Read http://www.drkoop.com/healthnews/rhn0714/t071402.asp for a summary of a report about the effect of praising a child's good grades. The article begins: "Surprising as it sounds, praising children for their ability or intelligence may actually have a negative effect on a child's academic performance, a study suggests. Such praise may make a youngster feel pressured to get good grades or reach certain goals, and may make them less able to cope with failure, according to a report in the Journal of Personality and Social Psychology. Instead, praising a child for their effort may spur them to try harder in the face of adversity, according to psychologists Drs. Claudia Mueller and Carol Dweck of Columbia University in New York. ..."
The conclusions stated in the report are consistent with Adler's principles of encouragement.