biological psychology

BIOLOGICAL PSYCHOLOGY

The central question is

Can we link biological

processes or structures

directly to human behaviour?


• Research suggests that brain dysfunction may PREDISPOSE a person to being violent

• The FRONTAL brain region may be associated with violent behaviour

• Some violent offenders plead NGRI (not guilty by reason of insanity) to murder charges


• Discussion points• What are the advantages to the Biological explanation of

behaviour?• What are the disadvantages?• Why is this approach described as determinist?• How else can violent behaviour be explained?

BIOLOGICAL PSYCHOLOGY RAINE

BIOLOGICAL PSYCHOLOGY RAINE

• The Raine hypothesis is that some seriously violent individuals have localised brain damage in certain areas of the brain including

the prefrontal cortex; the amygdala;the prefrontal cortex; the amygdala;

the thalamus; the hippocampus; and the corpus the thalamus; the hippocampus; and the corpus callosum.callosum.

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ADRIAN RAINE, MONTE BUCHSBAUM, AND LORI LACASSE(1997)

BRAIN ABNORMALITIES IN MURDERERS

INDICATED BY POSITRON EMISSION

TOMOGRAPHY.

Typical Criminals?

THE FRONTAL LOBE

is important for voluntary and planned motor behaviours - such things as voluntary movement of the eyes, trunk, limbs and the many muscles used for speech

Raine suggests three reasons why prefrontal prefrontal deficits may cause antisocial personality:1.The region appears to be critical for self-restraintself-restraint and deliberate foresight. "One thing we know about anti-socials is that they do not think ahead"

2.It’s crucial for learning conditioned responses e.g. a child learns to link the thought of a misdeed with anxiety over punishment. "Unconscious mental-emotional associations such as these lie at the core of what we call conscience"

3. Prefrontal deficits are associated with low levels of autonomic arousal. eople with Antisocial personality Disorder (APD) may unconsciously be trying to compensate by seeking stimulation

"For some kids one way of getting an arousal-buzz is by robbing stores or beating people up”

CORPUS CALLOSUM

Is the enormous bundle of fibres which interconnects the left and right cerebral hemispheres.

It disseminates information from the cerebral cortex on one side of the brain to the same region on the other side – it is a communication bridge .

TEMPORAL LOBE (TEMP' OR UL)

Various parts of it are important for the sense of hearing, for certain aspects of memory, and for emotional/affective behaviour.

RAINE (1997) THE STUDYRAINE (1997) THE STUDY

• The participants:

• 41 murderers (39 males 2 females)

• Charged with murder/manslaughter in California/USA

• All pled NGRI

• All were referred for physiological and psychological examination


• The ‘histories’

• head injury/brain damage(23)

• drug abuse (3)

• affective disorder (2)

• epilepsy (2)

• hyperactivity & learning impairment (3)

• personality disorder (2)

• Schizophrenia (6)


• CONTROL GROUP

• 41 normal individuals (non murderers)

• matched for sex and age

• including 6 ‘murdering’ schizophrenics who were matched with 6 ‘ non murdering’ schizophrenics

• IQ, ethnicity, brain injury not matched!


• The method• A ‘natural’ experiment (quasi) using independent measures design where participants were matched on key criteria.

• The procedure• PET Scans were used to examine the brain


What does ‘PET’ as in PET scan mean?

Positron Emission Tomography

How does it work?This method assesses the amount of metabolic activity in various parts of the brainA scanning machine detects positrons which are emitted. High amounts are associated with a higher level of metabolic activity.

RAINE ET AL (1997) BRAIN ABNORMALITIES IN MURDERERS

PET scans showing ‘hot spots’ for cognitive activities

RAINE ET AL (1997) BRAIN ABNORMALITIES IN MURDERERS

PET scan of a subject whilst practicing a new language skill

A scan of the same subject demonstrating

this skill after it had become familiar

PHYSIOLOGICAL PSYCHOLOGY - RAINE


• THE PET SCAN process • Patients are injected with fluorodeoxyglucose

tracer (radioactive glucose)• For about 30 minutes before the PET SCAN

the participants are engaged in a ‘continuous activity’ task

• This activity aimed to activate the FRONTAL LOBES, and the RIGHT TEMPORAL and PARIETAL LOBES

