According to Sigmund Freud, primary process thinking is
The id is theorised to be the original state of human mental apparatus with which a newborn baby is born. It is totally unconscious, containing the basic drives and instincts concerned with survival, sexual drive and aggression. It is characterised by primary process thinking and is based on the pleasure principle, lacking any direct link with reality. The only urge of these drives is immediate gratification. Ref: A Sho Textbook of Psychiatry, Niraj Ahuja, 7th Edition, pg. no.206
Illogical and Bizarre
Rational
Absent during sleep
Logical and Unconscious
Cognitive development and defence mechanism