Museums offer multisensory experiences as visitors move around exhibition spaces with their whole bodies, thus engaging their visual and hearing senses, proprioception (sense of movement and bodily awareness of space), olfaction (sense of smell), and in some exhibits, also touch and taste [see for example Park et al.’s (2022) report of food tourists enjoying varied taste experiences in museum restaurants].

Neurological findings confirm that humans perceive their environments through a converged and combined interaction of individual senses (Spence, 2011). The intensity, enjoyment and memory of an experience depends on the extent to which the relationships between individual senses (the so-called cross-modal correspondences) match or mismatch along some physical, semantic or cognitive characteristics (Driver and Spence, 1998; Knoeferle et al., 2015; Wang et al., 2022). According to the multisensory integration theory (Durgin et al., 2007), the congruence or match between individual senses needs to be spatially and temporally aligned for a smooth and enjoyable sensory experience (Spence, 2009). Senses might also counteract each other’s influence (the so-called cognitive load theories, see Kirschner, 2002). In addition, the individual’s own assumptions, which are based on previous experiences but also inborn differences (e.g., Iarocci and McDonald, 2006), influence the totality of an experience. It follows that the stimulation of individual senses needs to be balanced with the needs of individual visitors who might have sensory sensitivities, which require adjustments to either avoid or enhance the sensory input in museums (Schwartzman and Knowles, 2022).

For children, who are in the early stages of calibrating their sensory apparatus, attention to the ways in which individual senses inter- and counter-act each other is especially pertinent. These complex processes have been predominantly studied with children who have an impairment in one or more senses, often in the context of technologies and remediation approaches. For example Güldenpfennig et al. (2020) studied how specially designed tactile prototypes supported the haptic engagement of visually impaired children and triggered more advanced sensory and cognitive functions. For children with the autism spectrum disorder, who exhibit sensory hypersensitivity or hyposensitivity, innovative, research-based approaches that can improve these children’s participation in daily activities, are vital (Schaaf et al., 2015). The current research and development of accessible sensory technologies can be divided into tools that offer sensory substitution (compensating for lost senses like vision), sensory expansion (broadening current sensory experiences, such as detecting non-visible electromagnetic radiation), and sensory addition (introducing a new sense like magnetoreception, see Eagleman and Perrotta, 2023). But while it is of considerable interest to researchers and software engineers to design environments and resources that would accommodate diverse sensory responses of diverse children, not all types of sensory stimulation (visual, auditory, tactile, taste/smell stimulations) are equally well-studied. Olfactory stimulations are particularly under-studied and that is the case especially for young children.

It is widely known that marketing and consumer research with adults and their olfactory experiences of specific products and places is well-advanced (see Spence and Gallace, 2011 for an overview). For example, the use of ambient scents in galleries has been explored theoretically (Spence, 2020) as well as practically (e.g., in the recent Prado Museum exhibition with odours enhancing Jan Brueghel’s painting). However, research and practical examples of a fully multisensory experience that includes the engagement of all six senses, of museum visitors, and especially child visitors, is lagging behind. Following the critique that children’s educational experiences are focused on the higher senses of vision and hearing, and linguistic and cognitive forms of engagement, the argument for more multimodal (e.g., Jewitt, 2008) and sensory-oriented (e.g., Mills, 2015) learning has been made.

The sensory turn in children’s studies has stimulated scholars’ interest in the role of bodily movements across museum spaces (e.g., Hackett, 2016) and children’s sonic and music experiences in public areas (Gallagher, 2011). The potential of olfaction for children’s literacy learning in particular has been recently highlighted (e.g., Mills et al., 2022). As museums increasingly rest on participatory activities and position children as active and cultural citizens and social participants (Harris and Manatakis, 2013), the need for creating inclusive and empowering multisensory exhibitions that engage all six children’s senses (vision, hearing, touch, smell, taste and proprioception) is even more important. The role of olfaction has been seldom studied in children’s museum studies and is the specific focus for our study.

The loss of olfaction in COVID19 patients during the global pandemic in 2020–2022 led to increased public awareness of the role of smell in fully experiencing the world and leading a fulfilling life (e.g., see Otte et al., 2022). Olfactory researchers have documented the important predictive value of smell in degenerative diseases such as Parkinson’s (e.g., Doty, 2012) as well as the direct link between olfactory processing and emotions (Ehrlichman and Bastone, 1992) and between smell and memory (see Wilson and Stevenson, 2003). The close link between the sense of smell and emotional processing has been harnessed for associative learning and studied in relation to learner motivations (e.g., Herz et al., 2004). For example, research shows a positive contribution of peppermint to alertness and memory (Moss et al., 2008), and positive associations between rosemary, lemon and peppermint on memory and learning performance on video-games (Choi et al., 2022). Students’ preferences for individual smells mediate the learning effect, a concept known as the hedonic value of odors. Overall, odors are likely to be an important feature to integrate into museum exhibitions both in terms of enjoyment and the potential for learning.

