Like trainer, like bot? Inheritance of bias in algorithmic content moderation

TL;DR

This paper explores how biases in algorithmic content moderation systems reflect normative differences across demographic groups, affecting fairness and diversity in online discussions.

Contribution

It introduces methods to measure normative biases in moderation algorithms and demonstrates their application through a case study using demographic-labeled comment data.

Findings

Classifiers trained on different demographic labels show varying performance on test sets.

Normative biases influence moderation outcomes and can impact diversity of online discourse.

Bias measurement methods can inform more equitable content moderation practices.

Abstract

The internet has become a central medium through which `networked publics' express their opinions and engage in debate. Offensive comments and personal attacks can inhibit participation in these spaces. Automated content moderation aims to overcome this problem using machine learning classifiers trained on large corpora of texts manually annotated for offence. While such systems could help encourage more civil debate, they must navigate inherently normatively contestable boundaries, and are subject to the idiosyncratic norms of the human raters who provide the training data. An important objective for platforms implementing such measures might be to ensure that they are not unduly biased towards or against particular norms of offence. This paper provides some exploratory methods by which the normative biases of algorithmic content moderation systems can be measured, by way of a case study using an existing dataset of comments labelled for offence. We train classifiers on comments labelled by different demographic subsets (men and women) to understand how differences in conceptions of offence between these groups might affect the performance of the resulting models on various test sets. We conclude by discussing some of the ethical choices facing the implementers of algorithmic moderation systems, given various desired levels of diversity of viewpoints amongst discussion participants.