We often need to verify an individual's identity from their facial appearance. One common method of verification is the "one-to-one matching task", in which an observer is asked to decide whether a photo ID document (e.g., a passport or driver's licence) matches the person presenting it for inspection. Although this is a common task, average human performance is surprisingly poor - with error rates regularly between 20-30%. Recent technological advances mean that many facial recognition algorithms now outperform the average human on these verification tasks. Even so, often the human operator is responsible for reviewing the algorithm's response and then making the final identification decision. Despite such arrangements already being used for identity verification, very little is known about the collaborative performance of these human-algorithm teams. Here we investigate how knowing the decision of a facial recognition system influences the final identification decision made by the human operator in a one-to-one face matching task.