Alcohol is known to often impair explicit memory, however new research demonstrates that it leaves implicit memory unharmed.

The study, which was conducted by Suchismita Ray, an assistant research professor at the Center of Alcohol Studies at Rutgers University, examined whether acute alcohol intoxication disrupts memory for emotionally valenced and neutral images using explicit recall and an implicit repetition task.

The study comprised of 36 men and women between the ages of 21 to 24. Each participant consumed a placebo, nonalcoholic beverage or an alcoholic beverage aimed to raise the blood alcohol level to 0.8 percent, the nation's limit for legal driving. Participants were then instructed to observe emotionally negative, emotionally positive and emotionally neutral images. During the explicit memory test, they were asked to recall as many images as they could. For the implicit memory test, participants were shown 360 images. All images were a combination of things they've already seen and new images.  They were also instructed to conclude whether images were real or distorted. The speed in making this decision is a measure of implicit memory.

Results demonstrated alcohol intoxication disrupted explicit recall of emotionally negative, emotionally positive and emotionally neutral images. Implicit memory was not affected.

"Alcohol dampens overall emotional reactivity, but the brain still allocates more neural resources for emotional cues compared to neutral ones," Ray said. "And with good reason - emotional memories are important for survival."

Ray believes the emotion-memory connection can help improve alcohol treatment programs.

"If explicit memory processes for emotional cues are affected by alcohol intoxication and implicit processes are not, it’s very important to develop ways for future treatment and prevention programs to exploit these intact implicit memory processes," she continued.

Additionally, alcohol treatment programs that involve some forms of implicit memory may be beneficial for alcohol treatment because they don't rely heavily on the hippocampus, the area of the brain responsible for processing new information. According to Ray, this information is essential because once individuals damage their hippocampus, it may be challenging for them to retain new facts that they learn during treatment.

This study was published in the Journal of Studies on Alcohol and Drugs.