Tests show synagogue mass killer Robert Bowers has a high IQ but low processing speed that could indicate schizophrenia, according to a defense expert.
Testifying Monday in Bowers’ federal death penalty trial, retired Brigham Young University neuropsychologist Erin Bigler said he reviewed tests done by other experts showing the defendant’s IQ is in the top 10%.
But his processing speed was only in the 18th percentile, Bigler said.
That, he said, indicates that his brain “isn’t working quite the way it should” and could suggest schizophrenia.
No brain tests or imaging scans can be used to determine schizophrenia, a medical diagnosis.
So experts instead look for “associations” that could indicate the disorder. Bigler said slow processing speed is one of those associations in a subset of subjects.
Bigler also said that tests showed Bowers has memory problems. He remembers words well but not faces, Bigler said, indicating brain dysfunction. Other tests, he said, indicate that Bowers has “executive function” abnormalities and has trouble processing intonation in speech.
Bigler’s testimony came in the second week of the eligibility phase of the trial as part of a defense effort to convince the jury that the convicted shooter was mentally impaired and shouldn’t be eligible for execution.
The lawyers have presented various experts to bolster their contention that Bowers suffers from schizophrenia and other brain abnormalities.
Bigler was one of those experts. He didn’t examine the defendant but looked at the results of EEG, PET and MRI scans of his brain as well as cognitive test results, all at the request of the defense.
He acknowledged that the lawyers told him that schizophrenia was the “working diagnosis” for the defendant’s mental state.
U.S. Attorney Eric Olshan pounced on that in cross-examination, suggesting that Bigler had been influenced by confirmation bias since the scans and tests could indicate any number of mental conditions besides schizophrenia.
Bigler said he was aware of the dangers of confirmation bias but, like any good researcher, guarded against it.
Olshan cut to the core of the case early on by asking Bigler if he was testifying that Bowers was incapable of intent in murdering people.
“That’s not my role in this case,” Bigler said. “I’ve not been asked to make any opinion as to that.”
Olshan also asked Bigler if the results of the tests and scans could be associated with other brain conditions. Bigler said yes.
He also acknowledged under questioning that Bowers’ working memory is in the 97th percentile and that his processing speed is within the normal range.
As to Bowers’ executive function skills, Olshan asked if carefully planning an attack over months “would reflect” on that ability.
“That is part of executive function, that is correct,” Bigler said.
The jury last month convicted Bowers, 50, of slaughtering 11 worshippers from three congregations at the Tree of Life synagogue building on Oct. 27, 2018, in the worst attack on Jews in American history.
The next step is for the jury to determine if he is eligible for the death penalty. To do that, prosecutors have to first prove intent. They also have to convince the jury that at least one of four “aggravating” factors was present: that the shooter tried to kill others in the building; that he planned the crime; that the victims were vulnerable; or that he killed multiple people.
The defense team has focused almost entirely on intent, saying Bowers wasn’t able to form that intent because of brain impairments — including schizophrenia and epilepsy.
To try to prove that, the lawyers have presented experts to try to show that he suffers from brain dysfunction.
If the jury decides that Bowers is eligible for death, the jurors will move to the final phase of determining his sentence: life in prison or execution in the federal death chamber in Indiana.
That phase will focus largely on victim-impact statements from the prosecution and mitigating evidence about Bowers’ life from the defense.
Court will not be in session on July 4, and testimony will resume Wednesday.
This story is part of ongoing coverage of the Pittsburgh synagogue shooting trial by the Pittsburgh Jewish Chronicle and the Pittsburgh Union Progress in a collaboration supported by funding from the Pittsburgh Media Partnership.