[Solved] The attachment study of infant monkeys to wire and cloth surrogates suggested that the source of food is the most important factor in attachment. Bisexual Attractions: Bisexual Attractions describe a person's romantic or sexual attraction to more than one gender, not exclusively to people of a different sex or the same sex. Erotic Plasticity: The degree to which an individual's sex drive and sexual preferences are shaped by cultural, social, and situational factors. Heterosexual Couples: Romantic partnerships between individuals of opposite sex, typically involving sexual and emotional relationships. Erotic Pictures: Images intended to provoke sexual arousal.