Harlow proposed that an infant's attachment to its mother was
based primarily on feeding, the infant monkeys should have
preferred and become attached to whichever surrogate mother had the
bottle. Harlow's isolated monkeys showed a preference for the soft
cloth mom rather than the mom equipped with a bottle. This
preference is referred to as contact comfort which was provided by
the softness of the cloth covering, was more important than feeding
in the formation of an infant rhesus monkey's attachment to its
mother.