NORTH NEWTON, KAN. – In his three decades at Bethel College, Dwight Krehbiel, professor of psychology, has pursued several research interests, among them animal behavior, psychology of music and scientific computing. In recent years, his work has garnered recognition from both his colleagues and outside groups.
Last fall, Krehbiel presented the annual Honors Convocation as the 2007 recipient of the Julius A. and Agatha Dyck Franz Community Service Award. He spoke on “The promise of digital media: Resources for scholarship” in which he outlined some of his work during a sabbatical in France earlier in the year. There, Krehbiel collaborated in research on the physiological determinants of maternal behavior in sheep and goats.
Krehbiel will make another public presentation Monday, March 24, when he gives the final Faculty Seminar of the school year and returns to one of his long-time interests in a presentation he has titled “The affective science of music.”
He will speak at 7 p.m. in the Administration Building chapel. The Faculty Seminar is free and open to the public.
Krehbiel’s scholarship and interest in digital media were recently honored further by the National Science Foundation (NSF), which awarded a Small Grant for Exploratory Research to fund a series of cooperative experiments between the Department of Computer Science at the College of Charleston (S.C.) and the Department of Psychology at Bethel College. The faculty and students in these departments seek to produce a musical search engine based on aesthetic similarity.
The collaboration began when Krehbiel met Bill Manaris, professor of computer science at the College of Charleston, at a Sigma Xi research conference. Manaris’ interest lies in the nature of music, specifically those patterns within a musical work that make it beautiful. His efforts concerned the identification and analysis of musical metrics, such as intervals between notes or chords and whether patterns of these metrics affect the appeal of a song.
“We were naturally interested in each other’s work,” says Krehbiel, whose own interest lies particularly in music’s emotional dimensions.
Manaris’ research is based on Zipf’s Law, commonly associated with linguistics but which Manaris has applied to his analysis of music. In simplified terms, a body of text has a word that is used most frequently. The word with the next highest frequency of use in the text should, under Zipf’s Law, have a frequency half that of the first frequency. The third most frequently used word should have a frequency half that of the second frequency and so on. Manaris’ work shows that the same pattern sometimes exists in the musical metrics he has identified.
Songs with metrics that follow Zipf’s Law seem to be more classical sounding and are more initially pleasant than those pieces that deviate from the law. What Manaris has found is a way to compare pieces of music and predict how pleasant listeners will find a new piece of music. If two pieces of music have similar relationships between their metrics and Zipf’s Law, Manaris expects the listener to respond to them emotionally in a similar way. However, Krehbiel notes, that pleasantness and liking are somewhat different dimensions of emotional response, so someone might like a non-Zipfian piece better than a Zipfian one.
Krehbiel’s work could potentially verify Manaris’ hypothesis. In several experiments over the past few years, Krehbiel and Manaris have found that these computer-based metrics are indeed good predictors of human emotional response. For example, in studies reported by Manaris, emotional responses to computer-composed variations of a Bach two-part invention were shown to be predicted by these metrics.
Last fall Krehbiel and his students, with the support of the NSF grant, conducted an experiment to test the predictions of the musical search engine. Each participant in the experiment listened to a piece of music that he or she chose, along with six computer-selected pieces of music (three selected to be metrically similar to the original and three to be different). During the listening session, the researchers measured several aspects of emotional and physiological response, using equipment that was funded through this grant as well as an earlier grant awarded in 2005.
The emotional response data have been analyzed. Brittany Baker, junior psychology major from Kingman, will report on some of the results in April at the National Conference on Undergraduate Research. Other Bethel students involved in the research over the past year include seniors Megan Abrahams, Canton, Sarah Buller, Lenexa, and Rondell Burge, Moundridge, juniors Becky Buchta, Newton, and Katie Robertson, Lawrence, and sophomore José Rojas, Newton.
Favorable results would put Krehbiel and Manaris one step closer to the realization of a musical search engine capable of taking and analyzing Zipfian characteristics of any person’s favorite song and supplying a list of aesthetically similar songs across genres and a large database of music. Beyond the pop-culture phenomenon this would undoubtedly be, Manaris and Krehbiel’s combined work could inform music composition and education and research in the fields as diverse as of music, computer science and psychology.
Faculty Seminar provides a forum for presenting the achievements of the Bethel College faculty to the larger campus community. Recent dissertations, books, papers and fine arts productions usually form the core of the presented material. Sessions last approximately 90 minutes and include critical and wide-ranging discussion following each presentation. Students and interested members of the community are welcome at all sessions.
The Bethel College Faculty Seminar series is supported in part by the Earl and Meta Leisy Eymann Endowment. For more information, contact Faculty Seminar co-directors Nathan Bartel at (316) 284-5240 or Sharon Eicher at (316) 284-5319.
Bethel College is a four-year liberal arts college affiliated with Mennonite Church USA. Founded in 1887, it is the oldest Mennonite college in North America. Bethel is known for its academic excellence and was the highest ranked Kansas college in the national liberal arts category of U.S. News & World Report’s listing of “America’s Best Colleges” for 2008. For more information, see the Bethel Web site at www.bethelks.edu.