There has long been a popular perception that left-handed people are more likely to engage in criminal behavior than right-handed people. But is this perception accurate? Let’s take a look at what the research says.
Quick Answers
– Some studies have found a small association between left-handedness and criminal behavior, but the evidence is mixed and inconclusive.
– Left-handed people make up about 10-13% of the general population. The percentage of left-handed criminals is estimated to be somewhat higher, around 15-25% according to some studies.
– However, the causes behind this potential association are complex. Handedness alone does not determine criminality. Social, biological and environmental factors likely also play a role.
– Overall, the claim that “most criminals are left-handed” is not supported by research. Left-handed people are not inherently more prone to criminal behavior.
Looking at the Research
Several studies over the past few decades have explored whether left-handed people are more likely to engage in criminal conduct. Here is a brief overview of some of the key research in this area:
Prison Studies
Some of the earliest evidence of a link between left-handedness and criminality came from studies of prison populations. For example:
– A 1989 study of prisoners in New York found that 15% of inmates were left-handed, compared to 10% of the general population.
– A 1992 study of prisoners in Canada found that 25% of violent criminals were left-handed.
– A 1995 study of inmates in a Welsh prison found a left-handedness rate of 15%, compared to 11% among the general public.
These studies suggest that left-handed people may be over-represented in prison populations compared to the general public. However, prison studies alone cannot determine causality – there are many factors that influence criminality beyond handedness.
General Population Studies
Researchers have also looked at handedness and criminal tendencies within the general population:
– A 2009 study asked 500 college students to self-report their handedness and any criminal behaviors. Left-handed people were significantly more likely to report stealing or vandalizing property.
– However, a 2014 study using data from over 25,000 people in the National Longitudinal Study of Adolescent Health in the US found no relationship between left-handedness and rule-breaking or violent behavior.
Overall, studies of the general population have produced mixed results in terms of linking left-handedness and criminal tendencies.
Meta-Analyses
To get a broader view, some researchers have conducted meta-analyses – combining and statistically analyzing the results of multiple studies:
– A 1993 meta-analysis incorporating results from 15 prior studies found a statistically significant, but small association between left-handedness and criminality.
– However, a 2013 meta-analysis of 27 studies found no overall association between left-handedness and criminal behavior.
In general, meta-analyses suggest there may be a weak correlation between left-handedness and criminal activity. But the results are mixed and the association is likely minor at most.
Explaining the Association
If left-handed people are in fact slightly more likely to engage in criminal conduct, what could explain this association? Researchers have proposed several potential factors:
Brain Differences
Left-handed people’s brains are structured differently, which could hypothetically play a role. For example:
– Reduced lateralization between the hemispheres may be linked to impulse control issues and rule-breaking behavior.
– Differences in limbic neural circuits could be relevant, since these regions influence emotions and motivation.
However, conclusive evidence directly linking brain differences to criminality is lacking.
Neurological Development
Some researchers hypothesize that the same neurological factors influence both handedness and criminal proclivities during fetal development. However, this remains scientifically unproven.
Social Marginalization
Historically, left-handed people have faced social stigma and marginalization, which could potentially lead to antisocial tendencies. However, social views on left-handedness have dramatically changed over time.
Sample Bias
It’s possible that sampling bias in some studies skews the results. For example, prison studies may capture more lower socioeconomic status left-handers, a group more prone to conviction.
In the end, the origins of the handedness-criminality association (if one exists) are multi-faceted and not fully understood. Handedness alone cannot predict criminal behavior.
Left-Handedness Around the World
Rates of left-handedness vary globally, which provides another lens to examine the handedness-criminality question:
United States
– Around 10-13% of Americans are left-handed.
– A study of California prisoners found left-handers were 1.5 times as likely to have committed violent crimes compared to right-handers.
United Kingdom
– Roughly 10-13% of Britons are left-handed.
– A study of British prisoners found a left-handedness rate of 15%, higher than the general population.
Canada
– Around 10-13% of Canadians are left-handed.
– A Toronto prisoner study found left-handers were overrepresented among violent criminals.
Asia
– Left-handedness is rarer in Asia at around 5-10% prevalence.
– A study in India found incarcerated left-handers had higher rates of homicides, thefts and violent attacks compared to right-handed inmates.
Africa
– Left-handedness rates vary across Africa but tend to be low, around 5-10%.
– One study in Algeria found a higher proportion of left-handed prisoners compared to the general public.
In summary, the potential association between left-handedness and criminality appears in many different countries and cultures. However, variation in social views on left-handedness across societies likely impacts these statistics.
Theories on Left-Handed Criminality
Assuming left-handers are in fact more likely to engage in criminal conduct, theorists have proposed a few hypotheses:
Poor School Performance
In countries where left-handedness was strongly discouraged, left-handed children often underperformed academically. Poor school outcomes could be a risk factor for eventual criminality.
Traumatic Upbringing
Historical mistreatment of left-handed children occasionally caused lasting psychological trauma. Potential links between childhood trauma, mental illness and criminal behavior have been identified.
Low Conscientiousness
One study found left-handers scored lower on measures of conscientiousness. Low conscientiousness correlates to rule-breaking and low self-control.
High Risk-Taking
Some research indicates left-handers may be greater risk-takers, sensation-seekers and poor planners. These traits are sometimes associated with criminal behavior, albeit weakly.
