This document discusses measuring and manipulating player trust through game mechanics and choices. It defines trust and reputation, noting that trust concerns moral hazard while reputation concerns adverse selection. It argues that trustworthiness is isomorphic to an agent's discount factor in game theory. Several ways are described to measure a player's discount factor through their choices in a game. The document also discusses using non-player characters with varying levels of trustworthiness to explore and exploit a player's trust. Finally, it outlines direct applications of these concepts like determining NPC decisions and subordinates' obedience based on the player's measured trustworthiness.

1. Measuring and Manipulating
Player Trust through Choice and
Game Mechanics
Christopher J. Hazard, PhD
CEO Hazardous Software Inc.

2. ● having reason or understanding
● relating to, based on, or agreeable
to reason: reasonable

3. Rational
● having reason or understanding
● relating to, based on, or agreeable
to reason: reasonable
-Merriam Webster

4. Humans are rational*
*given limited computational
bounds, unfounded beliefs of
others, inaccurate capability
assessments, inexplicable
valuations, and some level of
[im]patience

5. Machines are rational*
*given limited computational
bounds, unfounded beliefs of world,
wrong models, inexplicable
valuations, and some level of
implicit [im]patience

10. from zap2it.com
from trutv.com
by tinyfroglet, cc
from supermanhomepage.com
from Seattle Weekly
from penny-arcade.com

11. Reputation
● Belief about attribute
● Hindsight, capabilities,
statistics
● Concern: adverse
selection
Trust
● Belief will not exploit
● Foresight, strategy, game
theory
● Concern: moral hazard

12. +

13. Trustworthiness ~ Patience

14. Trustworthiness Isomorphic to Discount Factor
● Compare two agents interacting with third in pure
moral hazard situation
● Assumptions
– Consistent valuations
– Quasilinearity
– Trustworthiness sufficiently consistent
– Individually rational
● All else equal, given definitions & assumptions,
only factor that affects trustworthiness is discount
factor

15. Discounting Everywhere

Stochastic search

Amortization

Bellman Equation

Reinforcement Learning

Markov Decision Processes & POMDPs

Normalize discount rate wrt time

16. Creeping Sniper's Dilemma
● Single sniper optimal strategy; slow creep out = low risk
● Multiple sniper optimal strategy
● Match quickest visible discount strategy unless too risky

17. Negotiating

Rubenstein Negotiation
 v1 = (1-γ2)/(1-γ1γ2)

Inequalities if rationality not guaranteed

Player & NPC interaction inequalities

Impatience

NPC disagreements with player over choices

18. Measuring discount factor by choice

19. Combining Observations: Bayesian Inference

20. Optimal Level of Patience for Given Scenario

21. Trust Exploration
● Measure valuations,
discount factor, beliefs,
maxent regions
● NPCs of different
trustworthiness
● Reputations Trust Exploitation
● Push player's ethics
buttons: “what is your
price?”
● Stability & comfort vs
conflict
● Trickery

22. Psychological Heuristics of Trust
Homophily
Embedding
Corroboration
Mass Effect 3
Image from WoW Cataclysm
Image from Heavenly Sword

23. Homophily
Embedding
Corroboration

24. Acceptance and Affirmation
Antitheses (Alliterated)
- Algorithm aversion Dietvorst et al., J Exp Psych 2013
+ Anthropomorphization
- Abeyance of absorbtion
+ Acceptance acquiered
after asking assistance
Flynn, Org Behav & Hum Dec Proc, 2003

25. Selling Trust With Nuance 1:
Don't [unintentionally] Scare Players
Nevermind (forthcoming) – Monitor fright
Balloon Brigade
NBA 2K14 - Swearing
IQ, Depression, Behavior, Health,
Preferences, Diet, Injuries, Friends, etc.
-Newman, Jerome, & Hazard, AIPLA, 2014
Psychometrics for Predicting Behavior
– Poore et al., J Cognitive Engineering, 2014.

26. Selling Trust With Nuance 2:
Physiology
● More permissive on right ear than left
- Marzoli & Tommasi, Sci of Nat, 2009
● Two-streams hypothesis for vision processing
● Foveal & spatial detail vs perifoveal & temporal
detail
● Mutual exclusion between physical & social
reasoning
– Jack et al., Neuroimage, 2012
● Push players to practice self-control
– Denson, DeWall, Finkel, Cur Dir in Psych Sci., 2012

27. Selling Trust With Nuance 3:
Hypnosis & Trance
● Relaxation
● Memory
● Creativity
● Suggestability
● Awe & comfort
● Biases
● Placebo effect

28. Trust & Society
● Enforcing/sanctioning to combat lies
● Incentive compatibility & revelation principle wrt
information asymmetry
● Level of trust req'd for system & efficiency
● Too trusting with homophily, embedding,
corroboration?
● Common inability to play “red player”

29. Direct Applications (Conclusions)

NPC decisions: favors, purchases, alliances

Measuring player patience

Adversary willingness to look ahead related to
organizational trust (e.g., big bad)

NPC subordinates following player commands
based on trustworthiness (explicit or implicit)

30. Questions?
info@hazardoussoftware.com