From: AAAI Technical Report SS-93-05. Compilation copyright © 1993, AAAI (www.aaai.org). All rights reserved. Norms as mental objects. From normative beliefs to normative goals. RosariaConte* Cristiano Castelfranchi* set up the value of the resources 1. Introduction exchanged, that is, what each is entitled to expect from others in retum, given the The study of norms (Ns) is resources invested. Without a norm of recent but growing concern in the AI reciprocation, such expectation would be field (cf. [MOS92];[SHO92]) as well easily disconfirmed when social within other formal approaches to social exchange, as often happens, does not action, such as Game Theory (where occur simultaneously. The utilitarian theories of Ns began to appear long agent would spontaneously respect the before, cf.[LEW69]; [ULL77]). The agreement only if the partner is regarded normative is an essential dimension of as stronger. Otherwise, he would get social life. An explicit model of such away with no costs, in a word, he would dimension is crucial for any theory of cheat. social action. Notions such as "social Analogously, joint intentions and commitment" (cf. [GAS91]; [COH90]; teamwork arise from true negotiation etc.) "joint intentions", "teamwork" and create rights based on commitments. [COH91], "negotiation" [DAV83], Finally, roles are but sets of obligations "social roles" [WER89] etc. will not and rights. escape a purely metaphorical use if their A norm-abiding behavior need normative character is not accounted for. not be based on the cognitive processing Indeed, one’s committing oneself of Ns (it might be simply due to before someoneelse causes the latter to imitation), nor does a normative mind be entitled, on the very basis of necessarily produce a behavior commitment, to expect, control, and corresponding to Ns (Ns are operating in exact the action one has committed the mind even if the agent’s final oneself to. Social commitment is a decision is to transgress against them). customary, if not the most frequent, To model the normative reasoning does source of entitlements in everyday not imply to model a norm-abiding interaction: first of all, a promisecreates system. However, a large portion of an entitled expectation in the addressee, autonomous agents’ normative behavior namely a belief that the promised course is allowed by a cognitive processing of of action will be realized. As a Ns. Therefore, Ns are not only an consequence, the addressee feels entitled essentially social but also a mentalistic to exact the action expected, that is, to notion. Ns are indeed a typical node of control its occurrence and react if it is the micro-macrolink, of the link between not performed. In particular, the individual agents and collective addressee is entitled to express a public phenomena, minds and social structures. protest and receive the consent and A view of normative systems as support of the community of witnesses "emerging properties" of the social before whomthe action of commitment systems, improving coordination within took place. the social systems themselves (cf. Furthermore, there is no true [MOS92])is not sufficient. negotiation without control for cheaters On one hand, that of and norm of reciprocation (of. coordination is only one of the [GOU60]). Whensocial agents negotiate functionalities of Ns. Amongothers, an exchange of resources, they actually consider the function of identification, (the good manners, for example, improve identification rather than coordination: on their grounds, in- SBSP- Social BehaviorSimulation Project, Istituto di Psicologia,CNR, V.le Marx15, 1- groups are allowed to be identified, etc.); 00137Roma, Italy. that of protecting the single’s interests Tel: (06) 8292626,Fax: (06) 824737,e-mail: beyond its own will (as happens with the PSCS~IRMKANT.BITNET norms prescribing to fasten seat belts, to wear helmets when riding motorcycles 40 etc.) Furthermore,there are at least two and someinitial solutions proposed. types of norms of coordination: those The problemsare the following: whichare aimedat improvingthe agents’ performances(like the traffic norms), - Howare Ns represented in the and those which are intended to reduce agents’ minds? Should they be displayed aggression (like the normof seen as a specific mental object, reciprocation). and if so, whichone? On the other hand, the - Whichrelation do they bear with emergenceparadigm gives an account of beliefs and goals? Howcan they conventional norms and conforming regulate the agents’ behaviors? behaviors (cf. [BIC90]), but leaves - Howis their prescriptive (and not unexplainedthe prescriptive character of simply conventional) character norms. Within the game-theoretic (that is, a more or less explicit paradigm,a social normis defined as an request and the corresponding equilibrium, a combinationof strategies duty) expressed? such that "each maximizeshis expected - Whydoes an autonomous agent utility by conforming,on the condition complywith norms, thus fulfilling that nearly everybodyelse conforms to others’ expectations? the norm." (cf. [BIC90: 842]) Social norms are defined as