Early Childhood. CARL GABBARD. MICHAEL DEAN. PATR1CIA HAENSLY. Texas A & M University. Inquiry into the genesis of foot laterality has become a topic ...
JOURNAL OF APPLIED DEVELOPMENTAL PSYCHOLOGY 12, 131-137 (1991)
Foot Preference Behavior During Early Childhood CARL GABBARD MICHAEL DEAN PATR1CIA HAENSLY Texas A & M University
Inquiry into the genesis of foot laterality has become a topic of scientific interest in recent years due to the potential utility of foot preference behavior measures in neuropsychological testing both in the cognitive and motor domains. With the goal of expanding the developmental perspective, this study examined foot (and hand) preference behavior in 205 3-, 4-, and 5-year-olds. Resultsindicated that although the majority of children displayed a preference for one foot over the other (dominance), a large portion exhibited nonestablished (mixed) behavior. The distribution of foot preference behaviors remained relatively stable over the cross-sectional period, suggesting that foot laterality may emerge after the fifth year of life in roughly one-third to one-fourth of the population. Previously reported suggestions that foot preference is established before hand dominance was not supported by these findings, nor were differences in the degree of laterality found between the sexes.
Brain lateralization behavior has interested scientists for over a century (e.g., Baldwin, 1890; Broca, 1865; Hall, 1891). By far, the most documented manifestation of lateral asymmetry has been that of hand preference behavior. Among the most cited conclusions from the literature are that individuals become more right-handed (i.e., left hemispheric dominance) with increasing age, and approximately 90% of the population establish that preference (Porac & Coren, 1981). Although an abundance of data is available on the genesis of hand preference, inquiries into the development of foot dominance have been few (Gabbard & Bonfigli, 1987; Peters, 1988; Porac, Coren, & Duncan, 1980). Early research endeavors of Belmont and Birch (1963) found that at age 5, 94% of the sample had established foot dominance, which remained relatively stable through childhood. For comparison, handedness data indicated much greater instability over the same period. These findings led to the suggestion noted in several subsequent reviews that young children establish an earlier preference (dominance) for the Correspondence and requests for reprints should be sent to Carl Gabbard, Child Movement Laboratory, Health and Physical Education Department,TexasA & M University,CollegeStation, TX 77843-4243. 131
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use of one foot over the other, compared to the development of hand preference behavior. Porac et al. (1980) summarized the results of 113 age-trend studies conducted over 90 years and reported no foot preference data for children below the age of 5 years. A subsequent review by Gabbard and Bonfigli (1987) also confirmed this lack of information. The researchers then collected foot and hand preference data from a sample of 4-year-olds and made comparisons with information reported in past studies. The investigation noted that a high percentage of the sample (approximately 50%) had not established lateral foot dominance, although handedness behavior indicated results quite similar to previous reports (i.e., over 80% displayed dominant behavior). This information led the researchers to speculate that foot dominance may not be established earlier than handedness, and the period between 4 and 5 years of age may be critical in the development of foot laterality. While the Gabbard and Bonfigli study may have provided the stimulus for additional considerations related to brain development and lateral foot preference behavior, its research design provided a limited developmental perspective (i.e., because it was neither a cross-sectional nor a longitudinal study). Since foot preference behavior in adults has been shown to be a sensitive indicator of general neuropsychological functioning and neurological problems associated with motor control (Chapman, Chapman, & Allen, 1987; Peters, 1988), the importance of delineating the developmental perspective associated with foot lateralization appears warranted. Additional justification for inquiry stems from the fact that, from a psychomotor perspective, the study of human laterality would appear quite limited without considering foot laterality because several gross motor skills contain lower limb preference in the organization of a motor program (e.g., kicking, jumping, climbing). Therefore, an investigation of foot laterality was designed with three primary objectives: (1) to collect data on a cross-sectional sample of young children, (2) to determine if sex differences exist, and (3) to compare the data with hand preference behavior.
METHOD Subjects A sample of 205 3-, 4-, and 5-year-old boys (n= 106) and girls (n = 99) was tested. The age range was 36 to 70 months with a mean age of 51.9 months. The sample was drawn from the total 3- to 5-year-old population of three private early childhood education and day-care centers and two university child-development programs. Parents of the children were predominantly middle-class, and the racial composition primarily Caucasian with a small percentage of several minorities. Children with known disabilities or who could not understand verbal instructions in English were not included. Other nonparticipants were those children who did not return permission slips, for whom permission was rejected, or who were absent during testing.
