- Email: [email protected]
Cloth color preference under the influence of face cooling
PII:
J. therm. Biol. Vol. 23, No. 6, pp. 335±340, 1998 # 1998 Published by Elsevier Science Ltd. All rights reserved Printed in Great Britain 0306-4565/98 $ - see front matter S0306-4565(98)00023-0
CLOTH COLOR PREFERENCE UNDER THE INFLUENCE OF FACE COOLING HEE SOOK KIM1 and TOKURA HIROMI1{ Department of Environmental Health, Nara Women's University, Nara 630, Japan
1
(Received 14 August 1997; accepted in revised form 15 June 1998) Abstract 1. We studied the eect of face cooling accompanied by a fall of tympanic temperature on color preference in 8 women at an ambient temperature of 288C. 2. The face only was cooled by blowing 158C air at 6 m/s on the face only. Controls received either no wind at all or a wind (248C, 6 m/s) on the body and appendages only. 3. Most subjects preferred warmer colors after facial cooling than after no facial cooling. 4. The facial cooling and decrease in tympanic temperature may indicate an increase in load error between core temperature and set-point. # 1998 Published by Elsevier Science Ltd. All rights reserved Key Word Index: Color preference; face cooling; tympanic temperature; set-point
INTRODUCTION
MATERIALS AND METHODS
A physiological component to color preference has not been studied systematically, although there are many studies of color preference by psychologists (Gelineau, 1981; Hafner and Corotto, 1980; Schuschke and Christiansen, 1994; Trinkaus, 1991). According to Fanger et al. (1977) the ®nding that subjects preferred lower (0.48C) ambient temperature in the extreme red light than in extreme blue light, suggests that ambient color in¯uences thermoregulation. Recently, Kim and Tokura (1997; 1998) found that the subjects preferred warmer colors during the luteal phase (L-phase) of the ovarian cycle than in the follicular phase (F-phase) at neutral ambient temperature. They related this to a higher set-point in core temperature during the L-phase than F-phase. They suggest that the determination of color preference may have a possible physiological basis. Further, facial cooling accelerated dressing rate in the cold (Kim and Tokura, 1994). They explained this behavior as due to a decrease in core temperature (tympanic) caused by facial cooling which resulted in an increase in the load error between core temperature and set-point. Here we ask whether facial cooling and the accompanying decrease in tympanic temperature would in¯uence color preference between ``warm'' and ``cool'' colors. { Author to whom all correspondence should be addressed: Tel.: 0742-20-3469; Fax: 0742-20-3499; email: [email protected]. 335
Subjects Eight adult females (age 20.13 20.35 yrs, height 156.75 2 1.21 cm, and body mass 50.13 2 1.66 kg, body surface area 1.442 0.03 m2, mean 2SEM) volunteered as subjects for face cooling/no face cooling experiments, and ®ve (age 19.83 2 0.45 yrs, height 156.33 2 1.79 cm, and body mass 50 2 2.53 kg, body surface area 1.432 0.04 m2, mean 2SEM) of those for wind experiment. After the general purpose, procedure and possible risks of the experiment were fully explained, all subjects gave their informed consent. Body surface area was calculated by the following equation (Fujimoto et al., 1968). BSA = W0.444H0.66388.33 10ÿ4 where BSA: Body surface area (m2), W: Weight (kg), H: Height (cm). Each test was conducted at the follicular phase to avoid the eects of the menstrual cycle on core temperature (Ascho and Heise, 1972; Bittel and Henane, 1974; Cunningham and Cabanac, 1971). No subject used oral contraceptives for the past month and all were asked to abstain from coffee and alcohol for 24 h before the start of each experiment. Procedure The subjects entered a chamber at 20:00 at 288C and 50% relative humidity. The subjects wearing half-sleeved shirts and knee-pants sat on a sofa for 30 min. Since perception of warm to cool colors might dier individually, before retiring each sub-
336
H. S. Kim and T. Hiromi
Fig. 1. Schematic drawing of method of face cooling.
