Intern. J. Neuroscience, 117:177–185, 2007 C 2007 Informa Healthcare Copyright ISSN: 0020-7454 / 1543-5245 online DOI: 10.1080/00207450600582033
RELATIONSHIPS BETWEEN HAND AND FOOT PREFERENCES
CAGATAY BARUT CENK MURAT OZER Karaelmas University School of Medicine, Department of Anatomy Zonguldak, Turkey OZDEMIR SEV˙INC Abant Izzet Baysal University Duzce School of Medicine, Department of Anatomy Duzce, Turkey MUSTAFA GUMUS Karaelmas University Department of Physical Education and Sports Zonguldak, Turkey ZAFER YUNTEN Karaelmas University School of Medicine Department of Biostatistics Zonguldak, Turkey
The aim of this study was to evaluate the relations between hand and foot preferences in male and female individuals (343 male, 290 female) aged between 18–42 years Received 7 December 2005. This study was presented as a poster presentation at the 4th Asian Pacific International Congress of Anatomists, Kusadasi, Turkey, September 7–10, 2005. Address correspondence to Dr. Cagatay Barut, Karaelmas University, School of Medicine, Department of Anatomy67600 Zonguldak, Turkey. E-mail:
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C. BARUT ET AL. (22.11 ± 2.07). Of the right-handed men, 75.5% preferred the right foot, 7.1% the left foot, and 17.4% both feet. Of ambidextrous men, 44.0% preferred the right foot, 28.0% the left foot, and 28.0% both feet. Of left-handed men, 32.3% preferred the right foot, 56.9% the left foot, and 10.8% both feet. The differences between these percentages were found to be statistically significant. Of the right-handed women, 89.9% preferred the right foot, left foot 1.2%, both feet 8.9%, whereas 50.0% preferred the right foot, 12.5% the left foot, and 37.5% both feet in the ambidextrous women. In the left-handed women, 8.8% preferred the right foot, 79.4% the left foot, and 11.8% both feet. The differences between these percentages were found to be statistically significant. The results suggested that the cultural differences among the different study groups may be the reason for the inconsistencies with regard to hand and foot preferences. Moreover, the results may bring insight into the foot preference in relation to hand preference in the Turkish population. Keywords foot preference, hand preference, laterality, men, women
INTRODUCTION The term “lateral preference” designates the asymmetrical use of limbs or sensory organs. In humans, handedness is the most widely studied lateral preference, but a similar asymmetrical use has been described for other paired organs such as feet, eyes, and ears (Mohr et al., 2003). Assessment of hand preference is a standard procedure in many investigations of human behavioral asymmetries and in many neuropsychological investigations (Dragovic, 2004). There are various studies investigating the relationship between hand preference and cerebral laterality (Rasmussen & Milner, 1977; Reiss et al., 1999; Singh et al., 2001; Mohr et al., 2003; Watson et al., 1998; Kang & Harris, 2000). Righthandedness is believed to be accompanied with more stable left hemisphere dominance than either left-handedness or ambidexterity (Mohr et al., 2003; Knecht et al., 2000; Pujol et al., 1999; Rasmussen & Milner, 1977). However, it has been found that the degree of the right-hand preference may be inversely related to the right-brain efficiency in right-handers (Tan, 1992; Tan & Akgun, 1992), whereas the degree of left-handedness may be related to the degree of the left brain in left-handers (Tan, 1990). Although handedness has long been taken as the most reliable predictor for language dominance, more recent findings stress a close relation between language dominance and footedness (Day & McNeilage, 1996; Elias & Bryden, 1998), or language dominance and lateral preferences in postural whole body actions (Mohr et al., 2003; Day & McNeilage, 1996). Recent studies indicate that foot preference can be a better indicator for language laterality because footedness is less biased by cultural influences than hand preference (Kang & Harris, 2000; Gentry & Gabbard, 2001; Singh et al., 2001; Watson et al., 1998;
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Elias & Bryden, 1998; Bell & Gabbard, 2000). From this point of view, the study of lower limb laterality may broaden the point of view for brain organization and function (Bell & Gabbard, 2000). On light of these studies this article investigated the relationship between hand preference and foot preference in a Turkish population. MATERIAL AND METHODS There were 633 individuals (343 male, 290 female) aged between 18–42 years (22.11 ± 2.07) who participated in this study. Hand preference was assessed using the Edinburgh Handedness Inventory, and the Geschwind Scores (see Tan, 1988) were calculated. The participants were asked 10 questions regarding their hand preferences for writing, drawing, throwing, using various implements like scissors, toothbrush, knife without fork, spoon, striking matches, and jar opening. They were asked to put “+” in the column associated with the hand they used to carry out the activity. They were asked to put “++” in the associated column if their preference for one hand was very strong; and to put a “+” in both columns if they were using both hands equally. A “++” in the right column was assigned 10 points, a “+” in the right column 5 points, whereas a “++” in the left column –10 points and a “+” in the left column –5 points. The sum of these points was used to determine the Geschwind Score (GS), as an indicator of the direction and degree of hand preference. Hand preference was evaluated in 5 groups depending on the value of GS, consistent righthanders: +80