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Procedure Because limb laterality is generally recognized as a continuum that ranges from fight to left, rather than a dichotomy (Bradshaw & Nettleton, 1983; Porac & Coren, 1981), and strength of preference should be considered, measurements for a number of motor tasks were collected and categorized using a procedure adopted from Tan (1985) and Briggs and Nebes (1975). Peters (1988) suggested that the preferred foot is the one used to manipulate an object or to lead out, as in jumping or stepping. The nonpreferred foot is the limb used to support the activities of the preferred foot by lending postural and stabilizing support. Motor tasks, such as kicking, appear to be the ideal foot preference measure due to the clear delineation between preferred and nonpreferred (support) functions. In contrast, the commonly used measurement task of hopping does not require a clear support (nonpreferred foot) function. The motor tasks used in this study were selected based upon a clear division of functional roles of the two feet (i.e., manipulation and support) and from recommendations of Chapman et al. (1987) and Peters (1988). Each subject was systematically presented three foot preferences tasks: (1) kicking a ball, (2) foot-stamping an imaginary bug (floor spot), and (3) foottracing letters while standing. Subjects were given two trials and scored as 0, 1, or 2. Zero indicated a right-footed preference on both trials, l indicated the use of right and left foot (nonestablished), and 2 indicated a preference for the left limb on both trials. Therefore, a total score of 0 on the three tasks represented a completely fight-footed preference, and a score of 6, the extreme on the left side of the laterality continuum. Subjects were also given three standard hand preference tasks: writing, throwing a ball, and stacking cubes; with the implement placed at the midline of the body to initiate the action. Subjects were individually administered all six limb preference tasks during a single session. The tasks were numbered and the order varied systematically by beginning each new subject with the next task in the sequence after that which the previous subject had begun. RESULTS Results of 2 × 3 (Sex x Age) two-way ANOVA procedures for unequal cell sizes indicated that there were no statistically significant (p < .05) sex or age differences in foot or hand preference behavior. Further analyses to delineate preference behaviors according to fight, left, and nonestablished categories within each age group were conducted using frequency data statistical techniques and procedures adopted from Tan (1985) and Briggs and Nebes (1975). From the original seven (0-6) laterality-continuum designations, scores were combined to reflect three preferential categories: right = 0/1, nonestablished = 2/4, and left = 5/6. Table 1 presents the results of the lateral foot and hand preference scores by preferential category. Analysis for foot preference data indicated that 68-74% of
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TABLE 1 Lateral Fool and Hand Preference Scores Age (yr) 3 (n = 74)
4 (n = 81)
5 (n = 50)
Foot Right Mixed Left
66 26 8
67 28 5
64 32 4
Hand Right Mixed Left
74 19 7
77 15 8
74 20 6
Preferences (% of n)
the total sample had established a preference (64-67% displayed right-footedness), whereas 26-32% revealed nonestablished behavior. In contrast, hand preference results showed that 80-85% had established a dominant limb preference (74-77% right), whereas 15-20% were classified as nonestablished. DISCUSSION As noted previously, earlier findings of Belmont and Birch (1963) indicated that, at age 5, 94% of the sample tested had established foot dominance, which then remained relatively stable (94-98%) over the next 6 years. In contrast, hand preference behavior showed greater instability over the same period, suggesting that children establish dominant foot behavior before the preference of one hand over the other. In another study, Coren, Porac, and Duncan (1981) reported combined data for 3- to 6-year-olds that also suggested a similar trend. In their sample of preschoolers, 87.5% had established foot (right or left) dominance, whereas dominant hand preference was displayed by 74.5%. Interestingly however, when the data were initially scored dichotomously (right or left only) to determine right-sidedness, 94% were right-handed and 77% were classified as right-footed. Results of this investigation indicate that, in general, the distribution of foot lateralization remains relatively unchanged from 3- to 5- years of age. And, although the majority of children display foot dominance by a preference for one foot, a large portion exhibit nonestablished (mixed) behavior. Further interpretation suggests that lateral foot preference is not established at an earlier age than dominant hand behavior when considering children 3 to 5 years of age. This notion is exemplified by the relatively larger percentage of young children who displayed nonestablished foot preference behavior (26-32%) compared to those
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individuals who exhibited nonestablished hand dominance (15-20%). A similar disparity was reported by Gabbard and Bonfigli (1987) in their investigation of foot preference among 4-year-olds. In that study, 50% of the sample exhibited nonestablished foot preference behavior, whereas only 16% were reported as not displaying a dominant hand preference. The findings related to hand preference behavior in the Gabbard and Bonfigli study and the investigation here are comparable to reports of previous studies. For example, Porac et al. (1980) reported a mean fight-handed preference of 83% for the four reviewed studies of preschool children. Other investigators, such as Flick (1966) and Coren et al. (1981), also reported dominant hand preference values above 80% for children 3 to 6 years of age. One of the considerations resulting from the Gabbard and Bonfigli (1987) study was that the period between 4 to 5 years of age may be critical in the genesis of foot laterality. This notion was based on the information that 50% of their 4-year-old sample did not exhibit dominant