ject was asked to array 41 randomly mixed cloth swatches (4 5 cm) from very warm to very cool colors. All subjects arrayed these cloth colors in the order from red through yellow and green to blue. They rose at 06:00 the next morning. The subjects were asked to sit for 30 min and during these
periods temperature sensors were attached to the skin and tympanum. From 06:30 to 07:00 a cool wind at 158C and at 6 m/s was blown to the face. The body was protected by a corrugated cardboard box (Fig. 1, ``face cooling''). The skin temperatures other than the face also decreased during ``face cooling'', although these areas were not blown upon directly. To control for the above lowering of skin temperature, a control group received wind (248C, 6 m/s) on the trunk and limbs but not the face which caused a lowering of body skin temperature comparable to the decrease seen in face cooling alone (``wind''). A further control group sat in the apparatus with no wind at all (``no face cooling''). At 07:00 the fans were shut o and the recovery followed until 08:00. Every ®ve minutes from 07:00 to 08:00, the subjects were instructed to choose one out of the 41 cloth colors (24 52 cm, cotton 100%) which they preferred. Selections were made under CIE (Commision Internationale de
Fig. 2. Experimental schedule. Table 1. Munsell values (HV/C) of cloth colors H 4.3R 5.4R 6.2R 6.3R 6.4R 6.9R 8.0R 9.2R 0.3YR 2.1YR 4.0YR 5.1YR 7.5YR 0.1Y
V/C 4.1/14.2 4.0/13.7 3.5/12.3 4.1/12.8 4.1/14.8 4.5/14.0 4.1/12.6 4.2/12.9 5.2/11.6 5.8/12.4 6.3/15.1 6.2/14.3 6.9/14.3 7.8/12.1
H 2.3Y 6.3Y 7.4Y 2.5GY 6.0GY 8.4GY 9.6GY 0.6G 2.7G 6.2G 8.1G 1.6BG 3.6BG 6.5BG
V/C 8.0/12.0 8.3/12.7 8.6/11.4 7.2/11.9 6.9/9.2 5.8/9.0 5.2/10.1 5.1/8.5 4.7/9.9 4.6/9.0 4.2/7.3 4.2/7.6 4.1/6.9 4.0/7.3
H 8.1BG 0.9B 4.7B 6.4B 9.7B 2.1PB 5.2PB 6.0PB 6.0PB 7.0PB 7.1PB 7.5PB 7.1PB
V/C 4.1/6.8 4.1/6.7 4.0/8.1 4.2/8.0 3.9/9.6 3.4/8.9 3.6/9.7 3.0/10.5 3.2/11.1 3.1/11.8 3.0/10.0 2.6/11.3 2.5/8.3
Cloth color preference under the in¯uence of face cooling
337
I'Eclairage) standard illumination (D65) with 1000 lux. The experimental schedule is shown in Fig. 2.
Munsell values (HV/C) of cloth color used are listed in Table 1 (Kelley et al., 1943).
Measurements
Data analysis
Tympanic temperature (Tty) was measured every minute by a thermistor probe (ST-21 S, Sensor Technica Co. Inc., accuracy 20.018C) attached to the tympanic membrane. The pinnae were covered by headphones during face cooling to avoid cooling the ear canal. Thermistor sensors were attached with adhesive tape on the skin surfaces of the forehead, trunk, arm, hand, thigh, leg and foot. Skin temperatures were recorded by Squirrel Data Logger (1200 Series Squirrel Meter/Logger, accuracy 20.058C) every minute throughout the test. The mean skin temperature (Tsk) was calculated by the Hardy and Dubois (1938).
The data analyzed in our present experiment were those collected for last 30 min from 07:30 to 08:00. The data with tympanic and skin temperatures, and color preference were compared between ``face cooling'' and ``no face cooling'', ``face cooling'' and ``wind'', ``no face cooling'' and ``wind'' by a paired t-test. ** and * represent statistically signi®cant dierences at 1% and 5% level using the two tailed t-test.
sk 0:07Tforehead 0:35Ttrunk 0:14Tarm T 0:05Thand 0:19Tthigh 0:13Tleg 0:07Tfoot :
RESULTS
Figure 3 shows an example of tympanic temperatures (Tty, top) and mean skin temperatures (Tsk , bottom) among ``face cooling'', ``no face cooling''
Fig. 3. A comparison of tympanic temperatures (Tty, top) and mean skin temperatures (Tsk, bottom) as a typical example among ``face cooling'', ``no face cooling'' and ``wind'' in a subject during the experimental period.
