Isolation also affected the monkeys' maternal behavior. when the isolated female monkeys became mothers themselves, they made spectacularly poor ones. These monkey mothers were negligent and abusive; refusing to allow their infants to nurse and sometimes beating them for trying to establish physical contact. Such negligent and abusive behavior did not support the concept of maternal instinct but rather suggested that the experience of isolation from their mothers affected their nurturing behavior. That is, this research suggests that caregiving is dependent on experience and not on any inherent biological factors.