Norman Vincent Peale was right, said John Cloud in Time. There is power in positive thinking, as Peale said in his 1952 book—but a study by Canadian psychologists just published in the journal Psychological Science says trying to get people to think more positively might "simply highlight how unhappy they are." The study suggests people might be better off accepting their negative thoughts instead of waging a futile battle against them—"call it the power of negative thinking."

Repeating the statement "I am a lovable person" will make you feel better if you already feel good about yourself, said the New York Post, but in the study it "made the already gloomy people feel worse." So "try this on for a new self-help mantra: "I'm not good enough, I'm not smart enough, and doggone it, people may not like me all that much."

Don't read too much into this study, said Robert Roy Britt in Live Science, or any study on self-esteem, for that matter. "Self-esteem and its close cousin self-confidence are slippery research topics. Scientists don't even know to what extent they are inherited versus fostered." There's sure to be another study soon that attempts to "trump" this one, so stay tuned.