338
H. S. Kim and T. Hiromi
and ``wind'' in one subject during the experimental period. Note that Tty fell only during ``face cooling'' experiments but continued to rise in the ``no face cooling'' and ``wind'' groups, possibly re¯ecting the circadian rhythm of body temperature. After 07:00 Tty of the ``face cooling'' group began to rise gradually but remained lower at all times than under the other two conditions. Tsk decreased most in the ``wind'' group, did not change in the ``no face cooling'' group and was intermediate in the ``face cooling'' group. Tsk began to increase immediately after 07:00. Figure 4 shows a comparison of average tympanic temperature (Tty, top), and mean skin temperature (Tsk, bottom) between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``no face cooling'' (right), measured every minute from 07:30 to 08:00. Five out of eight subjects participated in ``wind'' experiment. So, when tympanic temperature level is compared between ``no face cooling'' and ``wind'', and between ``face cooling'' and ``wind'', the data of ®ve subjects who participated both in ``face cooling'' and ``wind'' experiments, and both in ``no face
cooling'' and ``wind'' experiments were used for comparison. This is a reason why the levels of tympanic temperature were dierent between those in left (no face cooling) and middle (no face cooling) columns, and between those in left (face cooling) and right (face cooling) ones. Tty was signi®cantly lower in ``face cooling'' than in ``no face cooling'' (left) and also than in ``wind'' (right), while there were no signi®cant dierences between ``no face cooling'' and ``wind'' (middle). Tsk tended to be lower in ``face cooling'', and in ``wind'' than in ``no face cooling'' (left, middle), and in ``wind'' than in ``face cooling'' (right). Figure 5 shows an individual comparison of average preferred cloth color between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``face cooling'' (right), preferred every 5 minute from 07:30 to 08:00. The same reason is valid for Fig. 5 as for Fig. 4. Most subjects preferred warmer colors in ``face cooling'' than in ``no face cooling'' (left) and ``wind'' (right), while there were no signi®cant dierences between ``no face cooling'' and ``wind'' (middle).
Fig. 4. A comparison of average tympanic temperatures (Tty, top), and mean skin temperatures (Tsk, bottom) between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``no face cooling'' (right), measured every minute from 07:30 to 08:00. Circles: no face cooling. Squares: face cooling. Triangles: wind. **: P < 0.01.
Cloth color preference under the in¯uence of face cooling
339
Fig. 5. An individual comparison of average preferred cloth color between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``face cooling'' (right), preferred every 5 min from 07:30 to 08:00. Ordinate: The number arrayed from warm sensation (upper) to cool (bottom) by each individual before the start of experiments. Colors selected as ``warm'' by each subject were scored as high numbers and those as ``cool'' as low numbers, which was expressed as ``relative unit''. *: P < 0.05. DISCUSSION
Can physiological mechanisms explain our ®nding that ``face cooling'' and the fall in tympanic temperature changed color preference to warmer color selection? Kim and Tokura (1994) suggested that ``face cooling'' accelerated dressing behavior in the cold when compared with ``no face cooling'', because it correlates with a presumed change in load error between actual core temperature and its set-point. Similarly, ``face cooling'' might have made the dierences between actual core temperature and it set-point larger, which might explain the selection of warmer color preference in ``face cooling''. The subjects sought warmth not only physiologically by wearing thicker clothing (Kim and Tokura, 1994) but also psychologically by selecting warm colors such as red, seville orange and yellow which