The Effect of Age on Bilateral Transfer
Sponsored by Missouri Western State University Sponsored by a grant from the National Science Foundation DUE-97-51113
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The proper APA Style reference for this manuscript is:
CONROY, C. C. (2001). The Effect of Age on Bilateral Transfer. National Undergraduate Research Clearinghouse, 4. Available online at http://www.webclearinghouse.net/volume/. Retrieved April 25, 2017 .

The Effect of Age on Bilateral Transfer
CRAIG C. CONROY
MWSC DEPARTMENT OF

Sponsored by: Brian Cronk (cronk@missouriwestern.edu)
ABSTRACT
The purpose of this study was to find out if bilateral transfer increases with age. An early adulthood group, ages 18 to 39, and a middle adulthood group, ages 40-64, were compared. Each group consisted of 10 subjects, half-male, and half-female. Each subject completed a mirror-tracing exercise using a Lafayette Mirror tracer (model no. 31010). Subjects traced the outline of a six-pointed star, and each participant completed six trials. For each trial, the number of errors and time taken to complete the exercise were recorded. No significant difference was found for the number of errors committed (t(18) = .672, p > .05), or time to complete the exercise(t(18) = -1.583, p > .05). A significant difference was found for the difference in errors from the first trial to the last trial (t(18) = 2.359, p < .05). Since no significant differences were found between the number of errors committed, and the time taken to complete the exercise, it is unclear whether bilateral transfer increases with age.

INTRODUCTION
Bilateral transfer takes place when information is transferred from on hemisphere of the brain to the other. This phenomena has been replicated in many studies (Thakur, 1978). There are numerous methods and tasks that have been developed that allow researchers to measure these effects. Traditionally, most researchers have used a mirror-tracing task to measure bilateral transfer across hemispheres. Freeman conducted a study on this effect in 1938 when little was known about it. In his experiment subjects practiced the alphabet under two conditions, one condition had them simply write the alphabet, while the other had them use a mirror to write it. In each condition he had subjects first use their preferred hand, next they were instructed to practice with their non-preferred hand. Then they went back to the preferred hand to see if transfer had occurred. It was observed that transfer effects were more powerful when a mirror was used. This led to the mirror-drawing task being used to measure transfer effects. The mirror-tracing task was originally designed by Starch. Normally subjects trace a geometric figure using only the mirror as a reference. The mirror causes the subject to “develop a new hand-eye coordination” (Mandel, Singh, Asthana, & Srivastava, 1992). As time passed more research emerged on this topic. It was discovered that certain conditions inhibit transfer, such as schizophrenia and mental retardation. Thakur (1978) found that psychological stress can also inhibit bilateral transfer. It has also been found that certain conditions can increase transfer. Ambidextrous individuals, as opposed to right or left-handed individuals, complete the mirror-tracing task much quicker, but had the least amount of transfer (Bhushan, Dwivedi, Mishra, & Mandel, 2000). Experiments that compared only right and left-handed males and females have generated some interesting results. It was found that females outperform males on the mirror-tracing tasks. It was shown that females complete the task quicker and commit less errors than their counterparts (O’ Boyle, 1987). Once the gender relationship was discovered other researchers began looking at the effect of age on bilateral transfer. One such study looked at differences in bilateral transfer in females age 7 to 17. It was found that bilateral transfer increased with age, and older females committed less errors that the younger females (Byrd, Gibson, & Gleason, 1986). The study was not able to conclude the exact age at which maximum transfer effects are achieved. They were only able to conclude that it must be older than 17 years of age. The following study may help to pinpoint this age of maximum bilateral transfer. Two groups will be used in this experiment, an early adulthood group, and a middle adulthood group. Bilateral transfer will be measured using a mirror-tracing task. The amount of time to complete the task and the number of errors committed will be measured and compared. Both groups’ scores will then be compared, and analyzed. The main purpose of this study is to see whether bilateral transfer increases with age.


METHOD

PARTICIPANTS
Subjects were recruited from Missouri Western State College, and their ages ranged from 19 to 46. Depending on age, participants were put into one of two groups. The first group was an early adult group (18-39), and the other was a middle adult group (40-65). A total of 20 subjects were selected. There were 10 subjects in the early adult group (m = 19.8, sd = .919), and 10 subjects in the middle adulthood group (m = 42.1, sd = 2.025). Each group contained an equal number of males and females.

MATERIALS AND PROCEDURE
The first 20 Missouri Western State College students who agreed to participate and meet the criteria listed above (sex and age) were selected as subjects. Each subject then set up a time with the experimenter when they could participate, and no two subjects could use the same time frame. The subjects reported to a cubicle in the Psychology Department at their designated time. The subjects were then briefed on the nature of the study. Once final consent was obtained the subject was instructed on a mirror-tracing task. The apparatus used for this experiment was the Lafayette Mirror tracer (model no. 31010). A six-pointed star pattern was used in this study. They were instructed to draw a line as fast as they could within the boundaries of the star outline. Once they reached the point where they started they were done. If they crossed outside the boundary it was counted as an error. Each subject participated in 6 trials. In the first trial they traced using their non-preferred hand. The next three trials were done using the preferred hand, and the final two were again done with their non-preferred hand. There was a five-minute time limit on each trial, and a one-minute rest period between trials. For each trial, the time taken to finish and the number of errors were recorded.


