Children prefer certain individuals over perfect duplicates.

Adults value certain unique individuals--such as artwork, sentimental possessions, and memorabilia--more than perfect duplicates. Here we explore the origins of this bias in young children, by using a conjurer's illusion where we appear to produce identical copies of real-world objects. In Study 1, young children were less likely to accept an identical replacement for an attachment object than for a favorite toy. In Study 2, children often valued a personal possession of Queen Elizabeth II more than an identical copy, but showed no such bias for another sort of valuable object. These findings suggest that young children develop attachments to individuals that are independent of any perceptible properties that the individuals possess.