December 23, 2002
For Immediate Release
Contact: Brian Weaver
(202) 783.2077 ext. 3022
Study Finds that Alcohol Placebo Impairs Memory
In a unique study of memory, scientists have shown that people who believed they were under the influence of alcohol were both more suggestible and more adamant about the accuracy of their eyewitness testimony compared to people who knew they were drinking water.
Two psychology researchers at Victoria University in New Zealand, PhD student Seema Assefi and Dr. Maryanne Garry, show that memory can be affected by an alcohol placebo-in other words, by fake alcohol. Their results will be published in the January 2003 issue of Psychological Science, a journal of the American Psychological Society.
The study reveals new insights into how human memory works, showing social and nonsocial influences on cognitive recall such as eyewitness testimony. Research subjects who believed they had consumed alcohol were more swayed by misleading post-event information and more certain that their memory was correct than those who were told they were drinking water. Other attempts to prove that alcohol placebos could influence memory -- by simply getting people to remember lists of words -- had shown inconclusive relationships.
"We have made people's memory worse by telling them that they were intoxicated even though they had nothing stronger than plain flat tonic water with limes," says Garry. "What our research shows is that memory is not just about filing away information like a computer does. It's much more than that: memory is what we use to understand and remember events in a social setting, such as witnessing a crime. As well, it shows we have more control over our memory than we realize."
In the study, 148 undergraduate students were split into two groups, half told they were getting a vodka tonic and the others told they were getting only tonic water. In reality, all were getting plain tonic. The research was carried out in a room equipped with bartenders, Absolut® vodka bottles, tonic bottles, and glasses, to give the feel of a bar-like setting; flat tonic water was poured from sealed vodka bottles that appeared to be brand new. The deception occurred by rimming glasses with limes dunked in vodka.
Once the students consumed their drinks, they watched a sequence of slides depicting a crime. The participants then read a summary of the crime riddled with misleading information.
"We found people who thought they were intoxicated were more suggestible and made worse eyewitnesses in comparison to those who thought they were sober. In fact the 'vodka and tonic' students acted drunk, some even showing physical signs of intoxication," Assefi said. "When students were told the true nature of the experiment at the completion of the study, many were amazed that they had only received plain tonic, insisting that they had felt drunk at the time."
The complete article and others from the journal Psychological Science are available at www.psychologicalscience.org/media. For more information, contact Garry on 04 463-5402 or Ms Assefi on 04 463-5733.
Psychological Science was ranked among the top 10 general psychology journals for impact on the field by the Institute for Scientific Information. The American Psychological Society's mission focuses on the advancement of research and science-based psychology in the public's interest.