  Today, AI is being increasingly used to help human experts make decisions in
high-stakes scenarios. In these scenarios, full automation is often
undesirable, not only due to the significance of the outcome, but also because
human experts can draw on their domain knowledge complementary to the model's
to ensure task success. We refer to these scenarios as AI-assisted decision
making, where the individual strengths of the human and the AI come together to
optimize the joint decision outcome. A key to their success is to appropriately
\textit{calibrate} human trust in the AI on a case-by-case basis; knowing when
to trust or distrust the AI allows the human expert to appropriately apply
their knowledge, improving decision outcomes in cases where the model is likely
to perform poorly. This research conducts a case study of AI-assisted decision
making in which humans and AI have comparable performance alone, and explores
whether features that reveal case-specific model information can calibrate
trust and improve the joint performance of the human and AI. Specifically, we
study the effect of showing confidence score and local explanation for a
particular prediction. Through two human experiments, we show that confidence
score can help calibrate people's trust in an AI model, but trust calibration
alone is not sufficient to improve AI-assisted decision making, which may also
depend on whether the human can bring in enough unique knowledge to complement
the AI's errors. We also highlight the problems in using local explanation for
AI-assisted decision making scenarios and invite the research community to
explore new approaches to explainability for calibrating human trust in AI.
