Less is More: Efficient Black-box Attribution via Minimal Interpretable Subset Selection
Authors: Ruoyu Chen, Siyuan Liang, Jingzhi Li, Shiming Liu, Li Liu, Hua Zhang, Xiaochun Cao
Organizations: Institute of Information Engineering, Chinese Academy of Sciences, Beijing 100093, China · University of Chinese Academy of Sciences, Beijing 100049, China · College of Computing and Data Science, Nanyang Technological University, 639798, Singapore · School of Artificial Intelligence, University of Science and Technology Beijing, Beijing 100083, China · Department of Mechanical Engineering, Imperial College London, UK · Center for Machine Vision and Signal Analysis (CMVS), University of Oulu, Finland · School of Cyber Science and Technology, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China
To develop a trustworthy AI system, it is essential to understand its behavior using attribution methods, which aim to identify the input regions that most influence the model's decisions. For discrete inputs such as images, however, accurately identifying input-prediction interactions is particularly challenging because of combinatorial explosion. We formulate black-box attribution as an ordered interpretable subset-selection problem. Inspired by the marginal-gain principle of submodular optimization, the formulation permits redundancy, positive complementarity, and negative interference among input sub-regions. We propose LiMA (Less input is More faithful for Attribution), which ranks sub-regions by their contributions along a sequence of selected subsets. LiMA employs a composite objective that evaluates subsets through semantic consistency, collaboration, prediction confidence, and semantic effectiveness. We further design a bidirectional greedy search to efficiently identify important and non-critical sub-regions. Experiments on eight foundation models (CLIP, ImageBind, LanguageBind, QuiltNet, etc.) and six datasets (ImageNet, VGG-Sound, CUB-200-2011, etc.) demonstrate strong generalization and faithful interpretations with fewer sub-regions. LiMA achieves state-of-the-art Insertion, Deletion, and average highest confidence, with average improvements of 36.3% in Insertion and 39.6% in Deletion; it is also 1.6 times faster than naive greedy search. For failure attribution on incorrect predictions, LiMA improves average highest confidence by 86.1% over state-of-the-art methods. The code is available at https://github.com/RuoyuChen10/LIMA.
Figures & tables
Fig. 1: The left panel illustrates the Insertion and Average Highest Confidence metrics for various attribution mechanisms when attributing the model’s correct and incorrect predictions. Our method shows significant improvements across different datasets and models. The right panel shows the attribution maps of different methods, where our approach avoids noise and unnecessary region redundancy.
Fig. 2: The framework of the proposed LiMA method. We first divide the input into interpretable sub-regions using a superpixel- or semantic-based strategy. A composite objective and bidirectional greedy search then identify important and non-critical sub-regions and arrange them into an ordered sequence. Finally, consistency- and collaboration-based marginal changes are used to assign attribution scores. The resulting prefixes provide explanations at different region budgets and are evaluated using faithfulness metrics.
Fig. 3: Statistics of large response transitions along the insertion trajectory. A. Results for models with different pre-training scales and sizes. B. Results for correctly and incorrectly predicted samples.
Methods
CLIP (ViT-L) [ 31 ]
ImageBind (Huge) [ 32 ]
LanguageBind (Large) [ 33 ]
Del. ( ↓ )
Ins. ( ↑ )
μ Fid. ( ↑ )
F/B
Time
Del. ( ↓ )
Ins. ( ↑ )
μ Fid. ( ↑ )
F/B
Time
Del. ( ↓ )
Ins. ( ↑ )
μ Fid. ( ↑ )
F/B
Time
Saliency [ 41 ]
0.3040
0.1938
0.1010
1/1
0.095±0.002
0.3857
0.3473
0.1807
1/1
0.127±0.002
0.2237
0.2379
0.2395
1/1
0.402±0.002
Integrated Gradients [ 22 ]
0.1600
0.3560
0.0881
80/80
1.498±0.929
0.1405
0.5577
0.1919
80/80
5.059±0.033
0.0699
0.2733
0.1422
80/80
29.11±0.63
iGOS++ [ 24 ]
0.2934
0.4467
0.2313
16,426.7/1,600
85.48±11.13
0.2658
0.4417
0.2371
17,253.3/1,600
447.3±22.6
–
–
–
–
–
RISE [ 20 ]
0.1615
0.5345
0.3244
500/0
2.041±0.102
0.1528
0.4699
0.3459
500/0
11.23±0.10
0.1145
0.4750
0.2764
500/0
67.49±0.44
HSIC-Attribution [ 12 ]
0.1565
0.4397
0.3232
500/0
2.454±0.746
0.1875
0.4407
0.3413
500/0
11.46±0.04
0.1034
0.4070
0.4132
500/0
68.25±0.12
TABLE I: Faithfulness, absolute query counts, and wall-clock time for multimodal ViT backbone foundation models on ImageNet. F/B denotes forward queries/backward passes; time is mean ± sample standard deviation in seconds.
