What Triggers Human Remembering of Events?

Transcription

1 What Triggers Human Remembering of Events? Large-Scale Analysis of Collective Memory in Wikipedia Nattiya Kanhabua, Tu Ngoc Nguyen and Claudia Niederée L3S Research Center, Hannover, Germany Concise Preservation by Combining Managed Forgetting and Contextualized Remembering EU/FP7 ForgetIT Project ( )

2 Outline Motivation: ForgetIT Project Human Forgetting and Remembering Collective Memory in Wikipedia Experiments and Discussion Conclusions

3 A computer that forgets intentionally? And, in context of digital preservation?? However, we are facing: Dramatic increase in content creation (e.g. digital photos) Increasing use of mobile devices with restricted capacity Information overload and changing professional and private lives Inadvertent forgetting due to lack of systematic preservation Forgetting plays a crucial role for human remembering and life (focus on current, relevant information; ignore redundant details) Managed forgetting automatic deletion Instead: a range of forgetting options e.g. Resource condensation Change of indexing & ranking Reduction of redundancy

4 A computer that forgets intentionally? And, in context of digital preservation?? However, we are facing: Dramatic increase in content creation (e.g. digital photos) Increasing use of mobile devices with restricted capacity Information overload and changing professional and private lives Inadvertent forgetting due to lack of systematic preservation Forgetting plays a crucial role for human remembering and life (focus on current, relevant information; ignore redundant details) Managed forgetting = to remember the right information Managed forgetting automatic deletion Instead: a range of forgetting options e.g. Resource condensation Change of indexing & ranking Reduction of redundancy

5 Human Forgetting and Remembering Individual memories are subject to a fast forgetting process [Ebbinghaus, 1885] Rapidly forget details -> less redundancy Episodic memory (of one s past event) is reconstructed from similar events/context Rely on common patterns -> false memory Memory bumps in the forgetting curve is caused by reminding or triggering of: A physical object (e.g. a printed photo) A digital memory system Different subsequent events H. Ebbinghaus, Über das Gedächtnis. Untersuchungen zur experimentellen Psychologie. Duncker & Humblot, Leipzig, E. Tulving, Episodic memory: From mind to brain. Annual review of psychology, vol. 53, no. 1, pp. 1-25, 2002.

6 From Individual Memories to Collective Memory Collective memory is a socially constructed, common image (memory) of the past of a community, which frames its current understanding and actions. [Halbwachs, 1950] Crowd phenomenon and important to societal processes Not static as determined by the concerns of the present Flashbulb memories in cognitive psychology A study of remembering of high-impact events, e.g., The British Royal Wedding or September 11 attacks Aspects: details, confidence, consistency of memory over time, impact of media coverage Qualitative study: limited number of events and users M. Halbwachs, On collective memory. Chicago: The University of Chicago Press, 1950 (Translation).

7 Collective Memory in Wikipedia Wikipedia as a source for global memory Largest and most up-to-date online encyclopedia (19M registered users, 30K active editors) Social negotiation and construction reflected in early editing activities and talk pages Indicators for identifying real-world events View logs as the signal for collective memory Public page view traffics with a long time span Not directly reflect how people forget; significant patterns are a good estimate public remembering Large-scale analysis complements (1) qualitative studies (2) analyzing article content (scalability) C. Pentzold, The online encyclopaedia wikipedia as a global memory place, Memory Studies, M. Georgescu, N. Kanhabua, D. Krause, W. Nejdl, and S. Siersdorfer, Extracting event-related information from article updates in wikipedia, ECIR'2013.

8 Contributions First study of identifying catalysts for event memory triggering by using time series analysis techniques: temporal correlations in peaking page visits between events, a surprise score or the residual sum of squares on prediction error, and the skewness of view shapes as a catalyst for memories Identify the relationship between events by using different features the role of time passed, the same types of events, the size or magnitude of events, the near-by city or neighbor country Analyze over 5500 high-impact events from 11 event categories Related to the previous study by [Au Yeung and Jatowt, 2011] Analyzed references to the past (as an indicator to what is remembered) in a large news collection for identifying, which years are most frequently referenced C.-m. Au Yeung and A. Jatowt, Studying how the past is remembered: Towards computational history through large scale text mining, CIKM 2011

9 Our Approach We propose a 3-step approach, for a given event: 1. Compute remembering scores of past events within the same category 2. Rank related past events by the computed remembering scores 3. Identify features (e.g., time, location) having a high correlation with remembering

10 Measuring Signals for Memory Revival Remembering scores: a linear combination of three features: 1. Cross-correlation coefficient (CCF) 2. Sum of squared error (SSE) 3. Skewness (Kurtosis)

11 Measuring Signals for Memory Revival Remembering scores: a linear combination of three features: 1. Cross-correlation coefficient (CCF) 2. Sum of squared error (SSE) 3. Skewness (Kurtosis)

12 Measuring Signals for Memory Revival Remembering scores: a linear combination of three features: 1. Cross-correlation coefficient (CCF) 2. Sum of squared error (SSE) 3. Skewness (Kurtosis) Remembering = α CCF + β SSE + γ Kurtosis

13 Features for Triggered Remembering Temporal similarity: Time distance between two events (in days, months or years) Time distance based on exponential decay functions Location similarity: Map a geographic hierarchy of event locations as follows city -> state -> country -> neighbor countries -> continent Assign 4 scale values: 4 to same city, 3 to state, 2 to country,1 to continent Impact of Events: Damaged area/properties/cost/fatalities Magnitude (for earthquake events) Highest winds, lowest pressure (for Atlantic hurricanes) N. Kanhabua and K. Nørvåg: Determining time of queries for re-ranking search results. ECDL 2010 J. Strötgen, M. Gertz, and C. Junghans: An event-centric model for multilingual document similarity. SIGIR 2011

