Lingual tactile acuity and food texture preferences among children and their mothers

Abstract

Despite anecdotal reports of children being more sensitive to texture than adults, and of texture being one of the main drivers of food aversions, there is a paucity of scientific knowledge on the influence of texture perception on food choice in children. The primary goals of this study were to assess the use of a modified letter-identification task to study lingual tactile acuity, one aspect of oral sensitivity, in children and to examine age-related differences in sensitivity. The secondary goal was to explore whether lingual tactile acuity and age relate to various measures of food choice and preference. To this end, children 7-10 years old (31 girls, 21 boys) and their mothers were tested using identical procedures. To assess lingual tactile acuity, children and mothers were asked to use the tips of their tongues to identify raised alphabetical letters of varying size (2.5-8.0 mm) on Teflon strips. To relate lingual tactile acuity to food texture preferences, a forced-choice questionnaire assessed preferences for foods similar in flavor but different in texture (e.g., smooth versus crunchy peanut butter). Children were able to complete the lingual acuity task as well as their mothers and took less time to assess each letter stimulus (p < 0.001); however, there were no age-related differences in lingual acuity (p = 0.14). Age, but not lingual acuity, related to food texture preferences: mothers preferred harder foods (p < 0.001) and those containing more particles (p < 0.04) than did children, although children's preferences became more adult-like with increasing age. The availability of a rapid, child-friendly method for assessing oral sensitivity opens up new possibilities of examining differences in oral tactile perceptions across the life span. That food preferences changed with age and were not related to oral sensitivity underscores the fact that factors such as experience, culture and family food practices have a significant impact on children's food texture preferences.

Figure 1. Modified Essick Task

A 10-year-old subject performing the modified Essick letter identification task (A), and tracking grid (B) used to determine lingual acuity thresholds. After placing the embossed Teflon strip on the tongue, the subject was asked to identify the letter either verbally or by pointing to the corresponding letter on a sheet. The tracking grid (B) was used to record the identity of the stimulus given (upper letter) and the subject’s response (lower letter). Testing continued until subject attained eight reversals in performance (circled); the mean of the letter size (mm) of these reversals represents the lingual acuity threshold. For this subject, lingual acuity threshold was 3.94 mm. Parental consent was provided for use of the photograph.

Figure 2

Lingual tactile acuity task performance and lingual acuity threshold by age group: age-related differences in the number of letter stimuli presented between the first and eighth reversal (A), stimulus-identification time (the overall time required to complete the task divided by the number of stimulus presentations) (B), and lingual acuity threshold (C), which could range from 2.5 mm to 8 mm. Different letters indicate significant difference at p ≤ 0.05.

Figure 3

Age-related differences in food texture preference ratios: hard foods (A) and foods with particles (B). For each texture parameter, a preference ratio was calculated by dividing the number of times out of 11 (maximum) that the subject chose the “hard” version of the food as most preferred or the number of times out of 9 (maximum) that they chose the version of the food that contained “more particles” as preferred. Different letters indicate significant difference at p ≤ 0.05.

Figure 4

Particle preference ratio in children who were perceived by their mothers as “less,” “the same,” or “more” picky than other children of similar age. Preference ratios were calculated by dividing the number of times out of 9 (maximum) that they chose the version of the food that contained “more particles” as preferred. Different letters indicate significant difference at p ≤ 0.05.