Fig. 4: Visual explanations of the CLIP model using various attribution mechanisms, with our approach effectively reducing noise and eliminating redundant regions, leading to more interpretable attribution results.
Fig. 5: Attribution visualizations of decision results for different multimodal foundation models on the ImageNet dataset. The first row shows the interpretation results from the state-of-the-art baseline attribution methods, while the second row displays the interpretation results from our method. Each interpretation result includes the saliency map, the highest confidence score, and its corresponding region, as well as the Insertion AUC curve. The red line in the curve represents the highest confidence of the model’s response during the search.
Methods
CLIP (ResNet-101) [ 31 ]
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity ( ↑ )
F/B
Time
Saliency [ 41 ]
0.0801
0.1540
0.3648
1/1
0.084±0.005
Integrated Gradients [ 22 ]
0.0482
0.0804
0.1141
80/80
0.588±0.212
Kernel SHAP [ 26 ]
0.1198
0.1766
0.0923
1,000/0
2.454±0.342
RISE [ 20 ]
0.0719
0.4034
0.3355
500/0
0.744±0.011
HSIC-Attribution [ 12 ]
0.0659
0.3574
0.4373
500/0
0.831±0.021
TABLE II: Faithfulness, absolute query counts, and wall-clock time for CLIP with a ResNet-101 backbone on ImageNet.
Methods
ResNet-101 [ 78 ]
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity ( ↑ )
F/B
Time
Saliency [ 41 ]
0.1148
0.2613
0.4556
1/1
0.087±0.004
Integrated Gradients [ 22 ]
0.0521
0.1482
0.1822
80/80
0.602±0.056
iGOS++ [ 24 ]
0.1934
0.3779
0.3377
14,346.7/1,600
19.96±0.37
Kernel SHAP [ 26 ]
0.1944
0.2878
0.1399
1,000/0
2.212±0.271
RISE [ 20 ]
0.1101
0.4920
0.3827
500/0
0.839±0.042
TABLE III: Faithfulness, absolute query counts, and wall-clock time for the single-modal ResNet-101 backbone on ImageNet.
Methods
ViT-L [ 79 ]
Swin-L [ 80 ]
Del. ( ↓ )
Ins. ( ↑ )
F/B
Time
Del. ( ↓ )
Ins. ( ↑ )
F/B
Time
Saliency [ 41 ]
0.3499
0.3544
1/1
0.096±0.002
0.2888
0.4178
1/1
0.213±0.088
Integrated Gradients [ 22 ]
0.1530
0.2402
80/80
2.029±0.015
0.3074
0.4198
80/80
1.506±0.032
Kernel SHAP [ 26 ]
0.4155
0.4942
1,000/0
9.250±0.191
0.4300
0.4794
1,000/0
6.788±0.110
RISE [ 20 ]
0.1947
0.6177
500/0
4.335±0.052
0.3338
0.5655
500/0
3.273±0.030
HSIC-Attribution [ 12 ]
0.1898
0.5253
500/0
4.423±0.022
0.3589
0.5531
500/0
3.377±0.043
TABLE IV: Faithfulness, absolute query counts, and wall-clock time for single-modal vision transformer backbones on ImageNet.
