The BOID Architecture: Conflicts Between Beliefs, Obligations, Intentions and Desires

Reference: Broersen, Dastani, Hulstijn, Huang, van der Torre (2001). Proceedings of the Fifth International Conference on Autonomous Agents (AGENTS’01), Montreal. Source file: broersen_01_boid.pdf. URL

Summary

This paper introduces the BOID architecture, a deontic extension of the classic BDI (Belief-Desire-Intention) agent model that adds Obligations as a first-class motivational attitude alongside Beliefs, Desires, and Intentions. The authors argue that autonomous agents must reason not only about what they believe, want, and plan, but also about the norms and social commitments that constrain them, and that modeling obligations explicitly lets the architecture handle conflicts between self-interested goals and externally imposed duties.

The central contribution is a classification of conflict types between the four components (e.g., BO, BD, BI, OD, OI, DI, and triple/quadruple conflicts such as BOD and BOID) and a corresponding taxonomy of agent types determined by orderings over which component overrules which. Six “realistic” orderings yield named agent types: realistic, simple-minded/stable (BIDO, BIOD), selfish (BDIO, BDOI), social (BOID, BOID), and open-minded. Conflicts are resolved by feedback loops in the control cycle that iteratively apply rules from each component, producing one or multiple extensions in the sense of Reiter’s default logic. An additional planning component selects actions from intentions.

Key Ideas

Deontic extension of BDI: Obligations become a fourth motivational attitude.
Four components as input/output black boxes producing sets of formulas (extensions).
Taxonomy of conflicts: binary (BO, BD, BI, OD, OI, DI), triple (BOD, BOI, BDI, OID), quadruple (BOID).
Agent types as orderings over components: realistic, simple-minded, selfish, social, open-minded.
Conflict resolution via feedback-loop control architecture (extensions constructed before selection).
Connection to Reiter’s default logic and Thomason’s BDP logic.
Single-extension vs multiple-extension BOID; planning component selects one final extension.

Connections

Conceptual Contribution

Claim: Autonomous agents require obligations as a first-class motivational attitude alongside BDI, and an agent’s character can be formally identified with the priority ordering used to resolve conflicts between beliefs, obligations, intentions, and desires.
Mechanism: Four component black boxes (B, O, I, D) produce extensions over a propositional language; an ordering function rho on rules determines which components override others; a feedback-loop control cycle iteratively applies applicable rules; a planning component selects a single extension. The 24 possible orderings collapse to six realistic agent types.
Concepts introduced/used: BDI, Deontic Logic, Default Logic, Agent Types, Norms and Obligations, Agent Architecture, Multi-Agent Systems
Stance: formal
Relates to: Extends the BDI foundations referenced throughout the vault (Agent-Oriented Programming, BDI) with normative reasoning relevant to Agent Communication And Institutional Reality; provides a conflict-resolution substrate that agent communication languages (FIPA-ACL, KQML) implicitly assume when performatives carry commissive or directive force.

Tags

#bdi #deontic #agent-architecture #norms #multi-agent-systems

Backlinks

Summary

Fornara, Viganò, and Colombetti propose regarding an Agent Communication Language as a set of conventions acting on a fragment of institutional reality, defined within an artificial institution. They reformulate commitment-based ACL semantics so that all commonly used communicative act types reduce to a single basic type, declarations, within a Basic Institution that regulates the lifecycle of social commitments.

Special institutions (e.g., English Auctions) extend the Basic Institution with ontological and normative elements. The approach is notable for making the semantics of speech acts publicly verifiable and independent of agents’ mental states, while retaining a uniform formal account of institutional actions and counts-as relations.

Key Ideas

ACL messages are institutional actions governed by counts-as rules.

Basic Institution manages creation/update/cancellation of social commitments.

All speech act types reducible to declarations within the institution.

Special institutions layer domain norms and ontologies on top.

English Auction given as worked example.

Conceptual Contribution

Claim: An ACL is best understood as a set of conventions operating on institutional reality; all communicative act types reduce to declarations within a Basic Institution that governs the lifecycle of social commitments.

Mechanism: Defines artificial institutions with counts-as rules; models message effects as declarations creating/updating/cancelling commitments; layers domain norms in Special Institutions (English Auction worked example).

Concepts introduced/used: Commitment-based Semantics, Institutional Reality, Counts-as Rules, Declarations, Performatives, Speech Act Theory, Public Semantics, Verifiable Semantics, Mentalistic Semantics, Ontologies, FIPA-ACL, Multi-Agent Systems

Stance: formal-semantic

Relates to: Offers the publicly-verifiable alternative to mental-state semantics of FIPA-ACL, which A Common Ontology Of ACLs then unifies via roles; grounded philosophically in Foundations Of Illocutionary Logic.

Summary

Shoham introduces Agent-Oriented Programming (AOP) as a specialization of object-oriented programming in which the state of each module — now called an agent — is a mental state composed of beliefs, capabilities, decisions/choices, commitments, and obligations. Interpretation of these components is formally grounded in an extension of standard epistemic logics that adds temporality, obligation, decision, and capability operators.

Agents communicate via speech-act-inspired primitives (inform, request, offer, promise, decline, etc.), constrained by rules such as honesty and consistency. The paper defines a class of agent interpreters and presents AGENT-0, a concrete implemented language whose semantics is tied to the mental-state logic. Shoham also discusses “agentification” — converting arbitrary devices into AOP-programmable agents — and situates AOP against BDI architectures, speech act theory, and McCarthy’s Elephant2000.

Conceptual Contribution

Claim: Programming can be fruitfully specialised to an “agent” paradigm in which module state is a formally specified mental state and inter-module communication is a speech act constrained by rational/ethical rules.

Mechanism: Shoham extends standard modal-epistemic logic with temporal, obligation, decision and capability operators, defines the mental-state components of an agent (belief, capability, commitment, choice, obligation), then specifies a generic agent interpreter cycle (update mental state, execute commitments, handle incoming messages) and instantiates it in AGENT-0, whose programs are condition-action rules over mental state and whose messages are typed INFORM/REQUEST/UNREQUEST primitives.

Concepts introduced/used: Agent-Oriented Programming, Mental State, Commitment, AGENT-0, Speech Act Theory, Agentification, BDI, Honesty Constraint

Stance: foundational

Relates to: Establishes the mentalistic ACL stance later criticised by Agent Communication Languages - Rethinking the Principles and surveyed by Intelligent Agents Theory and Practice; AGENT-0’s speech-act primitives anticipate KQML as an Agent Communication Language and FIPA-ACL; the mental-state architecture is reused in An Interaction-oriented Agent Framework for Open Environments.