A physiological measurement device or wearable device simulator includes a frame and a plurality of surfaces distributed within the frame. For each surface, a surface actuator links the surface of the frame. At least one of: i) force or position imparted by the surface on a physiological feature of a subject by the surface actuator; and ii) the force imparted by the physiological feature of the subject on the surface, can be employed to modulate the positions of the surfaces relative to each other independently of the forces imparted by or on those surfaces, thereby measuring the physiological feature of the subject or simulating a wearable device interface.