Figure 4

Interaction between Chosen > Not-chosen * Luxurious > Non-luxurious using materialistic tendencies’ scores for each participant as a second-level covariate in the bilateral caudate body (a), thresholded at Psvc < 0.05 (voxel-wise FDR) using a mask including the ventral, dorsal striatum and the ventromedial prefrontal cortex. Percentage of signal change in the left (b) and right (c) caudate body. To illustrate the effect of materialism, panels (b,c) include a scatter plot in which each point represents, for each condition, the mean value of percentage of signal change for each individual participant (Y axis) according to his/her materialism score (X axis): a negative value indicates very low materialistic tendencies; a positive value indicates high materialistic tendencies; ‘0’ corresponds to an average level of materialism. Lines represent a linear regression tendency computed for each condition separately. Black shapes represent items chosen preferentially in the offline choice task (Squares/solid line: Luxurious items; Tilted squares/dashed line: Non-luxurious items). Red crosses represent items that were not chosen in the choice task (Normal red cross/solid line: Luxurious items; Modified red cross/dashed line: Non-luxurious items). The colored bar represents the statistical Z value of the contrast. MNI: Montreal Neurological Institute.