Chapter One continued...
Why do ASL signers prefer to provide descriptions using a survey perspective? One possibility is that signers prefer survey perspectives in general, perhaps because signing space can be used so effectively to represent a map. That is, subjects can locate landmarks on a horizontal plane in signing space in a manner that is isomorphic to the locations of landmarks on a map (in fact, this is how signing space is utilized for survey perspectives). Another possibility is that ASL signers, but not English speakers, were strongly influenced by the nature of the task. The fact that signers studied a map may have influenced how they structured signing space within their description. A mental representation of the map itself may be more easily expressed using a horizontal plane in signing space with a fixed "bird's eye view" vantage point, and this type of spatial format is more compatible with a survey perspective. English speakers were apparently not subject to such linguistic preferences.
However, ASL signers appear to choose either route or mixed descriptions when describing environments that they have actually experienced themselves. In a pilot study, we asked ASL signers to describe either their house (N=8) or the locations of the dormitories on the Gallaudet campus (N=5). Only one person produced a description with a survey perspective. Thus, the difference between English speakers and ASL signers does not appear to be due to a general preference for ASL signers to adopt a survey perspective.
Given that ASL signers and English speakers differ in perspective choice for the same environment, Taylor and Tversky's (1996) claim that the nature of the environment determines perspective choice must be qualified. The nature of the linguistic system may also influence which spatial perspective is chosen.
Comparing ASL and English language use
It is possible that the differences between ASL and English regarding perspective choice are due to differences in linguistic judgment criteria used by the ASL judges and by Taylor and Tversky.