Encoding the levels of information in pictures and words

From a levels-of -processing framework (e.g., Craik & Lockhart, 1972), we derive the idea that the levels of information implicit in a stimulus, such as its physical configuration, its name, and the category to which it belongs, may become available for subsequent processing at different times after stimulus onset. In particular, tasks which allow the use of physical codes should be performed more rapidly than those which require "deeper" information. There are two important implications here: The first is that the ability to use a code does not mean that that code has been "matched to" a representation in memory. The second is that "depth" effects (i.e., physical less than name less than conceptual) should be demonstrable within both pictorial and verbal materials. The approach as a whole may be contrasted with current dual-coding approaches (e.g., Paivio, Note 1), which, while they allow for different levels of meaning in both verbal and imaginal symbolic systems, seem forced to assume that certain types of cenceptual information are more easily accommodated within the verbal system. This leads to the prediction that some kinds of conceptual information will not be directly available from pictures, but must instead become available to the subject via an interaction between the symbolic systems. We tested these assumptions with a speeded-inference task (Van Rijn, 1973), which has properties that allow for unambiguous interpretation of reaction time differences across stimulus materials which require processing to the same explicit depth. Briefly, we found that pictures yield faster inferences than do words when the same semantic information is required for performance (Experiments 1 and 2), and that physical information is available sooner than conceptual information for both pictures (Experiment 4) and words (Experiment 5). Moreover, some types of pictorial materials (e.g., representations of proper nouns) function symbolically to the extent that they do not have an advantage in discriminability over words (Experiments 6 and 7), unless physical features are added to them which are redundant with the conceptual information the subject needs to perform (Experiment 8). The results are best interpreted within a levels-of-processing framework, in which multiple codes or representations do not exist to be activated by the appropriate stimuli, but rather the stimuli themselves embody levels of information which are encoded and used as needed.