Behavioral genetic methodologies from twin and adoption studies through DNA analysis will be described and applied to address longstanding questions about the origins of individual differences in behavioral traits.
8D: Behavioral Genetics, the Law and Personal Responsibility, Part II
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En provenance du cours de University of Minnesota
Introduction to Human Behavioral Genetics
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8
It is hard to believe we are already to the 8th and final week of the course. This unit begins with an overall summary of human behavioral genetic research organized around four general findings, or ‘laws’ of behavioral genetic research. We will then consider, I suppose more accurate speculate about, the application of behavioral genetic research in the field of individualized or genomic medicine and the implications of behavioral genetic research for personal responsibility. This week’s lectures will also include an interview with Professor Irving Gottesman, a pioneer in the field who undertook pioneering behavioral genetic research on schizophrenia and personality.
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Matt McGueRegents Professor
Psychology
This is the the module D in unit 8, and hopefully,
at, by this time, you've had a chance to look at a little bit of that video on,
from the National Geographic, on the so called RAGE gene.
And so I want to come back to the case of Barry, Bradley, I'm sorry,
Bradley Waldroup.
And one of the things that I think is interesting here is how popular
media accounts of genetics and behavior influences
our thinking about the extent to which people are responsible for their behavior.
In this case, legally responsible when we're talking about Bradley Waldroup, but
a little bit later, actually in this module here, how we are responsible for
medical issues or medical taking care of ourselves.
So just recall in the case of Bradley Waldroup.
There's really little doubt that he had killed his ex-wife's friend.
And that he had stabbed his ex-wife.
And what's more, and this is important aspect of,
of this particular sad case is that it was premeditated.
He had come to his wife's home with a gun.
He had told people,
before going to his wife, ex-wife's home that his wife was going to die.
Mr. Waldroup was found to carry a variant in the MAO-A gene.
We talked about this last module.
The MAO-A gene had been previously implicated in aggression in a,
in a famous study on a Dutch pedigree.
He didn't carry the genetic variant that was found in that Dutch study.
He, he, which is a very, very rare variant,
he carried a different variant in the promoter region of the gene.
Such that, people who carried the variant that he had
actually produced less of this particular enzyme.
And because they produce less of the enzyme, they have more serotonin inval,
available in the neuro neuro clip.
And then finally Mr. Waldroup had had a history of being maltreated as a child.
That particular combination of having an inherited, this parti,
the genetic variant in the MAO-A gene, the so called RAGE gene.
Or warrior gene, and a history of, of maltreatment actually
is thought to increase an individual's chance of being violent.
And a psychiatrist at Vanderbilt University had heard about
the Waldroup case, a psychiatrist named William Bernet, and
he ended up being an expert, a witness at Mr. Waldroup's trial.
Now usually, and I, I've said this before, it there are a lot of cases where
genetic evidence has been introduced into the legal proceeding that for
behavioral for some behavioral characteristic.
But when it has been introduced,
usually it's introduced in the sentencing phase of the trial.
Not in the initial phase where guilt versus innocence is being decided.
But rather when thus, when that has, when someone has been judged to be guilty and
the judge's trying to determine this, the appropriate sentence.
And, and then genetics might be introduced at that phase of the trial because it
might mitigate or the, the actual sentence an individual receives.
In this case, for some reason the judge allowed the psychiatrist
to testify during the trial phase of Mr.Waldroup's trial.
And what he, I won't read the quote here, but what he reported was that given Mr.
Waldroup's genetic background, he had this MAO-A variant, and
his history of maltreatment.
It made him prone to engaging in violence.
It reduced his responsibility for his criminal behavior.
Now since Mr. Walter didn't have the variant that the,
that was observed in that Dutch family.
He had this other variant.
What the psychiatrist was referring to
was the study we talked about in the last module.
And that was the study of gene environment interaction.
In this case I plotted it a little bit differently, or
I took a little, a different figure from the, from the paper by Caspi, et al.
But again, this is the variant that Mr.
Waldroup had, he had the low MAO-A variant.
And recall again that this is a variant that maps to the X chromosome.
So for a male they only have one copy of this variant.
So his one copy was a low activity version of the variant.
And he had a history of maltreatment, so his,
his profile here is in this particular area here.
Now, a couple things to look at here are, in,
in thinking about how this is relevant to his trial.
