Context bias detection with grid saliency . In the last column of Fig . 4 ( b ) , we report the context bias detection results for our perturbation - based grid saliency method , described in Sec . 3.1 , using the CBD metric ( see Eq . 6 ) . The mCBD values are visualized with respect to networks trained on data biased to different digits DS s / w - bias ( y - axis ) and for the different digit classes ( x - axis ) in the biased test set . The only exception is the first row ( labeled as N ) , where for comparison we show the results with no bias , for the network trained on DS no - bias . We observe that our grid saliency shows substantial evidence of context bias for digits with induced bias ( diagonal elements ) , both strong and weak . Even for the weak bias in Fig . 4 ( b ) the grid saliency still clearly differentiates between biased and unbiased digits ( diagonal vs. non - diagonal elements ) . Note that the bias detection using the grid saliency does not require an unbiased test set . In the suppl . material , we also study the influence of the bias texture as well as the choice of hyperparameters .