A University of Otago study suggests the ability to recognise deceit may wear down with age, making older people less able to lie or recognise they are being lied to.
University of Otago department of psychology researchers Ted Ruffman, Janice Murray and Jamin Halberstadt compared young and old adults' skills at deception as judged by listeners within and outside their age group.
The results of the lie detection test showed both young and old listeners found it easier to differentiate truths and lies when the speaker was an older adult compared to a young adult, Associate Professor Halberstadt said.
Video clips of 20 people - 10 aged 30 or under and 10 aged more than 60 -- expressing their actual or false views on topical issues were shown to participants. Two clips of each speaker were shown, one in which they were lying and the other being truthful.
The listeners, of two equal-sized groups with average ages of 21 and 71, were asked to determine if the person in each clip was being truthful or lying. They also underwent tests that required judgments of emotional expression and age in faces.
Lying placed demands on memory and planning ability and on social understanding. The findings related to similar findings on older people's inability to detect social gaffes and older men's tendencies to ramble and go off topic when talking, Prof Halberstadt said.
"We still don't know what exactly allows listeners to correctly detect lies, although we know that people can differentiate lies and truth at a rate above chance level, though they are far from perfect."
Prof Halberstadt said it would be interesting to study whether older adults' difficulties telling and detecting lies affected their susceptibility to fraud schemes and their general social well-being.
"As well as problems arising from being more easily deceived, a reduced ability to tell white lies that spare others' feelings may impair their relationships, for example."
The findings are to be published in US journal Psychology and Aging. Dr Murray presented the study today at the Association of Psychological Science's annual convention in Washington, DC.