Sensory properties of products represent the most ‘objective’ component of product experience. Indeed, whether we like it or not, we smell the food while cooking it, hear the sound of a vacuum cleaner while cleaning a room, and feel the bumps of the road while driving. Sensory experiences tie us to the material world and to the objects that make up our environment. Nevertheless, sensory experiences are not immune to the ‘subjectivity’ of our affective reactions, symbolic meanings, beliefs, and values that we attribute to products.
Almost all product experiences have associations with more than one sensory modality. The color of a dress can be ‘loud’; the voice of a singer can be ‘sweet’, and so on. Most of our product experiences are multisensory (Fenko et al., 2010a; Schifferstein & Spence, 2008). Our perception of a product is based on the integration of information gathered from different perceptual modalities: the products we perceive have shapes, colors, movements, but also sounds, odors and textures sensed through active touch. The senses interact and influence each other in extraordinary and sometimes unexpected ways. As a result, what we experience may be different from what our sensory systems have initially encoded.
People’s perception of the attributes of a product in a given sensory modality is frequently affected by the sensations that are simultaneously being perceived by another modality. For example, in a classic study, Laird (1932) found that women evaluated the quality of silk stockings more positively when they were scented with a narcissus scent compared to their natural (slightly rancid) scent. Demattè, Sanabria, Sugarman, and Spence (2006) followed up on Laird’s (1932) study. The participants in their experiment were asked to rate the perceived softness of fabric samples impregnated with different fragrances. Fabrics were rated as significantly softer when presented with a lemon or lavender odor than when presented with an animal-like odor. In another study, Zampini, Guest, and Spence (2003) asked their participants to evaluate the roughness of an electric toothbrush. The toothbrush was judged to be rougher when the overall sound level increased and when the high-frequency sounds were amplified. The same type of auditory manipulation has also been found to affect the perceived forcefulness of aerosol spray sounds (Zampini & Spence, 2007), the level of perceived carbonation in sparkling water drinks (Zampini & Spence, 2005), and the perceived crispness of potato chips (Zampini & Spence, 2004). Research on odor-texture interactions has shown that increasing the hardness of a gel leads to a decrease in perceived intensity of its flavor, while flavor release from the gel is hardly affected (Bult, de Wijk, & Hummel, 2007; Weel et al., 2002). Furthermore, essentially tasteless odorants may enhance the perceived intensity of a specific taste (Frank, van der Klaauw, & Schifferstein, 1993).
Correspondences that people perceive across different sensory modalities can be formed through prior experience (Spence, 2012). If certain pairs of sensory stimuli are more likely to occur together, people might perceive some resemblances among colors, sounds, tastes, smells, and other sensory stimuli. Cross-modal correspondences can be also linguistically mediated. For instance, pretty much every language uses the same words, “low” and “high,” to describe stimuli that vary in pitch. In addition, sensory experiences may be associated with symbolic meaning. For instance, the experience of warmth has both a literal aspect, associated with the thermal characteristics of products, and a figurative aspect associated with the metaphorical meaning of warmth (i.e., intimacy).
To study the importance of visual and tactile product properties on the multisensory experience of warmth, Fenko et al. (2010b) designed products (scarves and breakfast tables, see Figure 4) using warm and cold stimuli (colors and materials) in four different combinations and asked respondents to evaluate the warmth and pleasantness of each product. The results demonstrated that both color and material contribute equally to the judgments of warmth in both products. Spontaneous comments suggest that participants of the study assessed dark scarves as warmer, because they considered dark colors more suitable for a winter outfit than light colors. Surprisingly, wool had a lower warmth rating than fleece; in this case respondents commented that they did not like wool because it irritated their skin. This study demonstrates that sensory product experiences can be influenced by perceived product appropriateness. For instance, red and yellow are usually perceived as warm colors, while blue and green as cold colors (Wright, 1962). However, green scarves were rated higher on warmth than yellow scarves (Fenko et al., 2010). Participants commented that yellow is ‘too bright and more suitable for a spring scarf’, while green is ‘darker and more suitable for a warm winter scarf’.
Freshness is another example of multisensory product experience that can trigger different affective response. In the experimental study Fenko et al. (2009) created products (soft drinks, dishwashing liquids, and scented candles, see Figure 5) using fresh and non-fresh stimuli (colors and smells) in four different combinations and asked respondents to evaluate the freshness and pleasantness of each product. The results demonstrated that smell dominated the judgments of freshness for soft drinks and dishwashing liquids. However, for scented candles smell and color were equally important in determining freshness. These results imply that sensory dominance may differ between product categories. The results also indicate that negative emotions were mainly triggered by the inconsistent combinations of olfactory and visual stimuli rather than by the unpleasant smell as such.
Product noisiness is a multisensory product experience that integrates auditory and visual components. Fenko et al. (2011) manipulated auditory and visual properties of alarm clocks and whistle kettles to find out to what extent the overall product noisiness depended on sounds these products made, or could be influenced by the visual appearance of the products (see Figure 6). The results demonstrated that the overall experiences of noisiness and annoyance were influenced mainly by the sound. The noisiness of the sound had a negative influence on the overall pleasantness of the products. However, the results showed differences in sound experience between products. While mean noisiness ratings for whistle kettles varied depending on sound frequency and complexity, all alarm clock sounds were assessed as quite noisy. This result may be explained by a difference in affective associations attached to these two products. The sound of a whistling kettle may be associated with the pleasant experience of making tea, while the sound of an alarm clock is typically associated with the unpleasant experience of waking up early in the morning. These memories may influence the experience of noisiness of product sounds, suggesting that perception of sensory product properties depends on previous experience and affective associations.
The importance of a particular sensory modality in product experience depends on the type of product, the stage of user-product interaction, and the language that is used to conceptualize and communicate the experience (Fenko & Schifferstein, 2012). During the various stages of user–product interactions, different sensory modalities may be important. Schifferstein et al. (2013) investigated how a dehydrated food product was experienced at different stages of product usage: choosing a product on a supermarket shelf, opening a package, cooking and eating the food. At the buying stage, vision was the most important modality, followed by taste. This result is in line with previous research (Fenko et al., 2009), which demonstrated the dominance of vision at the buying stage for a variety of industrial products. Smell was dominant at the cooking stage, and taste was the most important sensation while eating the food. The most surprising finding in regard to sensory importance dynamics was the relatively high rating of taste at the buying stage, although participants had no actual gustatory sensations. This result shows that the answers may reflect not only actual sensory experiences, but also people’s expectations or ideas of what they might or should experience.