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 (2013-2016) http://www.forgetit-project.eu
Outline Motivation: ForgetIT Project Human Forgetting and Remembering Collective Memory in Wikipedia Experiments and Discussion Conclusions
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 •
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 •
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, 1885. E. Tulving, Episodic memory: From mind to brain . Annual review of psychology, vol. 53, no. 1, pp. 1-25, 2002.
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).
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, 2009. M. Georgescu, N. Kanhabua, D. Krause, W. Nejdl, and S. Siersdorfer, Extracting event-related information from article updates in wikipedia , ECIR'2013.
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
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
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)
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)
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
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
Experiments Datasets: • Page views statistics 2007-2013 • A large set of 5,500 events • From 11 event-related categories • α = 0.5, β = 0.4, γ = 0.1
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
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
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
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)
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)
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
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
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
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
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