Reductionist as it focuses on basic processes - reinforcement is too simplistic to explain complex attachment behaviours, therefore the theory is limited. Environmentally deterministic - ignoring potential biological influences, therefore the theory is incomplete. A lot of counter evidence - Schaffer and Emerson: around 40% were attached to someone who did not feed them / Harlow – monkeys attached for comfort not food / Fox – Nurses fed children, but mother’s were their main attachment.