The nature and measurement of meaning.

The language process within an individual may be viewed as a more or less continuous interaction between two parallel systems of behavioral organization: sequences of central events ("ideas") and sequences of instrumental skills, vocalic, gestural, or orthographic, which constitute the communicative product.A communicator vocalizes, "It looks like rain today; I'd better not wash the car."This output is a sequence of skilled movements, complicated to be sure, but not different in kind from tying one's shoes.Even the smallest units of the product, phonetic elements like the initial "l"-sound of "looks," result from precisely patterned muscle movements.The organization of these movements into word-units represents skill sequences of relatively high predictability; certain longer period sequences involving syntactical order are also relatively predictable for a given language system.But execution of such sequences brings the communicator repeatedly to what may be called "choice-points"-points where the next skill sequence is not highly predictable from the objective communicative product itself.The dependence of "I'd better not wash the car" upon "looks like rain today," the content, of the message, reflects determinants within the semantic system which effectively "load" the transitional probabilities at these choice-points.It is the communicative product, the spoken or written words which follow one another in varying orders, that we typically observe.Since we are unable to specify the stimuli which evoke these communicating reactions-since it is "emitted" rather than "elicited" behavior in Skinner's terminology (97)---measurements in terms of rates of occurrence and transitional probabilities (dependence of one event in the stream upon others) are particularly appropriate (cf., Miller,76).In-