A Study into Brain Contra-Lateralization

A Study into brain contra-lateralization

One of the most researched facets of the physiology of the brain is the concept of lateralization, or the separation of the brain into two hemispheres and the functions each side performs. It is understood that each side deals with the information received from the inverse side of the body; that is the left side of the brain is responsible for the right side of the body, and vice-versa (Matlin 1999). Also, the left hemisphere deals with language processing, where the right side primarily deals with spatial information. In order to investigate and demonstrate a contra-lateralization of the hemispheres it is necessary to perform a dual task, one which draws equally from each side of the brain. In this example language is being used in conjunction with a motor task - tapping a pencil on two parallel dots on a page while speaking. In theory, when conducting a motor task with the right hand whilst performing a speech task would mean that the left hemisphere has to control two processes at once and thus performance of one of the tasks, most likely the motor task, would decline. It is hypothesised that the experiment will return results that correlate with prior research - the motor task performance will decline as the left hemisphere is performing more than one task.

Method.

Participants

A sample of one hundred first year psychology (PSYC1020) students, all right handed, were selected, including seventy-three females and twenty-seven males. Participants were placed into self selected groups of three or four students under the control of the experimenter.

Design

Under scrutiny in this experiment was the use of right or left hand by the participants to dot the page, as well as whether or not they were orally reciting a pre-set script. Through the manipulation of these independent variables, results were returned, specifically the number of dots per five second interval - the dependant variable.

Materials

To complete this experiment only basic materials were required, including a classroom with sufficient lighting, chairs to seat the participants, tables, the participants themselves, a page with instructions including spaces with pre-measured marks for the participants to dot, reliable pens or pencils, timing device to keep five second intervals accurately, and a tutor, or experimenter.

Procedure

Upon entering the classroom, participants were assigned to groups where they were seated. Each participant was handed an instruction sheet, and explained the exact task. The tutor then instructed the participants as to the section of the experiment to be undertaken, for example left hand silent, or right hand speaking. Once giving the start signal all participants completed the task as many times as possibly before the tutor gave the stop signal after the five second interval. After completing each section twice, results were collected and tabulated for