WEBVTT
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Imagine someone who has spent most of his life behaving responsibly,
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then suffers a serious head injury. Months later, his family
3
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notices something disturbing. He's impulsive. His temper is worse. He
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00:00:11.949 --> 00:00:16.149
takes risks. Could the injury have played a role? Well,
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forensic psychologists increasingly encounter questions like this because the brain systems,
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especially the prefrontal cortex, involved in judgment, emotional regulation, and
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00:00:24.500 --> 00:00:27.899
impulse can be disrupted by a TBI, traumatic brain injury.
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It's located toward the front of the brain. The prefrontal
9
00:00:31.309 --> 00:00:36.329
cortex contributes to executive functions such as planning, anticipating consequences,
10
00:00:36.390 --> 00:00:43.859
inhibiting inappropriate behaviors, and regulating behavior. Damage affecting these systems
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00:00:43.920 --> 00:00:46.700
doesn't necessarily eliminate a person's understanding of right or wrong,
12
00:00:46.719 --> 00:00:49.340
but it can make controlling behavior more difficult. One of
13
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neuroscience's most famous examples is Phineas Gage. Remember him? Gage
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00:00:53.840 --> 00:00:56.469
was a railroad worker when an iron tamping rod passed
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00:00:56.490 --> 00:00:59.390
through his skull, severely damaged portions of his frontal brain.
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00:00:59.530 --> 00:01:02.729
He did survive, but his accounts suggest that aspects of
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his personality and behavior changed afterward. Now, Gage wasn't transformed
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into a murderer, and that's important. His behavior did change
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and kind of went back to normal towards the end.
20
00:01:13.650 --> 00:01:16.420
His case demonstrated something more fundamental, though. Changes to the
21
00:01:16.450 --> 00:01:21.109
brain can produce changes in behavior and personality. Modern TBI
22
00:01:21.170 --> 00:01:26.310
injuries can occur through automobile accidents, falls, sports injuries, assaults.
23
00:01:26.810 --> 00:01:29.730
Depending on the location and severity of the injury, consequences
24
00:01:29.769 --> 00:01:35.109
may include difficulties with attention, memory, emotional regulation, judgment. But
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this creates a dangerous temptation. If brain injury is associated
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with aggression or impulsivity, can we conclude that the injury caused?
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So we're looking at two different things, association and cause.
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And usually, no. Millions of people experience TBIs without committing
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serious crimes. Criminal behavior is rarely explained by a single variable.
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Substance use, developmental experiences, personality characteristics, social environment. This distinction
31
00:02:03.280 --> 00:02:07.920
becomes especially important in court. A forensic psychologist or neuropsychologist
32
00:02:07.969 --> 00:02:11.509
may evaluate whether a defendant has cognitive impairment, whether that
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00:02:11.569 --> 00:02:15.349
impairment is consistent with documented neurological injury, and how those
34
00:02:15.389 --> 00:02:20.039
limitations could potentially affect behavior. But finding an abnormality on
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a brain scan doesn't automatically answer the legal question. A
36
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defendant could have significant frontal lobe damage and still understand
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that an action was illegal. Another defendant might have cognitive
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deficits that affect planning or impulse control without meeting the
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jurisdiction's legal standard for insanity. Brain injury may also become
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relevant during sentencing. Attorneys sometimes introduce neurological evidence as mitigation,
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arguing that impaired brain functioning helps explain aspects of the
42
00:02:47.550 --> 00:02:51.960
defendant's behavior. That leaves forensic psychology with a difficult question.
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How much should biology matter when determining responsibility? The brain
44
00:02:56.699 --> 00:03:00.689
isn't separate from behavior. Every decision, emotion, and impulse ultimately
45
00:03:00.750 --> 00:03:05.280
involves neural processes. Yet explaining isn't the same as excusing it.
46
00:03:05.949 --> 00:03:08.090
The challenge for forensic psych is to determine what the
47
00:03:08.129 --> 00:03:12.009
evidence actually supports without assuming that a damaged brain automatically
48
00:03:12.069 --> 00:03:13.210
creates a criminal one.
1
00:00:01.480 --> 00:00:04.519
Imagine someone who has spent most of his life behaving responsibly,
2
00:00:04.740 --> 00:00:08.500
then suffers a serious head injury. Months later, his family
3
00:00:08.580 --> 00:00:11.900
notices something disturbing. He's impulsive. His temper is worse. He
4
00:00:11.949 --> 00:00:16.149
takes risks. Could the injury have played a role? Well,
5
00:00:16.170 --> 00:00:20.489
forensic psychologists increasingly encounter questions like this because the brain systems,
6
00:00:20.550 --> 00:00:24.480
especially the prefrontal cortex, involved in judgment, emotional regulation, and
7
00:00:24.500 --> 00:00:27.899
impulse can be disrupted by a TBI, traumatic brain injury.
