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DETECTING CHILD GROOMING 
BEHAVIOUR PATTERNS ON SOCIAL MEDIA 
Miriam Fernandez 
m.fernandez@open.ac.uk 
Harith Alani 
h.al...
INTRODUCTION 
SOCIAL MEDIA PLATFORMS 
• Widely spread across the Internet. 
• Quick and inexpensive tools for 
personal an...
INTRODUCTION 
ONLINE CHILDREN EXPOSURE TO 
PAEDOPHILES 
* Source: NSPCC 
• 12% of 11- 16 year olds in 
the UK received unw...
INTRODUCTION 
ONLINE CHILD GROOMING 
Premeditated behaviour intending to secure the trust of a minor as a first 
step towa...
INTRODUCTION 
ONLINE CHILD GROOMING 
Pseudo-victims 
posing as minors 
Predators seeking to 
groom minors 
Chat-conversati...
INTRODUCTION 
ONLINE CHILD GROOMING 
Pseudo-victims 
posing as minors 
Predators seeking to 
groom minors 
Chat-conversati...
INTRODUCTION 
IDENTIFYING GROOMING STAGES 
PERVERTED JUSTICE 
Perverted Justice 
! 
• 530 chat-room conversations. 
• Invo...
INTRODUCTION 
ONLINE CHILD GROOMING 
OLSON’S THEORY OF LURING COMMUNICATION (LTC) 
Gain 
Access 
age, gender, likes, 
disl...
INTRODUCTION 
ONLINE CHILD GROOMING 
OLSON’S THEORY OF LURING COMMUNICATION (LTC) 
Gain 
Access 
[1] Towards a Theory of C...
INTRODUCTION 
ONLINE CHILD GROOMING 
OLSON’S THEORY OF LURING COMMUNICATION (LTC) 
Gain 
Access 
Deceptive Trust 
Developm...
MOTIVATION 
IDENTIFYING GROOMING STAGES 
PERVERTED JUSTICE 
• Sexually abused children driven to voluntarily 
agree to phy...
RELATED WORK 
IDENTIFYING GROOMING STAGES 
Predators/Victims chat-room conversations 
• Predator detection (Kontostathis e...
OBJECTIVES 
DETECTING ONLINE CHILD GROOMING 
IN ONLINE CHAT-ROOMS 
• Create classification models to identify online 
chil...
APPROACH 
IDENTIFYING GROOMING STAGES 
PERVERTED JUSTICE DATA SET 
Annotated Chat-room Conversations (Kontostathis et al[1...
APPROACH 
IDENTIFYING GROOMING STAGES 
ARCHITECTURE 
PJ Conversations Preprocessing 
Predator 
Victim 
Removing Stopwords ...
APPROACH 
IDENTIFYING GROOMING STAGES 
DATA PREPROCESSING 
Challenges in processing chat-room conversations 
• Irregular a...
APPROACH 
IDENTIFYING GROOMING STAGES 
FEATURE EXTRACTION 
Feature Description 
n-grams n-grams (n=1,2,3) BoW extracted fr...
APPROACH 
IDENTIFYING GROOMING STAGES 
PSYCHO-LINGUISTIC FEATURES 
• Authorship profiling [12] shown that different groups...
APPROACH 
IDENTIFYING GROOMING STAGES 
DISCOURSE FEATURES 
• Qualitative analysis [5] of PJ’s predators transcripts reveal...
APPROACH 
IDENTIFYING GROOMING STAGES 
DISCOURSE FEATURES 
SEMAFOR [4] to extract semantic frames from sentences. 
Sentenc...
EXPERIMENTS 
IDENTIFYING GROOMING STAGES
EXPERIMENTS 
IDENTIFYING GROOMING STAGES 
FEATURE ANALYSIS 
Top discriminative features
EXPERIMENTS 
IDENTIFYING GROOMING STAGES 
FEATURE ANALYSIS 
Top discriminative features 
predator: lots of luck right like...
EXPERIMENTS 
IDENTIFYING GROOMING STAGES 
FEATURE ANALYSIS 
Top discriminative featuprreesdator: you ever had anyone 
run ...
EXPERIMENTS 
IDENTIFYING GROOMING STAGES 
FEATURE ANALYSIS 
Top discriminative features 
predator: do you want me to 
come...
EXPERIMENTS 
CONCLUSIONS 
• Psycho-linguistic and discourse features provide an insight of 
the mindset of predators in on...
EXPERIMENTS 
ampaeli@gmail.com 
@pixarelli 
https://www.gradtouch.com/uploads/images/questions.jpg
EXPERIMENTS 
FUTURE WORK 
• Some stages of online grooming are not sequential (e.g. 
predator convincing child to meet in ...
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Detecting child grooming behaviour patterns on social media

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Online paedophile activity in social media has become a major concern in society as Internet access is easily available to a broader younger population. One common form of online child exploitation is child grooming, where adults and minors exchange sexual text and media via social media platforms.
Such behaviour involves a number of stages performed by a predator (adult) with the final goal of approaching a victim (minor) in person. This paper presents a study of such online grooming stages from a machine learning perspective. We
propose to characterise such stages by a series of features covering sentiment polarity, content, and psycho-linguistic and discourse patterns. Our experiments with online chatroom conversations show good results in automatically classifying chatlines into various grooming stages. Such a deeper understanding and tracking of predatory behaviour is vital for building robust systems for detecting grooming conversations and potential predators on social media.

