Is picture recognition memory enhanced through sensory or cognitive facilitation?
Different features of pictures can be used as recognition clues, and colour is one of them. However, it is unclear whether enhanced recognition memory by colours is due to the distinctiveness of features highlighted by colours (sensory facilitation), or it is due to the colour representation in memory (cognitive facilitation). One way to defi ne mechanisms through which colour enhances memory is to investigate the role of colour diagnosticity in picture recognition memory which can be defi ned as the degree to which an object was associated with a specifi c colour. Colour diagnosticity was manipulated by using pictures in two colours modes: naturally (high colour diagnosticity) and unnaturally (low colour diagnosticity) coloured pictures. Unnatural coloured mode was complementary to the natural. Since there were two different versions of picture in the encoding phase and two in the recognition phase, there were four possible combinations of encoding and recognizing pictures. 60 participants were exposed to different combinations of encoding and recognizing pictures. Accuracy and recognition time were measured. Results showed strong encoding-specifi city effect, with no differences in correct recognitions of naturally and unnaturally coloured pictures. In other words, colour diagnosticity effect was not found. Furthermore, it was shown that colour diagnosticity takes part only during recognition time, but does not affect the accuracy itself.