Norms in Multi Agent Systems


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  • Good afternoon. I was asked by the organizers to give a presentation on Norms in MAS, which I was eager to accept as agent societies is the field in which my Lab and myself are mostly active. But I think it gives me also a good opportunity to draw the attention of the present audience on the necessity of a general theory of norms, a notion currently broken down into a myriad of specific notions, like conventions, social norms, and moral norms. It is particularly urgent to address such an objective in this occasion, since as I will argue during my presentation, what is missing is precisely a cognitive theory of norms as such.
  • Norms in Multi Agent Systems

    1. 1. Norms in Multi Agent Systems. ( What about Norms as Such ?)‏ Rosaria Conte LABSS/ISTC Laboratory of Agent Based Social Simulation , Institute of Cognitive Science and Technology, CNR, Rome. Italy http: //labss . istc . cnr .it/ MONTREAL, July 2008
    2. 2. Outline <ul><li>SoA </li></ul><ul><li>In search of unification </li></ul><ul><ul><li>A social cognitive view </li></ul></ul><ul><ul><li>The MAgent based approach. Normative agent architectures: </li></ul></ul><ul><ul><ul><li>BOID </li></ul></ul></ul><ul><ul><ul><li>EMIL-A </li></ul></ul></ul><ul><li>Simulation model and results </li></ul><ul><li>Conclusions and future work. </li></ul>
    3. 3. State of the art
    4. 4. Norms and the social/behavioral sciences <ul><li>Nonetheless (or consequently?), norms break down in too specific notions </li></ul><ul><li>Archipelago norm includes at least </li></ul><ul><ul><li>Conventions and social norms </li></ul></ul><ul><ul><li>Moral norms </li></ul></ul><ul><ul><li>Legal norms </li></ul></ul><ul><li>Norms are </li></ul><ul><ul><li>universally present in all human societies (Roberts, 1979; Brown, 1991; Sober and Wilson, 1998); </li></ul></ul><ul><ul><li>ancient : highly elaborated in all human groups, including hunter-gatherers and groups that are culturally isolated. </li></ul></ul><ul><ul><li>ubiquitous . governing all activities, from mate choice to burial </li></ul></ul><ul><ul><li>Impactful : on welfare and reproductive success. </li></ul></ul>
    5. 5. Conventions and social norms <ul><li>From analytical philosophy (Lewis), social sciences derived a conventionalistic view of norms as </li></ul><ul><ul><li>spontaneously emerging </li></ul></ul><ul><ul><li>behavioral regularities </li></ul></ul><ul><ul><li>based on conditioned preferences </li></ul></ul><ul><ul><li>enforced by sanctions </li></ul></ul><ul><li>Open questions </li></ul><ul><ul><li>How about mandatory force (Gilbert, 1993)? </li></ul></ul><ul><ul><li>How do norms innovate? </li></ul></ul><ul><ul><li>Why bother with sanctions, if norms are conditionally preferred? </li></ul></ul><ul><ul><li>Why do we violate norms? </li></ul></ul><ul><ul><li>How tell norms from behavioural regularities? </li></ul></ul>
    6. 6. Moral norms <ul><li>From (evolutionary) psychology, social sciences (but also robotics) derive a view of norms as moral motivations </li></ul><ul><ul><li>independently of any legal or social institution (independent normativity; Sripada & Stich, 2005) </li></ul></ul><ul><ul><li>based on subjective authority and internalized (intrinsic) motivations </li></ul></ul><ul><ul><li>compliance is valued even when there is no sanction from external source (Durkheim, 1968 [1912]; Scott, 1971). </li></ul></ul><ul><li>Questions </li></ul><ul><ul><li>What about internalization? Do agents keep the normative trace of moral motivations ? </li></ul></ul><ul><ul><li>Why norm violation? </li></ul></ul><ul><ul><li>What about unfair norms? </li></ul></ul>
    7. 7. Legal norms <ul><li>From philosophy of law and deontic philosophy (Von Wright, Kelsen), logicians and AI scientists derive an imperativistic view of norms as commands </li></ul><ul><ul><li>Deliberately issued </li></ul></ul><ul><ul><li>Enforced by explicit sanctions </li></ul></ul><ul><li>How do prescriptions emerge? </li></ul><ul><li>How to tell norms from coercion? </li></ul>
    8. 8. How about a general notion of norm? legal moral social religious What is common to them?