The extent to which individuals like specific odors or not has been the subject of several studies concerned with cultural and individual differences in olfactory hedonics. The reason that hedonic perception of odors is so important is that it constitutes the primary response to odors as acceptable or repulsive (Yeshurun and Sobel, 2010) and that plays an important survival role in avoiding dangerous places (for example those that smell of gas or smoke) and finding suitable mating partners (Herz, 2002). While earlier cross-cultural studies documented significant cultural differences between some odors (e.g., with participants from Germany and Japan who differed on which odors they perceived as pleasant or disgusting, Schleidt et al., 1988), more recent systematic comparative data report many similarities (Arshamian et al., 2022; Oleszkiewicz et al., 2022).

Although hedonic perception might differ across populations, the lack of language and olfactory vocabulary to describe different odors (Cain, 1979; Engen, 1987; Majid et al., 2018) is shared across cultures (at least western cultures, see Majid, 2021). The lack of olfactory language is particularly present among young children who are at the early stages of developing their general awareness of the world and words to describe it (Doty et al., 1984; Cain et al., 1995; Lehrner et al., 1999). Children’s olfactory preferences are detectable early on after birth (Schaal, 1988) but change and further develop until adult age (Ventura and Worobey, 2013). Children’s olfactory preferences are varied though often food-related (as shown in our studies in Malawi, Kucirkova and Mwenda Chinula, 2023 and Norway, Kucirkova and Bruheim Jensen, 2023). Recent studies show similarities in children’s olfactory perception across countries (Oleszkiewicz et al., 2022) and provide evidence for the predictive value of early odor perceptions for later life (Lindroos et al., 2022). The recent evidence is thus gradually strengthening the argument that children’s olfactory perceptions, preferences and experiences need to be more intensively studied and stimulated.

With a few exceptions, such as the Montessori kindergarten curriculum, there is a distinct lack of activities that would engage children’s sense of smell and increase their awareness of odors in their environment. Smell remains a largely untapped sense for both learning, play and interaction possibilities in early childhood. This gap presents museums with a valuable opportunity, which we were keen to explore and reflect on.

Museum studies on children and odors are currently few and far between, yet integrating odors into museum exhibitions has the potential to enhance the overall museum experience and what is learned from the experience (Verbeek et al., 2022). It has been shown that odors dispersed throughout a Viking museum acted as retrieval cues for memories of a museum visit several years later (Aggleton and Waskett, 1999). To the best of our knowledge, our research-based exhibition, which integrated odors with a fictional children’s story in a public exhibition at a children’s museum, was the world’s first. We decided to integrate odors with the story in order to strategically make children aware of their sense of smell during a story experience. We have described the participatory approach of academia-museum collaboration in conceptualizing, developing and curating the exhibition (Kucirkova and Gausel, 2023) and the story-related findings (Kucirkova, forthcoming). In this article, we reflect on the lessons learnt from the multisensory and cross-modal integration theories.

To gain insight into hedonic perception in children we analyzed children’s responses about their favorite smells at the exhibition and possible reasons for their hedonic preferences. Each odor was paired with a color and a story character. This allowed us to explore the ways in which crossmodal associations may influence children’s experience of the exhibition. In what follows, we outline the findings based on data collected as part of a research week before the official opening of the exhibition and that we interpret here in light of multisensory and cross-modal integration theories, with attention for their implications for museum curatorship.

The public exhibition was a collaboration between our university research center and a local children’s museum, as well as several other organizations and their representatives, including an olfactory expert, two children’s librarians and a children’s publisher. Capitalizing on the power of story to guide experiences and insights from a prior study in which we interviewed children about their multisensory preferences (Kucirkova and Kamola, 2022), the team members conceptualized an exhibition rooted in a fiction story and augmented with a selection of odors. The story was an adapted version of the traditional fairy-tale The Three Little Pigs, which we embedded into an adventure trail that children could follow in the exhibition area. The trail was aligned with the main storyline and consisted of houses where the three little pigs hid away from the bad wolf chasing them (the straw house, the tree house and the brick house), as well as added props and areas, such as plastic trees, cushions, pigpen for the Mother Pig or cushions and books inside the houses.

