This editorial appeared in Volume 1 (3) of The Semiotic Review
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,
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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I.M. Pepperberg is Associate Professor of Ecology
and Evolutionary Biology at the University of Arizona, Tucson, Arizona,
U.S.A. She is the author of numerous articles on interspecies communication
and on the communicative approach to animal cognition. The above editorial
is an excerpt of her articie: "Interspecific communication between
humans and a parrot: a two-way communication code facilitates study
of the cognitive capacities of an avian subject" to appear in Zeitschrift