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A Matter of Time: Revealing the Structure of Time in Vision-Language Models

Nidham Tekaya, Manuela Waldner, Matthias Zeppelzauer

TL;DR

This work investigates whether large vision-language models implicitly encode temporal information about objects and events. It introduces TIME10k, a temporally annotated image dataset, and a three-pronged framework to probe time, analyze embedding-space structure, and model an explicit timeline from VLM embeddings. The authors demonstrate that temporal information lies on a low-dimensional, non-linear manifold and present two timeline extraction methods—UMAP-based projection and Bézier-curve representation—achieving competitive or superior accuracy with improved efficiency compared to prompt-based baselines. The findings highlight the potential for rapid, scalable temporal reasoning in multimodal models and suggest broader implications for ordinal reasoning tasks in AI.

Abstract

Large-scale vision-language models (VLMs) such as CLIP have gained popularity for their generalizable and expressive multimodal representations. By leveraging large-scale training data with diverse textual metadata, VLMs acquire open-vocabulary capabilities, solving tasks beyond their training scope. This paper investigates the temporal awareness of VLMs, assessing their ability to position visual content in time. We introduce TIME10k, a benchmark dataset of over 10,000 images with temporal ground truth, and evaluate the time-awareness of 37 VLMs by a novel methodology. Our investigation reveals that temporal information is structured along a low-dimensional, non-linear manifold in the VLM embedding space. Based on this insight, we propose methods to derive an explicit ``timeline'' representation from the embedding space. These representations model time and its chronological progression and thereby facilitate temporal reasoning tasks. Our timeline approaches achieve competitive to superior accuracy compared to a prompt-based baseline while being computationally efficient. All code and data are available at https://tekayanidham.github.io/timeline-page/.

A Matter of Time: Revealing the Structure of Time in Vision-Language Models

TL;DR

This work investigates whether large vision-language models implicitly encode temporal information about objects and events. It introduces TIME10k, a temporally annotated image dataset, and a three-pronged framework to probe time, analyze embedding-space structure, and model an explicit timeline from VLM embeddings. The authors demonstrate that temporal information lies on a low-dimensional, non-linear manifold and present two timeline extraction methods—UMAP-based projection and Bézier-curve representation—achieving competitive or superior accuracy with improved efficiency compared to prompt-based baselines. The findings highlight the potential for rapid, scalable temporal reasoning in multimodal models and suggest broader implications for ordinal reasoning tasks in AI.

Abstract

Large-scale vision-language models (VLMs) such as CLIP have gained popularity for their generalizable and expressive multimodal representations. By leveraging large-scale training data with diverse textual metadata, VLMs acquire open-vocabulary capabilities, solving tasks beyond their training scope. This paper investigates the temporal awareness of VLMs, assessing their ability to position visual content in time. We introduce TIME10k, a benchmark dataset of over 10,000 images with temporal ground truth, and evaluate the time-awareness of 37 VLMs by a novel methodology. Our investigation reveals that temporal information is structured along a low-dimensional, non-linear manifold in the VLM embedding space. Based on this insight, we propose methods to derive an explicit ``timeline'' representation from the embedding space. These representations model time and its chronological progression and thereby facilitate temporal reasoning tasks. Our timeline approaches achieve competitive to superior accuracy compared to a prompt-based baseline while being computationally efficient. All code and data are available at https://tekayanidham.github.io/timeline-page/.
Paper Structure (25 sections, 5 equations, 5 figures, 5 tables)

This paper contains 25 sections, 5 equations, 5 figures, 5 tables.

Figures (5)

  • Figure 1: Time probing: temporal inference via dot-product similarity. Time embeddings (here for years 1700-2024) are compared with image embeddings. The time embedding with the highest similarity indicates the year of first appearance.
  • Figure 2: Left: The highest score (rank 1) is most often the correct year, followed by the second highest year (rank 2) etc. Right: Ground truth (red diagonal) vs. predicted year for highest (blue) and second-highest (orange) score. Vertical dotted lines represent their difference, which are mostly small.
  • Figure 3: 3D KPCA projection of CLIP time and image embeddings.
  • Figure 4: Fitting a Bézier curve to the time embeddings from CLIP in a 3D projection space. (a) Time embeddings coloured by year with selected control points marked with diamonds. (b) Fitting the Bézier curve. (c) Mapping points to the Bézier curve to obtain a 1D timeline representation.
  • Figure 5: MAE per dimension for (EVA-)CLIP using KPCA.