A Better and More Useful Jury Instruction on Witness Memory and Demeanor Reflecting the Teachings of
Judge Mark Bennett writes that most criminal cases turn on defense counsel’s ability to successfully attack the demeanor and memory of witnesses. Most pattern jury instructions about witness credibility, however, explain nothing about how a person’s memory works and nothing about how fallible memories actually are. Similarly, pattern jury instructions on demeanor seldom do more than ask jurors to speculate about a witness’s demeanor by instructing them to merely observe “the manner of the witness” while testifying. Yet cognitive psychological studies have provided major insights into witness memory and demeanor. The resulting cognitive psychological principles that are now widely accepted as the gold standard about witness memory and demeanor are often contrary to what jurors intuitively, but wrongly, believe.