Presentation held at the ISAGA 2013 conference in Stockholm

1. Analyzing the social dynamics
of non-player characters
Magnus Johansson, Björn Strååt, Henrik Warpefelt and Harko
Verhagen
ISAGA 2013 Stockholm
magnus@dsv.su.se, bjor-str@fc.dsv.su.se, hw@dsv.su.se,
verhagen@dsv.su.se

2. Aim
“[w]e like to address the behavioral properties of Non Player
Characters (NPCs) and the social awareness of and amongst
NPCs aiming for humanlike behavior in NPCs. ”
6/26/13
Magnus Johansson Department of Computer and Systems Sciences

3. Disclaimer
“[..]with existing game genres there is no real need for truly
smart NPCs, but that it would be interesting if indeed one such
genre would appear. ” (Johansson, Eladhari and Verhagen 2012)
6/26/13 Magnus Johansson Department of Computer and Systems Sciences
Do we need smart, believable and social NPCs?

4. Immersion
”[d]eep but effortless involvement, reduced concern
for self and sense of time” (Sweetser et al 2012, p.2)
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

5. 6/26/13 Magnus Johansson Department of Computer and Systems Sciences
Challenges and immersion
“Part of the struggle lies in the opposition posed by monsters
and NPCs; part of it in exploration of the world and the story;
part of it in traps or puzzles posed in the game’s physical world,
or in social difficulties posed in the game’s social
realm” (Costykian 2002, p.15)

6. Immersion (Ermi and Mäyre, 2007)
• Challenge based Immersion
• Sensory based Immersion
• Imaginative immersion
6/27/13 Magnus Johansson Department of Computer and Systems Sciences

7. The Gap
6/26/13 Magnus Johansson Department of Computer and Systems Sciences
Lankoski (2004); Björk and Lankoski (2007)
Loyall (1997); Mateas (1999)
?

8. Method
• In-game observations in 3 AAA-games
• From a black-box perspective
• 2-hour recordings from each game analyzed using the Game
Agent Matrix.
6/27/13 Magnus Johansson Department of Computer and Systems Sciences

9. Example
https://www.youtube.com/playlist?
list=PLPmxvKzF6p8VGekfzjSEpOELlpfmnHc38

10. The Game Agent Matrix
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

11. Acting agents
Acting agents (simple reflex agents). The acting agent does not
change its behavior according to changes in the context since it is
static and executes the actions it is created to perform. Therefore
the acting agent is unaware of other agents that appear in the
columns: “multiple agents” situation, the “social structural”
situations, situations marked by “social goals” and “cultural
historical”.
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

12. Reacting agents
Reacting agents (model-based reflex agents). The reacting agent
differs slightly from the acting agent in that it perceives changes
in its environment and can react accordingly. When the reacting
agent is socially aware, social knowledge and models of others is
seen as a prerequisite.
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

13. Interacting agents
Interacting agents. The interacting agent has a continuation of
actions that can have various levels of dynamics, depending on
the information that is available in the agent’s environment. It
also reacts dynamically in contrast to the reacting agent and the
acting agent that does so in a less dynamic and changing way.
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

14. Results
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

15. Acting agent/ Single agent
• Most NPCs manage to display these behaviors successfully
• Uses language, uses tools, “pantomimed” behaviors that with
few exceptions are successful.
• Pathfinding not a problem
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16. Reacting agent
• Adaption, Crisis response, Rapid emotional response and
Navigation showed non-trivial (i.e. occurring more than once)
positive values.
• Adaption and crisis response successful in combat situations.
• Navigation successful
• Lack of awareness the most immersive breaking behavior,
often in combination with failures to adapt.
• Models of self and models of others problematic
• Cultural historical situation often successful, but often in
static manner
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17. Interacting agent
• The values most often associated with reinforcing immersion
was related to social interaction and face to face interaction.
• Turn taking in dialogues at times disastrous (Skyrim)
• Group conflict, team player and cooperation displayed rarely
but with reinforcing effects on immersion when present.
• Sanctions rarely displayed but with reinforcing effects on
immersion when present.
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18. Conclusions
• Limited study
• 3 games, 2 hour in-game data recorded for each game
• Enough data to evaluate the Game Agent Matrix and inform
further tune-ups
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

19. Conclusions regarding method
• The Game Agent Matrix (GAM) useful for both detecting
negative and positive behaviors/traits in NPCs
• Some of the values in the matrix are just too similar and
should be refined for added clarity
• Lack of awareness, often causing a double negative
• Path-finding and route following useful additions from
previous version (Warpefelt and Strååt, 2012)
• More work remains with the Game Agent Matrix
6/27/13 Magnus Johansson Department of Computer and Systems Sciences

20. Conclusions regarding NPCs and Games AI
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21. Future work
• Analyzing Sims online, façade and prom week (games more
targeted at displaying social behaviour in NPCs)
• Explore the connection between some values in the matrix
that seem to be connected (adaption, Interruptability)
• Analyze more games to see to what extent more demanding
behaviors are lacking, and how they may influence immersion
negatively.
6/26/13 Magnus Johansson Department of Computer and Systems Sciences

22. Questions

23. Thank you for listening!
magnus@dsv.su.se
www.magnus.blogs.dsv.su.se