Consistency of sensory testing with 4- and 5-year-old children
Introduction
Children ranging in age from 0–10 years prefer higher concentrations of sucrose in foods than adults (De Graaf & Zandstra, 1999; Desor & Beauchamp, 1987; Desor, Greene, & Maller, 1975; Enns, Van Itallie, & Grinker, 1979; Zandstra & De Graaf, 1998). Furthermore, it has been suggested that children are less sensitive to sweet taste than adults (De Graaf & Zandstra, 1999; James, Laing, Oram, & Hutchinson, 1999; Kimmel, Sigman-Grant, & Guinard, 1994; Zandstra & De Graaf, 1998). In order to investigate what children prefer, and which levels of sweet they are able to discriminate, reliable sensory tests are needed. Tests that are reliable for adults do not always give reliable information when used with young children. In general, children tend to answer in the affirmative way, and have less experience with scales than most adults (Guinard, 2001).
Rank-order and paired comparison tests are the two most widely used methods to measure sensory perception and preferences in young children (Birch, 1979, Birch, 1980a, Birch, 1980b; Birch & Marlin, 1982; Guthrie, Rapoport, & Wardle, 2000; Kroll, 1990; Leon, Marcuz, Couronne, & Koster, 1999; Liem & Mennella, 2002; Liem & Mennella, 2003; Olson & Gemmill, 1981; Sullivan & Birch, 1990). Most sensory studies reported in the existing literature, grouped 4- and 5-year-old children together (Birch, 1980b; Birch & Marlin, 1982; Kimmel et al., 1994; Olson & Gemmill, 1981; Sullivan & Birch, 1990). However, children in this age range are rapidly changing. Their attention spans lengthen and their ability to categorize, analyze, and synthesize information rapidly becomes stronger and more efficient (Krug & Mikus, 1999). In the Netherlands, children normally enter kindergarten at the age of four, therefore it is important to asses differences between 4- and 5-year-olds.
Sensory taste tests with young children typically consist of two types: preference tests and discrimination tests. Most studies in children focus on preference rather than discrimination. Stimuli that are commonly used are not only different in taste, but are also different in color and appearance (e.g. different fruits, different sandwiches). It has been suggested that with these stimuli, rank-order and paired comparison tests give consistent data in young children (Leon et al., 1999).
However, it remains unknown whether rank-order and paired comparison tests give consistent data when the presented stimuli differ only in taste (e.g. orangeade with different concentrations of sucrose). It is also unknown if rank-order and paired comparison tests give consistent data when they are used to measure discriminatory ability in young children (i.e. which stimulus is more sweet) instead of preference.
The present study investigated the consistency between rank-order and paired comparison tests as measures of discriminatory ability and preference, using stimuli that differed only in sweetness. Subjects of the study were young adults, 4-year-olds and 5-year-olds.
Section snippets
Subjects
Twenty-one 4-year-old children (4.4 ± 0.3 years, 12 girls and 9 boys), 47 5-year-old children (5.4 ± 0.3 years, 23 girls and 24 boys) and 22 young adults (22.6 ± 1.8 years, 17 females and 5 males) participated in the study (see Table 1). The children attended a kindergarten in Bennekom, a village 4 km from Wageningen. Since the research study took place in October, and children in The Netherlands start kindergarten in September, the 5-years-olds (second graders) had almost one year more experience
Discriminatory ability, children and young adults
Fig. 1 shows the results of the rank-order and paired comparison tests for discriminatory ability. Children, compared to young adults, were less able to discriminate between the five different sugar concentrations. This was evident during the rank-order tests (t(88df)=−5.2; p<0.0001) and during the paired comparison tests (t(88df)=−6.2; p<0.001) (see also Table 2). No significant differences were observed between girls and boys during the rank-order tests (t(66df)=−0.48; p=0.63), or during the
Discussion
The present study suggests that 5-year-old children were able to carry out rank-order and paired comparison tests for discriminatory ability in a consistent manner. However, 5-year-olds were less able to discriminate between different sugar concentrations in an orange drink than adults. Four-year-olds failed to carry out both discriminatory ability tests in a consistent way. This was in contrast with the tests for preference. In these tests, young adults and both 4-and-5-year-old children,
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