We
do have a scientific paradigm for psychology. We know that genes and environment construct brains, that brains produce behaviour.
Individual differences in genomes and environmental divergences result in non-identical brains. Those differences have a measurable effect on neuroanatomy .. and thence on behaviour. We are different and we behave differently.
From behavioural genetics we know that the heritability of psychological traits is generally more than 50%. Nurturing differences are often really the consequence of genetic correlations. Disturbed parents tend to have disturbed children. Heritability in action. Non-shared environmental effects (eg
not family) typically have random and transient effects on psychological traits such as personality and intelligence. Real abuse and damage always excepted.
Psychology sort of knows this and sort of doesn't. There are researchers who know what a GWAS is, who know their way round a brain scan. And then there's the long legacy of pure nurturism: behaviourism, psychoanalysis, attachment theory, sociomoral reasoning, social information-processing theory and so on.
These one-sided plausible-sounding abstractions of commonplace observations have sadly produced neither real insight, reproducible results nor consistently-effective interventions. In many cases large scale experiments using twin studies and GWAS have shown their conclusions are simply false. Perhaps though this will change, now we're beginning to really understand the etiology of normal and abnormal psychology. Robert Plomin's "
Blueprint" is a readable review covering all these points.
All this has additional force in the case of
forensic psychology. But who would wish to be in the position of the textbook editor in 2018, forced to straddle competing and incompatible paradigms while maintaining the illusion that forensic psychology is a mature discipline on firm foundations, whose professionals can be relied upon in the investigation process, in court and during the follow-on treatment of prisoners.
Part 1: The Causes of Crime
Forensic psychology has two main aspects: the legal aspect deals with evidence, witnesses and the courts while the criminological aspect deals with crime and criminals. Our textbook starts by reviewing theories addressing the causes of crime: why do criminals offend and what is the effect on their victims? There are, of course, many kinds of theory and they tell very different kinds of story. Here is an illustrative quote (p. 58, section 2.2.1 - LCPs are life-course persistent offenders, constituting around 5% of the population).
“The main factors that encourage offending by the LCPs are cognitive deficits, an under-controlled temperament, hyperactivity, poor parenting, disrupted families, teenage parents, poverty and low socioeconomic status (SES).
Genetic and biological factors, such as a low heart rate, are also important (see Chapter 4).”
Of course all of the so-called main factors on the first list are strongly heritable, and therefore have substantial genetic causation.
Amazing to read this in a 2018 textbook.
Chapter 3 discusses psychopathy, a condition which is recognised as having a strong genetic component linked to systematic neuroanatomical features such as abnormal (underfunctioning?) amygdala activity. Do psychopaths fail to recognise fear reactions in others? Is this the reason for their sustained instrumental violence? Is this what amygdala hypoactivity is doing? It has been suggested on evolutionary grounds that psychopathy is an evolutionary stable strategy at low incidence in anonymised societies, but this doesn't get a mention.
Chapter 4 surveys the contribution of
neuroscience to the risk factors of offending. It covers the results of brain scans of offenders, twin studies looking at heritability and environmental inventories of adverse childhood experiences, attachment quality and brain injury. Many of the studies are now quite old (early 2000s) and there is a tendency to itemise results in technical jargon with inadequate interpretation. There is the usual confusion where poor family environment is treated as pure nurture dysfunction, uncorrelated with the genetic underpinning of criminality (recall disturbed parents have disturbed children).
This mistake leads to factors such as maternal binge drinking, smoking and chaotic upbringing being considered as separate, purely environmental, causal variables. Intervention would be so much more effective if this were true. It is certainly true, however, that traumatic brain injury (TBI) can proximately contribute to conduct disorder. Again though, the studies cited are old (1998, 2000). Interventions are briefly discussed (good advice, improved nutrition, fish oil) but these are old, with small or unspecified sample sizes and it's not clear whether the results replicated on larger studies and whether a ceiling effect kicked in. Section 4.5 is therefore almost useless.
The conclusions to this chapter are a list of wishful thinking bullet points grasping at every straw to persuade the reader that crime-prone genotypes and consequent neuroanatomy can be fixed. Previous chapters have already established that long-term persistent offending can't.
