Küster, D., Kappas, A., Theunis, M., & Tsankova, E. (2011, September). Bilateral plantar electrodermal activity elicited by contributing to online discussion forums: Do males and females recover asymmetrically? Poster presented at the 51st Annual Meeting of the Society for Psychophysiological Research, Boston, Massachusetts.

1. BILATERAL PLANTAR ELECTRODERMAL ACTIVITY ELICITED BY
DO MALES AND
ster,
Dennis Küster, Arvid Kappas,
ster
Jacobs University
Sex differences in hemispheric specialization have long been suspected to be reflected by left-hand/right-hand differences in electrodermal activity. Of particular interest to this
question are language processing and language production. However, most research has focused on recall of individual words rather than elaborative production, isolated stimulus-
responses rather than ecological emotional recovery, and palmar rather than plantar regions. Bilateral EDA recordings face methodological and technical problems that may be
partially avoidable by moving the region of recording to the feet. Here, we recorded bilateral EDA from the feet of 59 dextral participants (30 female, 29 male) who each produced 4
complete Internet forum posts (2 negative, 2 positive) with a mean of 86 words per post. Self-report showed that participants felt emotionally activated by thinking and writing
about the topics, and EDA was significantly correlated with perceived relative ranked arousal. Furthermore initial evidence suggests a pattern of EDA asymmetries that may be
influenced by gender, as well as a possible recovery-advantage of females. However, data on left/right asymmetries appears tentative and in need of further study. We argue that
recording bilateral EDA at plantar regions may be both feasible and useful in studies of lateralization during ecological writing. We will discuss the implications, practical
opportunities, and challenges posed by bilateral EDA-recordings from the feet during complex language production, including additional exploratory automated text-analyses.
Background Hypotheses
Prior studies on hemispheric asymmetry and bilateral electrodermal activity, IAPS, Females: Higher arousal to IAPS images, Forum Posts, Females: Higher arousal to IAPS
while partially positive and replicated (Boucsein, 1992), have produced especially if unpleasant (Bradley et al., 2001). images (subjective, EDA, correlations; Bradley et
al., 2001) should replicate for forum posts.
ambiguous results that have suffered from small effects and experimental
IAPS, Females: Stronger coupling between Forum Posts, Males: Due to gender differences
inconsistencies (Hugdahl, 1984). For example, while Martínez-Selva, Román, arousal and unpleasantness; for males between in expressive writing, males should exhibit
Garcia-Sánchez, and Gómez-Amor (1987) were able to show gender-specific arousal and pleasantness (Bradley et al., 2001). higher levels of arousal, and may use more
lateralization between hands in response to 80-dB tones, sex differences negative emotion words when writing about a
negative topic Langer, 2010).
disappeared in their replication study when controlling for handedness
IAPS, Males: More EDA asymmetry, with L > R; Forum Posts, Males: More EDA asymmetry,
(Román et al., 1989). Furthermore, research of this tradition has typically used Females: Less EDA asymmetry with R > L with L > R; Females: Less EDA asymmetry with R
reduced exposure-type stimuli like tones, line-drawings, or minimal word (Martínez-Selva et al, 1987). > L (Martínez-Selva et al, 1987).
sequences (e.g., Smith & Ketterer, 1982) allowing for little ecologically IAPS: F vs. M Arousal IAPS: F vs. M Arousal x Valence
meaningful responses by participants that would permit conclusions about 6 6 6
active coping with negative emotional states, and how this might be reflected F R² = 0.4574 F F R² = 0.5126
Subjective Arousal (IAPS)
by gender-specific EDA-asymmetries. 5 M 6260
M M 6260
5 9584 5 9584
Methods
9560 1275 9560
1275
4 6260
2070
Arousal
Arousal
6260 1750 9584
2410 2070 2410
9584 2230 1750 2230
3 4 2753 4 2753 9220
R² = 0.5197
2190
7211 2550 2550 2190 7211
7390 7390
7002 7002
9220 9560 5535 1440 5535 9560
1440
Participants: 59 dextral students (30 2 R² = 0.5607 2753
7211
2410 2070 2070 2410 2230
7211
2753
1275 2230 7284 2550 7284 1275
female; Mage = 20.4 yrs; SD = 2.0) 3 9220
2190
5535 7390 3 2550
7390
5535
2190
9220
1 7002 7284 1440
1750 7284
1440
7002
1750
0 2 2
iaps7284
iaps7002
iaps1440
iaps5535
iaps7390
iaps2190
iaps1750
iaps2550
iaps9220
iaps2753
iaps7211
iaps2230
iaps2410
iaps2070
iaps1275
iaps9560
iaps9584
iaps6260
F
1 2 3 4 5 6 7 1 2 3 4 5 6 7
Valence: “How pleasant?” Valence: “How unpleasant?”
