The Macdonald Triad
The Macdonald Triad is a set of three specific childhood behaviours that have been hypothesised to predict future violent behaviour, murder and even serial murder.
The Macdonald Triad, also known as the "homicidal triad", consists of three behaviours: bedwetting, fire-setting, and cruelty to animals. It was proposed by psychiatrist J.M. Macdonald in 1963 who initially suggested the presence of the triad in children was a potential early warning sign for the future development of violent behaviour and even serial murder. This article seeks to look further into the components of the Macdonald Triad and evaluate it’s reliability as a predictive model for violence.
Components of The Macdonald Triad
Bedwetting: Also referred to as enuresis, relates to repeated involuntary urination, particularly during sleep, beyond the age at which bladder control is typically achieved. While commonly seen as a developmental issue, persistent bedwetting past the age of five has been linked in some studies to stress, anxiety, and family dysfunction (Lindblad et al., 1990).
Fire-setting: Fire-setting or arson involves the deliberate act of igniting fires, often viewed as a manifestation of underlying psychological distress, thrill-seeking behaviour, or a cry for help. Early childhood fire-setting can indicate deeper emotional or behavioural issues, including a fascination with destruction or a method of expressing anger (Kolko, 2002).
Cruelty to Animals: This element is characterised by the intentional infliction of harm or suffering on animals. This behaviour is particularly concerning as it can reflect a lack of empathy, impulse control issues, and a propensity for aggression. Research has shown that individuals who engage in animal cruelty are more likely to exhibit violent behaviours toward humans later in life (Arluke et al., 1999).
The Macdonald Triad as a predictive model
The Macdonald Triad has been the subject of numerous studies aiming to establish a correlation between these early behaviours and later violent criminal activities. Some research supports the notion that these behaviours, particularly animal cruelty, are more prevalent among violent offenders compared to non-violent populations (Hodge et al., 2011). For instance, a study by Merz-Perez et al. (2001) found that incarcerated violent offenders were more likely to have histories of childhood animal cruelty.
However, the triad's predictive validity remains in contention. Critics argue that while the behaviours identified by the triad may be more common among violent individuals, in isolation they are sufficient predictors of future violence. Instead, these behaviours may co-occur with other risk factors such as familial abuse, neglect, or neurological impairments (Heath et al., 1984). Several key criticisms challenge the Macdonald Triad's utility and validity:
Correlation vs. Causation: Critics highlight the issue of correlation versus causation, arguing that while there may be an association between the triad behaviours and violent crime, this does not imply causation. The behaviours may be symptomatic of broader environmental and psychological issues rather than direct precursors to violence (Farrington, 1991).
Over-Simplification: The triad is criticised for oversimplifying the complex causes of violent behaviour. Human behaviour, particularly extreme violence, arises from a multitude of factors including genetic, environmental, psychological, and social influences. Focusing solely on the triad can obscure these complexities and lead to inaccurate profiling (Cohen, 2002).
Inconsistent Findings: Empirical support for the triad is inconsistent. Some studies fail to find a significant link between the triad behaviours and future violent acts, suggesting that these behaviours alone are not reliable predictors (Vaughn et al., 2009). This inconsistency undermines the triad's diagnostic value.
Ethical Concerns: There are ethical concerns regarding labelling and stigmatising children who exhibit one or more of the triad behaviours. Such labelling can lead to self-fulfilling prophecies and unjust treatment within the educational and judicial systems (Piquero et al., 2016).
Evidence of the Macdonald Triad in Scottish crime cases
I’ve previously written about the murder of Alesha McPhail in 2018 at the hands of potential child psychopath Aaron Campbell. If you missed this article you can check it out here:
Can children be psychopaths? - Scottish True Crime (substack.com)
There are unconfirmed reports in the UK tabloid media about Campbell’s early behaviour. Locals on the Isle of Bute have made claims that Campbell has been involved in both starting fires and cruelty to animals, with one reporting that Campbell was known to have skinned and tortured a cat. Previously available court documents that held details on the psychological assessment of Campbell are no longer available.
Do you know of any crime cases where evidence of the Macdonald Triad was present?
The Macdonald Triad is an interesting yet contentious concept in the field of criminal psychology. While it highlights potential early warning signs of future violent behaviour, there remains questions over it’s reliability. It is now generally accepted that a more holistic approach, integrating a range of psychological, social, and environmental factors should be adopted. From this approach, the field of criminal psychology can work towards a more effective and ethical strategy for identifying and treating at-risk individuals.
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