Where do you think Pinker’s analysis went wrong, if it did go wrong?
Pinker is not distinguishing between members of the audience and members of the jury.
For the audience, Pinker is basically correct. The prior probability that the defendant committed the acts charged is fairly high, given the evidence available to the audience that the government charged the defendant with a crime.
But the jury is given an instruction by the judge that the defendant is entitled to a presumption of innocence that must be overcome by the government. In Bayesian terms the judge means, “For social reasons not directly related to evidence, set your prior probability that the defendant is guilty as close to zero as is logically possible for you. If the probability of guilt is sufficiently high after hearing all the evidence, then you may vote to convict.”
If a rationalist juror ignores this instruction and acts like a rational audience member, then the juror is doing wrong, as Pinker notes. But ignoring the judge’s instruction is wrong, and Pinker is not presenting a great insight by essentially highlighting this point.
There shouldn’t be any such distinction. The audience (I assume you mean the courtroom audience) should reason the exact same way the jury does.
The prosecution is required to make an explicit presentation of the evidence for guilt, so that the mere fact that charges were brought is screened off. As a consequence, failure to present a convincing explicit case is strong evidence of innocence; prosecutors have no incentive to hide evidence of guilt! Hence any juror or audience member who reasons “the prosecution’s case as presented is weak, but the defendant has a high likelihood of guilt just because they suspect him” is almost certainly committing a Bayesian error. (Indeed, this is how information cascades are formed.)
See Argument Screens Off Authority: once in the courtroom, prosecutors have to present their arguments, which renders their “authority” worthless.
I wrote this long post defending my point, and about halfway through, I realize it was mostly wrong. I think the screening off point is probably a better description of what’s wrong with Pinker’s analysis. Specifically, the higher rate of crime among blacks should be screened off from consideration by the fact that this particular black defendant was charged.
To elaborate on my earlier point, the presumption of innocence also serves to remind the juror that the propensity of the population to commit crimes is screened off by the fact that this particular person went through the arrest and prosecution screening processes in order to arrive in the position of defendant. In other words, a rationalist should not use less evidence to convict black defendants than required for white defendants because this is double counting the crime rate of blacks.
Pinker is not distinguishing between members of the audience and members of the jury.
For the audience, Pinker is basically correct. The prior probability that the defendant committed the acts charged is fairly high, given the evidence available to the audience that the government charged the defendant with a crime.
But the jury is given an instruction by the judge that the defendant is entitled to a presumption of innocence that must be overcome by the government. In Bayesian terms the judge means, “For social reasons not directly related to evidence, set your prior probability that the defendant is guilty as close to zero as is logically possible for you. If the probability of guilt is sufficiently high after hearing all the evidence, then you may vote to convict.”
If a rationalist juror ignores this instruction and acts like a rational audience member, then the juror is doing wrong, as Pinker notes. But ignoring the judge’s instruction is wrong, and Pinker is not presenting a great insight by essentially highlighting this point.
There shouldn’t be any such distinction. The audience (I assume you mean the courtroom audience) should reason the exact same way the jury does.
The prosecution is required to make an explicit presentation of the evidence for guilt, so that the mere fact that charges were brought is screened off. As a consequence, failure to present a convincing explicit case is strong evidence of innocence; prosecutors have no incentive to hide evidence of guilt! Hence any juror or audience member who reasons “the prosecution’s case as presented is weak, but the defendant has a high likelihood of guilt just because they suspect him” is almost certainly committing a Bayesian error. (Indeed, this is how information cascades are formed.)
See Argument Screens Off Authority: once in the courtroom, prosecutors have to present their arguments, which renders their “authority” worthless.
I wrote this long post defending my point, and about halfway through, I realize it was mostly wrong. I think the screening off point is probably a better description of what’s wrong with Pinker’s analysis. Specifically, the higher rate of crime among blacks should be screened off from consideration by the fact that this particular black defendant was charged.
To elaborate on my earlier point, the presumption of innocence also serves to remind the juror that the propensity of the population to commit crimes is screened off by the fact that this particular person went through the arrest and prosecution screening processes in order to arrive in the position of defendant. In other words, a rationalist should not use less evidence to convict black defendants than required for white defendants because this is double counting the crime rate of blacks.