The authors repeatedly state the assumption that professional actors remember their lines verbatim ± an assumption that remains unsubstantiated until Chapter 10. Indeed, Chapter 4 delivers seemingly contradictory information. When encouraged to understand the underlying goals of a character they were portraying (the gist condition), professional actors retained slightly (non-signi®cantly) fewer `idea units' verbatim than college students did. The authors' explanation for the lack of superior gist recall in this experiment was that the actors had devoted more time to generating explanations about underlying beats than the students, therby reducing time to learn their lines. A subsequent test, perhaps preceded by one short study period, might have shown actor superiority of recall. In Chapter 10, the authors note some diculties of obtaining evidence of literal recall by professional stage actors. Speci®cally, it is illegal to use recording devices in any professional theatre, just as no line may be changed without the explicit permission of the play's author. However, in Chapter 10, the authors report the results of comparisons of original play scripts with lines given by professional actors as they played the roles. These comparisons yielded word-for-word correspondences ranging from about 85% for a contemporary farce to 98% for a classical verse play, variations that are to be expected on the basis of the constraints of the material in the plays. If this information had been presented earlier in the book it would have oset the scepticism engendered by the results of the ®rst experiment.
In summary, although the research does not explain how the professional actors gained their expertise in constructing the goals of the play's plot, it convincingly demonstrates the contents of these basic structures. The organizational structure coordinates well with previous demonstrations that experts develop qualitatively dierent organizational schemata for organizing their ®eld of expertise than do non-experts. The next step is to identify the processes that enable this development, as the authors point out in the last chapter. The primarily descriptive model suggests questions about how these kinds of demanding and sensitive interpretational analyses are acquired and how cognitive processes are involved. For example, how do aspiring actors decide the contents of a beat and what characteristics of beats change as expertise is gained? What kind of training is needed to try to `get into the head' of the play's author? How do the hierarchical structures of professional actors dier from those of other experts and from television actors and others who have more latitude with their lines? Answers should elucidate relevant cognitive processes. Moreover, interactions (interdependencies?) with other actors and the stage environment oers opportunities for investigating phenomena of social cognition. Just as professional actors use beats or emotional idea units to build the organizational structure of their roles, this book provides an excellent foundation for subsequent research.