Evolution of the empirical and theoretical foundations of eyewitness identification reform

Steven E. Clark, Molly B. Moreland, Scott D. Gronlund

Scientists in many disciplines have begun to raise questions about the evolution of research findings over time (Ioannidis in Epidemiology, 19, 640-648, 2008; Jennions & Møller in Proceedings of the Royal Society, Biological Sciences, 269, 43-48, 2002; Mullen, Muellerleile, & Bryan in Personality and Social Psychology Bulletin, 27, 1450-1462, 2001; Schooler in Nature, 470, 437, 2011), since many phenomena exhibit decline effects-reductions in the magnitudes of effect sizes as empirical evidence accumulates. The present article examines empirical and theoretical evolution in eyewitness identification research. For decades, the field has held that there are identification procedures that, if implemented by law enforcement, would increase eyewitness accuracy, either by reducing false identifications, with little or no change in correct identifications, or by increasing correct identifications, with little or no change in false identifications. Despite the durability of this no-cost view, it is unambiguously contradicted by data (Clark in Perspectives on Psychological Science, 7, 238-259, 2012a; Clark & Godfrey in Psychonomic Bulletin & Review, 16, 22-42, 2009; Clark, Moreland, & Rush, 2013; Palmer & Brewer in Law and Human Behavior, 36, 247-255, 2012), raising questions as to how the no-cost view became well-accepted and endured for so long. Our analyses suggest that (1) seminal studies produced, or were interpreted as having produced, the no-cost pattern of results; (2) a compelling theory was developed that appeared to account for the no-cost pattern; (3) empirical results changed over the years, and subsequent studies did not reliably replicate the no-cost pattern; and (4) the no-cost view survived despite the accumulation of contradictory empirical evidence. Theories of memory that were ruled out by early data now appear to be supported by data, and the theory developed to account for early data now appears to be incorrect.