For decades, the prevailing wisdom in education was that high self-esteem would lead to high achievement. The theory led to an avalanche of daily affirmations, awards ceremonies and attendance certificates - but few, if any, academic gains.

Now, an increasing number of teachers are weaning themselves from what some call empty praise. Drawing on psychology and brain research, these educators aim to articulate a more precise, and scientific, vocabulary for praise that will push children to work through mistakes and take on more challenging assignments. Consider teacher Shar Hellie's new approach in Montgomery County, Md.

To get students through the shaky first steps of Spanish grammar, Hellie spent years trying to boost their confidence. If someone couldn't answer a question easily, she would coach him, then follow up with a booming "Muy bien!"

But on a January morning at Rocky Hill Middle School, she gave nothing away. One seventh-grade boy returned to the overhead projector three times to rewrite a sentence, hesitating each time, while his classmates squirmed in silence.

"You like that?" Hellie asked when he settled on an answer. He nodded. Finally, she beamed and praised the progress he was making.

A growing body of research over three decades shows that easy, unearned praise does not help students but instead interferes with significant learning opportunities.

Stanford University psychologist Carol Dweck's studies, embraced in Montgomery schools and elsewhere, found that praising children for intelligence also backfires.

Studies show children rewarded for being smart become more likely to shy away from hard assignments that might tarnish their reputations.

Instead, children praised for trying hard or taking risks tend to enjoy challenges and find greater success.