Between the World Wars 73is sought. As with Maier’s work, this was part of the 1930s
effort in comparative cognition.
The fifth important comparatively oriented student to
work with Lashley at Chicago was Donald Olding Hebb.
Hebb moved to Chicago in 1934 and accompanied his men-
tor to Harvard after one year. He received a Harvard PhD in
- He then filled positions in Canada and, in 1942, re-
joined Lashley in Orange Park. In 1947, Hebb joined the fac-
ulty at McGill, from which he retired in 1974. Like Lashley,
Hebb is best remembered for his contributions to physiologi-
cal psychology. HisThe Organization of Behavior(1949) was
important in the reinvigoration of physiological psychology
after World War II and introduced the so-called Hebb synapse
to psychology. Like Beach and Schneirla, Hebb worked to-
ward reinterpretation of behavioral patterns that appeared to
be innate (Hebb, 1953). His comparative interests are also ap-
parent in his efforts to get studies of animal social behavior
more recognition in the field of social psychology (Hebb &
Thompson, 1954).
Two important comparative psychologists completed
PhDs under Stone at Stanford. Harry F. Harlow completed
the PhD in 1930 and spent the rest of his career at the
University of Wisconsin. He spent much of his career study-
ing learning in rhesus monkeys, where he developed an error
factor theory, according to which the primary process during
learning often involved the manner in which errors were
eliminated. Harlow is best known, however, for his work on
behavioral development. He found the social and reproduc-
tive behavior of rhesus monkeys reared in the absence of
their parents and siblings to be greatly distorted. Deficits in
learning were found to be much less severe. With many im-
portant students educated in his program and with his editor-
ial and administrative work, Harlow was a very influential
comparative psychologist.
The other Stanford-Stone graduate was C. Ray Carpenter,
who completed his studies in 1932 with work on endocrine
influences on pigeons. He is best known, however, as the
“father” of primate field research. With the help of Yerkes,
Carpenter began a series of field studies in locations such as
Panama, Southeast Asia, and India (e.g., Carpenter, 1934).
He established a colony of rhesus monkeys on the island of
Cayo Santiago, off Puerto Rico. This was the first sophisti-
cated work on primates in their native habitats. This field has
exploded in recent years with the work of such scientists as
Jane Goodall and George Schaller. Many people are sur-
prised to learn of the role of a psychologist in establishing the
subdiscipline of primate field research. Carpenter spent much
of his career at the Pennsylvania State University, where he
also devoted much effort to documenting studies of primates
and other species on film.
Other comparative psychologists completing graduate
work during this era included Curt P. Richter (Johns Hopkins,
1921), Carl Murchison (Johns Hopkins, 1923), Leonard
Carmichael (Harvard, 1924), Lucien H. Warner (Columbia,
1926), Otto L. Tinklepaugh (Berkeley, 1927), Winthrop N.
Kellogg (Columbia, 1929), and Meredith P. Crawford
(Columbia, 1935).The State of Comparative Psychology between the WarsThe comparative psychologists educated during the 1920s
and 1930s placed comparative psychology on a firm footing.
Unlike the pre–World War I cadre, this group was successful
in securing research support and in educating a next genera-
tion of comparative psychologists who would carry on the
tradition. Nevertheless, much was not well. This group of
comparative psychologists, which appears to coalesce as a
coherent unit when viewed in retrospect, did not appear so
when viewed in its time. There were a number of reasons for
this.
Disciplines and subdisciplines become recognizable and
influential with the development of a set of institutional land-
marks including departments, textbooks, courses, research
facilities, organizations, meetings, and journals. During this
period, comparative psychology was well established in
many departments, and courses were a staple in many places.
In other respects, however, it lacked elements that foster
cohesion.TextbooksThe 1930s saw the greatest burst of publication for textbooks
in the history of the field. Margaret Floy Washburn’s The An-
imal Mindhad been dominant since 1908. Her fourth edition
appeared in 1936. The most influential book of the era was
Maier and Schneirla’s Principles of Animal Psychology
(1935). The textbook provided a comprehensive overview of
the field, beginning with 11 chapters organized according to
animal taxa. Material concerning receptor equipment, sensi-
tivity, conduction, and the action system is provided for each
group. The second part of the book is concerned with natively
determined behavior, sensory function, and neural mecha-
nisms in mammals. Part III addresses learning and mental
processes.
The most comprehensive of the works was the three-
volumeComparative Psychology: A Comprehensive Treatise
(1935, 1936, 1940) by Warden, T. N. Jenkins, and Warner.
The first volume deals with principles and methods; the
second volume with plants and invertebrates; and the third
volume with vertebrates.