1
 Operant Sound Discrimination In Rats Emily
Fincher Laura Phillips Randolph
College Lynchburg, VA 24503
Introduction According to Chase (2006), operant
learning is when an organisms behavior is
strengthened or weakened as a result of the
consequences for that behavior. Positive
reinforcement is an operant procedure where
behavior is strengthened because of the
introduction of an appetitive stimulus. Discrimin
ation is when a behavior is more likely to occur
in one situation but not in others (Chase, 2006),
such as when sound is present. In operant
discrimination training, sound could be a
stimulus that indicates the availability of a
reward if the correct behavior is
performed. Past research has shown that it is
possible for animals to learn to discriminate
between different types of music, such as the
study by Porter and Neuringer (1984) using
pigeons. The study found that pigeons were able
to discriminate between the music of Bach and
Stravinsky. Through operant discrimination
training, the researchers hope to determine if it
is possible for rats to discriminate between
music and white noise.
Figure 1

• Results
• A paired samples t-test showed a significant
  decrease in latency to dig between the first
  trail day (M13.63, SD9.04) and the last trail
  day (M48, SD30.69), t(7)-3.36, p.01.
• By the fourth day, both subjects had achieved a
  50 correct cup choice.
• For the test trial the preference index scores
  were compared to chance (.33). Only one trial
  exceeded chance, with a score of .53. A paired
  samples t-test of all preference scores (M.30,
  SD.16) show no statistical significance,
  t(3)-.40, p.72.

• Discussion
• While the statistics show that the subjects were
  able to learn reinforcements were available, they
  did not show any discrimination to sound.
  Although, past research has shown that it is
  possible for animals to learn to discriminate
  between different types of music, the results of
  this study were not conclusive.
• The procedure used for the two rats differed in
  the with one rat receiving pre-exposure and the
  other receiving one additional training day.
• Future research might investigate whether it is
  easier for subjects to learn the difference
  between two types of music instead of one type of
  music and white noise.

• Method
• Subjects
• The subjects used were two adult male, Long Evans
  rats obtained from the Harlan Breeding Company.
  The subjects were placed on food deprivation and
  their weight was maintained at 85 of their
  free-feeding weight and water was available ad
  libitum.
• Apparatus
• The apparatus used was a T-maze consisting of
  three arms of equal lengths. One sand filled cup
  was placed at the end of each of two arms, one of
  which contained the reward (Fruit Loops). A CD
  with three tracks was used, the first track
  consisting of both music and white noise, the
  second track consisting of music alone, and the
  third with white noise.
• Procedure
• At the beginning of the experiment, one rat
  (Ivan) was exposed to the maze for five minutes
  while the first track played with no cups or
  rewards. The second rat (Mick) was not given a
  habituation period.
• Ivan received four training days and Mick
  received five.
• In all trials, the reward was placed in the left
  arm when music was played, and placed in the
  right arm when white noise was played. Latency to
  dig and first cup choice was recorded.
• All training and shaping days consisted of four
  trials, counterbalanced, and the rats were given
  a maximum of five minutes to retrieve at least 5
  fruit loops.
• The first day consisted of shaping with the
  reward first exposed and then gradually buried
  until it reached a shallow depth. The depth
  remained constant throughout the training.
• The testing day consisted of two trialone for
  music and the other for white noiseand the rats
  were given three minutes in the maze. The time
  spent in each arm was recorded as well as latency
  to dig and first cup choice.

Figure 2
References Chance, P. (2006). Learning and
behavior Active learning edition (5th ed.).
Belmont, CA Thomson/Wadsworth. Porter, D.,
Neuringer, A. (1984). Music discrimination by
pigeons. Journal of Experimental Psychology
Animal Behavior Processes, 10, 138-148.