We evaluate the performance of Vision Language Models in Visual Question Answering (VQA) when questions violate Grice's maxims. To do this, we use VLMs to generate question modifiers that add non-essential, ambiguous or false information and show that in the presence of such violations, the VLMs that we evaluate (ChatGPT, Claude, Gemini and Llava) show diminished performance. Further, we empirically show the difference between how humans reason pragmatically compared to VLMs, and the difference in VLM reasoning when it resolves violations that are human-induced compared to those that are AI-generated. Finally, we show that human cognitive effort (measured through time-on-task in an experiment) is lower for resolving VLM-induced violations, but VLMs themselves perform less accurately in such cases.
Figures & tables
Figure 1: Illustrating violations of Grice’s maxims in VQA
Figure 2: Illustration of the evaluation process. A VLM modifies the question which is verified by a human. A VLM answers the original and modified questions and a human compares their responses. For all the human tasks, we used Amazon Mechanical Turk (paid workers between 5−10 cents per individual response depending on the task complexity.)
Response-Model / Modification-Model
GPT
Gemini
Claude
LLava
Average±std
GPT
-3.13%
38.08%
2.97%
12.10%
12.51±18.16%
Gemini
10.05%
8.60%
9.07%
12.50%
10.06±1.74%
Claude
2.65%
2.72%
2.43%
11.48%
4.82±4.44%
Llava
15.56%
9.50%
10.51%
17.56%
13.28±3.89%
Average±std
6.28±8.21 %
14.73±15.86%
6.25±4.14%
13.41±2.80%
Table 1: % decrease in response accuracy for modified questions compared to original questions for binary and quantitative responses (smaller is better). Rows indicate the VLM providing the response and columns the VLM performing the modification.
Response-Model / Modification-Model
GPT
Gemini
Claude
LLava
Statistic
P-value
Statistic
P-value
Statistic
P-value
Statistic
P-value
GPT
4.84
0.028
15.05
0.00
3.45
0.063
9.25
0.002
Gemini
13.78
0.00
9.84
0.002
11.22
0.001
9.25
0.002
Claude
1.66
0.197
1.515
0.218
1.80
0.18
8.89
0.003
Llava
27.50
0.00
14.45
0.00
20.57
0.00
15.29
0.00
Table 2: Mcnemar’s test for assessing significance of the modifiers added to binary and quantitative questions.
Response-Model / Modification-Model
GPT-4o
Gemini-1.5-Flash
Claude-3.5-Sonnet
LLava-7B
Average±std
GPT4o
7.68%
15.55%
12.32%
15.96%
12.88±3.32 %
Gemini
16.15%
18.46%
16.15%
20.0%
17.69±1.63%
Claude
21.53%
20.76 %
13.07%
16.92%
18.07±3.37 %
Llava
25.38%
20.00%
20.00%
18.46%
20.96±2.63 %
Average±std
17.69±6.64 %
18.69±1.99 %
15.39±3.03 %
17.84±1.54 %
Table 3: Comparing open-ended responses before and after modifications. The % of questions where human users in AMT chose that the response after modification is worse than the response before modification (for each question, we have 3 workers and we use the majority choice).
Figure 3: Comparing the % of questions where the response to a question is unchanged after a hallucinated modifier is added. Results shown for binary and quantitative response types. The y-axis shows the average (and standard deviation) over 4 hallucinated modifications each added using one of the VLMs (graph created with Claude).
Response Type
GPT
Gemini
Claude
Llava
Binary & Quantitative
83.53%
80.83%
83.87%
77.44%
Open-ended
0.874
0.864
0.864
0.865
Table 4: Comparing VLM and human pragmatic reasoning. For binary & quantitative responses, we show the % of cases where the VLM and human answers match for hallucinated modifications. For open-ended responses, we show the BERTScore (F1-score) between human and VLM responses.
Human Response
GPT
Gemini
Claude
LLava
Negative Response
88.79%
89.47%
92.44%
86.14%
Positive Response
62.79%
48.35%
51.11%
45.05%
Table 5: Comparing binary responses of humans with VLMs. We show the % of VLM responses aligned with the positive and negative responses of humans.
Figure 4: Comparing the accuracy of models on the original questions, questions modified by humans, and questions modified by VLMs (the average accuracy and standard deviation is shown in this case since we have modifications by 4 models). Results shown for binary responses (graph created with Claude).
Figure 5: Comparing open-ended responses of models using human evaluation. Results show the % of cases where AMT-workers chose that the model’s response to the AI-modified question was worse than its response for the human-modified question (graph created with Claude).
Response Type
Human
GPT
Gemini
Claude
LLava
Binary & Quantitative
0.612
0.641
0.658
0.639
0.670
Open-ended
0.645
0.657
0.644
0.654
0.675
Table 6: CLIPScores of human and AI modifications
Figure 6: Distribution of time-on-task in seconds measured for the experiment where AMT workers were asked to answer modified questions and reflect on the modification by simplifying the question. Results are shown for human and AI (VLMs) modified questions (graph created with ChatGPT).
Question Type
#Questions
Is the
75
Is this
24
Are the
24
Is there a
18
Is this a
24
Is the girl
13
Table 7: Total number of Open-ended-response questions types to evaluate VLM accuracy.
Question Type
#Questions
What
351
Which
21
Who
38
Why
41
Where
63
Table 8: Total number of Open-ended-response questions types to evaluate VLM accuracy.
Question Type
#Questions
Is the
10
Is this
57
Are the
25
Is there a
54
Is this a
41
Is the girl
1
Table 9: Total number of binary-response and quantitative-response question types in the dataset used for comparing human and AI modifications.
Question Type
#Questions
Which
41
Who
16
Why
20
Where
51
Table 10: Total number of Open-ended-response questions types in the dataset used for comparing human and AI modifications.
Figure 7: AMT Task for verifying if humans can pragmatically infer VLM-modified questions. If they choose that the modification is correct, they need to demonstrate their understanding of the question by answering a sub-question based on the salient object in the question.
Figure 8: AMT Task for verifying if humans can pragmatically infer VLM-modified questions. If they choose that the modification is incorrect, then they need to correct the modification using a textbox as shown in the example.
Figure 9: AMT Task for evaluating open-ended VLM responses by comparing answers to original and modified questions.
Figure 10: AMT design to measure time-on-task for humans to answer a modified question and to reflect on the answer by simplifying the question.
Figure 11: Examples showing human and VLM responses on hallucinated modifications
Figure 12: Examples showing human and VLM responses on human and VLM modifications
Vision-language model evaluation measures multimodal systems’ perception, reasoning, grounding, robustness, and reliability across controlled and real-world tasks.