The detrimental impact of alcohol intoxication on facets of Miranda comprehension.

Objective: Law enforcement officers often encounter alcohol-intoxicated suspects, suggesting that many suspects are presented with the challenge of grasping the meaning and significance of their rights while intoxicated. Such comprehension is crucial, given that is intended to minimize the likelihood of coercive interrogations resulting in self-incrimination and protect suspects' constitutional rights. Yet, the effects of alcohol on individuals' ability to understand and appreciate their rights remain unknown-a gap that the present study sought to address.

Hypotheses: Informed by alcohol myopia theory (AMT), we predicted that intoxicated individuals would demonstrate impaired comprehension compared to sober individuals and those who believed they were intoxicated (but were in fact not; i.e., placebo participants).

Method: After health screenings, participants completed the Wechsler Abbreviated Scale of Intelligence-Second Edition verbal subtests, rendering a Verbal Comprehension Index (VCI) score. We randomly assigned participants to consume alcohol (n = 51; mean breath alcohol concentration [BrAC] = 0.07%), a placebo condition (n = 44; BrAC = 0.00%), or a sober control condition (n = 41; BrAC = 0.00%). All participants (N = 136) completed the Rights Comprehension Instruments (MRCI), which measured participants' understanding of the warnings, recognition of the warnings, appreciation of their rights in interrogation and court settings, and understanding of -related vocabulary.

Results: We found a significant effect of intoxication condition on participants' understanding of warnings (η² = .14) and Miranda-related vocabulary (η² = .05) when controlling for VCI scores. Specifically, intoxicated participants received lower scores for understanding of warnings compared to sober and placebo participants, and lower scores for understanding of vocabulary compared to sober participants. Alcohol did not significantly impact rights recognition or appreciation.

Conclusions: Alcohol intoxication may detrimentally impact some facets of comprehension. Thus, it is important that law enforcement consider refraining from questioning intoxicated suspects. (PsycInfo Database Record (c) 2022 APA, all rights reserved).