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This editorial appeared in Volume 1 (3) of The Semiotic Review of Books.

Editorial: Interspecies Communication

by Irene Maxine Pepperberg

Interspecies communication can play at least three different roles in the study of animal cognition. Some researchers, for example, view their attempts to teach, and the extent to which their animals can learn, a human code as an end in itself (e.g. Greenfield & Savage-Rumbaugh, 1984). In such studies, the extent to which the language code is acquired is often used as a measure of intelligence. Alternatively, teaching an animal to use a human-based code can be viewed as a means of fundamentally changing its mental processes in a manner not possible through any other type of training (e.g. Premack, 1983). Here the code becomes a means to influence intelligence. Finally, direct communication with animals via a language-like code can be seen as a tool for examining their abilities to process various types of information (Pepperberg, 1986a, 1988); that is, as a vehicle to evaluate different intelligent behaviours. Some discussion of these roles may help explain my preference for the third.

Although several non-human species have now acquired elements of various human-based communication codes, the exact relation of these behaviours to that of human language is unclear Furthermore, the assumption that there is a direct correlation between the extent to which an animal can acquire a human code and its intelligence may be unfounded. Because differences in competence between humans and non-humans - and even between different nonhuman species -- can, to some extent, be attributed to experimental design as well as to differing underlying cognitive capacities (note Gardner, Gardner, & Van Cantfort, 1989; Kamil, 1984; Menzel & Juno, 1982, 1985; Pepperberg, 1986b, 1987b, 1990a, in press; cf. Macphail, 1987), comparisons based solely on language competence can tell us little about relative intelligence. Moreover, because critics of interspecies communication programs (e.g., Sebeok & Rosenthal, 1981) have often defined "language" as that part of human communication that animals are incapable of achieving (see discussions in Fouts, 1973; Miles, 1983), arguments about the extent to which animals have acquired human language (Herman, 1988; Schusterman & Gisiner, 1988) become unresolvable. Such arguments can, furthermore, absorb resources that could be spent on the study of all forms of cognitive capacities.

Because language-trained animals often demonstrate considerably more complex capacities than their untrained counterparts (e.g., Premark,1983), the argument that language may instil intelligence appears, at least initially, quite reasonable. The problem is that competence that can be demonstrated only by language-trained animals might be mistaken for competence that exists only in such subjects. A comparison between the design of studies that do not and those that do involve interspecies communication will clarify this point.

Unquestionably, the study of animal cognition is influenced by most animals' lack of human language (Gallup, 1989): i.e. in most experiments the animal can not communicate directly with the experimenter and there exists no explicit transfer of information about the nature of the task to be learned. Instead, the animal must determine, through trial-and-error, not only the appropriate response but also the question that the experimenter wishes to communicate to it and to which it must respond; i.e., the experimenter is testing not just whether the animal can learn to choose red, or match the sample, but also how long it takes the animal to figure out what underlying relationship connects a specific choice and receipt of a reward. Such procedures may elucidate learning proclivities so basic as to exist in the absence of environmental facilitators, but the animal (like the bird that interpreted "Hello" as a request for a nut) may not respond to the intended relationship, and the full extent of its capacities may not be discovered.

In contrast, a system that uses an interspecies communication code enables researchers to study the animal ability to respond to the particular question. The animal can determine the precise nature of the question being asked and thus can be tested on Its ability to process the content of the question. Projects involving mini-human communication in wde an open and arbitrary system in which the subject can create subtle validations in response that encourage the researcher to examine the nature as well as the extent of the information perceived by the subject. Such systems also have enough flexibility to allow subjects to respond in novel and possibly innovative ways that can imply competence beyond that required by the intended task (Pepperberg, 1986a; 1990b). The subject is therefore given opportunities to demonstrate the full extent of its abilities.

Whether acquiring language actually does affect cognitive capacity or merely the ability to express such capacity is as yet unknown. The limited data available for animals suggest that the latter interpretation is more likely (e.g., Pepperberg & Funk, 1990) but considerable disagreement still exists (see Macphail, l987; Premack, l983). Studies on humans suggest but do not prove, that linguistic input cannot teach a nonlinguistic concept for which the subject is unready (see Rice, l980). Successful completion by nonlanguage arained subjects (and even prelinguistic children; Mandler, 1990) of certain cognitive tasks thought to require language competence (see reviews Pepperberg & Kozak, 1986) might for examples reflect a misunderstanding of the prerequisites of the tasks. Some data, however, suggest an alternative explanation. In certain instances linguistic and cognitive competence may simply be independent entities (see review in Damasio, 1990). Thus language competence needs not be considered a prerequisite for, or a means of, instilling certain cognitive capacities.

Language training not only can provide an efficient means of investigating intelligence, but a language-trained animal may also be more easily taught how to express an existing, possibly natural, cognitive capacity. Because learning is most efficient when new topics can be related to prior knowledge (Bruner,1977; Rogoff,1990), and subjects in an interspecies communication project can be instructed directly about such relationships, language-training may, for example, facilitate the transfer of skills from one domain (e.g., natural behaviours or a previously trained task) to another. Thus an animal that already can respond to "What's different?" may find a formal relative-size discrimination an easier task than would a non-language-trained subject with equal experience in, for example, choosing between two possible foraging areas based on the relative amounts of available food (note Pepperberg & Brezinsky, under review).

Another advantage to the use of interspecies communication as a tool for investigating cognitive capacities is that the codes that are used, because of their common basis in human language, often facilitate cross-species comparisons of cognitive ability (Pepperberg, 1986a).

Although other techniques can provide such information (see Macphail, 1987), only since the advent of interspecies communication studies have data in fact existed to compare directly, for example, the capacities of a chimpanzee and a parrot on concepts of "same different" and of a marine mammal and a parrot on that of "absence". At the least, interspecies communication has provided the impetus, as well as the means, to obtain data that have not only provided unexpected insights into avian abilities, but that have also allowed comparison of avian cognition with that of other animals.

In sum, communication is both a complex behaviour and a valuable tool. Communication occurs between many organism even between different species. Communication occurs for many different reasons, but generally involves some transfer of information. This transfer may be for the mutual benefit of both parties, or may simply allow one party to understand something about the abilities of the other. The study of communication in order to understand all its complexities is therefore likely to lead to a better understanding of all forms of behaviour.

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