mind-wandering(Mind wandering is a common feature of the human experience occurring when our attention shifts from the task at hand to inner thoughts.: Mind wandering activates diffuse areas called the brain's "default system" (Kalat, Biological Psychology, 2015).
nih.govMariaSNR)
If a time series follows a random walk with a drift, the intercept term is not equal to zero. That is, in addition to a random error term, the time series is expected to increase or decrease by a constant amount each period. A random walk with a drift can be described as: x t = b 0 + b 1 x t-1 + ε t