REPLICATION FAIL FOR A STUDY USING BASEBALL CARDS. During the baseball offseason the Economist reported on the replication of a psychological study of the hypothesis that people who smile more intensely tend to live longer. The original study was done with 196 baseball cards from 1952. Volunteers rated the smile on the cards according to their intensity. The study supported the hypothesis. Players with full smiles did tend to live longer. The probability that the result arose by chance was only two in fifty.
A replication was done of the experiment using 527 Baseball Register pictures from the period around 1952. This experiment showed no correlation between smiles and life spans. The Economist thinks the difference resulted from different coding of smiles by different sets of volunteers.
The Economist article featured a photograph of a Jackie Robinson baseball card.