Saturday, October 27, 2007

One More Advance Paper on Visualization of Evidence and Inference

This paper happens to be mine. See Peter Tillers, Introduction: visualizing evidence and inference in legal settings Law, Probability and Risk Advance Access published on October 27, 2007. doi:10.1093/lpr/mgm006 (But the diagram that appears above is just for show; it does not appear in this paper.)

The above link will expire when the hard copy of the paper appears. If you don't have a subscription to the journal Law, Probability and Risk, your employer or your law library may have a group license.

The paper will be available in about 12 months via WESTLAW.

Finally, a draft of the paper (substantially the same as the final version) is available at SSRN. Here are a few extracts (sans footnotes) from an earlier draft of this short paper:

One reason I am interested in visualization of evidence and inference is that I suspect and hope that visualization of evidence and inference can make the logic of formal analytical methods such as Bayesianism more readily intelligible to so-called ordinary people – to people such as judges, jurors, law teachers, and law students, to people such as me.

I am interested in visualization for another reason: I also suspect that visualization may help to remedy or ameliorate certain cognitive limitations that afflict even very extraordinary people, even people with extensive training in logic and mathematics, for example.

These two conjectures of mine can be stated in the following deliberately-suggestive way: I suspect that visualization can make it possible for the extraordinary computational capacity of the ordinary brain to do a better job of taking advantage of whatever assistance explicit formal argument about evidence is capable of providing.

Whether some complexities and nuances of real-world evidence and inference in legal proceedings are beyond the limits of formal analysis is still an open question. But I have a theoretical prejudice that bears on the question of how complex inference should be managed and addressed: I suspect that the people who tend to believe that the solution to the problem of complexity is generally to wash out some details – I suspect that the people who think we need simple and simplifying heuristics are on the wrong track. I suspect that the devil is generally in the details and I suspect that washing out detail generally degrades rather than enhances inferential performance. If I am right about this, every effort should be made to develop tools that makes it possible for human decision makers to increase (rather than decrease) the number of evidential premises and evidential inferences that decision makers should try to consider when they address uncertain factual hypotheses.

Having said that attention to detail is important, I hasten to say that large amounts of detail do present a serious problem, particularly for the enterprise of developing and deploying formal argument about evidence and inference. I take it as gospel that assessment of the sort of evidence ordinarily found in real-world litigation (and in many other decision making situations) usually involves numerous evidential premises and numerous evidential inferences. An abundance of evidentiary and inferential detail presents a serious difficulty for the dream of explicit and comprehensive formal analysis of evidence in legal proceedings. As the number of items of evidence increases and as the number of pertinent possible inferences increases, the resources required to consider the inferences suggested or supported by a body of evidence increases exponentially. If a human actor who uses a formal method of analysis (such as Bayesianism) must allocate even a very small increment of time – one or two or three seconds, let us say – to each premise and to each step in a complex evidential argument, it becomes hard to imagine how a comprehensive explicit formal analysis of even a relatively small amount of evidence presented in a legal proceeding can ever be done by any real human being. Furthermore, the difficulty of just keeping in mind all of the necessary or important parts of an inferential argument (including its evidential premises) seems to increase enormously as the number of evidential premises and inferential links increases; the task is akin to trying to play n-dimensional chess blindfolded.


I am trying to lead graph theorists down a particular garden path. I have noticed (and I suspect that many other people have noticed) that when graph theorists try to explain themselves, they often use visual images as well as mathematical expressions and equations to describe their reasoning. I imagine (but I don’t really know) that some graph theorists would explain their use of visual images as an unfortunate but necessary concession to the intellectual limitations and weaknesses of dunces such as P. Tillers, who often have trouble following lengthy arguments made only with mathematical expressions. But I wonder if this sort of condescending (though entirely accurate) response offers backhanded support for the conjecture that visual images are sometimes excellent vehicles for getting ordinary human brains to work the way we want them to work – and the way we think that our brains, if properly assisted, can work.

Seek and Ye Shall Find ... Torts, Crimes & Sexual Misconduct

Tortious misconduct, criminal misconduct, and sexual misconduct are everywhere. This was always so. It is even more so today, in this age with its innumerable legal proscriptions and regulations, a large fraction of which are known (if at all) only to certain legal specialists in certain fields of law.

The Associated Press has looked -- for six months -- and it has found (so the AP proclaims) widespread sexual misconduct by secondary and and primary school teachers. See Martha Irvine & Rovert Tanner, Sexual Misconduct Plagues US Schools.

This "discovery" of sexual misconduct by teachers naturally invites the question: How real singular or extraordinary is the "clergy abuse scandal" -- whose "discovery" won a Pulitzer Prize for some Boston Globe reporters?

The authors of the AP article indirectly raise the question themselves:

The findings [of the AP investigation] draw obvious comparisons to sex abuse scandals in other institutions, among them the Roman Catholic Church. A review by America's Catholic bishops found that about 4,400 of 110,000 priests were accused of molesting minors from 1950 through 2002.

