A hypnopompic state (or hypnopomp) is the state of consciousness leading out of sleep, a term coined by the spiritualist Frederick Myers. Its twin is the hypnagogic state at sleep onset; though often conflated, the two states are not identical. The hypnagogic state is rational waking cognition trying to make sense of non-linear images and associations; the hypnopompic state is emotional and credulous dreaming cognition trying to make sense of real world stolidity. They have a different phenomenological character. Depressed frontal lobe function in the first few minutes after waking – known as "sleep inertia" – causes slowed reaction time and impaired short-term memory. Sleepers often wake confused, or speak without making sense, a phenomenon the psychologist Peter McKeller calls "hypnopomp