IAPS: Viewing Image (EDA x Arousal) IAPS: Answering Questions (EDA x Arousal)
M R L
.6000
Left Foot
.6000
.5000 Left Foot
Mean EDA (µS∆2s)
.5000
Mean EDA (µS∆2s)
Right Foot .4000 Right Foot
∆
.4000
∆
.3000 Left Foot .3000 Left Foot
.2000 .2000 Right Foot
Right Foot
.1000 .1000
Stimuli: 18 IAPS control vs. 2x2 r= 0.44
.0000
r= 0.50
.0000 M r= 0.54 M
Forum posts written by participants -.1000
r= 0.47
-.1000
r= 0.56 r= 0.60
-.2000 F -.2000
F
r= 0.55 -.3000 r= 0.57
6 Pos 6 Neu 6 Neg -.3000
-.4000 -.4000
1.00 2.00 3.00 4.00 5.00 6.00 1.00 2.00 3.00 4.00 5.00 6.00
IAPS: L vs. R SCR IAPS: F vs. M EDA (R-L) Asymmetry
0.25 0.10
EDA Asymmetry (R-L; µS∆2s)
EDA Asymmetry (R-L; µS∆2s)
Control
Test
L R 0.08
∆
0.20
∆
0.15 0.06 F
0.04
M
0.10
0.02
0.05
0.00
0.00 -0.02
-0.05 -0.04
-0.10 -0.06 L R
-0.08
-0.15
-1500
-1000
-500
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
p500
p1000
p1500
p2000
p2500
p3000
p3500
p4000
p4500
-0.10
0
500
p1000
p1500
p2000
p2500
p3000
p3500
p4000
p4500
-1500
-1000
-500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
p500
Left Foot Positive Left Foot Neutral Left Foot Negative
Right Foot Positive Right Foot Neutral Right Foot Negative Positive Male Negative Male Positive Female Negative Female
Present Study
The present study investigated sex differences in subjective, electrodermal, and behavioral (word-analyses; LIWC) arousal in response to writing different types of emotional
Internet forum posts as compared to a more classical passive picture viewing paradigm (IAPS; Lang et al., 2008). As Bradley et al. (2001) have shown, females may respond with
higher subjective and electrodermal arousal when exposed to standardized images, in particular towards negative and threatening stimuli. For writing forum posts, two
contrasting hypotheses emerged. Either, higher female subjective arousal should replicate for the writing task(s), or males should exhibit higher arousal due to established
gender-specific differences in expressive writing (e.g., Langer et al., 2010). We chose a controlled but ecologically meaningful condition (writing-task) allowing for active coping
as compared to passive exposure (see Kappas, 2011). We aimed to show how such a more ecological task may differ in recruiting arousal systems, and how the ability to act on
this stimulus situation may induce differences in the time course of subjective and physiological arousal compared to picture viewing. For example, there may be gender-specific
differences in recovery related to emotional disclosure (see e.g., Langer, 2010). Finally, because active writing may elicit more intense and lasting arousal in subjects, it may be
associated with sufficiently strong gender-specific EDA asymmetries to be captured and studied in a bi-lateral recording, and thus might overcome some of the problems of
previous studies (see Hugdahl, 1984). In order to obtain this bi-lateral data while subjects were writing, we recorded electrodermal activity from medial sites of both feet
according to the guidelines detailed by Boucsein (1992).
Acknowledgments
Research funded by CYBEREMOTIONS: EU FP7 funded project, Theme 3: “Science of complex systems for socially intelligent ICT”, contract no. 231323
Presented at the 51st Annual Meeting of the Society for Psychophysiological Research, Boston, Ma, September 14-18, 2011
Contact
Dennis Küster, School of Humanities and Social Sciences, Jacobs University Bremen, Campus Ring 1, D-28759 Bremen, Germany
d.kuester@jacobs-university.de

2. FORUMS:
CONTRIBUTING TO ONLINE DISCUSSION FORUMS:
FEMALES RECOVER ASYMMETRICALLY ?