Veröffentlicht in: Daten & Analysen

Detecting child grooming behaviour patterns on social media

  1. 1. DETECTING CHILD GROOMING BEHAVIOUR PATTERNS ON SOCIAL MEDIA Miriam Fernandez m.fernandez@open.ac.uk Harith Alani h.alani@open.ac.uk A. Elizabeth Cano amparo.cano@open.ac.uk
  2. 2. INTRODUCTION SOCIAL MEDIA PLATFORMS • Widely spread across the Internet. • Quick and inexpensive tools for personal and group communications. • No age, geographical and cultural boundaries. • Anonymity of the users is not compromised. http://i.huffpost.com/gen/1539078/thumbs/o-SOCIAL-MEDIA-facebook.jpg
  3. 3. INTRODUCTION ONLINE CHILDREN EXPOSURE TO PAEDOPHILES * Source: NSPCC • 12% of 11- 16 year olds in the UK received unwanted sexual messages*. • 8% of 11-16 year olds in the UK received requests to send or respond to a sexual message*. http://news.bbcimg.co.uk/media/images/58277000/jpg/_58277172_138045933.jpg
  4. 4. INTRODUCTION ONLINE CHILD GROOMING Premeditated behaviour intending to secure the trust of a minor as a first step towards future engagement in sexual conduct. http://www.saferinternet.at/uploads/pics/442916_web_R_K_by_Christian_Seidel_pixelio.de.jpg
  5. 5. INTRODUCTION ONLINE CHILD GROOMING Pseudo-victims posing as minors Predators seeking to groom minors Chat-conversations
  6. 6. INTRODUCTION ONLINE CHILD GROOMING Pseudo-victims posing as minors Predators seeking to groom minors Chat-conversations Archive chat conversation Convicted Predators
  7. 7. INTRODUCTION IDENTIFYING GROOMING STAGES PERVERTED JUSTICE Perverted Justice ! • 530 chat-room conversations. • Involving: A. PJ volunteers posing as minors. B. Adults seeking to begin a sexual relationship with a minor. Perverted Justice, http://www.perverted-justice.com/Perverted Justice, http://www.perverted-justice.com/
  8. 8. INTRODUCTION ONLINE CHILD GROOMING OLSON’S THEORY OF LURING COMMUNICATION (LTC) Gain Access age, gender, likes, dislikes, family.. [1] Towards a Theory of Child Sexual Predator’s Luring Communication. L.N. Olson et al Time Approach predator: where are you from victim: where I from or where I am now? what’s your asl? Deceptive Trust Development
  9. 9. INTRODUCTION ONLINE CHILD GROOMING OLSON’S THEORY OF LURING COMMUNICATION (LTC) Gain Access [1] Towards a Theory of Child Sexual Predator’s Luring Communication. L.N. Olson et al Time Grooming Approach predatoCrO: sRoE do you masturbate? victim: not really that borin predator: what do you like in sex? raise victim’s curiosity, .
  10. 10. INTRODUCTION ONLINE CHILD GROOMING OLSON’S THEORY OF LURING COMMUNICATION (LTC) Gain Access Deceptive Trust Development [1] Towards a Theory of Child Sexual Predator’s Luring Communication. L.N. Olson et al Time Cycle of Entrapment Grooming Approach Isolation Physical Approach Sexual Conduct predator: do you like to meet sometime? victim: maybe you seem cool … predator: but i'm sorry your parents home all the time victim: no
  11. 11. MOTIVATION IDENTIFYING GROOMING STAGES PERVERTED JUSTICE • Sexually abused children driven to voluntarily agree to physically approach the predator [36]. • Understanding predator’s manipulative strategies could help in educating children on how to react when expose to such situations.
  12. 12. RELATED WORK IDENTIFYING GROOMING STAGES Predators/Victims chat-room conversations • Predator detection (Kontostathis et al. [15], Michalopoulos et al. [17], Escalante et al. [6]) Online Child Grooming • Annotation Tools (Kontostathis et al. [15]) • Empirical Analysis of child grooming stages (Gupta et al.[9]) • Discriminate child grooming from adults cyber-sex (Bogdanova et al.[2])
  13. 13. OBJECTIVES DETECTING ONLINE CHILD GROOMING IN ONLINE CHAT-ROOMS • Create classification models to identify online child grooming stages: 1. Trust development 2. Grooming 3. Physical approach ! • Analyse discriminative features characterising these stages.