Methods
Vision Mamba (base) [ 81 ]
MambaVision (L2) [ 82 ]
Del. ( ↓ )
Ins. ( ↑ )
F/B
Time
Del. ( ↓ )
Ins. ( ↑ )
F/B
Time
Saliency [ 41 ]
0.2793
0.1938
1/1
0.127±0.009
0.1681
0.1494
1/1
0.099±0.005
Integrated Gradients [ 22 ]
0.0914
0.2323
80/80
1.319±0.022
0.1067
0.2202
80/80
1.236±0.015
Kernel SHAP [ 26 ]
0.2947
0.3603
1,000/0
5.878±0.351
0.2030
0.2345
1,000/0
5.827±0.149
RISE [ 20 ]
0.2008
0.5352
500/0
2.789±0.425
0.1419
0.2937
500/0
2.511±0.027
HSIC-Attribution [ 12 ]
0.2067
0.4872
500/0
2.854±0.361
0.1541
0.2753
500/0
2.725±0.048
TABLE V: Faithfulness, absolute query counts, and wall-clock time for single-modal Mamba backbones on ImageNet.
Celeb-A (ArcFace ResNet-101)
VGGFace2 (ArcFace ResNet-101)
Methods
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity ( ↑ )
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity ( ↑ )
Saliency [ 41 ]
0.1453
0.4632
0.3258
0.1907
0.5612
0.5034
Grad-CAM [ 23 ]
0.2865
0.3721
0.0672
0.3103
0.4733
0.2773
Integrated Gradients [ 22 ]
0.0680
0.3578
0.3352
0.0749
0.5399
0.3853
LIME [ 49 ]
0.1484
0.5246
0.1985
0.2034
0.6185
0.4856
Kernel SHAP [ 26 ]
0.1409
0.5246
0.2722
0.2119
0.6132
0.4905
TABLE VI: Deletion, Insertion AUC scores, and μ Fidelity on the Celeb-A and VGG-Face2 validation sets.
CUB-200-2011
Methods
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity ( ↑ )
Saliency [ 41 ]
0.0682
0.6585
0.1409
Grad-CAM [ 23 ]
0.0810
0.7224
0.1486
Integrated Gradients [ 22 ]
0.1693
0.5263
0.2832
LIME [ 49 ]
0.1070
0.6812
0.0948
Kernel SHAP [ 26 ]
0.1016
0.6763
0.1452
TABLE VII: Deletion, Insertion AUC scores, and μ Fidelity on the CUB-200-2011 validation set.
Methods
ImageBind [ 32 ]
LanguageBind [ 33 ]
Del. ( ↓ )
Ins. ( ↑ )
F/B
Time
Del. ( ↓ )
Ins. ( ↑ )
F/B
Time
Saliency [ 41 ]
0.0999
0.1823
1/1
0.089±0.001
0.1024
0.2184
1/1
0.136±0.005
Gradient-Input [ 89 ]
0.0326
0.1257
1/1
0.079±0.003
0.0243
0.1388
1/1
0.134±0.004
SmoothGrad [ 90 ]
0.0734
0.0955
80/80
2.549±0.167
0.0535
0.1664
80/80
6.605±0.018
Integrated Gradients [ 22 ]
0.0313
0.1292
80/80
2.180±0.012
0.0165
0.2153
80/80
8.668±0.715
VarGrad [ 91 ]
0.0755
0.2121
80/80
2.298±0.030
0.0955
0.2643
80/80
6.548±0.052
TABLE VIII: Faithfulness, absolute query counts, and wall-clock time for multimodal ViT backbones on VGG-Sound.
Fig. 6: Attribution visualizations for audio classification on ImageBind and LanguageBind, highlighting the most critical spectrogram regions attributed to the model. Additionally, we provide the corresponding Insertion AUC curve.
Fig. 7: Visualization of failure attribution for CLIP on representative misclassified samples. In the attribution maps, green regions tend to support the ground-truth (GT) class, whereas red regions tend to support the originally predicted incorrect class. In the insertion curves, the green and red lines denote the recognition scores of the GT and incorrect classes, respectively. Failure attribution aims to identify a compact region whose revelation changes the prediction from the incorrect class back to the GT class, i.e., the GT recognition score becomes higher than that of the incorrect class. The searched region corresponds to the image content revealed at the turning point (dashed vertical line), representing the minimal region required to recover the correct prediction.
Average highest confidence ( ↑ )
Backbones
Methods
(0-25%)
(0-50%)
(0-75%)
(0-100%)
Insertion ( ↑ )
RISE [ 20 ]
0.2710
0.3985
0.4558
0.4879
0.1827
HSIC-Attribution [ 12 ]
0.2148
0.2723
0.3051
0.3462
0.1062
ViT-CX [ 45 ]
0.1268
0.2367
0.3137
0.3902
0.1236
EAC [ 27 ] (w/ Segment Anything)
0.1004
0.1861
0.2561
0.3397
0.1086
Grad-ECLIP [ 25 ]
0.2202
0.3404
0.3767
0.4123
0.1397
TABLE IX: Evaluation of failure attribution for different multimodal models on the ImageNet dataset.
Average highest confidence ( ↑ )
Backbones
Methods
(0-25%)
(0-50%)
(0-75%)
(0-100%)
Insertion ( ↑ )
Integrated Gradients [ 22 ]
0.0081
0.0318
0.0776
0.3904
0.0460
RISE [ 20 ]
0.0064
0.0533
0.1547
0.2546
0.0385
HSIC-Attribution [ 12 ]
0.0107
0.0441
0.0609
0.1657
0.0201
ImageBind [ 32 ]
LiMA ( 10×10 )
0.0955
0.1978
0.3992
0.5028
0.1813
Integrated Gradients [ 22 ]
0.0574
0.1092
0.1747
0.4254
0.1153
TABLE X: Evaluation of failure attribution for different multimodal models on the VGG-Sound dataset.
Fig. 8: Visualization of failure attribution for representative incorrect audio predictions.
Average highest confidence ( ↑ )
Backbone
Methods
(0-25%)
(0-50%)
(0-75%)
(0-100%)
Insertion ( ↑ )
Integrated Gradients [ 22 ]
0.2989
0.2989
0.2989
0.3012
0.1344
Kernel SHAP [ 26 ]
0.1957
0.1962
0.1965
0.2024
0.1359
RISE [ 20 ]
0.4986
0.5109
0.5163
0.5171
0.1470
HSIC-Attribution [ 12 ]
0.4858
0.4927
0.5005
0.5013
0.1468
ViT-CX [ 45 ]
0.3497
0.3595
0.3637
0.3658
0.1419
TABLE XI: Evaluation of failure attribution for the medical multimodal model QuiltNet on the LC25000 (Lung) dataset.
Fig. 9: Visualization of failure attribution for medical foundation model QuiltNet on representative misclassified samples.
Average highest confidence ( ↑ )
Backbones
Methods
(0-25%)
(0-50%)
(0-75%)
(0-100%)
Insertion ( ↑ )
Grad-CAM++ [ 43 ]
0.1988
0.2447
0.2544
0.2647
0.1094
Score-CAM [ 44 ]
0.1896
0.2323
0.2449
0.2510
0.1073
Kernel SHAP [ 26 ]
0.0083
0.0247
0.0574
0.2642
0.1008
RISE [ 20 ]
0.2406
0.3032
0.3316
0.3807
0.2238
HSIC-Attribution [ 12 ]
0.1709
0.2091
0.2250
0.2493
0.1446
TABLE XII: Evaluation of failure attribution for incorrect predictions across convolutional neural network backbones on the CUB-200-2011 dataset.
Bi-directional subset
Candidate pool size np
Faithfulness metrics
Exec. time (s)
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity ( ↑ )
✗
0
0.1260
0.8099
0.3669
32
✓
1
0.2048
0.6445
0.3344
16
✓
4
0.1309
0.7303
0.3508
18
✓
8
0.1280
0.7463
0.3526
20
✓
12
0.1271
0.7517
0.3551
22
TABLE XIII: Ablation study on the bidirectional greedy search algorithm for ImageBind on the ImageNet dataset.