First of all, in this particular study, they did in, indeed find that individuals
with Mr. Waldroup's background had an increased rate of violence.
In this case, conviction of a violent crime.
But clearly, the majority of individuals with his particular background
were not convicted of a violent crime.
It this maxes out at about 30%.
So the first thing maybe to note here even though this was the evidence introduced
into his trial is that the majority of men with this background don't
get convicted of a violent crime.
The other thing to think about here, is that, the relevance of ma the MAO-A
to violence is thought to be primarily relevant to impulsive violence,
not the type of premeditated violence Mr. Waldroup engaged in.
The type of violence that was seen in that type of pedigree.
Regardless, the, this testimony was introduced into the trial.
The jurors then heard that and needed to decide Mr. Waldroup's guilt, and
in the end what they decided to do is to convict him of a lesser crime,
rather than of a crime that could, in the US, could be a capital offense.
Could lead to a death penalty judgment.
In their case they convicted him of a much lesser crime.
That he had engaged in manslaughter.
When the verdict came out it was rather controversial in,
in Tennessee where this all happened.
And reporters then, interviewed some of the jurors and asked them,
well why did you why did you convict him of this much lesser crime?
And here's one quote from one juror, on the Waldroup case.
Why he, and I think it's kind of informative to, how,
the media representations of genetic findings begin to affect
how we think abouts individual's responsibility for their behavior.
In this case the juror said, listen Mr.
Waldroup had a bad gene and a bad gene is a bad gene.
And presumably it's something he did not have control of.
And because he did not have control of, he clearly did the crime.
But beca, because he, did not have control of it, this juror felt, and obviously, I
guess, the other jurors as well, that they shouldn't contric, convict him of murder.
But rather, they should convict him of the lesser crime of manslaughter.
That's sort of thinking is what has been called genetic essentialism.
That what genetics does is that is establishes
our essential psychological nature.
And that genetics is immutable, it's not changeable and
it determines what we are in the way we behave.
We cannot control it.
So presumably the reason that the jurors treated Mr. Waldroup's crime
this way is they were thinking along these lines, along these essentialist lines.
Now I want to bring this back.
Because really genetics behavior in, in, in the courtroom.
There aren't a lot of examples like Mr. Waldroup.
But where there are more examples where genetic essentialism
thinking might play a role is when we get into medical decision making.
And how we think about responsibility in that context.
I think when we think about genetics, behavior and disease, it's important and,
and, and responsibility, it's important distinguish,
to distinguish between an individual's responsibility for developing a disease
versus an individual's responsibility once they develop a disease,.
To manage our disease, and
I think it's important to distinguish between those because we might have
different notions of responsibility given what we've learned in behavioral genetics.
Take for example something that we talked about much earlier in the course
phenylketonuria.
It would be hard to say that a person who has phenylketonuria is responsible for
having that disease.
Right? It is a completely chance event.
They inherited the, the two recessive alleles.
They had no control over that.
They had no responsibility for developing that disease.
But once they've developed the disease, to what extent.
Do they have some responsibility for maintaining a diet low in phenylalanine.
In the case of phenylketonuria,
maybe one day a young child we could say that they have limited responsibility.
But as they get older and they learn about the disease, and
the consequences of their diet.
I think it's reasonable to,
to conclude that they now begin to share some responsibility for
managing the disease, for the treatment of the disease, for their lifestyle.
Even though they have no responsibility for having the disease.
[SOUND] That notion that we are not responsible for genetically
inherited diseases is actually been a part of a campaign in the mental health,
health area to try to destigmatize mental health, mental illness.
And this is actually an ad campaign, part of an ad campaign
by the National Alliance for Research on Schizophrenia and Depression.
And if you read through the campaign, this is just a, a part of the ad, what,
what you see is that they're arguing is that what used to be stigmatizing,
having depression or having schizophrenia, they're arguing here that it shouldn't
any longer by stigmatizing because the individual who has these diseases.
Doesn't really have any responsibility for developing the disease.
It's something that they inherited.
Has the introduction of genetic explanation though been successful in
destigmatizing mental illness.
Has campaigns like this help.
Well, the track record here is a little bit mixed if we look at the evidence.
What have genetic explanations done to our notion of responsibility for
mental health illness?
On a positive note if you look at both experiments where where people
are randomly assigned to a, a control group and some sort of intervention group.
