Researchers Discover New Law Guiding the Way Humans Perceive the World

Laws of perception explain why people see the world the way they do. Alan Stocker and his former graduate student Xue-Xin Wei, now a postdoc at Columbia University, have discovered a new such law, one of only a handful in existence.

The researchers confirmed a link between how sensitive people are to changes occurring in front of them, what’s called the discrimination threshold, and the perceptual bias, or the amount perception deviates from reality. They published their findings in the Proceedings of the National Academy of Sciences.

To understand the new connection, Stocker suggests considering a wall that’s uniformly lit. An experimenter changes the brightness of the light ever so slightly, then a little more and a little more. “The discrimination threshold tells us how fine the experimenter can actually change the light levels such that we still cannot detect it,” says Stocker, an associate professor of psychology. "Once we can detect it, we’ve crossed the discrimination threshold boundary."

Click here to read the full story.

Arts & Sciences News

Mark Trodden named Dean of Penn’s School of Arts & Sciences

A distinguished physicist and accomplished academic leader, Trodden will assume the role on June 1.

View Article >
2025 School of Arts & Sciences Teaching Awards Announced

Penn Arts & Sciences annually recognizes faculty, lecturers, and graduate students for their exemplary teaching. This year’s honorees come from 10 departments and two programs.

View Article >
2025 College of Arts & Sciences Graduation Speakers

Michael Platt, James S. Riepe University Professor, will speak at this year’s College of Arts & Sciences graduation ceremony, along with student speaker Anthony Wong, C’25, Sunday, May 18, at 6:30 p.m. on Franklin Field.

View Article >
Three from Penn Arts & Sciences Elected 2024 AAAS Fellows

They include Marlyse Baptista, President’s Distinguished Professor of Linguistics; M. Susan Lindee is the Janice and Julian Bers Professor of History and Sociology of Science; and Christopher Murray, Richard Perry University Professor.

View Article >
Penn Arts & Sciences Receives $8 Million Commitment from The Robert K. Johnson Foundation

The gift will name and endow the Integrated Studies Program, which offers an immersive, interdisciplinary learning experience for Benjamin Franklin Scholars students pursuing degrees in the College of Arts and Sciences.

View Article >
Kimberly Bowes Named BFC Presidential Professor of Classical Studies

Bowes' research interests include Roman archaeology and economic history, with a particular focus on the lived experiences of the ancient poor.

View Article >