Do you recall your early years in grade school when
your science teacher would ask you the five basic senses and then your whole
class would reply in unison with “sight, smell, hearing, taste and touch”?
Those truly were the good old days when everything was plain and simple. We
were taught how our senses perform their tasks independently and there was little
mixing between them aside from those that are obvious and readily observable.
But we know through experience that we
interpret our environment based on the collective information that our senses
detect. We recognize how our sense of smell and sense of taste go together; in
fact we can observe this personally whenever we have a really bad cold. Then
you can also say that vision and hearing are connected especially when
observing moving objects. But what about our vision and smell, or vision and taste,
are they even remotely connected? Can we actually know the color of scents and taste?
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| Low Sensitivity Sense of Smell... Yikes! |
Unlike the
data from our other senses that need decoding, the information we get from out
sense of smell goes directly to the cortex of our brain for immediate
processing. This, however, does not mean that our sense of smell is the fastest
among all the senses that we have. In fact it requires about 400 ms before we
can detect smells, which is 10x slower than our vision (Herz & Engen, 1996
as cited in Morrot et al). Moreover our sense of smell is relatively weak
compared to our other senses, which means that we actually use our other senses
when we try to interpret odors and scents. Of course this is not a bad thing.
It simply tells us that we use our other senses to compensate for the relative
weakness of our noses and generally, we confirm what we smell by what our other
senses observe. Problems, however, arise when signals that we detect with our
other senses contrast with what we pick up with our nose (or as we can see in
the picture above, when stronger scents like room fresheners can overpower foul
smells, in that case we are unable to detect the weaker scent).
Back in 2001, Morrot and his colleagues conducted a
very interesting study on the interference between our sense of smell and our
vision. This study, I guarantee, would interest wine enthusiasts out there for
in this study, Morrot showed that even experts in wine tasting can be fooled by
a simple odorless food color.
Wines,
especially to the nose of the experts, have very distinct smell. According to
the research white wine odor descriptors include floral, honey, citrus, apple,
banana etc. while red wine odor descriptors include wooded, cherry, raspberry.
When the wines are presented in the correct color, wine experts have no trouble
describing the scents and flavors. In other words, red wines were given typical
red wine descriptions and the same goes for white wines.
The question now is, would they still be able to
distinguish the red wines from the white wines if they are all presented looking
like red wines? Many would think that without a doubt wine experts would be
able to distinguish the two for they are experts in their fields, but
apparently this was not the case.
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| Sneaky, Sneaky... |
Although the wine experts were asked to
describe the given wines based on their scent alone, Morrot and his team
observed that color indeed played a large role in the description process. White
wines were consistently perceived as having red wine scents when they were
artificially colored red. The color of the presented wine misled the experts in
judging the scent and flavor of the wines. Moreover, this error happened more
regularly in the presence than in the absence of access to the wine color
(higher dependence on visual cues when contradicting pieces of information are
presented).
This
is consistent with the finding of previous researches where changing the
green-ness and yellow-ness of a lemon flavored sugar solution changed people’s
rating of its sweetness. Furthermore, Sakai showed that this perceptual
illusion is not exclusive to wines. In a research he conducted in 2004 (as
cited in Sakai, Imada, Saito, Kobayakawa, Deguchi, 2004), he found out that
people tend to misjudge the flavor of sodas when presented in a color that is
not typically associated with it (orange-flavored solution was correctly
identified when it was colored orange but was misidentified as tea or grape
flavor when it was colored dark brown).
These
results however were not seen in a similar experiment by Ballester and colleagues
(2009). They presented a total of 18 wines (white, red, and rose) in dark
colored glasses to wine experts and wine novices and determined that both
novices and experts were able to distinguish between red and white wines but
not rose wines. This opposes the results produced by Morrot’s group that smell
perception highly depends on color.
Which,
then, among the results are the most accurate in describing our sense of smell?
I don’t know for sure either. I for one believe that my smelling skill is highly
influenced by what I see. I don’t have a good sense of smell or really
sensitive taste buds so I can generally say that I partially taste and smell
with my eyes (this is why I really feel queasy when watching the new colored
ketchup advertisement). I imagine the blue ketchup tasting like blueberries or
bubblegum while the green one like broccoli (and I don’t really think that
those are good combinations).
Anyway, the difference between the results
from Morrot’s and Ballester’s study may have been due to the fact that there
was a significant difference in how they conducted the experiment. Morrot’s
group actively manipulated the color of the wines presented whereas Ballester
simply placed the different types of wines in dark tinted containers to prevent
the wine assessors from judging based on color. Since we have the tendency to
interpret scent signals in conjunction with other sensory information, we are
inclined to look for other cues to confirm what we have detected using our
sense of smell. My speculation on this
is that the participants in Ballester’s study may have focused more on the
scent because of the ambiguity in color (all wines seen on a darkly tinted
glass). Since the dark tinted glasses would ideally make the wines appear as if
they were of the same color, there was minimal interference between the scent
and the color of the wines (color, in that case, was not a good indicator of
the type of wine presented). Whereas Morrot provided clear cues on the color of
the wines, which may have given the assessors a clue to what type of wine was
provided (although it was misleading information). In this case, the knowledge
of the color of the wine directly influenced how the experts perceived the
scents and maybe since vision is more sensitive than the sense of smell, the
knowledge of the color took precedence oven the actual perceived scent.
I
shall reinstate that the last few paragraphs are just speculations. So let me
know what you think! Do you believe that color affects the way we perceive
scents and tastes?
Sources:
Ballester,
J., Abdi, H., Langlois, J., Peyron, D., & Valentin, D. (2009). The Odor of
Colors: Can Wine Experts and Novices Distinguish the Odors of White, Red and
Rose Wines? Chemosensory Perception , 2 (4), 203-213.
Morrot,
G., Brochet, F., & Dubourdieu, D. (2001). The Color of Odors. Brain and
Language , 79, 309-320.
Sakai,
N., Imada, S., Saito, S., Kobayakawa, T., & Deguchi, Y. (2005). The Effect
of Visual Images on Perception. Chemical Senses , 30 (1),
244-245.
Image Sources:
- Colored Soda
http://pixel.brit.co/wp-content/uploads/2014/06/rainbow-soda-bar-645x4291.jpg
- 5 Senses
http://cdns2.freepik.com/free-photo/_62147502195.jpg
- Febreze Social Experiment
http://theinspirationroom.com/daily/experience/2012/6/febreze-breathe-happy-social-experiment.jpg
- Glass with Food Color
https://buddyjournal.files.wordpress.com/2011/08/smoke-27in.jpg
- UFC Colored Ketchup
https://fbcdn-photos-g-a.akamaihd.net/hphotos-ak-xpf1/v/t1.0-0/p480x480/10801588_1686858324883278_8425796780354854249_n.jpg?oh=792e49e2bf64579eebb81191c76dce41&oe=56A14B83&__gda__=1449448232_ac81b6aeddd8c16011091cd2c0a376f0
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