Towards Learning Cross-Modal Perception-Trace Models
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Representation learning is a key element of state-of-the-art deep learning approaches. It enables to transform raw data into structured vector space embeddings. Such embeddings are able to capture the distributional semantics of their context, e.g. by word windows on natural language sentences, graph walks on knowledge graphs or convolutions on images. So far, this context is manually defined, resulting in heuristics which are solely optimized for computational performance on certain tasks like link-prediction. However, such heuristic models of context are fundamentally different to how humans capture information. For instance, when reading a multi-modal webpage (i) humans do not perceive all parts of a document equally: Some words and parts of images are skipped, others are revisited several times which makes the perception trace highly non-sequential; (ii) humans construct meaning from a document's content by shifting their attention between text and image, among other things, guided by layout and design elements. In this paper we empirically investigate the difference between human perception and context heuristics of basic embedding models. We conduct eye tracking experiments to capture the underlying characteristics of human perception of media documents containing a mixture of text and images. Based on that, we devise a prototypical computational perception-trace model, called CMPM. We evaluate empirically how CMPM can improve a basic skip-gram embedding approach. Our results suggest, that even with a basic human-inspired computational perception model, there is a huge potential for improving embeddings since such a model does inherently capture multiple modalities, as well as layout and design elements.
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