Four experiments assessed change detection performance for displays consisting of a single, novel, multipart object, leading to several new findings. First, larger changes (involving more object parts)
were more difficult to detect than smaller changes. Second, change detection performance for displays of a temporarily occluded moving object was no more or less sensitive than detection performance for
displays of static objects disappearing and reappearing; however, item analyses did indicate that detection may have been based on different representations in these two situations. Third, training observers
to recognize objects before the detection task had no measurable effect on sensitivity levels, but induced different biases depending on the training conditions. Finally, some participants' performance
revealed implicit change detection on trials in which they explicitly responded that they saw no change.