Harlow conducted a study into attachment using 8 Rhesus monkeys over a time period of 6 months. He place them in a cage with a 'mother' covered in cloth to represent a caring mother whilst also next to a wire 'mother' which had a bottle for feeding to represent a mother that could provide. He intended to investigate what innate tendencies the monkey's had and whether attachment was formed with a mother that cares or provides. He found that the monkeys were attracted to the cloth mother as a source of comfort despite the fact that it did not provide nourishment. This was further supported when he attempted to scare the monkeys with a mechanical robot device, in which case the monkeys hung to cloth mother for comfort and protection. From this he concluded that comfort was the most important factor in forming carer-infant attachments.