Paper presented at Wikisym 2012: Collective memories are precious resources for the society, because they help strengthening emotional bonding between community members, maintaining groups cohesion, and directing future behavior. Studying how people form their collective memories of emotional upheavals is important in order to better understand people's reactions and the consequences on their psychological health. Previous research investigated the effects of single traumatizing events, but few of them tried to compare different types of traumatic events like natural and man-made disasters. In this paper, interpreting Wikipedia as a collective memory place, we compare articles about natural and human-made disasters employing automated natural language techniques, in order to highlight the different psychological processes underlying users' sensemaking activities.

1. Psychological processes underlying
Wikipedia representations of
natural and manmade disasters
Michela Ferron Paolo Massa
Center for Mind/Brain Sciences Fondazione
University of Trento Bruno Kessler
m.ferron@unitn.it massa@fbk.eu

3. Anti-Islamic
hate crimes
after 9/11
movies
Legislation &
surveillance

4. Outline
 Collective Memories
 Wikipedia as a global memory place
 Automated natural language techniques
 Traumatic VS Non traumatic events
 Old VS recent traumatic events
 Traumatic events caused by man VS nature
 Conclusions
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

5. Collective Memories
 A set of ideas, images, feelings about the past, built
through an active process of sense-making through time
Memorial
Lincoln to the
memorial murdered
Jews of
Europe
Wahington Ocklaoma
memorial City
bombings
memorial
Photos: Wikipedia (1, 2, 3, 4)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

6. Traumatic events
September 11 attacks 2005 London bombings
2004 IndianTsunami Kennedy
assassination
Photos: Wikipedia (1, 2) and Flickr (3,
4)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

7. Traumatic events
short-term and long-term effects
After a traumatic event: Collective memories:
Anti-Islamic
hate crimes
 Violence increases  Maintain social bonds
after 9/11
(Pennebaker and Harber, 1993; FBI national hate crime statistics) (Wang, 2008; Irwin-Zarecka, 1994)
 Psychological/health problems
 increase of negative emotions  Direct behavior
(Wang, 2008; Pennebaker et al., 1997; Irwin-Zarecka, 1994)
(Koss & Kilpatrick, 2001; Stroebe, Hansson, Stroebe, & Schut,
2001)
 increase of cognitive activity  Are persistent for years and
(Davis & Nolen-Hoeksema, 2001; Pennebaker et al., 2003) can be at the root of wars,
 increase of social sharing and prejudice, cultural identities
social support (Pennebaker et al., 1997)
(Mehl & Pennebaker, 2003; Pyszczynski, Solomon, & Greenberg,
2002; Rimé et al.,1998)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

8. Wikipedia as a global memory place
What happens in Wikipedia
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

9. Wikipedia as a global memory place
“[…] the online encyclopaedia is a global memory place
where locally disconnected participants can express and
debate divergent points of view and that this leads to the
formation and ratification of shared knowledge that
constitutes collective memory.”
(Pentzold, 2009, p. 263)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

10. Automated natural language
processing techniques
 Goal: to analyze the content of Wikipedia articles about
natural and man-made disasters employing automated
content analysis tools
 Linguistic Inquiry & Word Count (Pennebaker et al., 2001)
searches for words across:
 Linguistic categories (e.g. pronouns, articles, tenses)
 Psychological categories (e.g. social, affective, cognitive processes)
 Traumatic VS non traumatic events
 Temporal focus of old VS recent events
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

11. Traumatic and non traumatic events
Hypotheses
Psychological processes Examples
Affective processes Happy, hate, kiss
Positive emotions Love, party, pleasant
Negative emotions Hurt, abuse, scary
Anxiety Worried, afraid
 LIWC to get a score Anger Kill, aggression, destroy
Sadness Sad, cry, depression
for each psychological Cognitive processes Cause, acknowledge, admit
variable Insight Think, assume, interpret
Causation Because, depend, elicit
Discrepancy Should, could, if
Tentative Maybe, apparently, suppose
Certainty Always, absolutely, clear
Inhibition Block, abstain, avoid
Inclusive And, add, along
Exclusive But, either, without
Social processes Mate, guy, boy
Family Daughter, brother, dad
Friends Buddy, friend, mate
Humans Adult, children, girl
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

12. Traumatic and non traumatic events
Data
 Wikipedia’s categories (“Events by topic”), History
Central and Information Britain
 66 articles about traumatic events (e.g. September 11
attacks, 7 July 2005 London bombings, Chernobyl disaster)
 40 articles about non traumatic events (e.g.
Coronation of Queen Elizabeth II, Woodstock Festival, Super
Bowl XXXVIII)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

13. Traumatic and non traumatic events
Hypotheses
Psychological processes Examples
Affective processes Happy, hate, kiss
Positive emotions Love, party, pleasant
 Higher presence in articles Negative emotions Hurt, abuse, scary
about traumatic events of: Anxiety
Anger
Worried, afraid
Kill, aggression, destroy
 negative emotions Sadness Sad, cry, depression
Cognitive processes Cause, acknowledge, admit
 cognitive processes Insight Think, assume, interpret
 social processes Causation Because, depend, elicit
Discrepancy Should, could, if
Tentative Maybe, apparently, suppose
Certainty Always, absolutely, clear
Inhibition Block, abstain, avoid
 In articles about non Inclusive
Exclusive
And, add, along
But, either, without
traumatic events: Social processes Mate, guy, boy
 positive emotions Family Daughter, brother, dad
Friends Buddy, friend, mate
Humans Adult, children, girl
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