However, these theories tend to make broad generalizations about left-handers. More research is needed to substantiate any clear causal links.
Concerns About Bias
Some researchers argue that promoting the notion left-handers are prone to criminality is problematic:
Reinforces Stigma
Left-handed people have faced social stigma throughout history. Associating left-handedness with criminality could reinforce unfair stereotyping.
Confirms Biased Expectations
Studies show people perceive left-handers more negatively. Linking left-handedness to criminality could confirm people’s inherent biases.
Neglects Context
Focusing narrowly on handedness overlooks how social, economic, cultural and neurological factors intersect to produce criminal tendencies.
Lacks Nuance on Causes
Crime has complex roots. Reducing it to a single factor like handedness is an oversimplification.
Wrongly Implies Predictive Power
Handedness has an extremely weak predictive relationship with criminality at best. Implying otherwise is misleading.
Overall, the research community remains appropriately cautious about drawing overly definitive links between left-handedness and criminality due to these concerns.
Left-Handedness in Executions
An interesting side note is whether left-handed people are more likely to be subjected to capital punishment:
| Study | Sample | Key Finding |
|---|---|---|
| Rueveni 1979 | 248 executed prisoners | 22% were left-handed |
| Brackenridge 1981 | 305 executed prisoners | 20% were left-handed |
– These studies of executed criminals in the US found approximately double the rate of left-handedness compared to the general population.
– This could support the theory left-handers tend to commit more violent crimes.
– However, legal bias against left-handed people may also play a role in death penalty outcomes.
More research is needed to analyze if handedness is relevant in capital punishment trends.
Left-Handedness in Specific Crimes
Some studies have looked at whether certain types of criminal offenses have higher rates of left-handed perpetrators:
Violent Crimes
– A 2013 meta-analysis found an association between left-handedness and violent crimes in men, but not women.
– However, other reviews conclude the evidence on links to violent crime is weak and inconsistent.
Firearm Crime
– One study found left-handed people were 2.5 times more likely to be admitted to a hospital with firearm injuries, hinting at greater involvement in gun violence.
– Though it’s also possible left-handers are just more accident prone with guns due to right-handed design.
Pedophilia
– A controversial 2002 study claimed left-handers were more prevalent among pedophiles. But subsequent analysis disputed this finding.
– Today, researchers find no credible link between handedness and pedophilia.
Overall, connections drawn between specific crime types and left-handedness tend to rely on limited evidence. As with criminality in general, handedness appears to have little predictive power.
Left-Handedness in Terrorism
Are those who commit ideologically motivated crimes like terrorism more likely to be left-handed? The data is sparse:
– In one study, left-handers made up nearly 25% of teenagers arrested for Islamic terrorism offenses, which the authors speculated could reflect neurological differences.
– However, others caution that the study used an extremely small sample size of just 24 individuals.
– Another study proposed that some left-handed children turned to terrorism due to poor school performance. But evidence directly linking poor grades to terrorism is lacking.
– Notably, the left-handedness rate among right-wing terrorists does not appear greater than normal.
In summary, the limited terrorism research is speculative and inconclusive at best regarding any handedness-motivation association.
Are Left-Handed Women More Criminal?
Most studies on handedness and criminality focus on male perpetrators. But a few have zoomed in on women:
– One 2016 study found a correlation between left-handedness and rule-breaking behavior among female university students.
– However, other research has found no meaningful differences in the handedness of female law-abiders versus female criminals.
– Left-handedness may be linked to slightly higher alcohol and drug use among female prisoners in some studies. But the association is weak.
– Overall, there is little reliable evidence that female left-handers are prone to criminal conduct. More data specific to women is needed.
Anti-Social Personalities
A few studies have looked at the link between left-handedness and certain anti-social personality traits:
– One study of narcissistic personality disorder found that 18% of those diagnosed were left-handed compared to 10% of healthy controls.
– Another small study observed a correlation between left-handedness and psychopathic personality tendencies among youth.
– However, meta-analyses find no conclusive link between left-handedness and psychopathy or anti-social personalities as a general pattern.
Much more research with larger sample sizes would be required to substantiate connections between left-handedness and specific personality disorders prone to criminality. Currently, evidence of such links is extremely limited and preliminary.
Positive Traits
While this article focuses on criminality, it is important to note:
– Many studies find no difference between left-handers and right-handers across a range of cognitive skills and personality traits.
– Left-handed people may have advantages in areas like visual-spatial skills, creativity and divergent thinking.
– No inherent attributes of left-handedness exist that make someone more prone to criminality. At most, small indirect factors may be at play.
Conclusion
In summary, the notion that “most criminals are left-handed” is not supported by scientific research. Some studies suggest left-handers may be slightly over-represented among criminals and prison populations compared to the general public. However, conclusive evidence of robust links between handedness and criminality is lacking.
While biological and neurological differences may subtly predispose some left-handers toward rule-breaking behavior, the causes are complex. Handedness itself does not directly determine someone’s proclivity to commit crimes. Focusing excessively on unproven handedness theories also risks unfairly stigmatizing left-handers.
Like right-handers, most left-handed people are law-abiding citizens. More nuanced, thoughtful and unbiased research is needed to further unpack any minor correlations between left-handedness and criminal offenses. But the broad evidence to date suggests no inherent association between left-or-right-handedness and one’s criminal disposition.
