Perceptual andMotor Skills, 1990, 71, 723-734.
63 Perceptual and Motor Skills 1990
FIELD D E P E N D E N C E A N D BODY BALANCE ' FUMIAKI KITAMURA AND KATSUYA MATSUNAGA Kyushu University Summary.-This study reports four points about the portable Rod and Frame Test performance of 30 Japanese women in terms of body balance. The primary findings using a stabilometer are: (a) field dependence correlated negatively with increased sway pach within 1 min. both while a dot pattern as a visual stimulus was stationary and while it was moving. (b) Field dependence correlated positively with the difference in sway path between the two following phases, in one of which the subiects watched the horizontal visual movement to the right and in the other movement to the left. (c) Motion aftereffect had no direct and immediate influence on sway path, but rather a latent and long-term effect. And on a pedograph which measures the hstribution of foot pressure and the shape of [he sole, (d) field dependence correlated negatively with anterior positions of the center of foot pressure and with the proportion of the front part to the rear of the sole. Over-all, field dependence measured by the Rod and Frame Test seems to be associated with body posture when dot patterns are viewed.
The term field dependence was first used to describe the effects of the tilted visual field in which a person has to resolve a conflict between visual and gravitational cues. O n the rod and frame apparatus, commonly used to measure field dependence, the conflict is created by showing a tilted square frame in an otherwise dark room. Witkin and his colleagues questioned the importance of visual cues in perceiving the vertical (Witkin & Asch, 1948). They soon found that people were consistent on field dependence across other tests of orientation perception (Witkin, Lewis, Herzman, Machover, Meissner, & Wapner, 1954). Then they introduced the Embedded Figures Test as another measure of field dependence, defined as the capacity to overcome or analyze an embedding context in perceptual functioning (Witkin, Dyk,Faterson, Goodenough, & Karp, 1962). A number of studies helped to describe the processes responsible for the phenomena of field dependence in more specific terms with the base of the cue conflict and disembedding in upright perception. Bischof (1974) suggested that field dependence in orientation perception might be related to a visual driving of the vestibular system. The idea that field dependence in upright perception might be based on a visual-vestibular interaction seemed consistent with other evidence as well. Physiological as well as perceptual 'We thank Mr. Himyuki Ito and Mr. Kazunori Shidoji for cheir experimental supporr We also express our gratitude to Prof. Minernitu Kusu, Mr. Satoru Okamoto, and Mr. Fumio Y ~ m ~ m o t o who readily consented to administem the tescs to their students. And we ap reciate the permission from Consulting Psychologists Press, Inc. to use the Japanese Version the Group Embedded Figures Tesc. Requests for reprints should be sent to Fumiaki Kicamura, Deparcment of Psychology, Faculty of Literature, Kyushu University, Hakozaki, Higashi-ku, Fukuoka 812, Japan.
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data indicate that movements in the visual field are capable of driving the vestibular system (Dichgans, Held, Young, & Brandt, 1972). The studies of dusions of object motion are one of the perceptual means of studying visual-vestibular interaction. The oculogyral &ion- is a perceptual response to vestibular stimulation. like the subjective experience to self-rotation in the dark; and susceptibiljty to this illusion is sometimes used as a measure of vestibular sensitivity. Moreover, Nilsson, Magnusson, and Vasko (1972) reported that susceptibdity to the oculogyral illusion is negatively correlated with susceptibility to the rod-and-frame illusion. The illusion of self-motion (circularvection) has also been studied. In this case, field-dependent people are susceptible to visually induced illusions of selfmotion (Barrett, Thornton, & Cabe, 1970; Nilsson, Magnusson, & Vasko, 1972). These findings were, however, difficult to understand in terms of a cognitive disembedding ability. Instead, what these data suggested to Witkin was that the rod-and-frame illusion results from a visual driving of the vestibular system and that individual differences in upright perception may be assessed by the relative importance assigned to visual and vestibular stimuli in resolving the perceptual conflict (Witkin & Goodenough, 1981). This visual-vestibular interpretation is a more specific form of Witkin's original cue-conflict hypothesis underlying field dependence in upright perception. This study was conducted to examine the effect of optolunetic stimuli on body balance in relation to field dependence. We hypothesized that optokinetic stimuli, which are often used as equilibrium tests, should induce differential body sway for field-dependent and field-independent people.
Subjects and Tests Thirty Japanese women were administered the Group Embedded Figures Test (Witkin, Oltman, Raskin, & Karp, 1971) and the portable Rod and Frame Test (Oltman, 1968). All the selected participants were considered right-handed because they held pens in their right hands and told us they had no experience of correction of their handedness. Their ages ranged from 19 to 23 yr. old. All had normal or corrected-to-normal vision. Both of the tests were used in the standard fashion. But the instructions for the Group Embedded Figures Test were translated into Japanese and the figures were reproduced. Moreover, the time limit for the second and third sections was shortened to 3 min. because Japanese students had shown better performance in our previous researches than had similar subjects in the USA. Each participant was asked if she was under the influence of drugs or alcohol and no one was eliminated for this reason. No participant knew the purpose of this study.
FIELD DEPENDENCE AND BODY BALANCE
Apparatus This experiment involved two systems. O n a stabilometer (NEC San-ei 1G02) the sway path travelled by the center of foot pressure on the platform was calculated by a personal computer (NEC PC-9801). The anteroposterior and lateral center of foot-pressure components were digitized by the sampling interval of 50 msec. and the sampling duration of 60 sec. during each phase. The influence of the subject's weight was computationally compensated. A pedograph was made for this experiment to measure the sole area and to calculate the center of foot pressure; see the Appendix (p. 733). The glass platform was surrounded by some auxiliary platforms to lessen the subject's anxiety about height. -
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Procedure Each subject stood erect, relaxed, hands at her sides, on a stabilometer and a pedograph platform with the feet close together. The experimenter told each of them, "From now, I'd like you to keep standing on the platform for a while, watchng some stimuli in several phases and closing your eyes in one phase. Please go on doing what I ask you to d o until I say, 'all right.' If you get tired or feel bad, or if you move your foot even an inch, please let me know immediately ." Standing on the stabilometer platform, each subject, during the seven phases, was asked to (1) watch the visual target in the frontal plane one meter away, (2) close the eyes while an imagined image was the visual target, (3) watch a stationary dot pattern, (4) watch a dot pattern moving from right to left, (5) watch a dot pattern which abruptly stopped after Phase 4, (6) watch a dot pattern moving from left to right, and (7) watch the dot pattern which abruptly stopped after Phase 6. The dot pattern consisted of about 150 dots of 6 mm in dameter on a video display (400 mm x 530 mm) in unit time. The speed of the moving pattern in both Phases 4 and 6 was about 15Olsec. Two-minute rests between phases occurred to allow the subjects to recover and the aftereffect to dissipate except between Phases 4 and 5 and between 6 and 7. Half of the subjects experienced Phases 4 and 5 after 6 and 7 to give a counterbalanced order. O n the pedograph platform, the subjects were told to watch the visual target presented in the frontal plane one meter away.
RESULTS The number of correct responses for the Group Embedded Figures Test were 12.9 on average (SD= 5.0). And the mean total of deviations from vertical on the portable Rod and Frame Test for eight trials was 14.3' (SD = 7.3). The scores on these tests had a low correlation with each other in this study (r = -.24, ns).
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K. MATSUNAGA
PHASES
FIG.1. Sway path of X, Y, and XY in each phase
The subject's sway path during each phase of the experiment is shown in Fig. 1. X refers to the lateral sway, Y to the sway in the anteroposterior direction (forward-backward), and XY to the sway of X and Y synthesized by the computer program. Means and standard deviations in each phase in three directions are as shown in Table 1. TABLE 1 MEANSAND STANDARD DEVIATIONS BY SWAYPATHAND PHASE
Phase
Sway Path X Y M SD
Sway Path X
M
SD
Sway Path Y
M
SD
As no significant Pearson correlations were found between the sway path during the phases and field dependence (Table 2), the 60-sec. periods in
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FIELD DEPENDENCE AND BODY BALANCE
TABLE 2 PEARSONCORRELATIONS OF EACHPIUSE Wmm MEASURES OF FIELDDEPENDENCE (N = 30) Measures
X l/Group Embedded Figures Test ort table Rod and Frame Test
.OO .01
X l/Gmup Embedded Figures Test Portable Rod and Frame Test
.03 .04
X l/Group Embedded Figures Test Portable Rod and Frame Test
Phase 1 Y X Y
X
.05
.01
.07
.11
.05
-.07
Phase 4 Y X Y
X
Phase 2 Y X Y .08
X
.07
.04
-.21 .04 Phase 5 Y X Y
.ll
X
.02
.01
-.05
-.09
-.OO
-.07
.04
.02
-.01
.03
-.05
.17
Phase 3 Y X Y -.04
.10
.12 .08 Phase 6 Y X Y -.05 .20
-.lo .14
Phase 7 Y X Y
-.08
-.07
-.08
-.01
.03
-.02
each phase were divided into two halves. And the proportion of the second 30 sec. to the first 30 sec. was defined as transition. In Phases 3, 4, and 6 the Rod and Frame deviations were negatively correlated for the proportion TABLE 3 PEARSONCORRELA'I'TONS OF TRANSITIOAS IN EACHPHASEWITH I v k ~ s w OF s FIELDDEPENDENCE ( N = 30) Measures
X l/Group Embedded Figures Test Portable Rod and Frame Test
.16 -.22
X l/Group Embedded Figures Test Portable Rod and Frame Test
.28 -.40t
X
Phase 1 Y X Y
X
.22
.05
.01
-.I2
-.29
.20
Phase 4 Y X Y
X
Phase 2 Y X Y .07
.05
.OO
-.01
Phase 5 Y X Y
X -.I5
Phase 3 Y X Y -.I4
-.I2
-.45* -.40f
.32
X
Phase 6 Y X Y
.33
.ll
-.04
.ll
.12
.16
.08
.22
-.34
-.34
.02
.06
.25
-.37"
-.20
-.44*
Phase 7 Y X Y
l/Group Embedded Figures .17 .07 .16 - Test Portable Rod and Frame Test .06 -.04 .15 * p < .05. NB.-Transition (t) is given by the following formula, t = (SPL - SPF)/(SPL + SPF) where SPL = sway path in the latter half in each phase; SPF = sway path in the first half i n each phase.
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of the second 30 sec, to the first 30 sec. That is, the field-independent subjects were somewhat more unstable during the second 30 sec. (Table 3). Neither Table 2 nor Table 3 indicate that the Group Embedded Figures Test scale is practically associated with body balance. For this reason, field dependence was defined only in terms of the Rod and Frame Test except a special reference to the Group Embedded Figures Test. Table 4 gives the values of Tukey multiple comparisons of the three sway paths XY,X, and Y between phases. A sway path was larger when the subjects closed their eyes and when the visual stimuli were moving. TABLE 4 VALUEOF DIFFERENCES AMONGMEANSOF PHASES FORTI-IREE SWAYPATHS BY TUKEY MULTIPLECOMPNUSONS (N = 30) Phases 1
Sway Path XY,MSe = 39.3 1l.lt 2 3 -2.4 4 8.5t 5 0.1 6 12.lt 7 4.0 Sway Path X, MSe = 21.8 8.8t 2 3 -0.9 4 7.3t 5 1.5 6 10.5t 7 2.8 Sway Path Y, MSe = 17.8 2 6.07 3 -1.5 4 3.9t 5 0.9 6 5.47 7 2.8 "p