By most estimates, the number of psychology experiments conducted on the World Wide Web is more than doubling each year. Studies range from straightforward questionnaires to complex reaction-time experiments. Here's just a handful of note- worthy studies that were being conducted as the Monitor went to press, as well as several sites that maintain lists of psychology-related Web- based studies.

From surveys to experiments

"Ewww...that's disgusting. An experiment on disgust sensitivity."

Researcher: Kathy Straub, PhD, Johns Hopkins University.

Through a questionnaire, this survey asks people to rate their level of disgust with a variety of events--from seeing someone bleeding to cockroaches. One aim of the study is to see whether people with high disgust thresholds are more likely to choose careers in medicine. Address:

"Anger disorder survey."

Researcher: Sharonne Navas, St. Johns University.

This questionnaire asks participants to make judgments about their level of anger in various situations. The study seeks to help determine variables involved in measuring anger. Address: consent.html.

"Are you a logical thinker?"

Researchers: Christoph Klauer, PhD, Birgit Naumer, PhD, and Jochen Musch, PhD, Bonn University.

This study asks participants to rate as correct or false eight logical reasoning problems randomly selected from a large pool of possible syllogisms first discussed by Aristotle. The aim of the study is to determine the difficulty of all 512 possible syllogisms and to test theories about the factors that influence the difficulty of these problems. After the participants finish rating the problems, the researchers allow the participants to see how well they did on the logical reasoning problems. Address:

"A study of human memory."

Researcher: Bem Allen, PhD, Western Illinois University.

This experiment uses a slide show and series of short stories to test people's visual memory using open-ended questions. To entice participation, Allen offers to send those who take the test information on their memory ability based on their performance. Address:

"Effects of war experience."

Researchers: Ian Robbins, PhD, and Nigel Hunt, PhD, University of Plymouth, Devon, United Kingdom.

This questionnaire is designed for combat veterans. It asks questions about participants' biographical background, combat experience and whether they experienced post-traumatic stress disorder. It is part of a program of research into the long-term psychological effects of war experience. Address:

"Online judgement and decision-making experiments."

Researchers: Michael Birnbaum, California State University, Fullerton.

Birnbaum and his students continually post new studies of judgment and decision-making on this Web site. Address:

"Implicit association test."

Researchers: Mahzarin Banaji, PhD, Yale University, and Anthony Greenwald, PhD, University of Washington.

This Web site provides a demonstration of a Web-based version of the Implicit Association Test--an experimental method used to determine people's unconscious attitudes about various topics from race to gender equality to age. Although the researchers are not collecting data on the site, it provides an excellent example of the potential of Web-based research. Address:

"Online jury study."

Researcher: Piers Steel, PhD, University of Minnesota.

Participants read a set of instructions about the guilt or innocence of an accused criminal. They then read a story about the accused and answer a series of questions pertaining to whether the accused did in fact commit the crime and his or her possible motivation for the crime. Address:

"Online language experiments."

Researcher: Michael Kelly, PhD, University of Pennsylvania.

Kelly posts a number of changing studies on this Web site related to understanding the basic processes people use to produce and understand language. One set of studies, for example, asked people to say how they would pronounce a series of nonsense words. Another had people compare pairs of sentences that say the same thing but have different wording and rate the wording they prefer. Address:

"Perception of friends."

Researcher: Nancy Frye, PhD, Texas Tech University.

This questionnaire asks general questions about sexual attitudes, behaviors and values. The goal of this research is to study and determine general patterns in dating relationships. Address:

"Religion and the 10 commandments."

Researcher: William E. Snell, Jr., PhD, Southeast Missouri State University.

This questionnaire asks people to assess how much they agree or disagree with statements related to the 10 commandments. It is part of a research program examining how religion and people's beliefs interact. Address:

"Web questionnaires on judgments and decisions."

Researcher: Jonathan Baron, PhD, University of Pennsylvania.

Baron and his students post a continuous series of judgment and decision-making experiments on this site. Most offer small monetary incentives to participants, ranging from $1 to $6. Address:

Study consolidators

"Psychological research on the Net."

Maintained for the American Psychological Society by John Krantz, PhD, Hanover College.

This page provides a list of psychology-related experiments on the Internet, organized by topic area. Krantz screens studies before listing them to ensure that they are serious studies that meet a minimum level of ethical standard. Address:

"Social psychology network."

Maintained by Scott Plous, PhD, of Weslyan University, this site contains a list of social psychology experiments on the Web. Address:

"Web experimental psychology lab."

A site set up by Ulf-D. Reips, PhD, of the Psychology Institute at the University of Tübingen, Germany, for psychology researchers to post Web-based experimental psychology studies. Researchers can request that their study be added to the site as long as they meet a list of conditions posted on the site by Reips. Interested participants can access several studies at any one time, examine archival studies that are no longer actively collecting data and view the results from studies that ran on the site. Address: (If you have trouble accessing this site, visit it through the APS site:

"Web experiments."

University of Tübingen. psychologist Hendrik-Jan van Veen, PhD, coordinates this page of Web-based cognitive and perceptual psychology experiments. The researchers, whose work ranges from studies of facial perception to studies of how people perceive and remember objects in the environment, have set up a standard protocol of informed consent and debriefing that they feel addresses many of the criticisms of Web-based research. Address: