Chemical Senses Vol. 30 No. suppl 1 © Oxford University
Press 2005; all rights reserved
The Effect of Visual Images on Perception of Odors
1 Kobe Shoin Women’s University, 2 Hiroshima Shudo University, 3 National Institute of Advanced Industrial Science and Technology (AIST) and 4 Takasago International Corporation
Correspondence to be sent to: Nobuyuki Sakai, e-mail: nob-sakai{at}shoin.ac.jp
Key words: appropriateness, cognition, hedonics, intensity, odor, visual stimuli
 |
Introduction |
|---|
 Top Introduction Colors and flavorsVisual images and odorsCognition and odor perceptionReferences |
|---|
We make full use of our sensory system, chiefly the visual system, to recognize objects around us. The visual and auditory systems are extroceptive systems, which can detect an object from a distance. On the other hand, gustatory and somatosentory systems are introceptive systems, which can detect an object only when the object is located near us. The olfactory system has both extroceptive and introceptive characteristics. But the effective distance from objects for theolfactory system is nearer than for the visual system. Thus it is highly adaptive to depend on the visual system to recognize objects in the external world.
We recognize an object firstly by the visual system and then we turn our attention to
the object and determine its other sensory characteristics, e.g. its odor. As
Dalton (2002
) described in her review,
olfaction has a strong tendency to be affected by top-down (or conceptually driven)
processes. Thus, it is hypothesized that we perceive and recognize an object’s odor
under the influence of a top-down process driven by the visual system.
In this paper, we first review the research on effects of vision (color) on olfactory perception and then we review studies concerning the effects of visual images (pictures) on olfactory perception. We then introduce a concept of this phenomenon.
|
Colors and flavors |
|---|
|
TopIntroductionColors and flavorsVisual images and odorsCognition and odor perceptionReferences |
|---|
Some researchers have reported that colors of odor stimuli affect identification of odors. Blackwell (1995
) reported that
participants misidentified orange flavor solution as lime when it was colored green.
Morrot et al. (2001) found
that red-colored white wine was identified as red wine by 54 tasters.
Sakai (2004) found that almost all
participants correctly identified a cola-flavored solution when it was colored dark
brown, but that many participants misidentified a cola-flavored solution as orange or tea
flavor when it was colored orange. On the other hand, an orange-flavored solution was
correctly identified when it was colored orange, but it was misidentified as tea or grape
flavor when it was colored dark brown. These results show there are many pairings of
colors and flavors that show interactions, suggesting that these interactions occur t a
cognitive level, not at a peripheral or physicochemical level. The reason for this phenomenon is explained using the association between the olfactory and visual systems. We make associations between odors and colors, e.g. cola flavor and black solution, orange flavor and orange solution and so on, through daily experience. According to this cognitive mechanism model, we make an association between the flavor and the color of a beverage and we retain this association in the brain. When we see the color of the beverage again, we have an expectation of the flavor of the beverage. Thus, when the ‘real’ flavor is the same as our expectation of the flavor, we can easily identify the flavor. These pairings of flavors and colors are called ‘appropriateness’, ‘congruency’, or ‘matching’. On the other hand, when the ‘real’ flavor is different from the expectated flavor, we must cancel the initial expectation and then concentrate our attention on perception of the actual flavor.
This hypothesis is supported by the work of
Zellner et al. (1991), who
found that participants identified flavors more correctly when they were appropriately
(e.g. red–strawberry) colored than when they were colored inappropriately
(red–lemon). They also showed that participants took more reaction time to identify
flavors in inappropriate combinations of color and flavor than in appropriate
combinations.
In contrast to these results of flavor identification, the effects of color on flavor
intensity are complicated. For example,
Zellner and Kautz (1990) found that
flavor solutions with color were judged as smelling more intensely than equally
concentrated flavor solutions without color. However, there is no difference in
enhancement between appropriately colored solutions and inappropriately colored
solutions.
Zellner and Whitten (1999) also
reported that coloring of the flavored solution enhanced perceived odor intensity and
that color appropriateness had only a small effect on evaluation of odor intensity. In
this study, color intensity, rather than color appropriateness, had more effect on
perceived intensity of odor. They discussed appropriateness of color as a ‘trivial
contributor’ for color-induced odor enhancement.
This inconsistency in the effect of appropriateness of color on odor perception can be interpreted as follows. When we are asked to evaluate the intensity of an odor, we concentrate our attention on odor intensity. In other words, in this case, we do not pay attention to what the odor is or whether we identify the odor correctly or incorrectly. Thus, color only enhances our expectation of odor intensity. In this point of view, the color may not be enough to evoke a strong (or concrete) image of an odorous object.
|
Visual images and odors |
|---|
|
TopIntroductionColors and flavorsVisual images and odorsCognition and odor perceptionReferences |
|---|
Although the preceding studies used only flavors and colors, we also experience aromas, visual images (shapes, movement and so on) and their interactions. In our everyday lives, we simultaneously experience odor and visual images of objects from which the odors may come. Thus, it is better to use visual images (e.g. pictures or movies) than colors when we want to evoke more real images of odorous objects.
Here, a part of the authors’ study is introduced. Twenty-four healthy
university students participated in this study. Nine odors from the set of the Odor Stick
Identification Test (Saito et al.,
2003) and several pictures for each odor were used as stimuli of odors and
visual images, respectively.
First, participants were asked to smell an odor and to evaluate their preference for the odor. After evaluation of odors, the participants were presented nine pictures and asked to select a picture that was most appropriate for the odor and a picture that was least appropriate for the odor. Participants repeated this procedure nine times (for each of the nine odors).
