Harry Harlow, American research psychologist, was responsible for some of the most controversial experiments to have been performed in animal laboratories.

On his 'Rape Rack', disturbed female monkeys were forced to breed against their will. In the 'Pit of Despair' baby monkeys were hung upside down in total darkness for up to two years. And with the 'Iron Maiden', infant primates were confronted by a placid surrogate mother that began suddenly to tear at their flesh.

So what motivated Harry Harlow to conduct such disturbing experiments? Experiments that made Harlow the 'poster boy' of the animal rights movement in the United States. Bizarrely, the answer is love. Harry Harlow's work was an attempt to understand the nature of love, particularly that between mother and child.

According to Harlow's defenders, it is work we benefit from today. Defenders maintain that Harlow revolutionised and brought warmth to the way we parent infants. That he influenced crucial policies which operate in children's homes, social service agencies and the birthing industry in Britain and throughout the world today.

Can cruelty teach us anything about love?

First aired on More4 in the UK on 4th December 2005.