Clergy abuse is part of the national consciousness after a string of highly publicized cases. But until now, there's been little sense of the extent of educator abuse.

A quick reading of the AP article might suggest that there is no real comparison between the two scandals: the article reports that 2570 educators were sanctioned for sexual misconduct 2001-2005 and that 4,400 of 100,000 priests were accused of sexual misconduct from 1950 through 2002, but the article notes there are roughly "3 million public school teachers nationwide." However, there is a difference between a charge or accusation of abuse and an official finding of sexual misconduct. Moreover, the sanctions against teachers cover only a five year period, and not a fifty-two year period. (One might surmise that perhaps ca. 25,000 teachers were reported to have been "sanctioned" from 1950-2002.)

The AP article itself notes the following (thoroughly hyperbolic-sounding) claim:

One report mandated by Congress estimated that as many as 4.5 million students, out of roughly 50 million in American schools, are subject to sexual misconduct by an employee of a school sometime between kindergarten and 12th grade.
Well, there's a stunner for you!

In the next sentence, however, the AP article notes: "That figure [4.5 million] includes verbal harassment that's sexual in nature."

Where does this qualifier -- the estimate includes verbal abuse -- where does this qualifier leave us? If we (i) split the baby -- i.e., the estimated total number of incidents of abuse --, (ii) prune away "school employees" who are not teachers, and (iii) somewhat reduce the estimated number of abusers to take into account that some (indeterminate number of) abusers are repeat abusers, perhaps we end up with two million or so (one million?) teachers in American schools who are child sex abusers during, say, a ca. 12-year period. The number of actual incidents of sexual misconduct, one presumes (or, in a sense, hopes), exceeds the number of accusations of sexual misconduct (but one should not entertain this assumption lightly).

Even with all of these qualifications in mind, one might still have reason to speculate that the proportion of abusers among school teachers is substantially greater than among Catholic clergy.

Well now, that's an interesting bit of speculation! Suppose this speculative thought turns out to be true -- and a bit of research reveals that some serious scholars who have studied the question directly and systematically assert that it is true that school teachers are more prone to abuse children than Catholic clergy are.

If the rate of sexual predation by school teachers against minors is in fact higher than the (past or present) rate of such sexual predation by Catholic clergy, is it fair to think of the Catholic clergy as being riddled with sexual predators?

Let's go one step further: Is it possible that the incidence of sexual abuse of children by adults is much higher in the population "parents of minor children" than it is among either the Catholic clergy or school teachers? If this possibility turns out to be true, what are we to make of the "Catholic clergy abuse scandal"?

One more question: Does the American litigation system yield accurate pictures of the ailments that afflict our society? Or does it take decades of retrospection to figure out "what really happened" in our society at large? (My guess is that the latter guess is more true than the former.)

Do You Believe in Sociobiology and Law? -- Chapter 4; A Response to Jerry Fodor

See Simon Blackburn, (under byline Why Pigs Don't Have Wings), Letter, London Review of Books (Nov. 1, 2007).

Do You Believe in Sociobiology and Law? -- Chapter 3; "Immediate Deadly Intent" and Paul Ekman's System of Facial Coding

Ian Hacking, How Shall We Repaint the Kitchen?, London Review of Books (November 1, 2007) (reviewing Cognitive Variations: Reflections on the Unity and Diversity of the Human Mind by G.E.R. Lloyd):
Once the cognitive revolution wrought by Chomsky was under way, nurture came tumbling down. The present imperative to find genes for absolutely everything reinforces the imbalance. Evolutionary psychology now propounds imaginative explanations of things that we do as adaptations acquired in our prehistoric past, while Chomsky has become an old fogey, complaining that we do not know enough about the brain, or about early human beings and their environment, to speculate on evolutionary pressures. (I agree.) But the turn to innate cognitive structures as opposed to socially acquired habits owes more to him than anyone else.


... Now universal emotions have returned with a vengeance. Paul Ekman led the charge, in parallel to but independently of Chomsky’s cognitive revolution. After doing clinical work on emotions and the body, and a stint as a US army psychologist, he travelled to New Guinea to see for himself, and made observations opposite to those of his predecessors. His conclusions are much like Darwin’s. They are now being enormously bolstered by brain research. At least this much is known for sure: one of the oldest parts of the human brain, the amygdala, is activated by immediate fear, and that is a fact about nature, not nurture, for everyone on the planet.

This is not an academic issue. ... The War on Terror supports research to design computer programs based on Ekman’s Facial Action Coding System, which will pick out in passenger queues the faces of people planning to blow up planes; Ekman’s personal website lists a project aimed at detecting expressions of IDI – Immediate Deadly Intent. He also plans to process pixels in order to expose a demeanour that betrays ‘lies about the intent to commit a harmful act’. Very roughly speaking, much of the cognitive science community thinks this approach is right on, even if IDI is taking things too far. Some anthropologists think it is nuts, megalomaniac.

