On the generality of the perceptual closure effect

Perceptual closure is a process whereby an incomplete stimulus is perceived to be complete. J. G. Snodgrass and K. Feenan (1990) argued that perceptual closure during a study episode is an important factor in producing large priming effects in picture fragment identification. They found that a moderately fragmented study picture produced more priming than either a very fragmented or an intact study picture and argued that this inverted U-shaped function is a signature of the perceptual closure effect. The experiments in this study, extend these results to word fragment identification by showing that (a) the most effective prime, for both unspeeded and speeded word fragment identification is a moderately fragmented study word; (b) the sharpness of the U-shaped gradient is the same whether the perceptual feedback during study is a word (in a font different from that of the fragmented study word) or a picture; and (c) although a fragmented study picture primes subsequent word fragment identification, it does not produce the inverted U-shaped function, thereby showing that perceptual closure reflects perceptual rather than conceptual priming.