A hallmark of our survival in the real world and of our capacity to navigate the complex social interactions of human society is our ability to show behavioral adaptation. Adaptation can be necessary for a number of reasons, making the study of the process challenging. Two classes of event can signal a need for adaptation: 1) Events caused by one's own actions and specifically FeedBack -FB- from those actions (e.g. the investigators adapt their strategy after an erroneous choice), and 2) Events not linked to our actions, specifically Action-InDependent Events -AiDE- (e.g. the investigators adapt their strategy after a change of rule). These two types of information - FB and AiDE - will frequently occur concurrently. A critical and difficult part of adapting appropriately involves resolving the difference between the two. So for example an incorrect FB can occur because the investigators made an error, or because something unexpected in the environment has changed -the rule switched, someone cheated, etc. The Investigators must work out which it is, as they will frequently require different behavioral adaptations. Their task is made even more complex by the fact that the dynamics of evidence accumulation after FB vs AiDE are very different. FB has a direct temporal and causal link to an executed action, which means that the investigators are certain to derive information about a given action from a given FB. In contrast, AiDE have no such contiguity and no initial relation to actions, which means that the investigators must accumulate evidence to identify the appropriate adaptation to an AiDE. So the crucial dilemma is this: after an unwanted outcome, should the investigators adapt as if they made an error and received a negative FB, or should they continue to accumulate evidence as if there has been an AiDE to which they need to know how to adapt. Animals are able to resolve this credit assignment problem, as evidenced by their ability to appropriately adapt their behavior. A breakdown of this ability to link unexpected events to their correct cause would seem to be at the source of impairments in a wide range of psychological and neurological disorders, from addiction and OCD to psychological symptoms in Parkinson's disease. Yet the neural basis of this process is currently unknown, and FB and AiDE processing have been assessed separately so far. ADAPCO will provide unprecedented characterization of brain systems critically involved in learning from and adapting to FB, AiDE, and their interactions, thanks to fMRI studies.

Inclusion Criteria:

• being able to provide a written consent form
• having a social insurance
• have a normal vision (with or without corrections)
• Right-handed

Exclusion Criteria:

• Subjects with MRI contraindications (e.g. pacemaker, claustrophobia, metal in the body, etc…).
• Subjects must be willing to be advise in case of discovery of brain abnormality.
• History of neurological or psychiatric illness
• Pregnant or nursing women
• Persons under guardianship, curatorship or any other administrative or judicial measure of deprivation of liberty