Participants were then asked to evaluate the intensity of and their preference for an odor presented with pictures, one of which (X) was most appropriate for the odor and the other (Y) was inappropriate for the odor. Participants repeated this procedure for each of the nine odors (thus, they evaluated 18 times in this experiment). When the odor was presented with X, the evaluated intensity was significantly higher than in the case when it was presented with Y. From this result it is suggested that appropriate pictures enhanced evaluation of odor intensity.
Preference ratings for odors which rated as preferable in the preliminary study were significantly higher when they were presented with picture X than those presented with picture Y. On the other hand, preference ratings for odors which were rated as undesirable in the preliminary study were significantly lower when they were presented with picture X than those presented with picture Y. Thus, it is suggested that appropriate pictures also enhanced evaluation of odor preference.
|
Cognition and odor perception |
|---|
|
TopIntroductionColors and flavorsVisual images and odorsCognition and odor perceptionReferences |
|---|
These results seem to indicate that the visual stimulus used in this study had evoked the object’s image strongly enough to give rise to an expectation of the object’s odor. Then, this expectation enhanced the perceived intensity and preference for the odor. These results have been supported by several studies, which used words instead of visual images to evoke expectation for odors.
Dalton (1996) found that participants
who were told that the odor was a ‘natural’ or ‘healthy’ extract
showed adaptation to the odor, but that participants who were told that the odor was
hazardous showed sensitization to the odor.
Sakai et al. (2004) also
found that participants who received negative information about an odor showed weaker
adaptation to the odor than those who received positive information about the odor. These
studies suggest that information about an odor led to the formation of an expectation for
the odor and that this expectation affected perception of the odor.
Distel and Hudson (2001) found that
participants appropriately informed about an odor identified the odor more correctly than
those informed inappropriately. They also found that appropriately informed participants
evaluate an odor as being more intense than those informed inappropriately. These results
are consistent with those reported here, in which pictures were used instead of verbally
presented information. Thus, it is suggested that words, pictures and colors evoke common
mental images for objects and that these mental images lead us to form expectations to
the odors.
Several studies have reported that olfactory images for tastes are developed by
association between vision and olfaction (e.g.
Stevenson et al., 1998;
Sakai and Imada, 2003). It is
conceivable that associations between vision and olfaction in our daily lives also
develop visual images for odors. The association between visual images and odors still
remains unclear.
|
References |
|---|
|
TopIntroductionColors and flavorsVisual images and odorsCognition and odor perceptionReferences |
|---|
Blackwell, L. (1995) Visual cues and their effects on odour assessment. Nutr. Food Sci., 5, 24–28.
Dalton, P. (1996) Odor perception and beliefs about risk. Chem. Senses, 21, 447–458.
Dalton, P. (2002) Olfaction. In Yantis, S. and Pashler, H. (eds), Steven’s Handbook of Experimental Psychology, Vol. 1, Sensation and Perception, 3rd edn. John Wiley, New York, pp. 691–746.
Davis, R.G. (1981) The role of nonolfactory context cues in odor identification. Percept. Psychophys., 30, 83–89.[Web of Science][Medline]
Distel, H. and Hudson, R. (2001) Judgement of odor intensity is influenced by subjects’ knowledge of the odor source. Chem. Senses, 26, 247–251.
Morrot, G., Brochet, F. and Dubourdieu, D. (2001) The color of odors. Brain Lang., 79, 309–320.[CrossRef][Web of Science][Medline]
Sakai, N. (2004) The effect of visual stimuli on perception of flavor. Poster presented at ISOT 2004.
Sakai, N. and Imada, S. (2003) Bilateral lesions of the insular cortex or of the prefrontal cortex block the association between taste and odor in the rat. Neurobiol. Learn. Mem., 80, 24–31.[CrossRef][Web of Science][Medline]
Sakai, N., Kobayakawa, T. and Saito, S. (2004) Effect of description of odor on perception and adaptation of the odor. J. Jpn. Assoc. Odor Environ., 35, 22–25 [in Japanese].[CrossRef]
Saito, S., Ayabe-Kanamura, S., Naito, N., Gotow, N., Kobayakawa, T., Mise, M. and Takashima, Y. (2003) Development of an odor identification test for Japanese people: verification of stick type and card type. J. Jpn. Associ. Odor Environ., 34, 1–6 [in Japanese].
Stevenson, R.J., Boakes, R.A. and Prescott, J. (1998) Changes in odor sweetness resulting from implicit learning of a simultaneous odor–sweetness association: an example of learned synesthesia. Learn. Motiv., 29, 113–132.[CrossRef][Web of Science]
Zellner, D.A. and Kautz, M.A. (1990) Color affects perceived odor intensity. J. Exp. Psychol. Hum. Percept. Perform., 16, 391–397.[CrossRef][Web of Science][Medline]
Zellner, D.A. and Whitten, L.A. (1999) The effect of color intensity and appropriateness on color-induced odor enhancement. Am. J. Psychol., 112, 585–604.[CrossRef][Web of Science][Medline]
Zellner, D.A., Bartoli, A.M. and Eckard, R. (1991) Influence of color on odor identification and liking ratings. Am. J. Psychol., 104, 547–561.[CrossRef][Web of Science][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. L. Dematte, D. Sanabria, and C. Spence Olfactory Discrimination: When Vision Matters? Chem Senses, February 1, 2009; 34(2): 103 - 109. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Gaygen and A. Hedge Effect of Acute Exposure to a Complex Fragrance on Lexical Decision Performance Chem Senses, January 1, 2009; 34(1): 85 - 91. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M Luisa Dematte, D. Sanabria, and C. Spence Cross-Modal Associations Between Odors and Colors Chem Senses, July 1, 2006; 31(6): 531 - 538. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||