Theunis,
Mathias Theunis, & Elena Tsankova
Bremen
As expected, females responded with systematically greater subjective arousal than males, in particular toward the most negative pictures – but apparently also towards some of
the most positive images in our selection, whereas males appeared to show a slightly more linear relationship between perceived arousal and valence. Viewing-related EDA
furthermore appeared to be tentatively more closely related to subjective arousal for males than for females, a pattern that emerged much more clearly for the writing task.
When writing, females again generally reported greater subjective arousal – however, physiologically, they did not show significantly larger skin conductance responses. Instead,
females rather appeared to have slight advantages in physiological recovery, in particular when asked to reply to a positive post. As expected, (R-L) EDA-asymmetries were
generally small, in particular when compared to the passive IAPS-viewing task. However, both the mean EDA levels and asymmetries were considerably elevated for active
writing compared to passive viewing. Furthermore, males showed significantly greater (R-L) EDA-asymmetry when asked to reply to a positive post – a pattern which was less
clear for the other writing tasks but which appeared to be consistent with apparent tendencies for greater male (R-L) asymmetries when exposed to positive images. While males
did not generally differ in the number of words produced for a post, they produced the least average number of words when asked to reply to a positive post, a task for which
females appeared to have considerably less difficulties. In the further textual characteristics, males did not generally use more or less emotional words than females, however,
males used significantly fewer pronouns.
Posts: Valence (Females vs. Males) Posts: Arousal (Females vs. Males) Posts: Ranked Arousal (Females) Posts: Ranked Arousal (Males)
14 7
1.1
12 F 6 F Left Foot
1.1
Left Foot
M M 0.9
10 5 Right Foot 0.9 Right Foot
EDA (µS∆2s)
EDA (µS∆2s)
0.7 r= 0.22 r= 0.72
∆
8 4 0.7
∆
r= 0.28 r= 0.86
6 3 0.5 0.5
4 2 0.3
F 0.3 M
2 1
0.1 0.1
Think: Write: Think: Write: Think: Write: Think: Write: Think: Write: Think: Write: Think: Write: Think: Write:
First First Reply Reply First First Reply Reply First First Reply Reply First First Reply Reply -0.1 -0.1
negative negative negative negative positive positive positive positive negative negative negative negative positive positive positive positive 1 2 3 4 5 6 7 1 2 3 4 5 6
Posts: EDA across Intervals (Right Foot; F vs. M)) EDA Asymmetry across Intervals (R-L: Females) EDA Asymmetry across Intervals (R-L: Males)
While reading/thinking about a topic (F) While reading/thinking about a topic (M) While reading/thinking about a topic (R-L) After reading/thinking about a topic (R-L) While writing the post / viewing IAPS control (R-L)
After reading/thinking about a topic (F) After reading/thinking about a topic (M) After writing the post (R-L) While answering questions afterwards (R-L)
While writing the post / viewing IAPS control (F) While writing the post/viewing IAPS control (M)
EDA Asymmetry (R-L; Me-MiΔ20s µS)
EDA Asymmetry (R-L; Me-MiΔ20s µS)
After writing the post (F) After writing the post (M) 0.9 0.9
While answering questions afterwards (F) While answering questions afterwards (M) 0.7 L R F 0.7 L R M
1.5
EDA (F vs. M; Me-MiΔ20s µS)
1.3 R F 0.5 0.5
1.1 M 0.3 0.3
0.9
0.7 0.1 0.1
0.5 -0.1 -0.1
0.3
0.1 -0.3 -0.3
-0.1
-0.5 -0.5
-0.3
-0.5 -0.7 -0.7
First negative Reply to a First positive Reply to a IAPS control First negative Reply to a First positive Reply to a IAPS control First negative Reply to a First positive Reply to a IAPS control
post negative post post positive post (lf) post negative post post positive post (lf) post negative post post positive post (lf)
Exploratory Text-Analyses (LIWC: Females vs. Males) First Posts: Skin Conductance (R vs. L: Females) First Posts: Skin Conductance (R vs. L: Males)
First Reply to a First Reply to a First Reply to a First Reply to a
negative negative negative negative positive positive First Positive Post L First Negative Post L First Positive Post R First Negative Post R
positive positive Time-window averaged (500ms bins)
post post post post post post post post Time-window averaged (500ms bins)
1.5 1.5
30 F
EDA Timeline (ΔµS; 500ms bins)
100
% Total pronouns
M