Nurture did not stay tumbled down for long. All sorts of pressing criticisms of nature began to emerge. The debate now infects every branch of the human sciences. Nature may still be winning, for the moment, almost everywhere, but much less is settled than one might have expected. ...

P. Tillers on Ekman:
If you look at me crossly -- animal-like, as it were --, I will infer hostile intent. I may even arrest and imprison you -- to prevent a deadly attack. And I have a facial chart in my hip pocket to back me up.
I must confess that this sort of stuff -- stuff like Paul Ekman's IDI, that is -- strikes me as absurd; it strikes me as not much better than phrenology. See P. Tillers, Unnatural Lie Detectors (Feb. 5, 2006). It would strike me as even more absurd (and frightening) to find that people in Homeland Security really take this sort of stuff seriously. (Rewrites, or updating, of 1984 and Brave New World seem to be called for -- this time with a narrative that emphasizes the dangers of government reliance on shoddy science.)

Thursday, October 25, 2007

Expert Testimony about Credibility, and the State of Legal Scholarship

I yield to no man or woman in my passion for "theory" and philosophical inquiry. Yet, I worry about the condition of legal scholarship in the U.S.

Question: What prompted the most recent wave of my unease?

Answer: I was frantically preparing for class and I discovered the interesting Texas case Schutz v. Texas, 957 S.W.2d 952 (Tex.Crim.App. 1997).

As I wrote in my class notes, the opinion of the Texas Court of Criminal Appeals in this case -- a case involving charges of aggravated sexual assault against a young child -- has "an elaborate but useful discussion ... of whether various types of expert evidence do or do not amount to prohibited opinion about the truthfulness of witnesses such as children. Cases in various states are surveyed. Court thinks that the prohibition in Rule 608(b) applies, in principle, to expert testimony about credibility or factors that affect the credibility or truthfulness of a witness. The issue is what forms of expert testimony amount to opinion about truthfulness vel non." I also discovered that the court had assembled, plainly after much labor, a comprehensive table (in an appendix) summarizing what forms of expert testimony affecting credibility and truthfulness are and are not admissible. I further found a simple but incisive concurring opinion and I also found a dissenting opinion that raised some excellent questions about the court's approach.

Well now -- I thought to myself -- this case is quite a find. The problem of sexual abuse of children is important. Texas is a big and populous state. The credibility of witnesses is almost always important in child abuse prosecutions. Experts or supposed experts are playing an increasingly important role in such criminal trials. And the question of the extent to which experts can give evidence that speaks to the believability, credibility, and truthfulness of witnesses who report being sexually abused is important. With these thoughts in mind, I did a LEXIS search for law journal articles about the Texas court's important and thoroughly-researched opinion in Schutz about this last question.

Question: What do you think I found?

Answer: Almost nothing.

I found only three brief references to Schutz in three law journal articles. Keep in mind that the Tex. Ct. Crim. App. decided Schutz and issued its opinion ten (10) years ago.

Something is wrong, isn't it?

N.B. Practicing lawyers do not think litigation and trials are unimportant. Judging by the growth of litigation departments in law firms during the last several decades, practicing lawyers (not to speak of judges) think litigation is perhaps more important than it ever was.

So what explains the paucity of academic commentary on cases such as Schutz? More important, what is the justification for this barren academic garden? (Note, the justification -- if any -- is not the importance of "theory." Good theorizing by legal academics can have very important "practical" implications. [Some people even believe that any theory worth its salt must have practical, or real-world, implications. I don't go that far. Still, the academic world should not be indifferent to "law in action.")

I shoot form the hip in this post. The reader will forgive me, I trust. I will return to this topic later.

Monday, October 22, 2007

Comparative Numbers

The following topics had the following number of GOOGLE news stories at ca. 3:30 p.m.:
World Series: 3,718
Fires in California: 2,816
Turkey-Iraq-Kurd Conflict: 2,588
Polish Election: 976

Sunday, October 21, 2007

The New Skype

Anne Applebaum, the author of Gulag: A History (Doubleday/Random House, 2003) [for which she won a Pulitzer Prize], has an interesting article in Slate on the role the (often miserable) past in the consciousness of Eastern Europeans. See Skype Dreams, Slate (October 15, 2007).

The Early Life of Korba the Dread

See the book review in the NYTimes of Simon Sebag Montefiore, Young Stalin (Knopf, 2007). Tagline: Stalin was no dummy. He was even a poet. But he was definitely a thug.

A Pean to Vasily Grossman's Life and Fate

See the (slightly belated) book review in 29 London Review of Books No. 20 (October 18, 2007). The reviewer is John Lanchester. The title of the review: "Good Day, Comrade Shtrum." (The caller is the dread Korba, Iosif Vissarionovich, Stalin.)

"Do You Believe in Sociobiology and Law?" - Chapter II

If so (and even if you don't), see the lovely and incisive essay: Jerry Fodor, Why Pigs Don't Have Wings, 29 London Review of Books No. 20 (October 18, 2007).