Chapter 5 reviews the effects of interpersonal crime on victims, including violent and sexual assaults. Much is said that is phenomenologically true, but the studies cited are shallow, inconsistent with each other and offer few non-obvious recommendations. One interesting and relevant recent result (not mentioned in the book) is the
substantial heritability of PTSD which probably accounts for its disparate impact.
Part 2: Investigating Crime
Chapter 6 looks at eyewitness evidence which normally falls lamentably short of CCTV standards. The taxonomy of failure modes is
useful (stereotyping, weapon focus, recovered memories etc); the superficial and unconvincing ‘models’ presented here, plucked out of the air it seems: not so much.
Chapter 7 introduces the “cognitive interview” (CI) for witnesses. This structured toolkit and checklist is far more successful in eliciting actionable information than normal police questioning. The chapter frames the CI mainly in terms of cognitive psychology, and indeed there are elements of that. However, the main reason for the structure technique's success appears to be that it counteracts the rather natural social presence of the police officer as a
dominant authority figure armed with prior assumptions, which tends to coerce and distort witness responses.
An interesting lacuna in this book, reflecting its instrumental purpose, is the absence of any systematic psychological characterisation of operational police officers themselves, those who are most likely to be interviewing witnesses and suspects. Studies have shown that lower-ranking officers tend to be concrete in their thinking (rather than abstract), conscientious and tough-minded. This ‘take-charge’ constellation of traits is probably a reason why officers spontaneously prefer a directive and sometimes confrontational style in gathering evidence and questioning suspects. The chapter notes that the rather
passive style of the ‘cognitive interview’ is difficult for officers to internalise, and that frequent retraining is necessary.
Similarly chapter 8’s coverage of the interviewing of
suspects shows that the macho, confrontational interview style common in the United States tends to feel more natural than the non-aggressive information-elicitation style preferred in the UK and many other countries. The latter is far more effective in avoiding false confessions, however. Whether it is less effective in convicting perpetrators is not discussed.
Chapter 9 deals with the detection of deception. Common sense tells us that liars are likely to be more stressed, to have greater problems keeping their stories straight and in presenting themselves as honest. Yet in interview settings, accuracy in detecting liars varies between 45% and 60%. This includes police officers. Not significantly better than tossing a coin. Perhaps we should look at what liars and truth-tellers actually
say. A number of techniques for text or voice analysis are discussed. They appear to have mixed, but not compelling results.
The polygraph (lie detector), used carefully, is considerably more accurate. Most innocent suspects pass the test (~90%) while many guilt suspects fail it (~ 60-80%). Coached countermeasures (eg tongue biting) can be effective, however. Lying is more cognitively demanding than telling the truth. This can be exploited in
active interviewing styles which force the suspect to do more work (‘give your account in reverse chronological order’) . There has also been some progress in detecting increased prefrontal cortical activity associated with lying using fMRI. It's too early to determine whether practical applications of scanning will emerge, however. It's surprising that, though the polygraph is presented as by far the most effective method of separating liars from truth-tellers, it doesn't get a mention in the chapter conclusions and recommendations. Why would that be?
Chapter 10 deals with crime linkage (identifying crimes committed by the same person) and offender profiling (inferring offender characteristics from crime scene behaviour). Both of these are somewhat familiar from TV dramas. Crime linkage is pattern synthesis and matching, exploiting behavioural consistency and distinctiveness on the part of the criminal. It has proven more effective with interpersonal crime than theft. It's work in progress. Offender profiling seems, on the account given, to be a real mess however. There are few empirical studies of effectiveness and those are not compelling There is little consensus on the traits to be predicted and a general lack of standardisation. The police investigation teams seem to like the service, but one feels for almost religious reasons, a form of uncertainty reduction.
Chapter 11 addresses intimate partner violence (IPV) and stalking. The field is dominated by feminist theories assuming the norm is male violence against females caused by 'the patriarchy’ (the authors are correctly skeptical and cite strong counter evidence) and much conflating of the
correlation between poor parenting and IPV with
causation (genetics airbrushed out). The chapter never gets beyond typology and doesn't mention the obvious evolutionary psychological dimensions behind both phenomena.
