Heuristics of Blame
Jurors will attribute greater causal significance to acts considered more morally blameworthy, even when the moral issue is irrelevant to the causation.
Research by Mark Alicke (1992) found, for example, that participants more often identified a driver's speeding as the cause of an accident and held the driver more responsible for the accident when the driver was rushing home to hide a vial of cocaine from his parents versus a narrative in which she was rushing home to hide an anniversary present he had bought for them.
Cerebral palsy may have many causes, one of which is anoxia during the time of labor and delivery. In mock juror research I conducted years ago, I found that participants did not find the doctor at fault (medical negligence + causation) when only told that he went back to sleep rather than going to the hospital.
Participants did find the doctor at fault when they learned that there had been three other incidents of sloppy care of the patient earlier in her pregnancy- such as screwing up appointment times and not responding to an earlier bleeding incident in a timely way, even though those incidents had nothing to do with the alleged causal event.
Fundamental Attribution Error
Lee Ross and Richard Nisbett, in their book The Person and the Situation (1991), explain that people tend to attribute the behavior of others to their personality traits or dispositions rather than to situational constraints, even when the circumstances explain behavior quite adequately.
Jurors will tend to assume that "accidents" do not happen unless someone was negligent.
Jurors will tend to judge a person's character and attitude (intent) and create a case narrative to link character and behavior even when the linkage is not relevant or justified.
Jurors will tend to assume a person of bad character will behave badly; a person of good character will behave well. Jurors will tend to attribute causation (along with fault and responsibility) on the basis of perceived personal dispositions to decide that the plaintiff or the defendant acted as he did because "he's that kind of guy."
Both "handsome is as handsome does," and its reverse are true.
The "halo effect" bias occurs in medical malpractice cases in which doctors are given the benefit of the doubt from the get go.
The "demon effect" would be the opposite. Right now, a hedge fund manager might be a challenge as a client.
Research has also shown similar undeserved attributions in a variety of other dimensions, for example, that attractive people are judged to be more intelligent, or that obese people are judged to have poor self control.
People in the "in-group" are judged to be more trustworthy than people in the "out-group." In the news recently, the same politician that claimed his Christian subgroup's freedom of religion was being infringed upon in the next sentence claimed that Muslims' rights must be limited.
Generally speaking, the law speaks to many of these halo and demon biases.
For example, because of their obvious prejudicial impact in criminal cases, a defendant's past crimes are typically not admitted into evidence.
Likewise in medical negligence cases, the fact that a defendant doctor has previously been sued is typically not admitted into evidence.
However, we now live in an age when irrelevant contextual information about plaintiffs and defendants are just a mouse click away. A judge's instruction to not research a subject case on the Internet has a high probability of being ignored by at least some on the jury panel, and the potential for prejudice associated with inadmissible evidence, and tangential information generally, has never been greater.