The big five traits openness and conscientiousness affect the memory of alcohol-intoxicated eyewitnesses

• Novel study on the effect of Big Five personality on intoxicated witnesses’ memory. • Quasi-experimental method recruited alcohol participants in bars for a witness study. • Higher Openness scores yielded a greater number of witness details recalled. • Highly intoxicated and highly Conscientious witnesses reported fewer details. • Increased intoxication reduced witness accuracy and increased reported uncertainty. This novel study was the first to examine how alcohol and personality affect witnesses’ memory. Using a quasi-experimental method, participants ( N = 65) recruited from local bars provided breath alcohol concentration measurements and personality ratings using Big Five (i.e., Openness, Conscientiousness, Extraversion, Agreeableness, Neuroticism). Participants viewed a filmed witness event, followed by an interview about the event. BAC ranged from 0.00-0.14 %, with a mean of 0.05 % ( SD = 0.03 %). Results showed that there was a significant effect of Openness on the quantity of witness recall, with higher Openness scores yielding a greater number of witness details recalled. Also, participants with increased intoxication levels in combination with higher Conscientiousness scores reported fewer details. Finally, increased alcohol-intoxication had a negative effect on memory as witnesses’ accuracy rate declined, while their number of “ I do not know ” answers increased. Our findings suggest that personality differences may play an important role in alcohol-intoxicated witnesses’ episodic long-term memory, despite being largely neglected by researchers. Future research is encouraged to continue disentangle the complexity of the interaction between personality, alcohol, and witness memory.