14. Traumatic and non traumatic events
Analysis
1 negative emotion
14 total words

 negative emotions
 Arcsine transformation
 T-tests for indipendent samples
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

15. Traumatic and non traumatic events
Results
All differences in the graphs
are statistically significant
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

16. Temporal focus of old and recent
traumatic events: Data & Analysis
 Articles in their early stage (after 500 revisions)
 Temporal focus more evident
 Many words per article
 Out of 55 articles
 26 about events happened before 2001 (e.g. John F. Kennedy
assassination)
 29 about events happened after 2001 (e.g. 2011 Tohoku
earthquake and tsunami)
 LIWC: linguistics categories (past, present and future tenses)
 Arcsine transformation and t-tests for independent samples
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

17. Temporal focus of old and recent traumatic
events: Hypotheses & Results
 HP: higher presence of past tense in old events, higher
presence of present/future tenses in recent events
*
*
*
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

18. LIWC applied to Wikipedia
 LIWC is effective in detecting
 Differences in content referred to psychological processes
emerging from articles about traumatic and non traumatic
events
 Differences in the temporal focus of articles about old and
recent traumatic events
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

19. Natural and human-made
traumatic events
 How people remember traumatic events:
 Understand the consequences on the physical and
psychological health of people and communities
 Differences in the psychological processes:
 First step toward the understanding and the prediction of
trauma, typical responses to it, and short and long-term effects
 Empirically validate theoretical findings in Wikipedia
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

20. Natural and human-made
traumatic events
 Traumatic events can be very different
 Theoretical reasons to distinguish between natural and
human-made traumatic events
 Literature: human accidents may have longer and more
insidious effects of physical and psychological health:
 negative emotions; nervousness and anxiety (Cohn et al., 2004; Adler, 1943)
 psychological and work-related problems (Leopold and Dillon, 1963; Henderson
and Bostock, 1977; Ploeger, 1972)
 depression, anxiety, personality changes (Titchener and Kapp, 1976)
 sleep disturbances and psychiatric problems (Gleser et al., 1981; Gleser et al.,
1978)
 war-related dreams and aggravated assaults (Pennebaker and Harber, 1993)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

21. Natural and human-made
traumatic events
Natural disasters Human disasters
Uncontrollable Loss of control
helplessness stress arousal
2004 IndianTsunami September 11 attacks
Baum et al., 1986
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

22. Natural and human-made traumatic events
Data
 Articles in their early stage (after 500 revisions)
 Out of 55 articles with at least 500 revisions
 36 about events caused by man (e.g. “Fort Hood shooting”,
“2011 Norway attacks”)
 Wikipedia’s categories, e.g. “Assassinations”, “Terrorist incidents”
 19 about events caused by nature (e.g. “2004 Indian Ocean
earthquake and tsunami”, “2010 Haiti earthquake”)
 Wikipedia’s categories, e.g. “2008 Atlantic Hurricane Season”, “1993
natural disasters”
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

23. Natural and human-made traumatic events
Hypotheses
 Affective processes
 Human-made disasters: loss of control (distress)  higher anxiety,
anger
 Natural disasters: uncontrollable (helplessness)  higher sadness
 Cognitive processes
 Human-made disasters: loss of control  higher cognitive processes
 Social processes
 Human-made disasters: increased orientation toward others + more
references to people  higher social processes
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

24. Natural and human-made traumatic events
Results
*  Human-made
*
traumatic events:
*  more anxiety,
anger (blame)
 Natural disasters:
 more sadness
Affective processes Happy, hate, kiss (passive behavior)
Positive emotions Love, party, pleasant
Negative emotions Hurt, abuse, scary
Anxiety Worried, afraid
Anger Kill, aggression, destroy
Sadness Sad, cry, depression
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

25. Natural and human-made traumatic events
Results
 Human-made
*
traumatic events:
 need for
explanation is
* critical (unexpected
* *
loss of control)
 Natural disasters:
Cognitive processes Cause, acknowledge, admit  need for
Insight Think, assume, interpret
Causation Because, depend, elicit
explanation is less
Discrepancy Should, could, if pressing (nature is
Tentative Maybe, apparently, suppose uncontrollable)
Certainty Always, absolutely, clear
Inhibition Block, abstain, avoid
Inclusive And, add, along
Exclusive But, either, without
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

26. Natural and human-made traumatic events
Results
*  Human-made
traumatic events:
 higher social
orientation?
*  more references
to people
(bomber’s family
or social relations)
Social processes Mate, guy, boy
Family Daughter, brother, dad
Friends Buddy, friend, mate
Humans Adult, children, girl
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

27. Considerations
 Difficult definition of human-made and natural disasters
 Wikipedia’s categories
 But the distinction is not always clear-cut (“2011 Tōhoku
earthquake and tsunami”)
 LIWC and other automated techniques
 Limitations (psychological categories are subjective and
context-dependent)
 Know your data (noise caused by bots, vandalism, templates)
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

28. Conclusions: Take-home message
 Different psychological and sensemaking processes
underlying users editing activity
 Specific patterns of emotional language
Arousal
stressful high
focused anger Man-made disasters activation
anger, anxiety
heavier effects
negative positive
Valence
passive responses Natural disasters
sadness
low
activation
Background Wikipedia LIWC Traum. - non traum. Old - recent Man - Nature Conclusions

29. Thank you!
Questions? Suggestions?