The paper presents findings on secular score gains in Raven’s Progressive Matrices during six decades in Polish adolescents. Seven groups are being compared, comprising of 20, 490 subjects in total. The representative groups examined in 2000 and 2009 are those of special interest as they are the most numerous and allowing formal means comparison using standard test for comparison of means and Welch’s test. Possible causes for the noted effect are being discussed, with special emphasis on the economic growth and (...) its implications - such as improved nutrition, education changes, growth of adolescent’s well-being and child upbringing practices. (shrink)