The state Supreme Judicial Court on Monday issued updated instructions that judges should give to jurors to help them assess the reliability of eyewitness testimony.
“The accuracy of an eyewitness identification is often the critical issue in a criminal case, the difference between a conviction and an acquittal,” wrote Chief Justice Ralph D. Gants in an opinion explaining the new instructions.
The opinion was issued in the case of Jeremy D. Gomes, who was convicted on charges that he slashed another man’s face with a boxcutter as the man sat in a vehicle in Pittsfield in September 2011.
Gomes appealed, arguing the trial judge erred in declining to provide jury instructions on eyewitness identification that his lawyer proposed, which were based largely on instructions recently adopted in New Jersey courts.
Gomes’s proposed instructions advised that human memory does not function like a video recording that a person can replay to recall what happened, a witness’s confidence level in making an identification does not always indicate accuracy, high levels of stress can reduce the likelihood of accuracy, information from other witnesses or outside sources can increase a witness’s confidence, and viewing the same person during multiple identification procedures can increase the risk of misidentification, Gants wrote.
In Monday’s ruling, the SJC upheld Gomes’s conviction on charges of mayhem and breaking and entering into a vehicle at night with the intent to commit a felony, finding the trial judge did not err in declining Gomes’s request, in part because his lawyer presented no expert witnesses to support the principles outlined in the proposed instructions.
However, Gants wrote, after reviewing the case along with an SJC study group report on eyewitness evidence that was completed in 2013, the high court has decided to issue a new template for judges to use when instructing jurors on eyewitness identification.
The provisional instructions are to be used immediately, but the SJC will solicit public comments before adopting an official model.
The SJC instructions include a warning that a witness’s expressed certainty may not indicate accuracy, especially when the witness did not express the same level of certainty when first making the identification.
The template also includes commentary on the complexity of recalling past events, the effect of stress on eyewitness identification, the length of time that elapsed between a crime and a person being identified, and issues associated with having a witness view a suspect multiple times during identification procedures.
In addition, the instructions allow jurors to consider whether witnesses were exposed to descriptions given by others, including police officers, which “may inflate the witness’s confidence in the identification.”
While judges in Massachusetts have advised jurors for decades on factors that may affect the accuracy of eyewitness identifications, the new instructions will “provide juries with more comprehensive guidance to evaluate and weigh” such testimony, Gants wrote.
Elizabeth A. Lunt, president of the Massachusetts Association of Criminal Defense Lawyers, said the ruling will help make jurors aware of scientific principles regarding eyewitness identifications. “This has been an issue for years and years,” Lunt said. “Jurors tend to believe eyewitness identification — ‘I’ll never forget that face’ ” — but researchers have highlighted the “difficulties people have making identifications, particularly under pressure.”
Jake Wark, a spokesman for Suffolk District Attorney Daniel F. Conley, said Suffolk County began taking steps years ago to ensure that eyewitness testimony is reliable. “We’re still digesting the decision and its provisional jury instructions, but we note that several of its recommendations have been in place for more than a decade in Boston and Suffolk County,’’ Wark wrote in an e-mail.
“Our policies for gathering and using accurate eyewitness identifications represent the gold standard,” he said. “Naturally, we’re always looking to make our evidence stronger, but eyewitness evidence is very familiar ground for police and prosecutors in Boston and Suffolk County.”
John R. Ellement of the Globe staff contributed to this report.