In September, APA's flagship journal American Psychologist published online a correction that formally withdrew part of a widely cited 2005 paper on positive psychology. The paper, titled "Positive Affect and the Complex Dynamics of Human Flourishing," used a statistical modeling method based on fluid dynamics to suggest that people need to reach a "tipping point" ratio of positive to negative thoughts — 2.9, the study found — to live a flourishing and happy life.

The "positivity ratio" idea caught on, and the paper has been cited more than 300 times in eight years. But the ratio never sat right with psychologist Harris Friedman, PhD, of the University of Florida. In July, American Psychologist published online a critique by graduate student Nicholas Brown, physicist Alan Sokal and Friedman demonstrating that the fluid dynamics equations could not reasonably be applied to describe changes in human emotions over time.

In response, the journal withdrew the portion of the paper based on the modeling. Marcial Losada, PhD, the Chilean psychologist who developed the modeling theory, declined to defend it in the journal. The paper's lead author, Barbara Fredrickson, PhD, of UNC–Chapel Hill, who relied on Losada's work, said that after reviewing the critique, she agreed that the model was inaccurate.

"As a scholarly publisher APA has a responsibility to evaluate any reasonable challenges to research we publish," says Gary VandenBos, PhD, APA's publisher. "If that challenge is found to be valid we move to correct the scientific record. That is what happened in this case. Once we realized we had published something in error we moved to correct the record by retracting that part of the article," he says.

— Lea Winerman