 Recall that in unitization, what previously looked like two or more objects, properties, or events later looks like a single object, property, or event. Cases of “stimulus imprinting” are like cases of unitization in the end state (you detect a whole pattern), but there is no need for the prior state—no need for that pattern to have previously looked like two or more objects, properties, or events. This is because in stimulus imprinting, the perceptual system builds specialized detectors for whole stimuli or parts of stimuli to which a subject has been repeatedly exposed (Goldstone 1998: 591). Cells in the inferior temporal cortex, for instance, can have a heightened response to particular familiar faces (Perrett et al., 1984, cited in Goldstone 1998: 594). One area where these specialized detectors are helpful is with unclear or quickly presented stimuli (Goldstone 1998: 592). Stimulus imprinting happens entirely without guidance or supervision (Goldstone 2003: 241).