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TO THE INSTRUCTOR

(and to the student users, too)

The text for this link is a modification of the text with the same heading in the user manual of Precision and Accuracy in Perception (H. Ono, 1993).

This website assumes that there are large variations in mathematical abilities and motivation to learn the material among the student users. By assuming little background knowledge and few skills outside of knowing how to use a calculator, it tries to overcome the difficulty in teaching psychophysical methods caused by these variations. It allows students to work at their own pace; they can repeat parts that they find difficult or they can continue rapidly. For a calculation or an answer to a question, immediate feedback is given. Moreover, the website provides “hands-on” experience, which makes the psychophysical concepts more concrete and the learning process more enjoyable than listening to a lecture. It is intended for laboratories, student projects (individual or group) or demonstrations in experimental, sensory, perceptual, and cognitive psychology courses. It can also be used for an experimental design course, since it places special emphasis on possible confounds that students may inadvertently introduce into their own studies and how these potential confounds may be circumvented.

This package has been evolving for the last twenty years and my hope is to keep improving it until all students can go through it without asking a question regarding its content. Hence, any suggestions from you to improve the package will be greatly appreciated. See HOME page for “Tell us What You Think.”

Below is a brief description of how the package evolved, which also explains different parts of the website. The first computer program was based on a somewhat naive idea that simply doing experiments using psychophysical methods would make concepts like precision (or JND) and accuracy (or constant error) compellingly clear. With Kenneth Ono, my son, a program was written to let the students actually measure precision and accuracy in three different experiments, each one using a different classical psychophysical method. Students enjoyed doing these experiments more than listening to my lectures, but merely doing the experiments did not increase their understanding.

Then, two other experiments, “Weber’s law” and “Mueller-Lyer illusions” were added with the idea that doing one experiment concerned with precision and doing another with accuracy would help in clarifying the difference between the two concepts. (The five experiments discussed above evolved into the present “Experiment and Data Analysis” parts, which enable students to design and execute their own experiments without having to build or acquire additional equipment. After students choose the parameters for their experiment, the computer takes care of the details of stimulus presentation, data collection and data analysis.) This addition of two experiments forced some students to think about the difference, but other students managed to go through the experiments mechanically, without much understanding.

To remedy this shortcoming, Mark Wagner, who was doing a post-doc with me, joined Kenneth Ono and me in adding the “Tutorial and Quiz” and “Review Quiz” sections. In the tutorials, students can generate their own data, and their data (or sample data) are shown in graphic and tabular form. The interpretation and analysis of the data are explained before the students systematically analyze their own data in response to queries that lead them step-by-step through the analysis. The quiz in a “Tutorial and Quiz” section tests what was learned in each tutorial. The “Review Quiz” provides a test on the whole package. Moreover, “Overview and Objective” sections were added to make explicit what students are expected to learrn—with the idea that students learn better when they know exactly what they are supposed to learn. "Psychophysical Dictionary" and "Calculation Help” were added to provide students with immediate help—faster than an instructor can give.

What has been described above culminated into two different packages (for Apple II as well as IBM), Classical Psychophysical Methods (1987) and Accuracy and Precision (1989), both distributed by Conduit. The next package, Precision and Accuracy in Perception used a friendlier Macintosh-HyperCard format and brought the two original packages into one with improvements and the addition of the “Sample Experiments” section, in which the importance of experimental design is emphasized. Intellimation (now defunct) distributed the second package.

The suggested order in which students do the three psychophysical methods is arbitrary. Doing the method of limits first, however, is pedagogically useful, because the operational definitions of upper and lower thresholds are more intuitive than those of the two other methods and leads to a better understanding of the concept of precision. A different order, however, may be better suited for some students, e.g., for students who just finished a statistical course, the method of adjustment may be the best one to start having learned to calculate standard deviation.

The adage that good students learn in spite of a teacher applies to this teaching website as well, and a few very good students in my undergraduate perception class have finished five tutorials, the “Review Quiz” and the three sample experiments on their own in less than three hours without asking questions. They had no difficulty in grasping the relevant concepts and subsequently performed well on an examination. Of course, for these students a traditional lecture format would have been sufficient and the package offers no special advantage except for an instructor being able to shorten the lecture time on this topic. For most other students, what seems to help is an explanation at the beginning that the website is written as though the instructor is there to give help at any time (i.e., the dictionary and calculation help are always available). These students require occasional non-computer help, but usually asking them to go back and read the text more carefully seem sufficient.

Before the package was converted into a web-based program, I required students to come to two three-hour computer laboratories classes to do the five tutorials and the three experiments listed under “Sample Experiments.” They were required to hand-in the completed worksheets for the five tutorials as well as the data and answers to the questions for the three sample experiments. Recently, Al Mapp and Kenzo Sakurai have assigned the web-based package as a two-week project. E-mail addresses were provided and the regular office hours were available to the students for asking questions. Al Mapp’s recent assignment, which is different than what I use to assign, is given below:

Psychophysics Lab

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