were perceived as warm while during ``no face cooling'' they selected blue-green, blue and purple-blue perceived as cold (Wright, 1962; Tinker, 1938). The greater deviation between the actual core temperature and its set-point due to ``face cooling'' may be responsible for not only behavioral temperature regulation, but also warmer color preference. Fanger et al. (1977) ®nding that the subjects preferred a slightly lower (0.48C) ambient temperature in the extreme red light than in the extreme blue light might also be interpreted in terms of a similar change in the thermoregulator. Alliesthesia could depend on the dierence between the actual internal state and its set-point, which were studied in thermal, gustatory and olfactory sensations (Cabanac, 1971; 1979). Our present
experiment shows that the preferred cloth color varied with a change in the tympanic temperature and correlated with the load error between internal temperature and its set-point. In other words, color preference may depend on ``milieu interieur''. It should be emphasized that the alliesthesia was observed also in the realm of visual sensation. Lowered skin temperatures did not seem related to color preference. Even if Tsk was greatly dierent between ``wind'' and ``no face cooling'', color preference was not in¯uenced by dierent Tsk but Tty was not dierent between the two conditions. Therefore, it is suggested that the load error between core temperature and its set-point is an important factor for the determination of color preference. REFERENCES
Ascho, J. and Heise, A. (1972) Advances in Climatic Physiology. Igaku Shoin, Tokyo, pp. 334±348. Bittel, J. and Henane, R. (1974) Comparison of thermal exchanges in men and women under neutral and hot conditions. J. Physiol. 250, 475±489. Cabanac, M. (1971) Physiological role of pleasure. Science 173, 1103±1107. Cabanac, M. (1979) Sensory pleasure. Quar. Rev. Biol. 54(1), 1±29. Cunningham, D. J. and Cabanac, M. (1971) Evidence from behavioral thermoregulatory responses of a shift in setpoint temperature related to the menstrual cycle. J. Physiol. 63, 236±238(Paris). Fanger, P. O., Breum, N. O. and Jerking, E. (1977) Can colour and noise in¯uence man's thermal comfort? Ergonomics 20(1), 11±18. Fujimoto, S., Watanabe, T., Sakamoto, A., Yukawa, K. and Morimoto, K. (1968) Studies on the physical sur-
340
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face area of Japanese. Jan J. hyg. 23, 443±450in Japanese. Gelineau, E. P. (1981) A psychometric approach to the measurement of color preference. Percept. Mot. Skills. 53(1), 163±174. Hafner, J. L. and Corotto, L. V. (1980) Age, sex, race, and the luscher color test. Percept. Mot. Skills. 50, 1144±1146. Hardy, J. D. and Dubois, E. F. (1938) The technic of measuring radiation and convection. J. Nutr. 15, 461± 510. Kelley, K. L., Gibson, K. S. and Nickerson, D. (1943) Tristimulus speci®cation of the Munsell book of color from spectro-photometric measurements. J. Opt. Soc. Am. A88, 355±376. Kim, H. E. and Tokura, H. (1994) Eects of time of day on dressing behavior under the in¯uence of ambient temperature fall from 308C to 158C. Physiol. Behav. 55(4), 645±650.
Kim, S. H. and Tokura, H. (1997) Cloth color preference under the in¯uence of menstrual cycle. Appl. Human Sci. 16(4), 149±151. Kim, S. H. and Tokura, H. (1998) Eects of menstrual cycle and room temperature on color preference. Biol. Rhythm Res. 29(2), 151±158. Schuschke, G. and Christiansen, H. (1994) Colour preference applying to patients and colour design at hospital. Zentralbl. Hyg. Umweltmed 195(56), 419±431. Tinker, M. A. (1938) Eect of stimulus-texture upon apparent warmth and aective value of colors. J. Psychol. 51, 532±535. Trinkaus, J. (1991) Color preference in sport shoes: an informal look. Percept. Mot. Skills. 73(2), 613±614. Wright, B. (1962) The in¯uence of hue, lightness, and saturation on apparent warmth and weight. Amer. J. Psychol. 75, 232±241.
J. therm. Biol. Vol. 23, No. 6, pp. 335±340, 1998 # 1998 Published by Elsevier Science Ltd. All rights reserved Printed in Great Britain 0306-4565/98 $ - see front matter S0306-4565(98)00023-0
CLOTH COLOR PREFERENCE UNDER THE INFLUENCE OF FACE COOLING HEE SOOK KIM1 and TOKURA HIROMI1{ Department of Environmental Health, Nara Women's University, Nara 630, Japan
1
(Received 14 August 1997; accepted in revised form 15 June 1998) Abstract 1. We studied the eect of face cooling accompanied by a fall of tympanic temperature on color preference in 8 women at an ambient temperature of 288C. 2. The face only was cooled by blowing 158C air at 6 m/s on the face only. Controls received either no wind at all or a wind (248C, 6 m/s) on the body and appendages only. 3. Most subjects preferred warmer colors after facial cooling than after no facial cooling. 4. The facial cooling and decrease in tympanic temperature may indicate an increase in load error between core temperature and set-point. # 1998 Published by Elsevier Science Ltd. All rights reserved Key Word Index: Color preference; face cooling; tympanic temperature; set-point
INTRODUCTION
MATERIALS AND METHODS
A physiological component to color preference has not been studied systematically, although there are many studies of color preference by psychologists (Gelineau, 1981; Hafner and Corotto, 1980; Schuschke and Christiansen, 1994; Trinkaus, 1991). According to Fanger et al. (1977) the ®nding that subjects preferred lower (0.48C) ambient temperature in the extreme red light than in extreme blue light, suggests that ambient color in¯uences thermoregulation. Recently, Kim and Tokura (1997; 1998) found that the subjects preferred warmer colors during the luteal phase (L-phase) of the ovarian cycle than in the follicular phase (F-phase) at neutral ambient temperature. They related this to a higher set-point in core temperature during the L-phase than F-phase. They suggest that the determination of color preference may have a possible physiological basis. Further, facial cooling accelerated dressing rate in the cold (Kim and Tokura, 1994). They explained this behavior as due to a decrease in core temperature (tympanic) caused by facial cooling which resulted in an increase in the load error between core temperature and set-point. Here we ask whether facial cooling and the accompanying decrease in tympanic temperature would in¯uence color preference between ``warm'' and ``cool'' colors. { Author to whom all correspondence should be addressed: Tel.: 0742-20-3469; Fax: 0742-20-3499; email: [email protected]. 335
Subjects Eight adult females (age 20.13 20.35 yrs, height 156.75 2 1.21 cm, and body mass 50.13 2 1.66 kg, body surface area 1.442 0.03 m2, mean 2SEM) volunteered as subjects for face cooling/no face cooling experiments, and ®ve (age 19.83 2 0.45 yrs, height 156.33 2 1.79 cm, and body mass 50 2 2.53 kg, body surface area 1.432 0.04 m2, mean 2SEM) of those for wind experiment. After the general purpose, procedure and possible risks of the experiment were fully explained, all subjects gave their informed consent. Body surface area was calculated by the following equation (Fujimoto et al., 1968). BSA = W0.444H0.66388.33 10ÿ4 where BSA: Body surface area (m2), W: Weight (kg), H: Height (cm). Each test was conducted at the follicular phase to avoid the eects of the menstrual cycle on core temperature (Ascho and Heise, 1972; Bittel and Henane, 1974; Cunningham and Cabanac, 1971). No subject used oral contraceptives for the past month and all were asked to abstain from coffee and alcohol for 24 h before the start of each experiment. Procedure The subjects entered a chamber at 20:00 at 288C and 50% relative humidity. The subjects wearing half-sleeved shirts and knee-pants sat on a sofa for 30 min. Since perception of warm to cool colors might dier individually, before retiring each sub-
336
H. S. Kim and T. Hiromi
Fig. 1. Schematic drawing of method of face cooling.