8
00:00:29.050 --> 00:00:31.269
It's located toward the front of the brain. The prefrontal
9
00:00:31.309 --> 00:00:36.329
cortex contributes to executive functions such as planning, anticipating consequences,
10
00:00:36.390 --> 00:00:43.859
inhibiting inappropriate behaviors, and regulating behavior. Damage affecting these systems
11
00:00:43.920 --> 00:00:46.700
doesn't necessarily eliminate a person's understanding of right or wrong,
12
00:00:46.719 --> 00:00:49.340
but it can make controlling behavior more difficult. One of
13
00:00:49.380 --> 00:00:53.829
neuroscience's most famous examples is Phineas Gage. Remember him? Gage
14
00:00:53.840 --> 00:00:56.469
was a railroad worker when an iron tamping rod passed
15
00:00:56.490 --> 00:00:59.390
through his skull, severely damaged portions of his frontal brain.
16
00:00:59.530 --> 00:01:02.729
He did survive, but his accounts suggest that aspects of
17
00:01:02.770 --> 00:01:06.890
his personality and behavior changed afterward. Now, Gage wasn't transformed
18
00:01:06.909 --> 00:01:09.689
into a murderer, and that's important. His behavior did change
19
00:01:10.170 --> 00:01:12.870
and kind of went back to normal towards the end.
20
00:01:13.650 --> 00:01:16.420
His case demonstrated something more fundamental, though. Changes to the
21
00:01:16.450 --> 00:01:21.109
brain can produce changes in behavior and personality. Modern TBI
22
00:01:21.170 --> 00:01:26.310
injuries can occur through automobile accidents, falls, sports injuries, assaults.
23
00:01:26.810 --> 00:01:29.730
Depending on the location and severity of the injury, consequences
24
00:01:29.769 --> 00:01:35.109
may include difficulties with attention, memory, emotional regulation, judgment. But
25
00:01:35.150 --> 00:01:38.930
this creates a dangerous temptation. If brain injury is associated
26
00:01:39.010 --> 00:01:43.170
with aggression or impulsivity, can we conclude that the injury caused?
27
00:01:43.609 --> 00:01:46.719
So we're looking at two different things, association and cause.
28
00:01:47.420 --> 00:01:51.500
And usually, no. Millions of people experience TBIs without committing
29
00:01:51.560 --> 00:01:55.659
serious crimes. Criminal behavior is rarely explained by a single variable.
30
00:01:56.180 --> 00:02:03.239
Substance use, developmental experiences, personality characteristics, social environment. This distinction
31
00:02:03.280 --> 00:02:07.920
becomes especially important in court. A forensic psychologist or neuropsychologist
32
00:02:07.969 --> 00:02:11.509
may evaluate whether a defendant has cognitive impairment, whether that
33
00:02:11.569 --> 00:02:15.349
impairment is consistent with documented neurological injury, and how those
34
00:02:15.389 --> 00:02:20.039
limitations could potentially affect behavior. But finding an abnormality on
35
00:02:20.080 --> 00:02:23.919
a brain scan doesn't automatically answer the legal question. A
36
00:02:23.960 --> 00:02:27.060
defendant could have significant frontal lobe damage and still understand
37
00:02:27.080 --> 00:02:30.539
that an action was illegal. Another defendant might have cognitive
38
00:02:30.580 --> 00:02:33.719
deficits that affect planning or impulse control without meeting the
39
00:02:33.759 --> 00:02:38.969
jurisdiction's legal standard for insanity. Brain injury may also become
40
00:02:39.030 --> 00:02:43.870
relevant during sentencing. Attorneys sometimes introduce neurological evidence as mitigation,
41
00:02:44.490 --> 00:02:47.509
arguing that impaired brain functioning helps explain aspects of the
42
00:02:47.550 --> 00:02:51.960
defendant's behavior. That leaves forensic psychology with a difficult question.
43
00:02:52.099 --> 00:02:56.639
How much should biology matter when determining responsibility? The brain
44
00:02:56.699 --> 00:03:00.689
isn't separate from behavior. Every decision, emotion, and impulse ultimately
45
00:03:00.750 --> 00:03:05.280
involves neural processes. Yet explaining isn't the same as excusing it.
46
00:03:05.949 --> 00:03:08.090
The challenge for forensic psych is to determine what the
47
00:03:08.129 --> 00:03:12.009
evidence actually supports without assuming that a damaged brain automatically
48
00:03:12.069 --> 00:03:13.210
creates a criminal one.