  14. 14. APPROACH IDENTIFYING GROOMING STAGES PERVERTED JUSTICE DATA SET Annotated Chat-room Conversations (Kontostathis et al[15]) • 50 conversations transcripts • Conversations with 83 to 12K lines. • Predator’s sentences manually labelled by two annotators. • Annotations labels: 1)Trust development, 2)Grooming, 3)Seek for physical approach, 4) Other.
  15. 15. APPROACH IDENTIFYING GROOMING STAGES ARCHITECTURE PJ Conversations Preprocessing Predator Victim Removing Stopwords Stemming N-gram Syntactical Content Sentiment Polarity Psycho-linguistic Discourse Translation Emoticon Chat-lingo Feature Extraction Feature Selection Info.Gain Build SVM Classifiers Trust Development Grooming Approach
  16. 16. APPROACH IDENTIFYING GROOMING STAGES DATA PREPROCESSING Challenges in processing chat-room conversations • Irregular and ill-formed words. • Chat slang and teen-lingo • Emoticons. ! Generated a list of over 1K terms and definitions:
  17. 17. APPROACH IDENTIFYING GROOMING STAGES FEATURE EXTRACTION Feature Description n-grams n-grams (n=1,2,3) BoW extracted from a sentence. Syntactic (POS) POS tags extracted from a sentence. Sentiment Polarity Average sentiment polarity of terms contained in a sentence Content Complexity, Readability, Length. Psycho-linguistic LIWC dimensions, based on cosine similarity of a sentence to a dictionary Discourse Semantic Frames, describing lexical use of English in texts.
  18. 18. APPROACH IDENTIFYING GROOMING STAGES PSYCHO-LINGUISTIC FEATURES • Authorship profiling [12] shown that different groups of people writing about a particular genre use language differently. • E.g. frequency in the use of certain words. • LIWC dataset [26] covers 60 dimensions of language. STYLE PATTERNS prepositions e.g., for, beside conjunctions e.g., however, whereas cause e.g., cuz, hence PSYCHOLOGICAL swearing e.g., damn, bloody affect e.g., agree, dislike sexual e.g., naked, porn
  19. 19. APPROACH IDENTIFYING GROOMING STAGES DISCOURSE FEATURES • Qualitative analysis [5] of PJ’s predators transcripts revealed frequent use of fixated discourse (i.e predator unwillingness to change a topic). • FrameNet [1], incorporate semantic generalisations of a discourse. • Covers 1K patterns used in English (e.g.,Intentionality act, Causality, Grant Permission)
  20. 20. APPROACH IDENTIFYING GROOMING STAGES DISCOURSE FEATURES SEMAFOR [4] to extract semantic frames from sentences. Sentence: Your mom will let you stay home?, I’m happy FRAME SEMANTIC ROLE LABEL Grant Permission Target Action you stay home Grantee Grantor Action you your mom stay home Emotion Directed Target Experiencer happy I
  21. 21. EXPERIMENTS IDENTIFYING GROOMING STAGES
  22. 22. EXPERIMENTS IDENTIFYING GROOMING STAGES FEATURE ANALYSIS Top discriminative features
  23. 23. EXPERIMENTS IDENTIFYING GROOMING STAGES FEATURE ANALYSIS Top discriminative features predator: lots of luck right like your pictures i see you keep it in place and look
  24. 24. EXPERIMENTS IDENTIFYING GROOMING STAGES FEATURE ANALYSIS Top discriminative featuprreesdator: you ever had anyone run there fingers real litely over your body
  25. 25. EXPERIMENTS IDENTIFYING GROOMING STAGES FEATURE ANALYSIS Top discriminative features predator: do you want me to come ther ? good
  26. 26. EXPERIMENTS CONCLUSIONS • Psycho-linguistic and discourse features provide an insight of the mindset of predators in online grooming stages. • Discourse patterns are effective features for the automatic classification of sentences into online grooming stages. !
  27. 27. EXPERIMENTS ampaeli@gmail.com @pixarelli https://www.gradtouch.com/uploads/images/questions.jpg
  28. 28. EXPERIMENTS FUTURE WORK • Some stages of online grooming are not sequential (e.g. predator convincing child to meet in person during trust-development). - Adding temporal features to the analysis could aid in characterising such back-forth changes on these stages. • Characterise sexual content between teens and between adults (challenging since both involve the use of sexual content).

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