ject was asked to array 41 randomly mixed cloth swatches (4 5 cm) from very warm to very cool colors. All subjects arrayed these cloth colors in the order from red through yellow and green to blue. They rose at 06:00 the next morning. The subjects were asked to sit for 30 min and during these
periods temperature sensors were attached to the skin and tympanum. From 06:30 to 07:00 a cool wind at 158C and at 6 m/s was blown to the face. The body was protected by a corrugated cardboard box (Fig. 1, ``face cooling''). The skin temperatures other than the face also decreased during ``face cooling'', although these areas were not blown upon directly. To control for the above lowering of skin temperature, a control group received wind (248C, 6 m/s) on the trunk and limbs but not the face which caused a lowering of body skin temperature comparable to the decrease seen in face cooling alone (``wind''). A further control group sat in the apparatus with no wind at all (``no face cooling''). At 07:00 the fans were shut o and the recovery followed until 08:00. Every ®ve minutes from 07:00 to 08:00, the subjects were instructed to choose one out of the 41 cloth colors (24 52 cm, cotton 100%) which they preferred. Selections were made under CIE (Commision Internationale de
Fig. 2. Experimental schedule. Table 1. Munsell values (HV/C) of cloth colors H 4.3R 5.4R 6.2R 6.3R 6.4R 6.9R 8.0R 9.2R 0.3YR 2.1YR 4.0YR 5.1YR 7.5YR 0.1Y
V/C 4.1/14.2 4.0/13.7 3.5/12.3 4.1/12.8 4.1/14.8 4.5/14.0 4.1/12.6 4.2/12.9 5.2/11.6 5.8/12.4 6.3/15.1 6.2/14.3 6.9/14.3 7.8/12.1
H 2.3Y 6.3Y 7.4Y 2.5GY 6.0GY 8.4GY 9.6GY 0.6G 2.7G 6.2G 8.1G 1.6BG 3.6BG 6.5BG
V/C 8.0/12.0 8.3/12.7 8.6/11.4 7.2/11.9 6.9/9.2 5.8/9.0 5.2/10.1 5.1/8.5 4.7/9.9 4.6/9.0 4.2/7.3 4.2/7.6 4.1/6.9 4.0/7.3
H 8.1BG 0.9B 4.7B 6.4B 9.7B 2.1PB 5.2PB 6.0PB 6.0PB 7.0PB 7.1PB 7.5PB 7.1PB
V/C 4.1/6.8 4.1/6.7 4.0/8.1 4.2/8.0 3.9/9.6 3.4/8.9 3.6/9.7 3.0/10.5 3.2/11.1 3.1/11.8 3.0/10.0 2.6/11.3 2.5/8.3
Cloth color preference under the in¯uence of face cooling
337
I'Eclairage) standard illumination (D65) with 1000 lux. The experimental schedule is shown in Fig. 2.
Munsell values (HV/C) of cloth color used are listed in Table 1 (Kelley et al., 1943).
Measurements
Data analysis
Tympanic temperature (Tty) was measured every minute by a thermistor probe (ST-21 S, Sensor Technica Co. Inc., accuracy 20.018C) attached to the tympanic membrane. The pinnae were covered by headphones during face cooling to avoid cooling the ear canal. Thermistor sensors were attached with adhesive tape on the skin surfaces of the forehead, trunk, arm, hand, thigh, leg and foot. Skin temperatures were recorded by Squirrel Data Logger (1200 Series Squirrel Meter/Logger, accuracy 20.058C) every minute throughout the test. The mean skin temperature (Tsk) was calculated by the Hardy and Dubois (1938).
The data analyzed in our present experiment were those collected for last 30 min from 07:30 to 08:00. The data with tympanic and skin temperatures, and color preference were compared between ``face cooling'' and ``no face cooling'', ``face cooling'' and ``wind'', ``no face cooling'' and ``wind'' by a paired t-test. ** and * represent statistically signi®cant dierences at 1% and 5% level using the two tailed t-test.
sk 0:07Tforehead 0:35Ttrunk 0:14Tarm T 0:05Thand 0:19Tthigh 0:13Tleg 0:07Tfoot :
RESULTS
Figure 3 shows an example of tympanic temperatures (Tty, top) and mean skin temperatures (Tsk , bottom) among ``face cooling'', ``no face cooling''
Fig. 3. A comparison of tympanic temperatures (Tty, top) and mean skin temperatures (Tsk, bottom) as a typical example among ``face cooling'', ``no face cooling'' and ``wind'' in a subject during the experimental period.
