Do Rats Have the Ability to Discriminate Between Words?

1
Do Rats Have the Ability to Discriminate Between
Words? Sarah R. Heckendorn and Christina M.
Scheele Randolph College Founded as
Randolph-Macon Womans College in 1891 Lynchburg,
VA 24503
Results There was no statistical significant
difference in latency to choose a cup choice
between the first trial (M7.49, SD 7.28) and
the last trial (M8.25, SD 15.20) for rat 1,
t(19)-0.189, p0.852. In contrast there was a
statistically significant difference between the
first latency (M11.34, SD 15.95) and last
trials latency (M2.94, SD 1.99) to choose
times for rat 2, t(19)2.311, p0.032. There was
no statistically significant difference between
correct cup choice between the first and last day
of training for either rat t(19)0.00, p1.00,
t(19)-0.52, p0.61, respectively. The preference
index for Rat 1 was 0.15 and was 0.08 for rat 2.
Introduction Discrimination is the ability to
learn when a stimulus is given a reward can be
retrieved (Chance 2006). Studies have showns rats
ability to discriminate between tones and no tone
in a T-maze (Eninger, 1951) and between two
different sounds, such as White noise and FM
radio (Sakai Kudoh, 2005). However there have
been few studies done to find whether rats can
discriminate between human words. Will the
sounds of the two words left and right alone be
enough for rats to learn to discriminate to get a
reward? This knowledge could aid in our
increasing knowledge of animal intelligence and
their ability to understand language.
Figure 1

• Discussion
• While other researchers (Eninger, 1951 Sakai
  Kudoh 2005) have found the possibility for rats
  to be able to discriminated between different
  tones, in this present experiment there was no
  conclusive evidence that supports the conclusion
  rats able to discriminate between two words left
  and right. Preference index scores do show slight
  learning did occurred. This is indicated by the
  positive scores, however the correct cup choice
  was never above chance for either rat.
• The one statically significant result, latency
  to dig between first trial and the last trial for
  rat 2, could be due to an accidental variation in
  experiment. Although this variation was
  completely accidental, there were also other
  slight variations between and with-in subjects
  that could have impacted results.
• The previous handling methods of the rats could
  be a possible confound. Rat 1, who has been
  handled by the experimenter giving the cues more,
  could be adjusted to the experiment methods,
  while the method used by the experimenter who
  handled rat 2 was completely different. Rat 1
  could have been more comfortable starting the
  experiment than rat 2, for whom this
  experimenters voice was novel.
• Other possible confounds include extraneous
  noise not reduced by the instrumental music and
  human error, in intonation and in exhaustion,
  could have negatively affected the results.
• Researchers suggest that if this experiment was
  to be repeated, a recording of someone saying
  left or right should be used, or the use of other
  words, as well as more training days. Also a
  noncontingent reinforcement plan should be used,
  where the rat is allowed to examine both cups
  even if he goes to the incorrect cup first.

Method Subjects The subjects were adult, male
Long-Evans rats (N2). Rats were on food
deprivation during the length of the experiment
but given water freely. Apparatus The T-Maze was
used with a small plastic cup at the end of each
choice arm. The plastic cups contained crushed
Froot Loops, with the specific reinforced cup
(switched randomly) having six half Froot Loop
pieces. Procedure Each Rat was allowed to
explore the T-maze for five minutes with 25 half
Froot Loops scattered throughout the maze and in
the cups during the shaping phase of the
experiment. During both shaping and training,
instrumental music was played in the background
to drown out extraneous noise. Training was then
done for five consecutive days each training day
consisted of 20 trials with left and right cup
reinforcement switching randomly. The correct
reinforcement location, left or right, determined
which direction the experimenter would say to the
rats. Verbal cues were repeated until the rat
made a cup choice (placed its head in the
plastic cup). If the cup choice was correct the
rats were allowed to eat three Froot Loop pieces
and then were removed from the maze. If the cup
choice was incorrect the rats were allowed to see
that the cup was empty and then taken out of the
maze. The latency to choose was timed from the
first word spoken to the time the rat put its
head in the cup to find the Froot Loops. During
the test section of the experiment, direction was
chosen at random and was continuously verbally
given to the rat for two minutes. The amount of
time spent in each arm was recorded and a
preference index was calculated.
Figure 2
References Chance, P. (2006). Learning and
behavior Active learning edition (5th ed.).
Belmont, CA Thomson Wadsworth. Eninger, M. U.
(1951). The rate of learning a tone-no- tone
discrimination as a function of the duration at
the time of the choice point response. Journal of
Experimental Psychology, 41(6). 440-445. Sakai
M., Kudoh, M. (2005). Characteristics of sound
discrimination enhancement after sound exposure
in adult rats. Behavioral Neuroscience 119(4).
961-973.