In short...

The artificial neural network powering expoze.io was first exposed to millions of images to learn to detect objects, and subsequently trained on thousands of images to learn to generate the correct attention heatmaps.

It uses all this experience when generating the attention prediction results for your image or video. That is why it is possible that when you click “create new heatmap” your attention heatmap matches real eye tracking results with an accuracy of 95%.