Confirming Weber's Law
During the nineteenth century, Ernst Heinrich Weber and his student Fechner developed a theory on human perception (http://ukdb.web.aol.com/hutchinson/encyclopedia/51/M0020351.htm). The law states that for a difference to be perceived, two stimuli must differ by a constant minimum percentage (Meyers, 1999). They went further to say that there was a just noticeable difference when comparing two stimuli. The just noticeable difference is the minimum difference that a person can detect between two stimuli fifty percent of the time (Meyers. 1999). Although their theory is necessary to study, most people now use Steven's law (http://www.medfak.uu.se/fysiologi/Lectures/WebFech.html). Our experiment sought to see if weight detection of pennies conforms to Weber's law. We wanted to replicate a situation in our classroom using weights to determine the just noticeable difference (jnd). According to the above theory, the jnd in the heavier weight will be significantly higher.
Method
Participants
The participants were the twenty-seven students of Professor David Otis' Experimental Psychology class. The group of twenty-seven was split into smaller groups. We were not paid with pecuniary funds, but we did receive partial credit towards our final grade in the class.
Apparatus
Approximately one hundred and fifty pennies were used as weights. Two plastic cups of equal size and weight were used to hold the pennies in, and the subjects used neckties donated by the professor as blindfolds.
Procedure
After the groups were separated into groups of three or four, we were instructed to perform three trials. In each group each person got to be an experimenter and a subject at least once. First we placed ten pennies into each cup, and let the blindfolded subject feel the cups at equal weight. We then placed a penny into the experiment cup (A) and told the subject to guess which was the heavier cup. If the subject guessed correctly, we would continue to give them the same two cups, in different hands and order, until they had guessed correctly five times. If the subject guessed incorrectly, another penny was added until they could guess right five times in a row. The purpose of the first weight was to get the subject and experimenter accustomed to the nature of the experiment. After the first trial of ten starting pennies, fifteen pennies were used as a starter. After that sixty pennies were used.
Results
Schacter, D. L., Gilbert, D. T., & Wegner, D. M. (2010). Psychology. (2nd ed., p. 600). New York: Worth Pub.
The World of Psychology. (2002). A Pearson Education Company. Boston, MA: Samuel Wood & Ellen Green Wood p. 593
Journal of Experimental Social Psychology, 13, 279-301.
"PSYCHOLOGICAL & BEHAVIOURAL ANIMAL EXPERIMENTS AND RESEARCH TESTING." Psychological Animal Experiments. N.p., n.d. Web. 20 Feb. 2014. .
Gall, S. B., Beins, B., & Feldman, A. (2001). The gale encyclopedia of psychology. (2nd ed., pp. 271-273). Detroit, MI: Gale Group.
An experiment is done which includes a few test subjects. They are supposedly supposed to
..., as well as the control, no picture, would be tested, a total of twenty trials, with four trials per picture during the subject’s test. The pictures were named Picture A, Picture B, Picture C, and Control. Then, the data gathered would be examined for similarities and differences with the picture shown, and the data would reveal whether the pictures influenced what the person saw in the inkblots. The independent variable of this test would be the pictures shown to the subjects before the test, and the dependent variable would be what was seen in the inkblots during the tests. There were four levels of independent variables including no picture, the control. The computer the test was taken on would be kept constant, the order of the slides shown, and the order of the pictures shown before the test. These factors are all needed in the experiment for clear data.
Hockenbury, Don H., and Sandra E. Hockenbury. Psychology. 6th ed. New York, NY: Worth, 2013. Print.
Shiro Ishii wasted no time collecting test subjects for use in his experiments and quickly gathered 500-600 men, women, and children. The test subjects were a mix of people that included prisoners of war, political...
The experiments were quite simple, in that there was a seemingly harmless task to be performed, and the participants were instructed to choose the estimation of the lengths of a line when compared to two ...
Hewstone, M. Fincham, F. and Foster, J (2005). Psychology. Oxford: The British Psychological Society, and Blackwell Publishing. P3-23.
Boyd, D., Wood, E.G., Wood, S.E. (2014, 2011, 2008). Mastering the world of psychology. Upper Saddle River, NJ: Pearson Education, Inc. 128-129, 329-330, 335-340. Print.
Edited by Raymond J. Corsini. Encyclopedia of Psychology, Second Edition, Volume 1. New York: John Wiley and Sons Inc.
Weiner, I. Healy, A. Freedheim, D. Proctor,R.W., Schinka,J.A. (2003) Handbook of Psychology: Experimental psychology,18, pp 500
For the purposes of the exploration, volunteers will be labeled, Spectator A, Spectator B, Spectator C, and Spectator D. Throughout this exploration, the coins used will be in CAD. The magician brings $1.96 to a table, consisting of six pennies, six nickels, six dimes, and four quarters. Spectator A is asked to pick up one coin. Spectator B is asked to pick up a different valued coin. This process is repeated for Spectator C and Spectator D. Then, the performer asks Spectator D to pick up coins which adds up to four times the value of the original coin taken. Spectator A is asked to pick up the same value of coins they picked up before. Spectator B is asked to pick up double the value of coins they picked up, and Spectator C is asked to pick up three times the initial value of the coin they were asked to pick up. The magician then turns around and correctly identifies the initial value of the coin picked up by each of the spectators.