Smells that one cannot detect on their own can be perceived if you sniff and taste at the same time, claims a new study. This finding may help us to appreciate people who complain of unpleasant environmental odours that tests show are below detectable levels. Scientists have known for sometime that efficacy of a single sensory system such as taste can be enhanced if several senses are combined. They tested volunteers starting with benzaldehyde that has a cherry-almond odour and and saccharin, a sweetner. They were asked to rinse their mouths with saccharin and then sniff pairs of odours to decide which has smell. Combining the taste and smell made the odour more obvious