Mathematics and Psychology Kashif Shah University of Southern Indiana 2012-04-08 Mathematics and Psychology The Use of Statistics in Psychology Research in any scientific field requires precise observations and record keeping. Psychology is no different when it comes to needing a mechanism to ensuring the validity of a research project, providing precise data, or analyzing their observations. Psychologists often use statistics to organize and analyze their data, and to also uncover any hidden patterns that may not be noticeable through pure observation. Through the development of statistics it is now possible to contain “messy” data, and it has shown us the need for descent research practices in order to obtain valid conclusions (Brysbaert & Rastle, 2009, p. 68). Whenever researchers apply statistical tests to assess the results of their studies the term “statistical significance” is often used. Statistical significance is the “process of judging whether or not a particular statistical outcome is likely or unlikely to be due to chance” (Cowles, 2001, p.7). The statistical test themselves serve as an evaluation method to make sure that a researcher’s findings can be verified and gives the researcher a way to figure if the outcome of the experiment was due to an unforeseen situation (Statistical significance, 2004). So, as a result, statistical significance helps to maintain a more precise study. Statistics not only help with organizing the end results of a study, but they also help researcher’s design proper studies that will ultimately lead to a valid conclusion. It has been shown that the construction of appropriate questions in a “systematic framework” deliver data that, with the tools of statistics, lead to valid answers (Cowles, 2001, p. 31). A researcher can develop and run a study from beginning to end, however if the study is not constructed carefully the end result will produce patterns that become complex and almost impossible to draw any conclusion from. So, when the researcher takes advantage of the statistical tools that they have at their disposal it is much more advantageous to design a study from the start that would rule out any confounding variables. As a result the end data would be organized and easier to draw conclusions from (Brysbaert & Rastle, 2009, p. 69). Quantitative / Mathematical Psychology According to the American Psychological Association (APA), there are more jobs for quantitative psychologists than there are students of quantitative psychology (APA, 2012). Quantitative Psychology is a field of study that encompasses all aspects of psychology itself. Research in quantitative psychology is important for developing research methods, new techniques for measuring psychological phenomenon, data analysis, and modeling of psychological processes (APA, 2012). Mathematical Psychology in particular is heavily based in mathematics. Mathematical models are inherently necessary for studying and making hypothesis for brain mechanism, decision-making, understanding perception, language, and behavior, as well as the mechanisms by which environmental stimuli are converted into biopsychological representations. Mathematical psychologists utilize game theory, probability and statistics, as well as general mathematical approaches and physics based models (APA, 2012). Some of the earliest mathematical models in Psychology were developed as ways to map physical stimuli to psychological perception. The early psychologist Ernst Weber developed the differential equation dp = k*(dS/S) to describe the relationship between change in weight and change in perception of weight. Further analysis of this equation produces the equation p = k* ln (S/S0) which describes the intensity of weight perception in terms of the product of an experimentally determined constant k and the natural log of the ratio of stimulus intensity to the stimulus threshold. Later, Stanley Stevens developed what is now called Steven’s Power Law, Psi(I) = k*I^alpha, which relates the magnitude of physical stimulus to the psychological intensity. Stevens derived this equation by fitting a power function to data collected from different participants across many different sensory modalities (Smelser, 2001). These early examples of mathematical models of perception are still discussed in introductory sensation and perception courses but the techniques used to model perception have gone far beyond these simplistic models to include signal detection theory (Luce, 1990) and neural network models. Parallel Distributed Processing [IMAGE] Psychology of Mathematics [IMAGE] Psychometrics Psychometrics is the study of measuring psychological phenomenon such as knowledge, intelligence, personality, education, and attitudes. Psychometric measurements are taken by way of questionnaires, surveys, and assessments. According to Mitchell (1997), “measure is the numerical estimation and expression of the magnitude of one quantity relative to another.” In response to a physicist, one psychologist said: "Measurement in psychology and physics are in no sense different. Physicists can measure when they can find the operations by which they may meet the necessary criteria; psychologists have but to do the same. They need not worry about the mysterious differences between the meaning of measurement in the two sciences." (Reese, 1943, p. 49) Almost everyone has taken a psychometric test of one sort or the other –some common psychometric tests are the SAT, GRE, IQ tests, and the Myers-Briggs Personality Type Indicator. Psychometric tests not only require means for analyzing test data but also require rigorous procedures for creating validated tests. Psychometric tests need to be able to measure the phenomenon of interest to the exclusion of other confounding phenomenon, personal biases, and societal expectations to name just a few problem areas for developers of psychometric tests. Psychometricians use advanced mathematical models of their variable of interest as well as statistical methods to analyze and compare data from tests to behavioral data from psychological experiments. Some mathematical methods utilized by Psychometricians include correlations and other statistical techniques, multidimensional scaling, data clustering, structural equation modeling, and path analysis. References American Psychological Association (2012). “Quantitative Psychology”. http://www.apa.org/research/tools/quantitative/index.aspx Brysbaert, M., & Rastle, K. (2009). Historical and conceptual issues in psychology. Harlow, England: Pearson/Prentice Hall. Cowles, M. (2001). Statistics in psychology: An historical perspective. Mahwah, NJ: L. Erlbaum Associates. Luce, R.D. (1990), "Psychophysical laws: cross-modal matching",Psychological Review 97 (1): 66–77, doi:10.1037/0033-295X.97.1.66 Michell, J. B (1997). "Quantitative science and the definition of measurement in psychology". British Journal of Psychology 88 (3): 355–383. doi:10.1111/j.2044-8295.1997.tb02641.x. Reese, T.W. (1943). "The application of the theory of physical measurement to the measurement of psychological magnitudes, with three experimental examples". Psychological Monographs 55: 1–89. Smelser, N.J., & Baltes, P.B. (2001). International encyclopedia of the social & behavioral sciences. pp. 15105–15106. Amsterdam; New York: Elsevier.ISBN 0-08-043076-7. Statistical Significance. (2004). In The Concise Corsini Encyclopedia of Psychology and Behavioral Science. Retrieved from http://www.credoreference.com/entry/wileypsych/statistical_significance