In the intervention group would read a, a vignette,
a story about a, a genetic explanation, let's say for depression.
And then they're asked later in the, in the control group does,
doesn't read that genetic explanation.
And they're, then they're asked later to what extent the individuals with
depression bear responsibility for having this disorder.
If you look at experiments, as well as observational studies, we just go out and
you correlate the extent to which people view
depression to have a genetic component versus the extent to
which they think the people with depression are responsible for having it.
Both those types of studies indicate that.
Greater genetic ex,
explanations lead to reduce blame of individuals for having the disorder.
The effects are not gigantic, but they're definitely there.
So that's the positive of it all.
That's what the, the, the previous ad was trying to do.
To try to explain the people that people aren't responsible for
developing these disorders.
On a negative note though, perhaps unexpectedly, is that genetic
explanations, even though they've reduced their attribution of responsibility
of the individuals who suffer this, they increase the notion that we think
individuals with mental illness, serious mental illness are dangerous individuals.
And this gets back to this essentialist thinking,
is that because they've inherited the disease maybe they're not responsible for
that, but they can't control their behavior.
They're much more dangerous to deal with.
What about this second aspect of responsibility,
our responsibility to act on our illness once we know we have it.
And I've already talked about this example from Francis Collins from the Shattuck
lecture, in the 1990s that he gave where he talked about this fictitious case,
John, who was given a genetic profile where associated with higher risk for
some disorders, lower risk behavioral disorders.
And the hope it was at that time and, and probably still is, is that okay,
John is not responsible for inheriting these various genetic variance.
But once john is given the information that he carries the variance
as well as information about how he can address his risk.
Then he will act in a responsible way.
And what Collins foresaw, and we talked a little bit about this before
a couple of modules ago, is that once, and this is a quote from the article,
once John gets his information, he's going to change his lifestyle.
He'll lose weight, he'll stop smoking, he'll eat better, he'll exercise.
And we talked a little bit about, well those are hard things to affect, but
the question I want to try to answer here is, well does research support this?
That is, when people are given genetic information information that a,
a disorder is genetically influenced, does that increase their responsibility for
acting or their sense of responsibility for acting or
taking an active role in their treatment.
Again the research is a little bit mixed, genetic explanations for the etiology of
mental illness, I have been consistently, it's very consistent in the literature,
it's not a large literature, but very consistently has shown that when people
are told this, either about other people's illnesses, or about their own.
That, that increases their pessimism that either other people or
they themselves can change.
If somebody for example is told that genetic factors influenced your risk for
obesity.
It reduces the likelihood that you think
that you could change your behavior to reduce your risk for obesity.
It also generally reduces our confidence in psychosocial,
quote on quote, talk therapies.
What it does is it increases confidence in biological interventions,
pharmacological interventions.
So telling somebody, and, and again, there's a little research literature there
and you can follow the citation that given at the bottom of the slide there.
Telling somebody that genetics influences their risk of
obesity based on what we know today.
Probably has the following effects.
It, it, it probably reduces the, their perception that they can actually
do something behaviorally to reduce their chance of obesity, and
it probably increases their motivation to try to find some biological,
pharmacological drug intervention.
One of the reasons I like going through this here is I think there,
there are two reasons.
One is that our perceptions are the way behavioral genetic research
gets represented in the broader media affects the way we think about
our responsibility for our behavior.
And I think there's a complex linkage there that you don't often see
conveyed in the popular media accounts.
I think we all need to be a little more sophisticated about the way we think about
genetics and personal responsibility.
The second thing I wanted to highlight by going through this here is that, and it,
we've talked a little bit about this before, is that because of
the Human Genome Project and because of advances in the technology of genetics,
more and more we're going to be faced with dealing with genetic data.
10 years ago or 15 or 20 years ago,
Francis Collins thought about the way we were going to deal with that genetic data.
We now know that we don't quite deal with it in that way.
Sometimes, it might motivate it, to do certain things,
other times it might demotivate us.
We need much more research about how people are going to deal with the genetic
information that their doctors and the medical system is going to be giving them.
And that's an area of genetic counseling.
[SOUND] So next time, in the next module what's going to be a special treat for
me going to have an interview with really one of the giants,
one of the founders of the field of behavioral genetics.
Hope to see you then.
Thanks.
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