Objective Function
Deletion ( ↓ )
Insertion ( ↑ )
Cons. Score
Colla. Score
Conf. Score
Eff. Score
(Equation 3 )
(Equation 4 )
(Equation 5 )
(Equation 7 )
✓
✗
✗
✗
0.2567
0.6324
✗
✓
✗
✗
0.1031
0.5598
✗
✗
✓
✗
0.3416
0.3609
✗
✗
✗
✓
0.3267
0.3909
TABLE XIV: revisionAblation study of the composite objective components for ImageBind on the ImageNet dataset.
Cons. Score
Colla. Score
Average highest confidence ( ↑ )
Insertion ( ↑ )
(Equation 3 )
(Equation 4 )
(0-25%)
(0-50%)
(0-75%)
(0-100%)
✗
✓
0.0821
0.3075
0.5869
0.6113
0.2691
✓
✗
0.5033
0.6087
0.6183
0.6392
0.2949
✓
✓
0.5351
0.6816
0.7445
0.7557
0.4681
TABLE XV: Ablation study of the composite objective components for incorrectly predicted samples using ImageBind on ImageNet.
Strategies
μ Fidelity ( ↑ )
CLIP (ViT-L)
ImageBind (Huge)
LanguageBind (Large)
Consistent subset difference
0.3208
0.3378
0.3889
Importance Assessment
0.3334
0.3551
0.4096
TABLE XVI: Ablation study on importance assessment for ImageBind on the ImageNet dataset.
Fig. 10: An example of attribution results. A. Search region at the Insertion curve inflection point. B. Visualization using our strategy. C. Visualization using the baseline.
Sub-region Number ∣V∣
Deletion ( ↓ )
Insertion ( ↑ )
μ Fidelity
Execution time (s)
49
0.1280
0.7463
0.3551
20
64
0.1230
0.7506
0.3473
39
77
0.1216
0.7532
0.3407
59
100
0.1199
0.7492
0.3291
158
TABLE XVII: Ablation study on the effect of sub-region division number ∣V∣ for ImageBind on the ImageNet dataset.
Sub-region Number ∣V∣
Average highest confidence ( ↑ )
Insertion ( ↑ )
(0-25%)
(0-50%)
(0-75%)
(0-100%)
49
0.5351
0.6816
0.7445
0.7557
0.4681
64
0.5579
0.7100
0.7689
0.7803
0.4934
77
0.5731
0.7194
0.7765
0.7884
0.5004
100
0.5987
0.7418
0.7958
0.8100
0.5144
121
0.6167
0.7599
0.8094
0.8247
0.5285
TABLE XVIII: Ablation study on the effect of sub-region division number ∣V∣ in incorrect sample attribution for ImageBind on the ImageNet dataset.
Fig. 11: Additional attribution visualizations for different multimodal foundation models on the ImageNet dataset.
Fig. 12: Additional interpretation visualization for CLIP (ResNet-101) on the ImageNet dataset.
Fig. 13: Additional interpretation visualization for single-modal ResNet-101 on the ImageNet dataset.
Fig. 14: Additional interpretation visualization for single-modal vision transformer (Large) and swin-transformer (Large) on the ImageNet dataset.
Fig. 15: Additional interpretation visualization for single-modal vision mamba (base) and mambavision (L2) on the ImageNet dataset.
Fig. 16: Visualization of failure attribution on the CUB-200-2011 dataset. The first row shows the results of HSIC-Attribution and the previous version, and the second row shows the current method. The insertion curve reports the relationship between progressively revealed regions and the ground-truth response. The highlighted prefix provides model-level evidence associated with prediction reversal under this intervention; the visualization is not interpreted as formal causal identification.
Fig. 17: Visualization of failure attribution on the CUB-200-2011 dataset across different recognition models. The insertion curve reports the relationship between progressively revealed regions and the ground-truth response. The highlighted prefix provides model-level evidence associated with prediction reversal under this intervention; the visualization is not interpreted as formal causal identification.
Fig. 18: Controlled analysis of SLICO- and SAM-based sub-regions. A. oversized or decision-heterogeneous SAM masks delay recognition. B. boundary-aligned SAM masks isolate the object or its discriminative parts more effectively than low-level superpixels.
School of Cyber Science and Technology, Sun Yat-Sen University, Guangdong Province, China · Institute of Perception, PC Laboratory, Guangdong Province, China · University of Chinese Academy of Sciences, Beijing, China +3