We receive constant environmental input through our five senses.
Combining information from two or more senses, such as between odours and the
smoothness of textures, pitch, colour, and musical dimensions, is one way our
brain makes sense of this flood of information.
As a result of this sensory integration, we also link certain
colours to the flavours of specific meals, such as the flavour of oranges with
the colour of the same name, and greater temperatures with warmer colours,
lower sound pitches with less elevated places, and so on.
Now, a study published in Frontiers in Psychology has
experimentally demonstrated that such unintentional links with our sense of
smell might influence how we perceive colours.
“Here we show that the presence of different odours influences how
humans perceive colour,” said lead author Dr Ryan Ward, a senior lecturer at
Liverpool John Moores University in Liverpool, UK.
Ward and colleagues tested for the existence and strength of odour-colour
associations in 24 adult women and men between 20 and 57 years of age.
The participants were seated in front of a screen in a room devoid
of unwanted sensory stimuli for the duration of the experiments. They wore no
deodorants or perfumes, and none reported being colour-blind or having an
impaired sense of smell.
All ambient odours in the isolation room were purged with an air
purifier for four minutes. Then one of six odours (chosen at random from
caramel, cherry, coffee, lemon, and peppermint, plus odourless water as a
control) was broadcast into the room with an ultrasonic diffuser for five
minutes.
“In a previous study, we had shown that the odour of caramel
commonly constitutes a cross modal association with dark brown and yellow, just
like coffee with dark brown and red, cherry with pink, red, and purple,
peppermint with green and blue, and lemon with yellow, green, and pink,”
explained Ward.
Participants were presented with a screen that showed them a square
filled with a random colour (from an infinite range) and were invited to
manually adjust two sliders – one for yellow to blue, and another for green to
red – to change its colour to neutral grey.
After the final choice had been recorded, the procedure was
repeated, until all odours had been presented five times.
The results showed that participants had a weak but significant
tendency to adjust one or both of the sliders too far away from neutral grey.
For example, when presented with the odour of coffee, they wrongly
perceived ‘grey’ to be more of a red-brown colour than true neutral grey.
Likewise, when presented with the odour of caramel, they wrongly
perceived a colour enriched in blue as grey. The presence of the smell thus
distorted the participants’ colour perception in a predictable manner.
An exception was when the odour of peppermint was presented: here,
the participants’ choice of hue was different from the typical cross modal
association demonstrated for the other odours.
As expected, the participants’ selection likewise corresponded to
true grey when presented with the neutral scent of water.
“These results show that the perception of grey tended towards
their anticipated cross modal correspondences for four out of five scents,
namely lemon, caramel, cherry, and coffee,” said Ward.
“This ‘overcompensation’ suggests that the role of cross modal associations
in processing sensory input is strong enough to influence how we perceive
information from different senses, here between odours and colours.”
ANI
