Modeling Content Creator Incentives on Algorithm-Curated Platforms

TL;DR

This paper introduces an exposure game model to analyze how algorithmic choices influence content creator incentives and equilibrium outcomes on online platforms, highlighting implications for content diversity and bias.

Contribution

It formalizes the impact of algorithmic design on creator incentives, providing tools for pre-deployment audits to align content with desired objectives.

Findings

Algorithmic choices significantly affect equilibrium existence and nature.

Content diversity is influenced by exploration strategies and model expressivity.

Bias towards gender groups is linked to model design and exploration policies.

Abstract

Content creators compete for user attention. Their reach crucially depends on algorithmic choices made by developers on online platforms. To maximize exposure, many creators adapt strategically, as evidenced by examples like the sprawling search engine optimization industry. This begets competition for the finite user attention pool. We formalize these dynamics in what we call an exposure game, a model of incentives induced by algorithms, including modern factorization and (deep) two-tower architectures. We prove that seemingly innocuous algorithmic choices, e.g., non-negative vs. unconstrained factorization, significantly affect the existence and character of (Nash) equilibria in exposure games. We proffer use of creator behavior models, like exposure games, for an (ex-ante) pre-deployment audit. Such an audit can identify misalignment between desirable and incentivized content, and thus complement post-hoc measures like content filtering and moderation. To this end, we propose tools for numerically finding equilibria in exposure games, and illustrate results of an audit on the MovieLens and LastFM datasets. Among else, we find that the strategically produced content exhibits strong dependence between algorithmic exploration and content diversity, and between model expressivity and bias towards gender-based user and creator groups.