Douglas Mitchell Biology 111 Laboratory Report 18 FEB 2013 The Scientific Method Introduction In life, both human and animal, reaction time can mean the difference between life and death. Reaction time is defined as “the time it takes to react to a stimuli (Norman, 2011). ” In humans, hand dominance (left-handed vs. right-handed) can further impact this reaction time. In this case a simple study of reaction time and hand dominance is being used to illustrate the practical application of the scientific method in the laboratory. Observation

Human reaction times vary person to person and often increase with age. This change in reaction time can have little impact on a person’s daily life, such as when answering a ringing telephone. But this change can also have a dramatic impact when driving, working in dangerous environments, and negotiating busy streets and sidewalks. Literature Search “Reaction time has been used as a psychological test since the mid-19th century (Deary, 1). ” Several studies have been conducted dealing with reaction time and the factors that can affect it.

In their study titled “Validation of reaction time as a measure of cognitive function and quality of life in healthy subjects and patients”, Jakobsen, Sorensen, et al studied and reported findings regarding diminished reaction times and the effect that poor health had on those times. Findings were conclusive that the healthier the individual, the better their responses. Hypothesis Individual’s reaction time with their dominant hand is faster than those with their non-dominant hand. Conversely, there may be no statistically valid difference in the reaction time from one hand to the other. Experiment

To test the variance in reaction time from dominant hand to non-dominant hand we set up an experiment using a simple reaction time test found in the free marketplace on an Android telephone. This application required the user to touch one of four colored stars that match the color of an identified star in the upper right hand corner. The subject was asked to repeat this response 20 times and the total time was scored as the reaction time. If a subject made an incorrect “touch” then their time would continue until the correctly touched 20 stars. The subject would then be ask to repeat this test with their non-dominant hand.

To standardize the testing instructions were provided by my team mates and it was decided that the subject would place the device on a flat surface in front of them and use the index finger on first their dominant hand and then their non-dominant hand. Data was collected for 30 random subjects and analysis performed. Data Analysis Data collected from the 30 random subjects was input and the following summary statistics were produced. Dominant Hand Mean Reaction Time (D)| | | 18. 865 sec. | Median Reaction Time (D)| | | 17. 264 sec. | Variance (D)| | | 28. 235 sec. | Standard Deviation (D)| | | 5. 314 sec. | Non-dominant Hand

Mean Reaction Time (N)| | | 17. 734 sec. | Median Reaction Time (N)| | 16. 412 sec. | Variance (N)| | | 16. 130 sec. | Standard Deviation (N)| | | 4. 016 sec. | The graphs below illustrate the mean for each hand as well as error with in plus or minus one standard deviation. Conclusion After conducting this experiment and reviewing the data, a few things became clear. One is that age of the subject had a significant impact on results with both hands. This is presumed to be the result of the interaction with a new technology. Younger subjects seemed to grasp the concept of what they were expected to do more quickly.

Second, in this case, familiarity did not breed contempt, but it did breed faster reaction times. As subjects became more comfortable with the application they were using, their response times decreased. The later of these two factors had a more global effect on our outcomes, thus disproving our hypothesis in this case. I do not believe these results to be conclusive or authoritative and simply put, more research is needed. References Deary, I. J. , Liewald, D. & Nissan, J. (2011) A free, easy-to-use, computer-based simple and four-choice reaction time programme: The dearly-liewald reaction time task.

Behavior Research Methods (Online), 43(1), 258-268. Retrieved from http://search. proquest. com/docview/920259801? accountid=39001 Jakobsen, L. H. , Sorensen, J. M. , Rask, I. K. , Jensen, B. S. , & Kondrup, J. (2011). Validation of reaction time as a measure of cognitive function and quality of life in healthy subjects and patients. Nutrition, 27(5), 561-570. Doi: http://dx. doi. org/10. 1016/j. nut. 2010. 08. 003 Norman, Celia (2011). General Biology 111: Laboratory Manual. Denver, CO: Department of Biology, Arapahoe Community College.