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 Woman’s College in 1891 Lynchburg, VA 24503 Results There was no statistical significant difference in latency to choose a cup choice between the first trial (M=7.49, SD= 7.28) and the last trial (M=8.25, SD= 15.20) for rat 1, t(19)=-0.189, p=0.852. In contrast there was a statistically significant difference between the first latency (M=11.34, SD= 15.95) and last trial’s latency (M=2.94, SD= 1.99) to choose times for rat 2, t(19)=2.311, p=0.032. 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, p=1.00, t(19)=-0.52, p=0.61, 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 experimenter’s 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 (N=2). 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 it’s 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.