Wellington (dpa) - The affects of alcohol are partly psychological said researchers on Tuesday, reporting the results of a study showing that memory can be affected by plain water if people think they are drinking alcohol.
"We have made people's memory worse by telling them that they were intoxicated even though they had drunk nothing stronger than plain flat tonic water with limes," said Dr Maryanne Garry, senior psychology lecturer at Wellington's Victoria University.
Garry and her student Seema Assefi split 148 undergraduates into two groups, telling half they were getting vodka and tonic and the rest just tonic water.
But in reality the "drinkers" also got plain tonic water poured from sealed vodka bottles that appeared brand new.
Assefi said all the students then watched a sequence of slides depicting a crime and read a summary that was deliberately riddled with misleading information.
"We found people who thought they were intoxicated were more suggestible and made worse eyewitnesses compared to those who thought they were sober," she said.
"In fact, the vodka and tonic students acted drunk, some even showing physical signs of intoxication.
"When told the true nature of the experiment, many were amazed that they had only received plain tonic, insisting they had felt drunk at the time," Assefi said.
Garry said: "It showed that even thinking you've been drinking affects your behaviour.
"The male students flirted with Seema as she conducted the experiment and the girls giggled a lot."
Garry said the research had given new insights into how human memory works and how both social and non-social influences can affect a person's recall of events.
"Those who believed they had consumed alcohol were more swayed by misleading information and more certain their memory was correct than those who were told they were drinking tonic water."
They said the results of their research will be published in next month's issue of Psychological Science, published by the American Psychological Association.
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