5Physiological Psychology The central question:Can we link physiologicalprocess or structuredirectly to human behaviour?
6Physiological Psychology Research suggests that brain dysfunction may PREDISPOSE a person to being violentThe FRONTAL brain region may be associated with violent behaviourSome violent offenders plead NGRI (not guilty by reason of insanity) to murder charges
7Physiological Psychology Discussion pointsWhat are the advantages to the physiological explanation of behaviour?What are the disadvantages?Why is this approach described as determinist?How else can violent behaviour be explained?
8Physiological Psychology - Raine The Raine hypothesisThat the seriously violent individuals have localised brain damage inthe prefrontal cortex; the amygdala;the thalamus; the hippocampus;
10frontal lobeIt is important for voluntary and planned motor behaviours - such things as voluntary movement of eyes, trunk, limbs and the many muscles used for speechThe motor speech area (Broca's area) is usually in the frontal lobe of the left hemisphere regardless of which hemisphere is dominant for handedness (i.e. the left hemisphere for right handers).
15Raine suggests three reasons why prefrontal deficits may cause antisocial personality: First, the region appears to be critical for self-restraint and deliberate foresight. "One thing we know about antisocials is that they do not think ahead," said Raine.Second, it’s crucial for learning conditioned responses — essential, for example, to a child’s linking 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," Raine said.Third, if prefrontal deficits underlie the Antisocial Personality Disorder (APD) group’s low levels of autonomic arousal, these people may unconsciously be trying to compensate through stimulation-seeking. "For some kids," said Raine, "one way of getting an arousal-jag is by robbing stores or beating people up."
16parietal lobe (pa rye' it ul) It is important for aspects of somesthetic sensation (i.e. touch, kinesthesia, pain), taste, and other sophisticated perceptive abilities.An example of the latter would be the receptive speech area (Wernicke's area) which is in the inferior part of the parietal lobe on the left side regardless of which hemisphere is dominant for handedness.The parietal lobe of the right hemisphere appears to be especially important for perceiving spatial relationships.
20corpus callosum (cull low' sum) It is an enormous bundle of axons which interconnects the left and right cerebral hemispheres. Therefore, it is a commissure.It disseminates information from the cerebral cortex on one side of the brain to the same region on the other side .
24thalamus (thal' uh mus)A large mass of grey matter deeply situated in the forebrain. There is one on either side of the midline.It relays to the cerebral cortex information received from diverse brain regions. Sort of a requisite 'last pit stop' for information going to cortex.Axons from every sensory system (except olfaction) synapse here as the last relay site before the information reaches the cerebral cortex.There are other thalamic nuclei that receive input from cerebellar-, basal ganglia- and limbic-related brain regions.
33Physiological Psychology - Raine CONTROL GROUP41 normal individuals (non murderers)matched for sex and ageincluding 6 ‘murdering’ schizophrenics who were matched with 6 ‘ non murdering’ schizophrenics
34Physiological Psychology - Raine The methodA ‘natural’ experimentThe procedurePET Scans to examine the brain
35Physiological Psychology - Raine What is a PET SCAN?Positron Emission TomographyThis method assesses the amount of metabolic activity in various parts of the brainA scanning machine detects positrons emitted through the head with high amounts being associated with a higher level of metabolic activity.
38Physiological Psychology - Raine THE PET SCAN processPatients are injected with fluorodeoxyglucose tracer (radioactive glucose)For about 30 minutes before the PET SCAN the participants are engaged in a ‘continuous activity’This activity aimed to activate the FRONTAL LOBES, and the RIGHT TEMPORAL and PARIETAL LOBES
43Physiological Psychology - Raine THE RESULTSDIFFERENCES in the brains of the murderersCORTICAL REGIONSLOWER ACTIVITY
44Physiological Psychology - Raine THE RESULTSDIFFERENCES in the brains of the murderersSUBCORTICAL REGIONSLOWER ACTIVITY
45Physiological Psychology - Raine THE RESULTSSUMMARY OF DIFFERENCES in the brains of the murderersReduced activity in prefrontal cortex, parietal region & corpus callosumLeft hemisphere less activity than rightAbnormal asymmetries in amygdala & thalamus
46Physiological Psychology - Raine THE RESULTSBoth groups performed similarly on performance taskNOT CONTROLLED6 murderers were left handed14 murderers were non white23 murderers had history of head injury
47Physiological Psychology - Raine DISCUSSION POINTSPre Frontal deficit - associated with impulsivityHippocampus & amygdala - associated with aggressive behaviour & with conditioned emotional responsesAmygdala - reduced activity associated with fearlessnessCorpus Callosum - dysfunction associated with predisposition to violence
48Physiological Psychology - Raine CONCLUSIONUnlikely that violence is due to a single brain mechanismEvidence that - murderers pleading NGRI may have different brain functions to ‘normal’ peopleEvidence that - murderers have different brain functions to psychiatric patients
49Physiological Psychology - Raine Validity & reliability of the research?Large sampleSignificant results (non trivial)Two tailed testsAreas of brain selected based on previous researchCould IQ differences be a factor?
50Physiological Psychology - Raine WHAT these findings DO NOT demonstrateThat violent behaviour is ‘caused’ by biologyThat murderers are NOT RESPONSIBLE for their actionsThat brain dysfunction causes violent behaviour
51Physiological Psychology - Raine WHAT these findings DO demonstrateThat there MAY BE a link between brain activity and a predisposition towards violence which should be investigated further
52Physiological Psychology - Raine Ethics - how might you criticise this study?Generalisation - can the findings of this study be generalised to all murderers?Why or why not?
53EthicsRaine’s findings raise important ethical questions about culpability and free will. "To what extent," he asked, "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?"
54Physiological Psychology - Raine QuestionsSuggest one thing that cannot be concluded from this studyThe conclusions suggest that murderers who plead NGRI are different to 2 groups - which 2 groups?
55Physiological Psychology - Raine QuestionsDescribe the strengths & weaknesses of the NATURAL experimental method?What do you think might be the main difficulty in drawing conclusions from PET observed ‘brain activity’?
56Physiological Psychology - Raine Application - how is this study useful?
57InterventionsRaine suggested a number of interventions that could be applied.Cognitive and behavioural therapy and drug therapy have potential.Biofeedback – training children or adults to control their own arousal levels – could be a useful tool.And children could be channelled into safe activities that might satisfy their natural stimulation-seeking and aggressive proclivities.