14 Experiments Datasets: Page views statistics A large set of 5,500 events From 11 event-related categories α = 0.5, β = 0.4, γ = 0.1

15 Temporal and Spatial Distributions Temporal and spatial distributions Strong focus on more recent events Better coverage with increasing popularity Most frequent locations depending on event types

16 Temporal and Spatial Distributions Temporal and spatial distributions Strong focus on more recent events Better coverage with increasing popularity Most frequent locations depending on event types

17 Temporal and Spatial Distributions Temporal and spatial distributions Strong focus on more recent events Better coverage with increasing popularity Most frequent locations depending on event types

18 Category: Atlantic Hurricane Distributions of remembering scores Hurricane Sandy (Form date: October 22, 2012, Affected area: Mid-Atlantic) Hurricane Hanna (Form date: August 28, 2008, Affected area: US east coast)

19 Category: Atlantic Hurricane Distributions of remembering scores Location and time have a low effect on Hurricane Sandy (Form date: October 22, 2012, Affected area: Mid-Atlantic) remembering scores for this category. Hurricane Hanna (Form date: August 28, 2008, Affected area: US east coast)

20 Category: Atlantic Hurricane Top-10 events triggered by the two events Hurricane Hanna commemorates Hurricane Gustav, the freshest hurricane stuck at the area of Puerto Rico and East Coast Hurricane Sandy triggers 1991 Perfect Storm initially formed around Canada area, which t is high impact and most destructive

21 Category: Atlantic Hurricane Top-10 events triggered by the two events Hurricane Hanna commemorates Hurricane Gustav, the freshest hurricane stuck at the area of Puerto Rico and East Coast Hurricane Sandy triggers 1991 Perfect Storm initially formed around Canada area, which t is high impact and most destructive

22 Category: Aviation accidents Mixture of impact factors, such as, time and location Qantas Flight 32 (crashed on 4 November 2010) triggers remembering of (1) Qantas Flight 30 and British Airways Flight 9 (both going to Australia), and (2) Aero Caribbean Flight 883 (most recent event) Most recent

23 Category: Aviation accidents Mixture of impact factors, such as, time and location Qantas Flight 32 (crashed on 4 November 2010) triggers remembering of (1) Qantas Flight 30 and British Airways Flight 9 (both going to Australia), and (2) Aero Caribbean Flight 883 (most recent event) Same destination

24 Category: Aviation accidents Mixture of impact factors, such as, time and location Qantas Flight 32 (crashed on 4 November 2010) triggers remembering of (1) Qantas Flight 30 and British Airways Flight 9 (both going to Australia), and (2) Aero Caribbean Flight 883 (most recent event) Same destination Concorde Deadliest (two aircraft collided)

25 Category: Earthquakes A series of earthquake events at Christchurch, New Zealand 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and highimpact) and two close-by events, and high-impact historical earthquakes 2011 Christchurch earthquake shows locality focus, i.e., people seem to be interested in the previous events in the same region June 2011 Christchurch earthquake, the remembered events are dominated by the two predecessor events

26 Category: Earthquakes A series of earthquake events at Christchurch, New Zealand 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and highimpact) and two close-by events, and high-impact historical earthquakes 2011 Christchurch earthquake shows locality focus, i.e., people seem to be interested in the previous events in the same region June 2011 Christchurch earthquake, the remembered events are dominated by the two predecessor events

27 Category: Earthquakes A series of earthquake events at Christchurch, New Zealand 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and highimpact) and two close-by events, and high-impact historical earthquakes 2011 Christchurch earthquake shows locality focus, i.e., people seem to be interested in the previous events in the same region June 2011 Christchurch earthquake, the remembered events are dominated by the two predecessor events

28 Category: Earthquakes A series of earthquake events at Christchurch, New Zealand 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and highimpact) and two close-by events, and high-impact historical earthquakes 2011 Christchurch earthquake shows locality focus, i.e., people seem to be interested in the previous events in the same region June 2011 Christchurch earthquake, the remembered events are dominated by the two predecessor events Look beyond single events, especially, if there are several events in temporal and local proximity.

29 Category: Earthquakes A series of earthquake events at Christchurch, New Zealand 2010 Canterbury earthquake triggers 2010 Haiti earthquake (recent and highimpact) and two close-by events, and high-impact historical earthquakes 2011 Christchurch earthquake shows locality focus, i.e., people seem to be interested in the previous events in the same region June 2011 Christchurch earthquake, the remembered events are dominated by the two predecessor events Look beyond single events, especially, if there are several events in temporal and local proximity.

30 Category: Terrorist incidents Interesting observation: semantic similarity between events June 2012 Kaduna church bombings triggers other religion terror attacks 2008 Mumbai attacks trigger terror attacks in business, entertainment and hotels 2nd 5th 24th

31 Category: Terrorist incidents Interesting observation: semantic similarity between events June 2012 Kaduna church bombings triggers other religion terror attacks 2008 Mumbai attacks trigger terror attacks in business, entertainment and hotels 2nd 15th 7th

32 Conclusions We identified some first pattern for event memory triggering for diverse event types including natural and manmade disasters as well as accidents and terrorism. Our analysis confirmed the influence of closeness in time and location, but the semantic similarity of events also influences which event memories are triggered by an event. In our future work, we plan to deepen our systematic analysis of factors for revisiting past events and of the combination of those factors. We also plan to investigate external factors such as media coverage linking new events to past events or reflection of such relationships in other types of social media.

33 What do you remember? Thanks for your attention!