Chewing gum harms short-term memory contrary to previous studies that suggested gum could improve recall, according to researchers.
Michail Kozlov et al. at Cardiff University in the UK have claimed that chewing gum negatively impacts short term memory (STM) in the same way as a peripheral speech impairment.
The study ‘Gummed-up memory: Chewing gum impairs short-term recall’, published in the Quarterly Journal of Experimental Psychology, challenges assertions by earlier studies that chewing gum benefits STM (Baker et.al 2004, Stephens & Tunney 2004, Wilkinson et. al 2002).
Questions earlier research
“We show for the first time that fundamental aspects of STM – recall of both order and item identity – are in fact impaired by chewing gum,” said the researchers.
“It is striking that none of the studies that have examined the effects of chewing gum on STM have employed the classic test of STM capacity – that is the reproduction of a short sequence of items,” they continued.
The study used three tests to determine the impact of chewing gum on STM.
Firstly, around 40 students were asked to chew flavourless gum vigorously and remember a sequence of seven randomly ordered letters (e.g. P, V, B, C, D, G, T). A smaller sample was then asked to repeat the experiment, but told to chew naturally.
In the second test, students chewed flavourless gum and were tasked to find the missing item in a sequence (e.g. seven is missing from the list: 28149365).
In both tests gum chewing was found to harm STM.
Finally, participants were asked to tap their fingers rather than chew gum and repeat the second test to compare the differences between chewing and tapping.
The two activities were found to be markedly similar; both impairing memory recall.
Flavour may reduce the impact
The researchers warned that a flavoured gum could possibly offset the negative impact on short-term memory.
“However, because chewing gum usually loses its flavour after several minutes of chewing…it seems advisable, that chewing gum is only considered a performance enhancer as long as flavour lasts.”
Michail D. Kozlov, Robert W. Hughes & Dylan M. Jones (2011): Gummed-up memory: Chewing gum impairs short-term recall, The Quarterly Journal of Experimental Psychology, DOI:10.1080/17470218.2011.629054