The Effect of Early Data Returns on Data Subsequently Obtained by Outcome-Biased Experimenters

Twelve biased experimenters, each running six subjects on a photo-rating task, were equally and randomly divided into three treatment conditions. One group of experimenters obtained or expected data from their first two subjects (who were actually accomplices), another group of experimenters obtained or unexpected data from their first two subjects (who were also accomplices), while the third group, utilizing only naive subjects, served as a control. Comparisons were made of the mean data obtained by experimenters from the last four naive subjects run. Results indicated that experimenters obtaining initial data also obtained good subsequent data. Experimenters obtaining initial data obtained bad subsequent data. Methodological implications of the early returns effect were discussed.