72 Comparative Psychology
development and the relative roles of nature and nurture. At
various stages of his career he concluded that there was either
little evidence of genetic effects or that genetic and environ-
mental influences were so intimately entwined that it was im-
possible to separate them. Although he was able to publish
some articles throughout his career, his difficulty in finding
employment in the United States and his involvement in ad-
ministrative and political turmoil in China greatly limited his
influence.
Carl J. Warden completed a PhD at the University of
Chicago in 1922; he spent much of his career at Columbia
University. Among his contributions to the field were his
writings on the history of comparative psychology, text-
books, and research. The latter often entailed use of the
Columbia Obstruction Box, in which a rat had to cross a
shock grid in order to reach an incentive (e.g., Warden, 1931).
The greater the intensity of the shock the animal was willing
to endure, the greater was the animal’s drive believed to be.
Henry W. Nissen completed a PhD with Warden at
Columbia in 1929. He spent much of career working on pri-
mate behavior under the influence of Yerkes, first at Yale
University and later at the Yerkes Laboratories of Primate
Biology. He was the director of the latter facility from 1955
to 1958. Nissen is said to have known more about chim-
panzees and their behavior than anyone else of his time but
was a self-effacing psychologist whose influence was limited
by his reticence. Nevertheless, his career was prominent
enough to earn him election to the prestigious National
Academy of Sciences of the United States.
A remarkable cluster of students worked with Lashley at
the University of Chicago during the early 1930s (Dewsbury,
in press-a). Norman R. F. Maier completed a PhD with
Shepard at Michigan in 1928 and, after a year on the faculty
at Long Island University, went to work with Lashley during
1929–1931. He then spent most of his career back at
Michigan. In comparative psychology, Maier is best known
for his studies of problem solving in which he suggested that
rats do not learn to solve complex processes via the simple
associative processes suggested by Thorndike but rather use
a process of reasoning (e.g., Maier, 1937). This was part of a
fairly substantial interest in cognitive approaches to behavior
during the 1930s (Dewsbury, 2000). He was also interested in
the abnormal behavior, including fixations and seizures, that
sometimes occurred in his testing situations.
Theodore C. Schneirla also completed his doctorate with
Shepard at Michigan in 1928. Shepard interested Schneirla
in studies of the behavior of ants, which became the focus
of Schneirla’s career. In 1927, he moved to New York Uni-
versity, combining his duties there with a position at the
American Museum of Natural History during much of his
career. He went to work with Lashley in Chicago during
1930–1931. Schneirla was a primary exemplar of the role of
field research in comparative psychology, as he made many
trips to study the complex adaptive patterns of various
species of ants at many sites. He also conducted notable lab-
oratory research on learning in ants. Schneirla also engaged
in theory construction. He advocated a concept of integrative
levels, occupied by different species. With this concept, he
called for caution in generalizing across widely diverse taxa.
He also was a strong advocate of the epigenetic approach to
development and opposed the notion that some behavioral
patterns are innate. He believed that tendencies to approach
toward and withdraw from stimuli of varying intensities
played an important role in development (see Aronson,
Tobach, Rosenblatt, & Lehrman, 1969).
Frank A. Beach completed an MA degree at the Kansas
State Teachers College in Emporia before going to Chicago
to complete his doctorate. He worked with Lashley during
1933–1934, taught high school for a year, and then returned
to Chicago for further graduate work. Lashley was gone by
then, but Beach followed him to Harvard in 1936. He com-
pleted the final requirements for the Chicago PhD in 1940.
Beach spent his career at the American Museum of Natural
History, Yale University, and the University of California,
Berkeley. He is probably best known today for a series of
incisive articles he wrote about the state of comparative psy-
chology and the conceptual foundations thereof. The best-
known example is his “The Snark Was a Boojum” (Beach,
1950). Beach argued that throughout the first half of the
twentieth century, comparative psychologists had become
interested in a more narrow range of behavioral patterns
and progressively fewer species, primarily white rats. He
suggested that this was not a healthy development. In “The
Descent of Instinct” (1955), he criticized simplistic concep-
tions of the concept of instinct. His research program was a
broadly based attack directed primarily at the determinants of
reproductive behavior. He was interested in the neural bases,
endocrine correlates, evolution, development, and situational
determinants of reproductive and social behavioral patterns.
Isadore Krechevsky, later David Krech, studied first at
New York University but completed his doctorate with
Edward C. Tolman at the University of California at Berke-
ley. He then moved to the University of Chicago, initially
with Lashley, where he remained from 1933 to 1937. A polit-
ical activist, he had to change affiliations with some fre-
quency because of difficulties with administrators, but he
spent the last part of his career, beginning in 1947, at Berke-
ley. Krechevsky (1932) showed that as rats learn mazes, they
appear to form “hypotheses,” systematic runs of choices gov-
erned by different rules, each of which is tried as a solution