behavioral 2. The normativecoin. regularities which emerge from the strategic agents’ choices to conform. What is a norm in an agent’s This is an account of the spreading of mind?This question leaves aside another certain behaviors over a population of fundamental question, namely what is a strategic agents, in a word, a modelof N tout court. Althoughprioritary, wewill social conventions. However, such a not face this question here (however,see model does not account for a crucial [CAS91]).Therefore, we will not try to aspect of the normative mechanism, answer the question what the "external" which plays a role in the spreading of side of Ns is, namely, how Ns are normative behaviors, namely the encountered in social life, which normativerequest. Whatis lacking in the functionalities they have, whichfeatures game-theoretic definition define de facto (independent of agents’ aforementioned is a reference to the beliefs) a normativesource, etc.. agent’s will that others conformto the Here, we will focus exclusively norms. A social norm, indeed, is such if on the "internal" side of Ns, that is: it is associated at least with a general Whichcognitive role do Ns play in the wantthat it be observed. Such a wantis agents’ minds and in which format are usually conveyed in many ways: from they represented? Whatkind of mental simple expectations (note that the term object is a N? Whatis a normativesource expectation is often used to refer to a in the agents’beliefs? hybrid mental object, namely a There are at least two distinct goal/belief: if you expect the weather ways in which norms can be tomorrow to be sunny and warm you implemented on a computer system: as both believe and wish it to be so), to built-in functioning rules and constraints explicit commandsand requests; from (like productionrules) or as explicit and implicit disapproval of transgressors, to specific mentalobjects (i.e. obligations, explicit reproachetc.. duties, etc.) distinct from, say, goals and Therefore, here it is intended to beliefs. Of course, there might be draw the attention on both the following intermediate solutions: for example,and aspects: in line with the game-theoreticview, one might think of noms as a way of ¯ the prescriptive character of Ns, describing the behaviors of strategic that is, their role in controlling and agents in interaction: no specific regulating the behaviors of agents normativeobject is implementedin those subject to them; agents’ mindsalthough cognitive action is allowed. A further alternative consists ¯ a need for a mentalistic notion of of implementingNs just as goals, namely Ns allowing cognitive agents to final ends: In this case, cognitive agents becomenormative agents as well. Ns would be allowed to choose amongtheir are not yet sufficiently characterized (competing) goals (instead of simply as mental objects (cf [SHO92]).Here, applying procedures and routines) but some crucial problems concerning they wouldtreat Ns as any other goal of the mentalnature of Ns will be raised theirs. At least two undesirable 41 consequences seem to derive from the the future behavior of the agents subject latter eventuality: the observance of Ns to them, their addressees (As). would come to depend exclusively upon To this end, they ought to give the agents’ subjective preferences, and rise to some new goal in an A’s mind there would be no social control and (cfr. [CON91b]): for autonomous agents influencing. To implement norms as to undertake (or abstain from) a course specific mental objects, although a costly of action, it is not sufficient that they alternative, is required in a cognitive knowthat this course of action is wanted modelling approach to social agenthood, (by someone else) (cf. [ROS88]; in which the present work is framed. [GAL90]). It is necessary that these Moreover, the cognitive regulatory agents have the goal to do so. Norms endowment of the human species has may act as a mechanism of goal- undoubtedly profited by the explicit generation. Indeed, they represent a representation of norms. A crucial but powerful mechanism for inducing new difficult task, beyond the scope of the goals in people’s minds in a cognitive present work, would then be to explore way. Howis this possible? these advantages and confront them with At first, Ns need being those of all alternatives considered. represented as beliefs in an A’s mind. Let Our language draws on us start from beliefs about requests. A [COH90]’smodel for describing rational simple request, before succeeding and interaction. For the readability of the producing acceptance on the side of the paper, let us provide the semantics of the required person, is nothing but a belief, main predicates used and the axiom namely a belief about someone’s will. (A1) here called the axiom of goal- Such a belief can be expressed as generation (for further analysis, see follows: [COH90], [CON91a], [CON91b]): (BELx (GOALy (GOALx p))) (1) a: action; p andq: states of the world; where agent x believes someone else, v: a worldstatepositively valued; agent y, has the goal that x has the goal x ,y, andz single agents; that p.