  Evaluating grounded neural language model performance with respect to
pragmatic qualities like the trade off between truthfulness, contrastivity and
overinformativity of generated utterances remains a challenge in absence of
data collected from humans. To enable such evaluation, we present a novel open
source image-text dataset "Annotated 3D Shapes" (A3DS) comprising over nine
million exhaustive natural language annotations and over 12 million
variable-granularity captions for the 480,000 images provided by Burges & Kim
(2018). We showcase the evaluation of pragmatic abilities developed by a
task-neutral image captioner fine-tuned in a multi-agent communication setting
to produce contrastive captions. The evaluation is enabled by the dataset
because the exhaustive annotations allow to quantify the presence of
contrastive features in the model's generations. We show that the model
develops human-like patterns (informativity, brevity, over-informativity for
specific features (e.g., shape, color biases)).