"Continuous Performance Task: Single digits (0-9) were presented for 40 ms at a rate of one every 2 seconds. Subjects were told to press a button using their right hand each time that they detected the digit 0 and that it was equally important to respond to zeros and not respond to non-zeros. Targets were presented irregularly with a probability of occurrence of 0.25. Stimuli were presented silently by rear projection on a 24 x 24 cm screen, with a Kodak carousel slide projector fitted with an Ilex No. 4 Synchro-Electronic Shutter and blurred to a degree that makes digits barely recognizable (such that a 2.8 diopter correction is required to refocus clearly). The subject’s eyes were 1.2m from the rear projection screen.”

FINDINGS FINDINGS

• Both groups performed similarly on performance task

• There were certain characteristics that were NOT CONTROLLED..i.e

• 6 murderers were left handed

• 14 murderers were non white

• 23 murderers had history of head injury

RAINE FOUND SOME SIGNIFICANT RESULTSRAINE FOUND SOME

SIGNIFICANT RESULTS

• He suggested there was evidence for DIFFERENCES in the brains of the murderers

• He found amongst other things LOWER ACTIVITY in some

CORTICAL REGIONS of the brain

NORMAL MURDERER

ACTIVITY DEFICIT Raine's PET scans show greater activity (red regions) in the prefrontal cortex of a normal brain than in a murderer's

brain.

Diagrams from Raine’s research

SUMMARY OF DIFFERENCES IN THE BRAINS OF THE MURDERERS

SUMMARY OF DIFFERENCES IN THE BRAINS OF THE MURDERERS

Reduced activity in prefrontal cortex & corpus callosumThe Left hemisphere showed less activity than the rightAbnormal asymmetries in the amygdala



Pre Frontal deficit - associated with impulsivityAmygdala - associated with aggressive behaviourAmygdala - reduced activity associated with fearlessnessCorpus Callosum - dysfunction associated with predisposition to violence

CONCLUSIONCONCLUSION

It is unlikely that violence is due to a single brain mechanismThere is evidence that - murderers pleading NGRI may have different brain functions to ‘normal’ peopleThere is some evidence that - murderers have different brain functions to psychiatric patients

WHAT these findings DO demonstrate

WHAT these findings DO demonstrate

That there MAY BE a link between brain activity and a predisposition towards violence which should be investigated further

WHAT THESE FINDINGS DO NOT DEMONSTRATE

WHAT THESE FINDINGS DO NOT DEMONSTRATE

• That violent behaviour is ‘caused’ by brain pathology

• That murderers are NOT RESPONSIBLE for their actions

• That brain dysfunction causes violent behaviour

EVALUATION ISSUES EVALUATION ISSUES

Is the research Valid?

Areas of brain selected based on previous research

but

Could IQ differences be a factor?

Is the research Reliable?

Could the same technique be used on other people?

ETHICSETHICSHow might you criticise this study from an ethical point of view?

Raine’s findings raise important ethical questions about culpability and free will.

"To what extent, should we take disordered brain functioning into account as part of the reason for certain types of crime?

“Assuming these people are not responsible for their own brain damage, should we hold them fully responsible for their criminal acts?"

GENERALISATIONGENERALISATION

Can the findings of this study be generalised to all murderers?Why or why not?

Application - how is this study Application - how is this study useful?useful?

INTERVENTIONS

• Raine suggested a number of interventions that could be applied.

• Cognitive and behavioural therapy and drug therapy.

• Biofeedback – training children or adults to control their own arousal levels.

• Children could be channelled into safe activities that might satisfy their natural stimulation-seeking and aggressive proclivities.

QUESTIONS QUESTIONS

• Describe the strengths & weaknesses of the NATURAL (Quasi) experimental method.

• What do you think might be the main difficulty in drawing conclusions from PET observed ‘brain activity’?

Identify one thing that cannot be concluded from this study

biological psychology

Documents

biological psychology

brain tutorials

brain injury

brain dysfunction

raine hypothesis

adrian raine

speech raine

localised brain damage