, but more flexible information processing possible. Like most cognitive processes, theory of mind could be decomposed into implicit and explicit processes. These two mechanisms can compete with each other and contribute separately to our ability to understand other people’s mental states.


First, we have studied through these games theory of mind mechanisms, and some of the executive functions associated. More specifically, we tried to understand to what extent general cognitive abilities such as working memory or inhibiting control contribute to performance in theory of mind tasks. The idea is that executive functions’ contribution could vary considerably with age, as time and experience make each of us a theory of mind “expert”.


First, we have studied executive functions’ contribution according to the person’s age. The participants, from 5 to 90, were divided in 5 year age groups and we have calculated their average performance on two theory of mind tests, and two executive functions, working memory, and inhibiting control tests, then we have analyzed performance according to time.


All performances have a similar general pattern. During development, namely from 5 to 20, Success in tests improves with age: people work better and better ! Performance remains almost stable from 20 to 40, and then declines from 40 to 90 (we talk about “cognitive decline “). Roughly, this dynamic performance to tests falls into line with maturation and degeneration dynamics of the prefrontal cortex, seat of executive functions.

What is interesting is that performance for executive functions decline more rapidly than performance for theory of mind tests.

There is thus a late decoupling between executive functions and theory of mind. It is quite possible that theory of mind construction is contingent to the development of executive functions. To sum up, young adults are superior to children in theory of mind because they have a better working memory and better inhibiting control. That being said, progressive loss of executive functions during aging process does not imply a significant loss in theory of mind. It is possible that some implicit, automatic and specialised processes are implemented and can partially compensate for executive functions decline. In other words, it seems that our understanding of others is an island of youth at the heart of intellectual erosion signing the weight of years !


The ability that allows us to understand other people’s intentions and emotions, called theory of mind, consists in two components, one being automatic or implicit, the other one being controlled or explicit. This last one has itself sub-components, executive functions, such as working memory and inhibiting control. The question is whether the contribution of these sub-components to theory of mind varies with age. To explore this, researchers have analyzed whether performance in different tests varied with age. They observe a perfect alignment between performance in theory of mind and executive functions during development, from 5 to 20, and a de-correlation after 40, the beginning of cognitive decline. The loss of executive components may be compensated by automatic mechanisms maintaining performance in theory of mind at a more advanced age.

For more information on BRAIN’US games, find below Jean Daunizeau and Marie Devaine’s explanations.

3 steps behind

This test aims to assess your ” working memory “, that is to say, the memory required to solve simple tasks, such as memorising a phone number while dialling it.


This test aims to assess your ability to interrupt an action prepared in advance or during execution.

The perfect match

This test aims to assess the flexibility with which you adapt to objective or strategy changes.

A picky chick

It is a ” trial and error ” learning test. The test aims to assess your ability to identify the best rewarding action.

Emilie and the donuts

If you make the difference between what you know and what others know, this test won’t cause you any problem.

Triangles at the box-office

This test aims to assess your ability to recognize other people’s intentions and emotions from their behaviour (we would like to sincerely thank Pr. U. Frith for his help during the development of this game).

The appointment time

It is a ” strategic reasoning ” test. The test aims to assess your ability to anticipate other people’s behaviour when they are also trying to anticipate your own behaviour. This game is played by several people (in groups of 100 players).


It is a competitive game engaging most of the cognitive skills assessed in the other games.