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Proximity and gaze influences facial temperature: a thermal infrared imaging study.

Ioannou S, Morris P, Mercer H, Baker M, Gallese V, Reddy V - Front Psychol (2014)

Bottom Line: We know little, however, about subtler facial reactions such as rise and fall in temperature, which may be sensitive to contextual effects and functional in social interactions.Direct gaze, compared to averted gaze, led to a thermal increase at both distances with a stronger effect at intimate distance, in both orders of distance variation.These results demonstrate the powerful effects of another person's gaze on psycho-physiological responses, even at a distance and independent of context.

View Article: PubMed Central - PubMed

Affiliation: Section of Human Physiology, Department of Neuroscience, Parma University Parma, Italy ; Department of Psychology, Centre for Situated Action and Communication, University of Portsmouth Portsmouth, UK.

ABSTRACT
Direct gaze and interpersonal proximity are known to lead to changes in psycho-physiology, behavior and brain function. We know little, however, about subtler facial reactions such as rise and fall in temperature, which may be sensitive to contextual effects and functional in social interactions. Using thermal infrared imaging cameras 18 female adult participants were filmed at two interpersonal distances (intimate and social) and two gaze conditions (averted and direct). The order of variation in distance was counterbalanced: half the participants experienced a female experimenter's gaze at the social distance first before the intimate distance (a socially "normal" order) and half experienced the intimate distance first and then the social distance (an odd social order). At both distances averted gaze always preceded direct gaze. We found strong correlations in thermal changes between six areas of the face (forehead, chin, cheeks, nose, maxilliary, and periorbital regions) for all experimental conditions and developed a composite measure of thermal shifts for all analyses. Interpersonal proximity led to a thermal rise, but only in the "normal" social order. Direct gaze, compared to averted gaze, led to a thermal increase at both distances with a stronger effect at intimate distance, in both orders of distance variation. Participants reported direct gaze as more intrusive than averted gaze, especially at the intimate distance. These results demonstrate the powerful effects of another person's gaze on psycho-physiological responses, even at a distance and independent of context.

No MeSH data available.


Related in: MedlinePlus

Line graph illustrating the temperature of the face based on the experimental order of the four conditions.
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Figure 1: Line graph illustrating the temperature of the face based on the experimental order of the four conditions.

Mentions: To obtain a more clear and robust pattern on the effects that interpersonal distance and gaze had on facial skin temperature, all ROI were averaged (see Table 2, Figure 1) and a 2 × 2 × 2 mixed factorial ANOVA was performed on the averaged data. No significant interaction effects were observed between interpersonal distance, gaze and order, Wilks' Lambda = 0.96, F(1, 16) = 0.66, p = 0.429, η2p = 0.04 or order and gaze, Wilks' Lambda = 0.80, F(1, 16) = 3.89, p = 0.066, η2p = 0.19. There was a significant interaction between interpersonal distance and order, Wilks' Lambda = 0.41, F(1, 16) = 22.68, p = 0.000, η2p = 0.58 (see Figure 2). From Figure 2 it seems that the interaction is a function of the fact that temperature increases when the experimenter moves from social space to intimate space but is relatively unaffected by distance when moving from intimate space to social space. This interpretation is supported by simple main effects analyses (with Sidak adjustment). It was observed that there was a significant increase in temperature when the experimenter moved from social space (M = 33.20, SD = 1.05) to intimate space (M = 33.62, SD = 1.01), p = 0.000. However, no significant difference was observed in temperature when the experimenter moved from intimate space (M = 34.25, SD = 1.22) to social space (M = 34.32, SD = 1.18), p = 0.054 (see also Table 3). There was also an interpersonal distance and gaze interaction, Wilks' Lambda = 0.76, F(1, 16) = 5.03, p = 0.039, η2p = 0.24 (Figure 3). From Figure 3 it appears that the interaction is the result of the fact that the effect of direct gaze increasing temperature is greater in the intimate space condition than the social space condition. Simple main effects analyses provide some limited supported for this interpretation as there was a significantly higher temperature in the intimate space, direct gaze (M = 34.02, SD = 1.14) condition compared to intimate space gaze aversion condition (M = 33.84, SD = 1.75), p = 0.000. The temperature was also significantly higher in the social space condition when the experimenter engaged in direct (M = 33.79, SD = 1.21) compared to averted gaze (M = 33.72, SD = 1.29) p = 0.014. However, the difference was greater in the intimate space condition (see also Table 3). There was a significant main effect of gaze with direct gaze having a higher temperature (M = 33.90, SD = 1.21) than the gaze aversion (M = 33.78, SD = 1.16), Wilks' Lambda = 0.36, F(1, 16) = 28.35, p = 0.000, η2p = 0.64, with a large effect size. Given the ordinal interaction between gaze and distance it is safe to interpret this main effect and conclude that direct gaze always produces a large effect on facial temperature. There was also a significant effect of interpersonal distance with temperature being higher in the intimate space condition (M = 33.93, SD = 1.15) than the social space condition (M = 33.76, SD = 1.23) Wilks' Lambda = 0.58, F(1, 16) = 11.66, p = 0.004, η2p = 0.42 with a large effect size. Given the interaction results we can again be relatively confident that there is a pervasive and robust elevation of temperature in intimate space. Finally in order to provide a visual illustration of the effects of the experimental protocol on facial temperature four images were created from two randomly selected individuals for each experimental order (Figure 4). The images were taken 10 s prior of the end of each phase. This was performed in order to allow enough time for large temperature effects to take place on the skin surface that would enable a vibrant visual illustration of the infrared image.