foot behavior; previous data by Belmont and Birth (1963) reported that 94-98% of children 5 to 11 years had established foot dominance. The results of this study do not support this notion due to the fact that the 5-year-olds were not significantly different from the two younger age groups. These findings would, therefore, suggest that foot laterality may emerge after the fifth year of life in roughly % to I/4 of the population. Unfortunately, just as there is a lack of data on foot laterality for young children in general, there is also a void in the literature concerning possible sex differences. In the study mentioned earlier on children 3 to 6 years of age conducted by Coren et al. (1981), the researchers reported results matching those found in this investigation. That is, there were no sex differences within or across age groups in the degree of foot or hand preference behavior. The literature on older subjects appears quite mixed in regard to foot and hand preference. In their review of laterality data from previous published studies, which included 1,964 subjects aged 8 to 100 years, Porac et al. (1980) reported no significant sex differences in handedness, but males were significantly more left-footed than females. However, more recent reports included evidence that right-handedness emerges earlier in females (Carlson & Harris, 1985; Humphrey & Humphrey, 1987) An important point should be stressed in interpreting these results and those of other studies of this nature; although the findings of this study have been compared to the general conclusions reported in previous investigations, some differences may be due to variations in the scoring system used to identify preference categories and in measurement procedures (e.g., tasks, trials). For example, in the Belmont and Birch (1963) study, kicking was the only task used to determine foot lateralization, and the description of mixed (nonestablished) behavior was somewhat different from that used in this study. In other studies where more than one measurement task was used, right-sidedness and left-sidedness were used to identify only those individuals who scored to the extreme on either
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end (i.e., all right or all left responses), and those with any deviation were labeled as mixed (e.g., Coren et al., 1981). In summary, this investigation found that, whereas the majority of children 3 to 5 years of age display foot dominance, a large portion exhibit nonestablished (mixed) behavior. Therefore, suggesting that the age-related genesis of foot laterality continues beyond the fifth year of life in roughly 1,4 to ¼ of the population. Previously reported suggestions that foot preference is established before hand dominance was not supported by these findings, nor were differences in the degree of foot or hand preference found between the sexes. In regard to the theoretical and applied implications of these findings, a few notes seem warranted. As indicated earlier, foot preference (performance) tests have been suggested as useful adjuncts to neuropsychological testing and the prediction of hemispheric dominance among adults (Chapman et al., 1987; Peters, 1988). Although hand preference tests are commonly used to indicate degree of laterality and found in several general testing batteries, there are indications that foot preference may be a more sensitive indicator of developmental motor and cognitive delays than degree of hand laterality (Bradshaw, 1989; Peters, 1988). It has also been suggested that the development of foot preference is generally less subject to cultural influences than hand preference. In summation, if foot preference tests are to be considered as part of neuropsychological testing, age-related characteristics (such as found in this study) would appear to be critical in determining population performance parameters. For example, as more of the developmental perspective is revealed, along with its relationship to selected motor and cognitive performance characteristics, lack of foot preference by an individual may serve as a marker indicating the need for additional testing and special remedial assistance.
REFERENCES Baldwin, J.M. (1890). Origin of fight- or left-handedness. Science, 16, 247-248. Belmont, L., & Birch, H.G. (1963). Lateral dominanceand right-left awareness in normal children. Child Development, 34, 257-270. Bradshaw, J. (1989). Hemispheric specialization and psychological function. New York: Wiley. Bradshaw, J., & Nettleton, N. (1983). Human cerebral asymmetry. EnglewoodCliffs, NJ: PrenticeHall. Briggs, G.G., & Nebes, R.D. (1975). Patterns of hand preference in a student population. Cortex, 11, 230-238. Broca, P. (1865). Sur la faute du langage articul6 ]On the dearth of articulated speech]. Bulletin of Social Anthropology, 6, 493-494. Carlson, D.F., & Harris, L.J. (1985). Development of the infant's hand preference for visually directed reaching: Preliminaryreport of a longitudinal study. Infant Mental Health Journal, 6, 158-172. Chapman, J.P., Chapman, L.J., & Allen, J.J. (1987). The measurement of foot preference. Neuropsychologia, 25, 579-584.
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Coren, S., Porac, C., & Duncan, P. (1981). Lateral preference behaviors in preschool children and young adults. Child Development, 52, 443-450. Flick, G.L. (1966). Sinistrality revisited: A perceptual-motor approach. Child Development, 37, 612-622. Gabbard, C., & Bonfigli, D. (1987). Foot laterality in four-year-olds. Perceptual and Motor Skills, 65, 943-946. Hall, G.S. (1891). Notes on the study of infants. Pedagogical Seminary, 1, 127-138. Humphrey, D.E., & Humphrey, G.K. (1987). Sex differences in infant reaching. Neuropsychologia, 25, 971-975. Peters, M. (1988). Footedness: Asymmetries in foot preference and skill and neuropsychological assessment of foot movement. Psychological Bulletin, 103, 179-192. Porac, C., & Coren, S. (1981). Lateral preferences and human behavior. New York: SpringerVerlag. Porac, C., Coren, S., & Duncan, P. (1980). Life-span age trends in laterality. Journal of Gerontology, 35, 715-721. Tan, L.E (1985). Laterality and motor skills in four-year-olds. C'hild Development, 56, 119-124.
