Before revision:  We provide baseline model performance results for both retrieval and correlations with human rankings, emphasizing both intra- and inter-modality learning.
After revision:  We report baseline results on CxC for strong existing unimodal and multimodal models. We also evaluate a multitask dual encoder trained on both image-caption and caption-caption pairs that crucially demonstrates CxC's value for measuring the influence of intra- and inter-modality learning.