Kittens knead mama’s belly to stimulate milk flow rewards. This gets wired as a comforting habit continuing into adulthood.
Nursing
Cats have sweat glands in paws releasing smells kneading spreads over preferred people/places to mingle scents feeling ownership.
Scenting
The rhythmic motion promotes relaxing hormones like oxytocin in cats otherwise anxious when left alone or adjusting to new homes.
Calming
Male cats often erotically knead objects/owners associated with past mating experiences or current attractions.
Arousal
Kneading helps cats claim their most beloved owners when allowed into laps by mixing scents and triggering nurturing protective instincts.
Bonding
Senior cats with memory decline reconnect unfamiliar surroundings kneading to establish security. It’s instinctive and comforting.
Old Age
Arthritic cats self-massage sore, swollen joints via alternate leg pushes increasing circulation to ease chronic discomforts.
Stiffness