why do we get more lost in thought while laying down?

We tend to get more lost in thought while lying down because it promotes a kind of mental environment conducive to increased visual imagery and internal exploration. When we lie down or sit motionless and close our eyes, our focus on the outside world diminishes, which enhances our ability to engage in what's known as divergent thinking. This state allows for a greater library of potential interactions with our thoughts, boosting creative and imaginative processes. Essentially, the reduction in physical movement when lying down enhances our internal visualization and thought wanderings 1.

Moreover, lying down facilitates a decrease in bodily readiness for action, which in turn elevates visual imagery and mental exploration. This inverse relationship between bodily movement and visual imagination implies that stillness can enhance the richness of our mental landscape, allowing us to become more absorbed in thought during these times of restfulness 2.