Proximity and gaze influences facial temperature: a thermal infrared imaging study.

Ioannou S, Morris P, Mercer H, Baker M, Gallese V, Reddy V - Front Psychol (2014)

Line graph illustrating the temperature of the face based on the experimental order of the four conditions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4120854&req=5

Figure 1: Line graph illustrating the temperature of the face based on the experimental order of the four conditions.
Mentions: To obtain a more clear and robust pattern on the effects that interpersonal distance and gaze had on facial skin temperature, all ROI were averaged (see Table 2, Figure 1) and a 2 × 2 × 2 mixed factorial ANOVA was performed on the averaged data. No significant interaction effects were observed between interpersonal distance, gaze and order, Wilks' Lambda = 0.96, F(1, 16) = 0.66, p = 0.429, η2p = 0.04 or order and gaze, Wilks' Lambda = 0.80, F(1, 16) = 3.89, p = 0.066, η2p = 0.19. There was a significant interaction between interpersonal distance and order, Wilks' Lambda = 0.41, F(1, 16) = 22.68, p = 0.000, η2p = 0.58 (see Figure 2). From Figure 2 it seems that the interaction is a function of the fact that temperature increases when the experimenter moves from social space to intimate space but is relatively unaffected by distance when moving from intimate space to social space. This interpretation is supported by simple main effects analyses (with Sidak adjustment). It was observed that there was a significant increase in temperature when the experimenter moved from social space (M = 33.20, SD = 1.05) to intimate space (M = 33.62, SD = 1.01), p = 0.000. However, no significant difference was observed in temperature when the experimenter moved from intimate space (M = 34.25, SD = 1.22) to social space (M = 34.32, SD = 1.18), p = 0.054 (see also Table 3). There was also an interpersonal distance and gaze interaction, Wilks' Lambda = 0.76, F(1, 16) = 5.03, p = 0.039, η2p = 0.24 (Figure 3). From Figure 3 it appears that the interaction is the result of the fact that the effect of direct gaze increasing temperature is greater in the intimate space condition than the social space condition. Simple main effects analyses provide some limited supported for this interpretation as there was a significantly higher temperature in the intimate space, direct gaze (M = 34.02, SD = 1.14) condition compared to intimate space gaze aversion condition (M = 33.84, SD = 1.75), p = 0.000. The temperature was also significantly higher in the social space condition when the experimenter engaged in direct (M = 33.79, SD = 1.21) compared to averted gaze (M = 33.72, SD = 1.29) p = 0.014. However, the difference was greater in the intimate space condition (see also Table 3). There was a significant main effect of gaze with direct gaze having a higher temperature (M = 33.90, SD = 1.21) than the gaze aversion (M = 33.78, SD = 1.16), Wilks' Lambda = 0.36, F(1, 16) = 28.35, p = 0.000, η2p = 0.64, with a large effect size. Given the ordinal interaction between gaze and distance it is safe to interpret this main effect and conclude that direct gaze always produces a large effect on facial temperature. There was also a significant effect of interpersonal distance with temperature being higher in the intimate space condition (M = 33.93, SD = 1.15) than the social space condition (M = 33.76, SD = 1.23) Wilks' Lambda = 0.58, F(1, 16) = 11.66, p = 0.004, η2p = 0.42 with a large effect size. Given the interaction results we can again be relatively confident that there is a pervasive and robust elevation of temperature in intimate space. Finally in order to provide a visual illustration of the effects of the experimental protocol on facial temperature four images were created from two randomly selected individuals for each experimental order (Figure 4). The images were taken 10 s prior of the end of each phase. This was performed in order to allow enough time for large temperature effects to take place on the skin surface that would enable a vibrant visual illustration of the infrared image.

Bottom Line: We know little, however, about subtler facial reactions such as rise and fall in temperature, which may be sensitive to contextual effects and functional in social interactions.Direct gaze, compared to averted gaze, led to a thermal increase at both distances with a stronger effect at intimate distance, in both orders of distance variation.These results demonstrate the powerful effects of another person's gaze on psycho-physiological responses, even at a distance and independent of context.

View Article: PubMed Central - PubMed

Affiliation: Section of Human Physiology, Department of Neuroscience, Parma University Parma, Italy ; Department of Psychology, Centre for Situated Action and Communication, University of Portsmouth Portsmouth, UK.

ABSTRACT
Direct gaze and interpersonal proximity are known to lead to changes in psycho-physiology, behavior and brain function. We know little, however, about subtler facial reactions such as rise and fall in temperature, which may be sensitive to contextual effects and functional in social interactions. Using thermal infrared imaging cameras 18 female adult participants were filmed at two interpersonal distances (intimate and social) and two gaze conditions (averted and direct). The order of variation in distance was counterbalanced: half the participants experienced a female experimenter's gaze at the social distance first before the intimate distance (a socially "normal" order) and half experienced the intimate distance first and then the social distance (an odd social order). At both distances averted gaze always preceded direct gaze. We found strong correlations in thermal changes between six areas of the face (forehead, chin, cheeks, nose, maxilliary, and periorbital regions) for all experimental conditions and developed a composite measure of thermal shifts for all analyses. Interpersonal proximity led to a thermal rise, but only in the "normal" social order. Direct gaze, compared to averted gaze, led to a thermal increase at both distances with a stronger effect at intimate distance, in both orders of distance variation. Participants reported direct gaze as more intrusive than averted gaze, especially at the intimate distance. These results demonstrate the powerful effects of another person's gaze on psycho-physiological responses, even at a distance and independent of context.

No MeSH data available.


Related in: MedlinePlus