Evaluating Attention in Convolutional Neural Networks for Blended Images
Andrea Portscher, Sebastian Stabinger, Antonio J. Rodríguez-Sánchez · 2022
In neuroscientific experiments, blended images are used to examine how attention mechanisms in the human brain work. They are particularly suited for this research area, as a subject needs to focus on particular features in an image to be able to classify superimposed objects. As Convolutional Neural Networks (CNNs) take some inspiration from the mammalian visual system – such as the hierarchical structure where different levels of abstraction are processed on different network layers – we examine how CNNs perform on this task. More specifically, we evaluate the performance of four popular CNN architectures (ResNet18, ResNet50, CORnet-Z, and Inception V3) on the classification of objects in blended images. Since humans can rather easily solve this task by applying object-based attention, we also augment all architectures with a multi-headed self-attention mechanism to examine its effect on performance. Lastly, we analyse if there is a correlation between the similarity of a network architecture's structure to the human visual system and its ability to correctly classify objects in blended images. Our findings showed that adding a self-attention mechanism reliably increases the similarity to the V4 area of the human ventral stream, an area where attention has a large influence on the processing of visual stimuli.