EDA Timeline (ΔµS; 500ms bins)
Words per post
90 1.0 1.0
80
70 20
60
50 0.5 0.5
40 10
30
20
10 0.0 0.0
0 0
15 15
% Impersonal Pronouns
-0.5 -0.5
% Personal pronouns
10 10 -1.0 -1.0
INS Thinking ATh Questions INS Writing AWr Questions INS Thinking ATh Questions INS Writing AWr Questions
5 5 Reply Posts: Skin Conductance (R vs. L: Females) Reply Posts: Skin Conductance (R vs. L: Males)
0 Reply Positive Post L Reply Negative Post L Reply Positive Post R Reply Negative Post R
0
Time-window averaged (500ms bins) Time-window averaged (500ms bins)
1.5 1.5
10 10
EDA Timeline (ΔµS; 500ms bins)
% Negative Emotion
F
% Positive Emotion
F
EDA Timeline (ΔµS; 500ms bins)
F M
M M 1.0 1.0
5 5 0.5 0.5
0.0 0.0
0 0 -0.5 -0.5
First Reply to a First Reply to a First Reply to a First Reply to a
negative negative positive positive negative negative positive positive
-1.0 -1.0
post post post post post post post post INS Thinking ATh Questions INS Writing AWr Questions INS ATh Questions INS Writing AWr Questions
Conclusions
We have presented first evidence on gender-specific differences of plantar tonic EDA and EDA-asymmetries in dextral participants that builds upon a systematic comparison
between passive picture viewing and more engaging active writing. Furthermore, while some of our data may appear tentative, we argue that a multi-level perspective as
employed in this study including subjective, physiological, and textual (behavioral) data is both necessary and fruitful to overcome some of the inconsistencies and limitations in
the study of EDA asymmetries detailed by Hugdahl (1984). For example, different gender-specific levels of subjective arousal or valence may have partially confounded earlier
results on EDA asymmetries which could not be controlled for because they were not measured.
Related to expressive writing, we found that contrary to recent suggestions by Langer (2010), males did not appear to use significantly more negative or otherwise emotional
words than females when writing about negative emotional topics, nor was there any indication that they benefit more from writing about negative topics than females.
Subjectively, females in fact reported generally more negative valence and higher arousal, a tendency that matches predictions from established findings on picture viewing
surprisingly well. Specifically, while it is e.g., possible .01, *** p < .001 may be less experienced or less comfortable with personal emotional disclosure about traumatic or intimate
** p < that males
events, we found little evidence for this if participants were given the choice to write about negative emotions associated with, for example, political topics. Conversely,
however, males appeared to have greater difficulties than females to write a reply to a positive forum post, as indicated in several of our measures.
References
Boucsein, W. (1992). Electrodermal activity. New York., NY: Plenum Press.
Bradley, M.M., Codispoti, M., Sabatinelli, D., & Lang, P.J. (2001). Emotion and motivation II: Sex differences in picture processing. Emotion, 1, 300-319. doi: 10.1037/1528-3542.1.3.300
Hugdahl, K. (1984). Hemispheric asymmetry and bilateral electrodermal recordings: A review of the evidence. Psychophysiology, 21, 371-393. doi: 10.1111/j.1469-8986.1984.tb00215.x
Kappas, A. (2011). Emotion and regulation are one! Emotion Review, 3, 17-25. doi: doi:10.1016/j.physa.2011.03.040
Lang, P.J., Bradley, M.M., & Cuthbert, B.N. (2008). International affective picture system (IAPS): Affective ratings of pictures and instruction manual. Technical Report A-8. University of Florida, Gainesville, FL. The following pictures were used: 1440, 1750, 2070,
2550, 7284, 7390, 2190, 2230, 2410, 5535, 7002, 7211, 1275, 2753, 6260, 9220, 9560, 9584.
Langer, S.L. (2010). Gender differences in experimental disclosure: Evidence, theoretical explanations, and avenues for future research. Sex Roles, 63, 178-183. doi: 10.1007/s11199-010-9795-1
Martinez-Selva, J.M., Román, F., Garcia-Sánchez, F.A., & Gómez-Amor, J. (1987). Sex differences and the asymmetry of specific and non-specific electrodermal responses. International Journal of Psychophysiology, 5, 155-160. doi:10.1016/0167-8760(87)90001-8
Smith, B.D., & Ketterer, M.W. (1982). Lateralized cortical/cognitive processing and bilateral electrodermal activity: Effects of sensory mode and sex. Biological Psychology, 15, 191-201. doi:10.1016/0301-0511(82)90041-2