Study in Cognitively Intact Seniors Aiming to Assess the Effects of Meditation Training

1. Inclusion Criteria : For all participants * Age ≥ 65 years ; * To be autonomous * Live in their home; * Educational level ≥ 7 years (from the Preparatory Course (First grade) included); * To be registered to the social security system ; * To be motivated to effectively participate in the project and to sign the consent form in agreement with the local ethic committee ; * Neuropsychological performances within the normal range (according to age, sex, and educational level), as assessed by the diagnostic battery. For participants without previous meditation practice * French mother tongue; * Available for the trial duration (24 months); * Retired since 1 year or more; * No preference regarding the intervention group ; * Not having regularly or intensively practiced meditation or comparable practices (yoga, Qi Gong, Alexander technique) as follows : * more than one day per week for more than six months consecutively over the last 10 years, * intensively (internship or retreat \> five consecutive days) over the past 10 years, * more than 25 days of retreats (cumulatively) prior to the last 10 years ; * Not speaking English fluently. For expert meditators : * Formal meditation practice \> 10 000 hours in the whole life, including at least 6 cumulated months of retreat; * Daily meditation practice (at least 6 days/week, 45 minutes/day); * Mindfulness meditation practice (i.e. mindfulness, samatha/vipassa…