How does the presence and level of intellectual disability and type of behaviour displayed shape public perceptions of culpability?

People with intellectual disability are overrepresented and disadvantaged at all stages of the criminal justice system. This study contributes to an understanding of how people with intellectual disability encounter the criminal justice system through investigating public perceptions of culpability. Using an online survey design, 641 participants were randomised into one of six vignette conditions that described a person with varying levels of intellectual disability displaying either challenging behaviour or assault. Standardised measures of culpability, procedural justice and stigmatising attributions were completed. Results indicated gender differences in culpability scores, with females perceiving the subject as less culpable than males. Culpability scores differed according to the level of intellectual disability of the subject, with culpability scores reducing as level of intellectual disability increased. However, culpability scores were most strongly associated with legitimacy, legal cynicism, and attribution scores, with more stigmatising attributions of subjects’ behaviour being the strongest predictor of increased culpability. These findings highlight the importance of targeting stigmatising attributions of the public to improve understandings of intellectual disability as a mitigating factor and, ultimately, improve experiences and outcomes for people with intellectual disability.