Relational out-of-distribution errors are easy to describe and hard to evaluate cleanly. An image may be natural, a caption may be fluent, and all mentioned objects may be common, yet the caption may describe the wrong relation in the image. Many evaluations intended to test this behavior can be solved without checking the pairing at all, because negatives differ in caption style, template, length, object frequency, or image statistics. We propose counterfactual pairing cycles, a blocked evaluation primitive that reuses the same two images and the same two captions on both sides of the comparison, changing only which image is paired with which caption. This makes image-only, text-only, and additive component shortcuts cancel exactly in finite samples. The same contrast also gives a training loss for relational outlier exposure and a diagnostic for bilinear vision-language scores. Across synthetic controls, GQA, and COCO, cycles separate coarse image-caption matching from directional role-binding failures, while also identifying geometric size relations that remain strongly visible in global features. In a shortcut-contaminated COCO outlier-exposure stress test, a model selected by a near-perfect shortcut validation AUROC retains substantial relational signal but remains below cycle training on exact cycles; cycle training improves CycleAcc from 0.882 to 0.927. The main lesson is simple: to test whether a model understands a pairing, the benchmark should keep the parts fixed, change the pairing, and ask only about coupling. The official implementation is available online.
Figures & tables
Table 1: Synthetic controls. AUROC is reported for these unblocked two-sample diagnostics. The vertical tick in each mini-bar marks chance.
Split group
Additive audit
Interaction scores
Reading
GQA scene-graph cycles
Attribute / caption mismatch
0.500±0.000
0.594 – 0.954
Attribute coupling varies across families and can be strong.
Relation / object swaps
0.500±0.000
0.500 – 0.835
Performance ranges from chance to substantial relation signal.
COCO raw-image cycles
Coarse coupling
0.500±0.000
0.997 – 1.000
Coarse image-caption matching is easy.
Matched / neighbor hard
0.500±0.000
0.941 – 0.987
Coarse object signal remains strong.
Table 2: Exact-cycle diagnostics on GQA and COCO. Values are exact CycleAcc. Additive probes are implementation consistency checks. For COCO, the interaction ranges are zero-shot CLIP cosine ranges only; trained bilinear and low-rank bilinear probes are reported separately. For GQA, the interaction ranges summarize the evaluated diagonal, full-bilinear, and rank-64 probes. The GQA binding family is omitted because it yields only 18–19 validation cycles per seed, below the prespecified minimum of 30.
Figure 1: Strict COCO relation cycles separate directional role binding from recoverable geometric cues. Left/right remains near chance, while size is strongly exposed and above/below and same-pair relation changes retain moderate trained-probe signal.
Split
Rank 1
Rank 4
Rank 16
Rank 64
Object-matched COCO
0.784±0.018
0.905±0.011
0.936±0.009
0.959±0.001
Text-neighbor hard
0.720±0.020
0.797±0.026
0.858±0.018
0.888±0.006
Box left/right
0.707±0.029
0.812±0.005
0.843±0.005
0.858±0.019
Strict present left/right
0.514±0.014
0.518±0.017
0.489±0.025
0.505±0.036
Strict same-pair relation diff.
0.567±0.019
0.614±0.020
0.587±0.023
0.599±0.016
Strict size
0.687±0.023
0.745±0.014
0.796±0.014
0.787±0.010
Table 3: Low-rank bilinear probes. Values are CycleAcc . Rank helps for recoverable interactions but does not rescue strict present left/right.
Figure 2: Rank sweeps characterize recoverability within the evaluated bilinear probe class. Some interactions improve with rank, while strict present left/right remains near chance.
Table 5: Exact cycle-construction audits. All accepted validation cycles have exact marginal balance and no validity violations. GQA binding is not reported because it does not satisfy the minimum-cycle requirement.
Dataset
Family
Train
Validation
Test
COCO
All reported families except strict same-pair
3000
500
1000
COCO
Strict same-pair
3000
466
1000
GQA
AD, CD, SR, RS, OP, OO, SS
3000
500
1000
GQA
BS binding
732–772
18–19
155–174
Appendix
Table 6: Cycle counts and image pools. Counts are reported as train/validation/test cycles. COCO train and validation cycles are constructed from image-disjoint subsets of the COCO train2017 pool, while test cycles use the separate COCO val2017 pool. GQA uses an image-disjoint 60/10/30 split.
Seed
Cycle OE
Shortcut OE
Difference
0
0.919
0.884
+0.035
1
0.934
0.880
+0.054
2
0.928
0.881
+0.047
Mean
0.9270
0.8817
+0.0453
Std.
0.0075
0.0021
0.0096
Appendix
Table 7: Per-seed Shortcut OE results. Differences are computed as Cycle OE minus Shortcut OE. Means and standard deviations are computed across seeds 0 , 1 , and 2 .
Control score
Exact CycleAcc
Text-only score
0.5000
Image-only score
0.5000
Additive image-plus-text score
0.5000
Appendix
Table 8: Additive and unimodal controls under exact CycleAcc. Every control produces tied cycle contrasts and therefore receives exactly half credit on every cycle.
Counterfactual evaluation of vision-language models tests whether their answers change appropriately when relevant visual evidence is minimally altered.