notes on forensic


70s, sexually motivated serial killers, look at personality behavours crimes and motivations.

main features: wiling to inc exp and intuition, conc on serious, bizzare extreme crimes, inv extensive contact with polic

1. data assimilation= police and path reports,photo's, attemp psyc signiture, distinctive action/charac of offender, place into typology

2. organised/disorganised crime scenes, differ in personality, post offence behavouir makes interviews

3.crimscene recon= dynamic process. min of 2 peoples offender and victim, sequence of events, victims response, modus operandi is identified, crimes are linked.

4. profile gen= hyp are drawn together, demo issies, lifestyle, habits, peronality dynamics (history of depression) 

profiel is made :D 

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evaluation of profiling

tested in real life criminal investigations, more validity that stat approach, even though it is less scientific

however, hardly any evidence

leads to improvments in pooling of data, efficieny, link crimes, possible offenders, helps police

douglas- 77% crimes helped by FBI

police find it helpful only 3% of detections..

lack of empirical support, small in comp to method used, only 36 offenders, lacks pop validity, individual differences.

unscientific, subjective canter said 'special art'

if it workds? does it not matter....practical applications.

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stat approach to profiling- SSA

david canter,soughts through patterns in crimes using emp evidence, incorp quant data and simple info ie maps. shows locations of crimes and looks at simularities and differences of crimes.

used to plot relationship between crime scene charac onto 2dmap.

occur togeteher, close on map.

common in middlem, further away= uncommon.

based on data from variety of incidents of same crime

EG ****, clothing removed is common, but biting isnt, if may uncommon things happen, easier to catch criminal, DNA evidence is needed. 

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evaluation of SSA

practical application, priotise searches of suspects in serious crimes, link offenders...past criminal records. however sadistic section have deception.

however, limited usefulness, helps manage routine police workd but could never prove, DNA evidence is needed. 

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Geographical Profiling.

attempts to link crimes...location where he/she lives, socialises, worls.

recognised env factors in crime, not evenly spread out, hot spots.

criminals know area before crime

frist used in the case of the yorkshire ripper, looking at locations, infact in his home town- bradford.

eval.. practical app rossomo, criminals offend close to home and this decreases further away from their home, precise patterns vary with crime type

on other hand, cannot differentiate single offender and multiple offences. bernasco solo and group burglars....recruitment.

however theres always exceptions, its limited in its usefullness 

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Decision making of juries

physical attractiveness, dion et al, halo effct a form of cognitive bias, based on one trait

involved in implicit personality theory, first traits influence our expectations.

humans have a need for personal control, predict daily events

use IPT to draw conc on other traits

depends on serious of crime, gender of defendant.

eval, efran lighter sentences, baron and byrne found same - because of halo effect

gained sympathy of jurors...adding ecological validity.

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less consistant than physical attrac

depends on race of victim, juror and nature of crime.

changes of going to prison, stereotyping by jurors led to 32% back males in prison.

black females 16 times to likely to go prison than white females, stereotype that black women are more agressive than white. 

eval,race of victim: mock trails, white students said black defendans were guilty, asked to justify the effect disapeared = stereotyping.

race of juror: real life british trials, black defendant wrongly acquitted even by black jurors.

mazeella found no overall effect.

51% ethnicity, 49% pure evidence.

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Minority Influence

miscovici said one or small group of people can influence jury vote it:

consistant and commited, acting on principle, not overly rigid and reasonable in opinions. 


8.42% naivety conformed - miscovi

flexibilty rather than consistancy, minority had no effect, minority membar changed his mind, moved in direction of majority.

louise woodward

foreperson effect, socio ecomonic men who have exp. take control, outspokem, allows for everyone to be heard, thus creating an effect on individuals. 

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Majority influence

ash study on conformity, single p would conform to majority view

haste et al opinion differs from majority leads to conformity.

smith and mackie, varied opinion,deeper discussions, greater confidence


ash- 32% conformity, juror privately agree defendant is innocent but convict as guilty due to group pressure

vollrath and davis, jury size signif affect verdicts some level of conformity, minority feel pressured

hastie et al, majority jury of 10:2 spend less time put more pressure on minority to agree

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Theories of Crime

sheldon, 3 body types correlated to personality,ectomorphs = introverted and restrained,mesomorphs= agressive and adven

endomorphs= sociable and relaxed

mesomorphs are more likely to commit crime, rated body types of college in comparison to delinquents. mesomorphy found higher delinquents that students by 4.6 to 3.8.


cortes, 100 delinquents 47%, 19% control, supports

small but signif

unclear what relationship is, stereotyping? environmental factors

successful outcomes lead to rewards

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Genetic Theory

faulty NOS1 gene leads to impulsivity, high levels of aggression

reduced brain activity in the anterior cingulate cortex area involved with emotion

family patterns: adoption studies, check weather genetic parents of upbringing parents in criminality.  neither parents, 13.5%, 20% biological, 14.7% adoptive, both is 24.5%....comment on these

evaluation....  125 bio sons, 7% adoptive sons, increases validity however androcentric, no record for mothers and daughters

just biology, genetic influence but not a complete explanation, weak patterns- correlation

however more genes to be discovered could strengthen the theory

MZ twins only slightly similar in criminality than DZ twins, genes alone is not determining factor, environment may have an impact

free will/determinism arguements

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Eysenck's personality theory

questionairre, measure personality types, 3 dimensions, Extraversion, neurotic-ism and psychotic-ism.

Extroversion= sociable active and lively. Nuerotism= anxious and depressed, P= aggressive and antisocial.

high E, N and P scores were more likely to commit crimes.

extroverts do not condition easily, classical conditioning, not learn associations.

evaluation... 100 deliqients/100 students, higher D on E P and N scores

other studies haven't found links between E,P and N scores link with criminality 

16 studies, high P and N but not E. reduces validity, people may not answer truthfully, response bias, reluctant to admit there are anxious/nervous.

no consistency really exists?

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