Scientists have debated for decades what experimental method is the most effective overall. In recent years, a study has come out that has claimed that one method – specifically the non-adaptive method of constant stimuli – does indeed trump the others statistically (Simpson, 1988). We decided to test this concept on our own by dissolving different amounts of sugar into cups of water and preparing a test in which a blind participant would drink and rate the labeled cups on a binary scale of measurement. In this experiment, we determined our hypothesis so that the result would occur in a difference between groups such that the method of limits will yield lower thresholds.


The participants in this study were 24 students (male = 4, female = 20) at Sierra College who are currently enrolled in the Research Methods in Psychology (PSYC 105) course taught on Mondays and Wednesdays by Dr. Katherine Campi. The participants were told the reason for the study prior to their participation in the experiment. Then, the participants were split into pairs, and were given their respective materials. Participants were then instructed on how to mix the sample solutions in five separate cups containing sugar of differing values. Once the samples were properly prepared, the participants tested each other using the method of limits, blindfolding the tester who was actively tasting the solutions as they went. After testing the method of limits, the participants tested each other using the method of constant stimuli. Then, the participants regrouped to analyze and chart the data of both tests.


Our analysis concluded that our hypothesis, which stated we would see a difference between groups such that the method of limits would yield lower thresholds, was proven through our experiment. The method of constant stimuli gives a significantly higher threshold (x̅ = 2.92, SD = 0.83) than the method of limits (x̅ = 2.63, SD = 0.71) , t(23) = -2.22, p = 0.04. These results are relatively consistent with previous research studies on this topic.


The results of this experiment have proven to be conclusive with our stated hypothesis. Previous research studies have also proven that the method of constant stimuli is adequate in maximizing efficiency in experiments, like Fernberger did in 1914 with the elimination of polar opposites in data. Although the limitation in a lack of a control group was present in the study, and it was not taken into account if the participants had anything sweet our research did seem to line up accurately with both our hypothesis and prior research professionals in the field have done. It seems as though there are rather minimal differences between the adaptive and non-adaptive methods, but that, ultimately, it is the method of constant stimuli that allows for a smaller margin of error and simplifies data enough to get more accurate, and therefore effective, datasets. In conclusion, our experiment does seem to be consistent with our hypothesis.


Simpson, W. (1988). The method of constant stimuli is efficient. Perception &
Psychophysics, 44(5), 433-436.

Fernberger, S. (1914). On the elimination of the two extreme intensities of the
comparison stimuli in the method of constant stimuli. Psychological Review,
21(5), 335-355.