Martie Haselton, a psychologist at UCLA, considers romantic love a "commitment device" or mechanism that encourages two humans to form a lasting bond. She has explored the evolutionary rationale that has shaped modern romantic love and has concluded that long-lasting relationships are helpful to ensure that children reach reproductive age and are fed and cared for by two parents. Haselton and her colleagues have found evidence in their experiments that suggest love's adaptation. The first part of the experiments consists of having people think about how much they love someone and then suppress thoughts of other attractive people. In the second part of the experiment the same people are asked to think about how much they sexually desire those same partners and then try to suppress thoughts about others. The results showed that love is more efficient in pushing out those rivals than sex.