ABSTRACT
This chapter considers the problems of separating the contributions of visual and non-visual traces to memory for visual stimuli, and how much visual detail can be retained and for how long. The starting point is the study of iconic memory and the way this short-lived store may be considered to hold visual information just long enough for it to be recoded into more permanent visual and verbal codes. The chapter describes some examples of eidetic imagery, the ability of certain subjects to demonstrate the retention of detailed visual information. The term 'mental imagery' is generally taken to have connotations of sensory-like experiences generated from within. Evidence points strongly to the presence of a pre-categorical iconic memory but there is a need to elaborate the model proposed by Sperling to take account of recent findings. The icon must be distinguished from the visual codes identified by Posner with his letter-matching paradigm because it is more durable and not susceptible to masking.
