Using Rats!
“If an environment (nurture)
is significant, then it can
overcome heredity (nature)
in regards to intelligence.”
 Test a large random population for intelligence by
using a maze (Assume speed to complete the maze =
intelligence)
 Separate smart rats and have them breed. Test their
offspring, separate the smartest and have them breed.
Do this for multiple generations to secure a population
of “born smart rats.”
 Do the same thing, with multiple generations, to
secure a population of “born dumb rats.”
 Place equal numbers of smart and dumb rats into
environment #1 “Restricted Stimuli”—a covered cage.
Let them stay in there for a while.
 Place equal numbers of smart and dumb rats into
environment #2 “Normal Stimuli” (a regular, normal
rat cage). Let them stay in there for a while.
 Place equal numbers of smart and dumb rats into
environment #3 “Enriched stimuli” (lots of toys, bells,
etc). Let them stay in there for a while.
Each cage is the same in
terms of size, food and water!
 Retest ALL rats in maze
 Environment 1 (restricted stimuli)
 Dumb rats stay dumb
 Smart rats get dumb
 Environment #2 (normal stimuli)
 Dumb rats stay dumb
 Smart rats stay smart
 Environment #3 (Enriched stimuli)
 Dumb rats get smart
 Smart rats stay smart
 What does this prove about nature v. nurture?
 Remember the hypothesis of the experiment:
 “If an environment (nurture) is significant,
then it can overcome heredity (nature) in
regards to intelligence.”
 Thoughts?
 When the environment was normal
(as in environment #2) nature
(heredity) seems to be the major
factor in intelligence.
 When the environment was
significant (really bad as in
environment #1 or really great as in
environment #3) nurture
(environment) seems to
overcome nature.
 Are slums version of the restricted cage? Is being
raised in affluence comparable to being in
environment #3?