A photo shared on Facebook shows a picture of a rosemary sprig with the caption “Scientists find sniffing rosemary can increase memory by 75%”.
This claim appears to originate from a Daily Mail article published in 2013. The article reported on an academic presentation analysing how the smell of rosemary may improve memory. However, one of the researchers has since said the Mail had incorrectly reported a 7.5% difference.
Researchers presented findings on an experiment with 66 participants, asked to perform memory tests in either rosemary-scented or unscented rooms.
The Mail quotes Northumbria University researcher Jemma McCready as saying: “The difference between the two groups was 60-75 per cent, for example one group would remember to do seven things compared with four tasks completed by those who did not smell the oil, and they were quicker.”
However, this figure was not mentioned in the press release attached to the presentation and other fact checkers have been unable to contact Ms McCready to verify the quote. USA Today and Snopes both spoke to Mark Moss, head of Northumbria University’s psychology department and another researcher on the project, who said the Mail had got it wrong. He told USA Today: “I’m afraid the Daily Mail missed out a decimal point. My research suggests a 7.5% improvement”.
The core research the presentation is based on does not appear to be published online, so we don’t know whether it was peer-reviewed.
Further research in 2017 by Dr Moss appears to support a 7% effect.