Research Infographic (IMAGE) Arizona State University Caption Four-thousand to 8,000 years ago, there was an extreme reduction in the number of males who reproduced, but not in the number females. Wealth and power may have played a stronger role in shaping recent human evolution than "survival of the fittest." Credit Sabine Deviche Usage Restrictions With artist credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.