338
H. S. Kim and T. Hiromi
and ``wind'' in one subject during the experimental period. Note that Tty fell only during ``face cooling'' experiments but continued to rise in the ``no face cooling'' and ``wind'' groups, possibly re¯ecting the circadian rhythm of body temperature. After 07:00 Tty of the ``face cooling'' group began to rise gradually but remained lower at all times than under the other two conditions. Tsk decreased most in the ``wind'' group, did not change in the ``no face cooling'' group and was intermediate in the ``face cooling'' group. Tsk began to increase immediately after 07:00. Figure 4 shows a comparison of average tympanic temperature (Tty, top), and mean skin temperature (Tsk, bottom) between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``no face cooling'' (right), measured every minute from 07:30 to 08:00. Five out of eight subjects participated in ``wind'' experiment. So, when tympanic temperature level is compared between ``no face cooling'' and ``wind'', and between ``face cooling'' and ``wind'', the data of ®ve subjects who participated both in ``face cooling'' and ``wind'' experiments, and both in ``no face
cooling'' and ``wind'' experiments were used for comparison. This is a reason why the levels of tympanic temperature were dierent between those in left (no face cooling) and middle (no face cooling) columns, and between those in left (face cooling) and right (face cooling) ones. Tty was signi®cantly lower in ``face cooling'' than in ``no face cooling'' (left) and also than in ``wind'' (right), while there were no signi®cant dierences between ``no face cooling'' and ``wind'' (middle). Tsk tended to be lower in ``face cooling'', and in ``wind'' than in ``no face cooling'' (left, middle), and in ``wind'' than in ``face cooling'' (right). Figure 5 shows an individual comparison of average preferred cloth color between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``face cooling'' (right), preferred every 5 minute from 07:30 to 08:00. The same reason is valid for Fig. 5 as for Fig. 4. Most subjects preferred warmer colors in ``face cooling'' than in ``no face cooling'' (left) and ``wind'' (right), while there were no signi®cant dierences between ``no face cooling'' and ``wind'' (middle).
Fig. 4. A comparison of average tympanic temperatures (Tty, top), and mean skin temperatures (Tsk, bottom) between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``no face cooling'' (right), measured every minute from 07:30 to 08:00. Circles: no face cooling. Squares: face cooling. Triangles: wind. **: P < 0.01.
Cloth color preference under the in¯uence of face cooling
339
Fig. 5. An individual comparison of average preferred cloth color between ``no face cooling'' and ``face cooling'' (left), ``no face cooling'' and ``wind'' (middle), ``wind'' and ``face cooling'' (right), preferred every 5 min from 07:30 to 08:00. Ordinate: The number arrayed from warm sensation (upper) to cool (bottom) by each individual before the start of experiments. Colors selected as ``warm'' by each subject were scored as high numbers and those as ``cool'' as low numbers, which was expressed as ``relative unit''. *: P < 0.05. DISCUSSION
Can physiological mechanisms explain our ®nding that ``face cooling'' and the fall in tympanic temperature changed color preference to warmer color selection? Kim and Tokura (1994) suggested that ``face cooling'' accelerated dressing behavior in the cold when compared with ``no face cooling'', because it correlates with a presumed change in load error between actual core temperature and its set-point. Similarly, ``face cooling'' might have made the dierences between actual core temperature and it set-point larger, which might explain the selection of warmer color preference in ``face cooling''. The subjects sought warmth not only physiologically by wearing thicker clothing (Kim and Tokura, 1994) but also psychologically by selecting warm colors such as red, seville orange and yellow which were perceived as warm while during ``no face cooling'' they selected blue-green, blue and purple-blue perceived as cold (Wright, 1962; Tinker, 1938). The greater deviation between the actual core temperature and its set-point due to ``face cooling'' may be responsible for not only behavioral temperature regulation, but also warmer color preference. Fanger et al. (1977) ®nding that the subjects preferred a slightly lower (0.48C) ambient temperature in the extreme red light than in the extreme blue light might also be interpreted in terms of a similar change in the thermoregulator. Alliesthesia could depend on the dierence between the actual internal state and its set-point, which were studied in thermal, gustatory and olfactory sensations (Cabanac, 1971; 1979). Our present
experiment shows that the preferred cloth color varied with a change in the tympanic temperature and correlated with the load error between internal temperature and its set-point. In other words, color preference may depend on ``milieu interieur''. It should be emphasized that the alliesthesia was observed also in the realm of visual sensation. Lowered skin temperatures did not seem related to color preference. Even if Tsk was greatly dierent between ``wind'' and ``no face cooling'', color preference was not in¯uenced by dierent Tsk but Tty was not dierent between the two conditions. Therefore, it is suggested that the load error between core temperature and its set-point is an important factor for the determination of color preference. REFERENCES
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