a = if soft object serves same functions as mother
p = 16 baby rhesus monkeys and two wire model mothers
condition 1 - milk dispensed by plain wire mother
condition 2 - milk dispensed by cloth covered mother
f = both groups spent more time with the cloth mother, even if she had no milk. infants in group 2 - only went to the wire mother when hungry, once fed returned to cloth mother. if frightening object in room, took refuge with cloth mother. infant explored more when cloth mother was present