Time, Age, Gender, and Test Practice Effects on Children’s Olfactory Performance: a Two-Year Longitudinal Study

Six-week engagement in after-school activities involving chemosensory education does not affect olfactory abilities and personal significance of olfaction in 9-11-year-olds: Preliminary evidence

Chemosensory learning is a lifelong process of acquiring perceptual expertise and semantic knowledge about chemical stimuli within the everyday environment. In the research context, it is usually simulated using olfactory training, which typically involves repeated exposure to a set of odors over a period of time. Following olfactory training, enhanced olfactory performance has been observed in adults, and similar evidence is beginning to emerge in children. However, the literature is scant concerning the effects of interventions that more closely resemble how chemosensory experience is acquired in daily life. Since children's chemosensory ecology appears to play a crucial role in olfactory development, we investigated whether engaging in activities that stimulate the chemical senses enhances olfactory performance and metacognition. To this end, we invited 20 children aged 9-11 years to participate in teacher-assisted after-school activities for 30-60 minutes a day for six weeks. During the odd weeks, the children appraised herbal and spice blends and used them to prepare dishes and make beauty products. During the even ones, they explored the city by smellwalking and created smellscape maps. The educational outcomes were evaluated using the Sniffin' Sticks test for odor identification and discrimination and the Children's Personal Significance of Olfaction. Bayesian analyses did not reveal any compelling evidence in support of the alternative hypothesis that children in the chemosensory education group outperform those in the comparison group at the post-test. Rates of reliable increase but also decrease in performance on the Sniffin' Sticks identification and discrimination tests were similar in both groups. We corroborated the previous findings regarding girls' and older children's greater proficiency at identifying odors and the female keener interest in the sense of smell. We offer several practical suggestions researchers may want to consider to tailor their research protocols to reflect more closely the broader context in which chemosensory learning takes place and better capture the nuanced outcomes of such interventions.

Children's odor pleasantness ratings may not differ according to pubertal status: Preliminary results from a sample of 11-14-year-old Czech children

Puberty tends to be viewed as a "turning point" in hedonic perception of body odor (BO)-related smells. The pubertal stage, a potential proxy for the underlying physiological changes, may contribute to variation in odor hedonic perception. Other potential modulators of odor hedonics are general semantic knowledge about odors (which also tends to be subsumed under the term "age") and perceived odor intensity. The present cross-sectional study examined differences in hedonic odor perception across puberty in 205 Czech children aged 11-14 (89 boys). We investigated whether children differ in the hedonic appraisal of BO-related (16-androstenes and castoreum control), but also food and non-food odors according to their pubertal (penis/breast and pubic hair) development and general semantic knowledge about odors (operationalized as odor identification), controlling for age and perceived odor intensity. As a subsidiary aim, we examined variation in odor identification. We asked the children to self-stage themselves using drawings depicting Tanner's penis/breast and pubic hair stages of pubertal development, estimated their general semantic knowledge about odors with a Sniffin' Sticks identification test, and obtained their pleasantness and intensity ratings of body odor-related, food, a non-food smells. We found that the participants' ratings of the 16-androstenes and those of the perceptually similar odor of castoreum differed according to perceived intensity and, in the latter case, in boys vs. girls as well, but there were no influences of pubertal status or odor identification on the perceived pleasantness. Similarly, hedonic appraisal of non-food (but not food) odors was only influenced by perceived intensity. Regarding odor identification, differences between boys and girls were limited to younger children and did not become more marked throughout puberty. Perceived pleasantness of odors, irrespective of whether they are associated with body smells, food, or other, does not appear to vary across puberty, and boys and girls seem to achieve similar levels of semantic odor knowledge as they grow up.