    9. 9. A requirement for unification <ul><li>“ Despite the vital role of norms in human lives and human behavior, and the central role they play in explanations in the social sciences, there has been very little systematic attention devoted to norms in cognitive science .” (Sripada & Stich, 2005)‏ </li></ul><ul><li>Only such a systematic attention can contribute to an integrated theory of norms. </li></ul>
    10. 10. Lets try: A social cognitive definition <ul><li>Norms = behaviors spreading in population (P i ) as long as </li></ul><ul><li>Corresponding prescriptions and mental constructs (Conte and Castelfranchi, 1995;2006) spread over P i </li></ul><ul><ul><li>N-beliefs: beliefs that for given sets of agents given wss/actions are obliged/forbidden/permitted </li></ul></ul><ul><ul><li>N-goals: goals to (not) achieve/accomplish obligatory/forbidden/permitted wss/actions. </li></ul></ul>
    11. 11. Cognitive puzzles <ul><li>What are obligations? </li></ul><ul><li>And prescriptions? </li></ul><ul><li>Very tentatively </li></ul><ul><ul><li>Command is supported by a normative belief, </li></ul></ul><ul><ul><li>Source (vector) wants (the prescription) to be obeyed on the grounds of a normative belief </li></ul></ul><ul><ul><li>Hence, source (vector) wants recipient to form a normative belief. </li></ul></ul>
    12. 12. Properties of norms <ul><li>Hybrid </li></ul><ul><ul><li>behaviour </li></ul></ul><ul><ul><li>mental construct </li></ul></ul><ul><li>dynamic: undergoing two processes </li></ul><ul><ul><li>emergence : process by means of which a norm not deliberately issued spreads through a society </li></ul></ul><ul><ul><li>immergence : process by means of which a normative belief is formed into the agents’ minds (Castelfranchi, 1998; Conte et al., 2007)‏ </li></ul></ul>
    13. 13. Implementing norms on agents <ul><li>MAgent based approach. Normative architectures The BOID architecture (Broersen et al., 2001). </li></ul><ul><li>EMIL-A (from a ICT-funded European project “EMergence In the Loop. The 2-way dynamics of norm-innovation”)‏ </li></ul>
    14. 14. The BOID architecture <ul><li>BDI architecture with obligations: Beliefs, Desires, Intentions, Obligations. </li></ul><ul><li>Interactions at study: which component is overriden? </li></ul><ul><ul><li>Realism: B override all others </li></ul></ul><ul><ul><li>Selfishness: D override obligations </li></ul></ul><ul><ul><li>Sociality: O override intentions. </li></ul></ul><ul><li>Why no direct interactions among D, I and O? No trace of the norm in goals </li></ul><ul><li>Why O is a separate component? Cognitively implausible… </li></ul><ul><li>How are O acquired? </li></ul>Reproduced from Broersen et al. (2001)‏ B O I D P Obs Act
    15. 15. <ul><li>OTHERWISE </li></ul><ul><li>How acquire norms autonomously? </li></ul><ul><li>How to account for transgression? </li></ul><ul><li>How to account for conflict resolution? </li></ul>N-action Norm-recognition N-Belief N-Goal N-intention EMIL ARCHITECTURE Decision making Norm-adoption N- Board
    16. 16. N-action Norm-recognition N-Belief N-Goal N-intention EMIL ARCHITECTURE Decision making Norm-adoption N- Board <ul><li>What about reactive behaviour? </li></ul><ul><ul><li>automated conformity? </li></ul></ul><ul><ul><li>What does it mean? </li></ul></ul><ul><li>Shortcuts are possible </li></ul><ul><li>But, “thoughtless” conformity is semi-automatic: </li></ul><ul><li>Agents can re-gain control over the whole process and </li></ul><ul><li>Perform decision-making </li></ul><ul><li>Finally, what about internalization? </li></ul>
    17. 17. Norm Recognition
    18. 18. Input <ul><li>Each input is presented as an ordered vector </li></ul><ul><ul><li>Source (x); </li></ul></ul><ul><ul><li>Action transmitted (a) (potential norm)‏ </li></ul></ul><ul><ul><li>Type of input: </li></ul></ul><ul><ul><ul><li>Behaviors </li></ul></ul></ul><ul><ul><ul><li>Messages: assertions (A), behaviours (B), requests (R), deontics (D), evaluations (V), sanctions (S); </li></ul></ul></ul><ul><ul><li>Observer (y); </li></ul></ul>X a T Y