Summary
This paper proposes UniKE, a novel multimodal editing method that establishes a unified perspective for intrinsic knowledge editing and external knowledge resorting. On this basis, the authors combine both types of knowledge editing methods, executing them in the latent space with a unified paradigm. Furthermore, this paper proposes to disentangle the knowledge representations into the semantic and truthfulness spaces, effectively enhancing the collaboration between intrinsic knowledge and external knowledge resorting. Extensive experimental results show that UniKE achieves promising results under various settings, ensuring that the post-edit MLLM maintains excellent reliability, generality, and locality.
Strengths
(1) I think knowledge editing for MLLMs is a relatively new topic. Previously, a few studies merely adapted existing knowledge editing methods from the NLP field into multimodal domain. To the best of my knowledge, this paper is the first to conduct a detailed and systematic analysis of the strengths and weaknesses of existing methods when applied to editing multimodal LLMs.
(2) The proposed method is very novel and effective. Previous efforts in knowledge editing show significant differences between intrinsic knowledge editing methods and external knowledge resorting methods. In this work, the authors ingeniously convert in-context editing into the format of feature shifting, achieving a unification of the editing paradigms that can operate simultaneously within the same transformer layer with synergistic correlation. I find this to be a very inspiring design. Moreover, the design of knowledge collaboration is closely integrated with this unified paradigm.
(3) The experiments are very solid and thorough, clearly demonstrating that UniKE effectively addresses multimodal knowledge editing tasks under various setups. Meanwhile, the authors have also provided the implementation code for the experiments.
(4) I commend the authors for conducting an extensive set of ablations and analyses, which are very helpful in understanding the impact of each component within UniKE.
(5) Additionally, I believe that the method proposed by the authors is not only applicable to knowledge editing tasks. By converting in-context learning into the representation space and avoiding the need to increase the context window space, it better synergizes with parameter update learning. I consider this to have significant implications for further studies on how to construct more powerful MLLMs.
Weaknesses
(1) In the NLP community, some studies will discuss the resilience to overediting [1] of knowledge editing methods by adopting the contrastive knowledge assessment [2] (CKA). Unlike the locality property that measures whether LLMs forget previous knowledge, overediting can be understood as excessive generalized to seemingly similar but unrelated samples. Although there may be no current work on multimodal editing that discusses the phenomenon of overediting, I encourage authors to add relevant experiments for a straightforward comparison of the resilience to overediting among each method (UniKE, MEND, T-Patcher, and IKE).
(2) A more challenging task of knowledge editing is counterfactual editing, where the edited answer $y$ to the question $x$ can sometimes be counterfactual to the real world. A typical counterfactual editing dataset in the NLP community is called COUNTERFACT [3], which more accurately reflects the true effectiveness of knowledge editing methods by avoiding the effects of LLMs knowing this knowledge before editing. I encourage authors to construct multimodal counterfactual editing datasets and conduct more experiments to verify whether UniKE performs better in counterfactual editing scenarios compared to MEND, T-Patcher and IKE.
[1] Zheng, Ce, et al. "Can we edit factual knowledge by in-context learning?." arXiv preprint arXiv:2305.12740 (2023).
[2] Dong, Qingxiu, et al. "Calibrating factual knowledge in pretrained language models." arXiv preprint arXiv:2210.03329 (2022).
[3] Meng, Kevin, et al. "Locating and editing factual associations in GPT." Advances in Neural Information Processing Systems 35 (2022): 17359-17372.
Questions
See the weaknesses.
Limitations
The authors have adequately discussed the limitations and potential negative societal impact.