Richter's Approach to Research
Overview of Research Activities
Similarly, Richter's many discoveries in biological clocks were linked to clever inventions.
The early cage, described above, evolved to include a wheel, which
allowed for improved activity
quantification. Mounted on their axes, the cages could spin, allowing the rats to run. By
counting the number of revolutions, Richter could better determine the level of activity. These
"activity cages" yielded data for numerous articles detailing phenomena in rats and supplementing
parallel observations on humans. Richter's investigations included topics such as daily activity
and sleep cycles, body temperature variation, mood swings, and numerous cycles in psychiatric
patients, which led to his famous "shock-phase" hypothesis--that tissues of all organs have cycles
which normally balance one another for continuous function, yet can be seen when realigned (in
phase) by shock, trauma, allergy, and such.
(See Richter's bibliography on spontaneous activity and biological clocks.)
Perhaps the best known of all the studies Richter conducted, the behavioral homeostasis
experiments revealed adaptive appetite in rats under nutritional deprivation. The rats developed
"specific hungers" for substances missing in their diets, such as salt, protein, or fat. The key
experiment, the "self-selection" or "cafeteria" study, gave the rats 10 or so choices of various
nutrients. Richter monitored the animals' intake of the substances
as related to deficiencies in
their diet. Animals deprived of vitamins in their diets would specifically seek them out when given
the choice. Similarly, operations that modified the rats' ability to taste or synthesize various
minerals prompted corrective ingestive behaviors. Removing the rat's adrenal glands promoted
sodium excretion, but also increased the salt appetite, helping to preserve the total amount
available for use by the body.
This holistic maintenance in rats had similar analogues in human beings, which Richter
thought would be useful in the study and treatment of psychiatric patients. Partial breakdown of
these internal regulatory functions, he reasoned, could be blamed for a host of psychiatric
eating disorders such as anorexia, or catatonic patients' inability to discern external stimuli.
Richter's experimental prowess helped to confirm and extend theoretical claims made by Claude
Bernard and Walter Cannon about the "wisdom of the body" and its internal homeostasis.
(See Richter's bibliography on homeostasis.)
Richter's contributions in neurology encompassed both the motor and the sympathetic nervous
systems. His motor system inquiries were prompted by Sherrington's experiments with
decerebrate cats, dogs, and monkeys, which had shown "reflex standing"; the animals would stand
rigidly following transection of the brain stem. Noting that all were quadrupeds, Richter
wondered whether animals who adapted to other forms of locomotion would behave the same
way. Subsequent investigation with the three- and two-toed sloths discovered "reflex hanging,"
neatly confirming the adaptive nature of decerebrate reflexes. During the experiment Richter
observed that the decerebrate sloth also exhibited a grasp reflex, much like that he had seen in
newborn humans over in the hospital. This in turn spawned another series of studies of the grasp
reflex and its relation to age in animals and humans from cradle to grave.
(See Richter's bibliography on sympathetic nervous system and grasp reflex.)
Richter's studies of the sympathetic nervous system were conducted with both the test of
electrical skin resistance, which used the conductivity of nerves as a measure of their continuity,
and the galvanic skin response, which was a sensitive index of psychiatric condition. With these
methods, he produced pioneering anatomical maps of the sympathetic nervous system, as well as
information about its injury and repair, and discovered various patterns of resistance typical of
different mental conditions.
Centered on elucidating the differences between domesticated laboratory rats and the wild ones he
caught himself on the streets of Baltimore, Richter's domestication studies had important
theoretical analogues in the study of human domestication, manifested in problems such as
arthritis and sudden death. Domestication of the rat, Richter discovered, had decreased the
weight of the adrenal glands, heart, spleen, liver, kidneys, and brain, among other things;
increased the weight of some glands; and promoted earlier development of the reproductive
system. Furthermore, there were many important behavioral differences. Wild rats proved far
feistier, more clever, neophobic, vigilant, unable to breed well, and eager to escape. By contrast,
were relatively tame, content with captivity, unlikely to fight with other rats, and able to breed
successfully in the lab. Highly suspicious wild rats quickly failed the self-selection tests because
they were unwilling to try new substances. In the laboratory setting, this behavior led to
starvation, but on the streets, it helped them to avoid poisons. Domesticated rats repeatedly ate
poisonous substances along with nutritious ones, as they had apparently lost the suspicion of their
Many of Richter's observations on wild rats were made in conjunction with an earlier
project--developing a rat poison for the government during World War II. Worried that the Axis
would try to vector disease to U.S. cities with rats, the government contracted the Richter lab to
develop a defense. Richter and his collaborators tested and refined many poisons, including the
highly successful alpha-naphthyl thiourea (ANTU), which was widely used.
(See Richter's bibliography on domestication and poisons.)
Richter's research design was primarily instrument-driven. His nimble mind and adept hands
created custom laboratory apparatus for all of his major lines of inquiry. These were the tools
that he used to facilitate data gathering and standardization, and as such they represent a
cornerstone of his research methodology. Richter's basic goal was to observe and to standardize.
Instruments allowed him the chance to observe things that had not before been seen. Theorists
had long suspected that there was some kind of behavioral homeostasis mechanism, but it took
the inventive creativity of Richter to prove it in the lab through unique cages and meticulous
That Richter needed so much specialized equipment speaks more generally to his staunch commitment to free research. He despised result-driven "design research" and was consequently quick to redirect or expand his research efforts to include anything that caught his sharp eye. Galvanic skin response testing led to skin resistance studies, which in turn spawned investigations of nervous anatomy. Spontaneous activity pointed the way to self-selection, biological clocks, rat poison, and domestication. The unpredictable nature of his curiosity frequently steered Richter away from established lines of research and their instruments, forcing him to make his own. In cyclical fashion, his new instruments often revealed capabilities beyond their original intent, which fostered still more lines of research.
In addition to patients, Richter used medical and nursing students as subjects, particularly in the grasp reflex experiments. The psychobiology laboratory staff also participated in experiments as human subjects.
1. For experimental philosophy, see Richter, Curt P. Free Research versus Design
Research. Science 118, no. 24 July (1953): 91-3; Richter, Curt P. It's a Long
Way to Tipperary, the Land of My Genes, In Leaders in the Study of Animal Behavior:
Autobiographical Perspectives, edited by D. A. Dewsbury, 356-386. Lewisburg, PA:
Bucknell University Press, 1985.
Equipment and instrumentation