Understandably, investigators often have more faith in an eyewitness account if it appears to be supported by an account of the same incident from another eyewitness. However, it is very likely to be the case that witnesses will have discussed the incident amongst themselves before ever being formally interviewed by investigators. In the light of findings from research on conformity, we might expect that witnesses will influence each other's reports to a greater or lesser extent. Recent experimental work (e.g., Gabbert et al., in press, submitted) has shown that this is indeed the case. In a sense, such research on misinformation effects provides a link between that dealing mainly with naturally arising memory distortions for witnessed events and that dealing primarily with false memories for events that never actually took place at all.
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For example, even under perfect viewing conditions, our memories of what we saw may be highly influenced by our view of what we think we must have seen. French and Richards (1993) showed participants an ordinary clock face with Roman numerals under perfect viewing conditions for an extended period. Participants were asked to draw the clock face from memory. They tended to represent the four as 'IV' in line with their general expectations of Roman numerals. In fact, however, the four on clocks and watches is almost always represented as 'IIII'. Most people are quite surprised when this is first pointed out to them, as they reflect upon the literally thousands of occasions they must have looked at clocks and watches without noticing this oddity. Even thousands of exposures to a simple stimulus under perfect viewing conditions may not be enough to lead to accurate recall.
Studies have typically involved assessing the recall of eyewitnesses for staged events, either using live action or video presentation. When we are able to assess witness reports against some form of objective record, it becomes clear that both perception and memory are constructive processes, influenced not only by input from the senses ('bottom-up' influences) but by our own knowledge, belief and expectations about the world ('top-down' influences).