RESULTS
An independent t test was calculated comparing the mean amount of time the early adulthood group improved from their first trial to their last trial to the mean amount of time the middle adulthood group improved from their first trial to their last trial. No significant difference was found (t(18) = 1.482, p > .05). The mean of the early adulthood group (m = 128 sec., sd = 80.72 sec.) was not significantly different from the mean of the middle adulthood group (m = 175.5 sec., sd = 61.26 sec.). An independent t test was calculated comparing the mean number of errors the early adulthood group improved from their first trial to their last trial to the mean number of errors the middle adulthood group improved from their first trial to their last trial. A significant difference was found (t(18) = 2.359, p < .05). The mean of the early adulthood group (m = -2.4, sd = 18.3) was significantly higher than the mean of the middle adulthood group (m = -23.3, sd = 21.2). An independent t test was calculated comparing the mean amount of time it took the early adulthood group to finish the mirror-tracing task to the mean amount of time it took the middle adulthood group to finish the mirror-tracing task. No significant difference was found (t(18) = -1.583, p > .05). The mean of the early adulthood group (m = 130.4 sec., sd = 81.37 sec.) was not significantly different from the mean of the middle adulthood group (m = 192.2 sec., sd = 92.9 sec.). An independent t test was calculated comparing the number of errors committed by the early adulthood group to the mean number of errors committed by the middle adulthood group. No significant difference was found (t(18) = .672, p > .05). The mean of the early adulthood group (m = 50.8, sd = 29.9 ) was not significantly different from the mean of the middle adulthood group (m = 42.5, sd = 25.15).


DISCUSSION
In this study bilateral transfer was not shown to increase with age. It was hypothesized that the middle-adulthood group would outperform the early adulthood group by committing fewer errors and completing the exercise quicker. The results did not support the hypothesis. Actually, the early adulthood group and the middle adulthood group performed at about the same level on the mirror tracing exercise. This suggests that bilateral transfer remains fairly consistent from early to middle age. The number of errors on the first trial was subtracted from the number of errors on the last trial for each group. When those means were compared a significant relationship was found. The number of errors committed by the early adult group did not change that much from the first to the last trial. But there was a difference across trials for the middle adult group. They committed lots of errors on their first trial, but by the sixth trial they were committing less errors than the early adulthood group. The sex differences found were inconsistent with previous findings. In the introduction it was stated that females are better at mirror tracing than males. My results showed the opposite. Males did commit more errors than females, but their times were faster than those of the females. The times were not significantly faster, but males on the average were 17 seconds faster than females on the mirror tracing exercise. There many problems with this study. For one, the experimenter administered the exercise to the subjects. This may have introduced bias into the results. The experimenter may have unconsciously persuaded the subjects to do better or worse on the mirror-tracing exercise. Another problem is that the data was collected over a period of three weeks. It is possible that some of the early subjects may have informed later subjects about the study. That may have helped subjects to do better than they would have knowing nothing about the study. These results would probably be very different with a larger sample size. As I stated before males do not usually outperform females, but they did in this study. That inconsistency was probably due to the small sample size. The study would be greatly improved if 100 or more subjects participated. It would also be interesting to add a late adulthood group, and compare those three groups. An adolescent group could also be added, and compared.


REFERENCES
Bhushan, B., Dwivedi, C. B., Mishra, R., & Mandel, M. K. (2000). Performance on a mirror-drawing task by non-right-handers. Journal of General Psychology, 127(3), 271-278.Byrd, R., Gibson, M., Gleason, M. H. (1986). Bilateral transfer across ages 7 to 17 years. Perceptual & Motor Skills, 62(1), 87-90.Freeman, G. L. (1938). Studies in the psychophysiology of transfer: Bilateral practice effects in normal and mirror writing. Journal of Psychology, 5, 285-289.Mandel, M. K., Singh, S. K., Asthana, H. S., & Srivastava, P. (1992). Bilateral transfer deficit in schizophrenia. Comprehensive Psychiatry, 33(5), 319-324.O’ Boyle, M. W. (1987). Gender and handedness differences in mirror-tracing random forms: Evidence for female superiority in a visuospatial task. Paper presented at 15th annual meeting of the International Neuropsychological Society, Washington, D.C., February, 19, 1987.Thakur, R. C. (1978). The effect of anxiety and psychological stress on bilateral transfer. Journal of Psychological Researches, 22(1), 1-4.

Submitted 11/28/2001 9:10:01 PM
Last Edited 11/28/2001 9:21:34 PM
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