The design of the exhibition followed the Nordic tradition of nature-based materials wherever possible with fairly muted colors and reasonable space between the individual props (the exhibition needed to be regulated for the number of visitors to allow for sufficient space). The exhibition was specifically designed for children aged 3–8 years, so all props were child-sized. Nevertheless, there were elements that adults accompanying children could choose to use, such as for example QR codes on posters above the piglets’ houses. The QR codes activated a voice-over for the individual story parts.

Unlike the pigs and their houses, the wolf’s story character was not visually represented in any of the posters or images at the exhibition. However, sounds of the wolf’s whines and his threat that he will blow the piglets’ house down was played throughout the exhibition at regular intervals from the ceiling loudspeakers. While the exhibition was clearly multisensory with the possibilities for children to move around, sit on cushions and touch all props with their various materials and textures, we were particularly keen to integrate olfactory stimulation into the adventure trail. This was achieved through the selection of five specific odors (aromas) that were embedded in specially designed smell boxes.

Children’s answers to the researcher’s interview question about which box they liked and which one they disliked and additional comments, are summarized in Table 1.

Children’s responses to the individual smells indicated that for most of them, the fragrances in the brown, black and yellow boxes were perceived as unpleasant, while the fragrance in the pink box as pleasant. Children generally described the odors with one of two strategies: they either evaluated the smell (e.g., good), or identified the source of the smell (e.g., candies). Only one child used both strategies. Children’s pointing to the boxes with the darker colored handles and their accompanying comments indicated that they did not distinguish the chocolate fragrance as positive but rather perceived all three boxes (yellow, brown, and black) as negative. The imitation of the poo smell in the yellow box placed at the beginning of the adventure trail seemed to have influenced children’s perception and primed them for a negative perception of all subsequent smells. Furthermore, the choice of colours on the handles and inside the boxes may have influenced children’s responses.

The associations conveyed through the posters and olfactory boxes did not seem to be picked up by the children as neither of their comments regarding the individual odors mentioned the pigs and very few of the drawings matched the colors of the pig characters. What seemed to be a clear pattern was children’s responses to their most and least favorite smells and their corresponding colors in the pointing task. In drawings, 18 of the children’s drawings had arbitrary colors. The black and brown colors were attributed to the wolf character, even though in the exhibition, the brown color was associated with the positive chocolate smell in the brick house of the Clever Pig.

Unexpectedly, the odor of chocolate was perceived as unpleasant. This is striking considering it is typically experienced as highly pleasant in adults (Dravnieks et al., 1984), and is likely to be a smell encountered frequently by children in positive contexts. According to the multisensory theory, this was a sub-additive effect of color and olfaction, where the sensory dominance of the visual sense (color brown) took over the olfactory sense (smell of chocolate). Whilst there was sensory congruence in that the color matched the smell quality (semantic congruence) and there was temporal and spatial congruence in that the colors were directly on the handles and the plate, thus not far from the olfactory experience in time or space, the dark brown color prompted children to think that the smell inside the box was the same or similarly unpleasant smell as that in the black wolf box (see Figure 3). Our finding corresponds to studies with adult participants, which found a crossmodal correspondence between odor and color, whereby a change in one directly impacts the other. For example, a study with wine-tasting studies with adult participants found that the color of the wine glass changed the wine tasters’ evaluation of the wine’s odor (Morrot et al., 2001). The color brown is likely to have negatively influenced the perceived pleasantness of the odor due to existing associations between brown and disgusting objects (e.g., poo and rotten food; Palmer and Schloss, 2010). It is possible that seeing the color brown before smelling the odor already lead to negative associations.

Another possible influence of color that we had not anticipated was the color congruence between the color of the pigs depicted on the posters (pink), and the pink color of the smell box for the candy odor. Whilst the odor of candy is likely to be perceived as highly pleasant anyway, it is possible the color congruence heightened such pleasant associations. Other visual features of the smell boxes may also have influenced perception of the odors. Angular shapes, such as the one used in our smell boxes, tend to be associated with more intense and unpleasant odors (Demattè et al., 2006). If our unpleasant smells had been presented in round boxes, children may have perceived them more positively (see also Adams and Doucé, 2017). Furthermore, the fact that children physically manipulated the box to open and close it added haptic stimulation, which could have intensified the perception of the odors by potentially making them too intense at the first encounter. Supportive evidence for this interpretation comes from adult studies (e.g., Delwiche and Pelchat, 2002), so we can only speculate on this interpretation. It has been suggested however that some associations between odor and shape, texture, and color may not develop until after age 6 (Speed et al., 2021). Future work should aim to disentangle the effect of such multisensory features on children’s odor experience in museum contexts.