The investigators objective is twofold. Investigators propose to study how the vestibular and auditory information interact in the construction of coherence between the staff and extrapersonal space.

Furthermore, investigators want to investigate whether, even in the absence of gravity, the auditory spatial information allocentric provide a framework for spatial reference.

Inclusion Criteria:

• Healthy volunteers (men or women)
• Aged between 18-65 years
• Affiliates to a social security system or, for non-residents in France, holder of a European Health Insurance Card European (EHIC European Health Insurance Card)
• Who are willing to take part in the study,
• Who gave written informed consent,
• Declared fit after a similar visit to a medical aeronautical medical fitness for the non-professional cabin crew in civil aviation. There will be no other aptitude tests for the selection of subjects.

Exclusion Criteria:

• People who took part in a biomedical research protocol for which the exclusion period is complete,
• People with psychotic disorders and / or depression,
• People receiving psychotropic medication,
• People with alcohol dependence or illicit substances,
• People with visual acuity less than 8 / 10ths corrected by lenses or glasses,
• People with a significant decrease in hearing,
• pregnant women.