Chapter 12 is a long essay about terrorism which effectively concludes that the term is an ideological tagging of the normal human propensity to band together around a cause against perceived enemies. Forensic psychology does not seem to have contributed either to a deeper understanding than this or to compelling means of prevention. Perhaps resolution is not a matter for psychology.
Part 3: The Trial Process
Chapter 13 describes trial processes including judge and jury behaviours. An interesting review which highlights many process issues but there is little in the way of analysis or compelling recommendations.
Chapter 14 reviews the disturbing issues of vulnerable witnesses, often abused in cross-examination or subject to intimidation. Techniques for mitigation include prerecorded evidence and videolink testimony.
Chapter 15 discusses the identification of perpetrators focussing on lineups and CCTV. Interestingly, in English lineups a study found that 40% of the witnesses identified the suspect, 40% did not make an identification and 20% misidentified. For CCTV evidence the role of police super-recognisers is highlighted but there is no discussion of automated facial recognition systems. This
is within the scope of forensic psychology.
Chapter 16 is a useful tutorial on the roles of the expert witness.
Part 4: Dealing with Offenders
In chapter 17 we encounter the controversial topic: ‘crime and punishment - what works?’ Given the imprecision in terms, widely variant framings, and the strength of emotions this essay was never going to be definitive. It's a useful survey, but superficial and does not engage with results from behavioural genetics. Truly it's not even clear whether psychology
as is can contribute a meaningful input into these topics.
Chapter 18 starts with offender risk assessment (clinical individualistic assessment vs actuarial statistical - the latter works better). I would have thought there was scope for machine learning techniques here but the topic is not mentioned. In fairness, there is no discussion of underlying statistical techniques at all. In terms of instruments, Hare's psychopathology checklist (PCL-R) gets a brief mention. Rehabilitation programmes are reviewed: the commonsense view that these are ineffective except at the margin is confirmed.
Some offenders are truly dangerous and chapter 19 discusses their 'treatment’. A listing of the typology of offenders (violent, murderous, sexual) is followed by an assessment of treatment programme types (anger management, cognitive, 'good lives’). These programmes have in common a lack of effectiveness. Particularly for psychopaths. The chapter summary tries hard to remain upbeat. Contributions from behavioural genetics are nowhere to be found.
Chapter 20 looks at female offenders. The prior orthodoxy that factors leading to criminal behaviour are gender-blind has been overthrown. Today forensic psychologists are 'gender informed’. Women are dramatically underrepresented in the criminal population (about 5%) and as you might expect are far less violent than males. As usual the analysis is completely nurturist. It is not clear how successful intervention strategies have been.
Chapters 21 and 22 address offenders with intellectual disabilities (IQ less than ~70, autism) and the mentally disordered (eg suffering from a mental illness such as schizophrenia). As usual, these are characterized via a typology and then types of intervention and their success rates are assessed. As one might expect, these are mixed at best.
After so much depressing evidence of the recalcitrance of criminal behaviour and the uniformly poor effectiveness of intervention programmes, the book ends with chapter 23 on the 'Good Lives Model'. This is a 'hopey-changey’ celebration of the possibilities of rehabilitation despite all the evidence. As a framework, the GLM is immune to refutation although specific programmes within its paradigm do not seem compelling. Reading the chapter (pages of abstract liberal wish-fulfillment fantasies) is an experience akin to eating cotton wool.
Conclusions
Psychology suffers from a number of well-attested problems. Hypotheses and models are frequently no more than shallow, commonplace intuitions dressed up in over-abstract, process-oriented language. Laboratory experiments, based typically on small groups of psychology students, are heavily range-restricted by IQ and personality type. Published results have been non-reproducible and in some cases generated by p-hacking.
Forensic psychology addresses a target criminal population whose psychological parameters (low IQ, prevalence of ASD and various psychopathologies) could scarcely be more distant from the typical experimental population of college undergraduates. It's understandable that a textbook has to reflect the discipline as it is, but there are just too many models, assertions and assessments here which are plain wrong. May the next revision not be long in coming.
