(CN) — A memory expert testifying Thursday in Georgia's hot car death trial said it was "absolutely" possible defendant Justin Ross Harris did not intentionally leave his toddler in a hot SUV to die in June 2014, but was instead distracted and simply forgot to drop his son off at preschool.
Dr. Gene Brewer explained that "prospective memory failures" can be caused by internal and external factors.
Brewer said that a phone call would be an external distraction while fatigue and stress would qualify as internal distractions.
Harris, who faces murder charges, sent an email expressing his dissatisfaction with his job performance the night before 22-month-old Cooper Harris's death.
Cooper woke Harris early the next morning, which Brewer said could have caused Harris to be fatigued.
Brewer faced a tough cross-examination by lead prosecutor Chuck Boring, who grilled him about the extent of his knowledge of the case.
Boring brought up Brewer's assertion that there was nothing unique about Harris's case compared to other incidents of parents leaving their children in cars.
Boring pointed out the fact that Harris had been sexting a number of women that day, which didn't happen in other cases.
No one who saw Harris that day said he looked tired, Boring said.
"You didn't talk to these witnesses," Boring said. "You just had what the defense gave you."
Brewer responded that he was also given information by prosecutors.
Lead defense attorney Maddox Kilgore then re-examined Brewer, asking him if he remembered everything provided to him in the case. Brewer said no.
Brewer was asked if Harris was smart, to which he replied yes. Kilgore followed up by asking if smart people are immune to memory failures.
"That makes them in no way immune to forgetting," he said. "The very best of us are not immune from having failures in anything that we do."
Brewer said it is possible to have a memory failure without distractions.
Boring closed out Brewer's testimony by asking him if people can have self-inflicted memory lapses and pointing out that Harris had stayed up late the night before Cooper's death sexting women.
"He didn't choose to be tired," Brewer said. "He didn't choose to be negligent."
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