I was only helping the professor verify the statistical portions of his paper, and general review of the rest of it before he published. That study helped push me solidly toward the camp of “the death penalty is inappropriate, at least for all but the most obvious, clear, unmistakable cases.”
We’ve had too many people executed and then exonerated, and we’ll never know how many additional executed were innocent but never exonerated. Many exonerated innocents originally confessed to their crime.
More detail on the study just for fun:
We had a plant also taking the test in the same room as them. The plant was supposed to once ask the other person for an answer, and a second time clearly be looking at their paper such that they could notice. If they actually gave the other person an answer, they fell into the smaller category of “actually cheated” and we still accused them to see what would happen, how many guilty people would confess vs. hide it.
I can’t recall if the different between innocents and guilty confessing was statistically different, but it wasn’t far different.
Following the test, the proctor would take their tests, then come back and harrumph and separate them. We’d explain to the subject that it’s clear they cheated, because the two of them had different tests but selected the same answers, and the other person was correct whereas the subject wasn’t, so it’s clear you took answers from them. Then we started in on, “Listen we’re just here to get the data, we don’t want to deal with reporting people either. So just tell us you cheated and we’ll throw away your results, you’ll still get the class credit and we won’t have to report you. Deal?”
We knew the results weren’t perfectly analogous, but it was enlightening. And definitely I can see that relative to 20 years in prison, 5 years is “basically no consequence” when the police say they have you dead to rights, and staying silent only makes their jobs harder and the judge will be annoyed. But we can get you the minimum sentence if you help speed this up. (NOTE: The police do not decide sentencing, but are allowed to say they do.)