Hasn’t it seemed odd that as the graphic details in the Boston Marathon Bombing trial became more prominent in the press, public support for giving Dzhokhar Tsarnaev the death penalty has declined? Does this mean anything? The answer may lie in the fact that Judge George O’Toole is making mental health counseling services available for the jurors, but not for the poll respondents.

One of the criticisms Neil Postman made of public opinion polling in Amusing Ourselves to Death was that pollsters routinely ask us questions about topics we know little about. That may be the case here. Bostonians all suffered through the trauma of the bombings and the aftermath and many of us follow daily updates from the trial. But only the jurors have seen all the evidence and are hearing all the arguments of the prosecution and defense. They’ve assessed the witnesses and observed all the exhibits, many of them graphic videos, photos, and testimony of suffering. They’ve no doubt pondered more than we have the photograph of Tsarnaev standing behind the Richards family moments before he murdered their eight year old son. They’ve assessed Sister Helen Prejean’s testimony that Tsarnaev expressed remorse about the suffering of his victims, and they’ve heard about the unpleasant prospect of a life in prison.

The four recent polls I’ve seen were from WBUR in March, WBUR in April, Suffolk University in April, and the Boston Globe in April. In the March WBUR poll of Boston area residents, 38% favored the death penalty and 49% supported life in prison for Tsarnaev. When WBUR polled area residents again in April, those favoring death had dropped to 31% and favoring life in prison rose to 58%. Suffolk’s statewide poll of registered voters was consistent, 31%-58%. The Boston Globe survey of registered voters had it 19% - 63%.

In the Globe story accompanying the poll experts sought to explain what might have produced the oddly anomalous survey results. Professor Daniel S. Medwed of Northeastern University School of Law offered that it may have been that the appeal of Bill and Denise Richards, the parents of Martin, to spare Tsarnaev’s life had an impact. Or perhaps it is harder to favor the execution of a real person than to favor the death penalty generally, or that life in prison would be worse and death would turn Tsarnaev into a martyr. Attorney David Hoose thought the defendant’s youth might play a role, or the cost of the death penalty process.

Could any of the factors identified by Professor Medwed and Attorney Hoose have influenced the public? We don’t know. None of the polls asked more than two questions about the death penalty. Once the headline question was asked, it was time to move on.

It’s obviously not possible to get a representative sample of the only population that has full information of the evidence – the jurors themselves. So polling doesn’t tell us anything there. Recent headlines offered an unexpected result – as the ghastly evidence against Tsarnaev mounted, support for executing him dropped. But polling offered no explanation.

So what have we polls taught us here?