ValueGraph: Value-Signal Guided Graph Pre-training for Contextualized User Representation
Authors: Yitong Han, Wei Gao, Yi Zhao, Prasanta Bhattacharya, Fengzhu Zeng, Mohammad Amanlou
Organizations: School of Computing and Information Systems, Singapore Management University, Singapore · Institute of Advanced Intelligence and Computing, A*STAR, Singapore
Value signals are aggregated user-level moral representations that capture users' inferred value-related tendencies from their online discourse. User behavior on social media is shaped not only by what users say or whom they interact with, but also by the value signal through which they express attitudes. Existing user representation methods largely miss this value-relevant dimension. We propose ValueGraph, a graph pre-training framework that uses automatically inferred moral-value signals as noisy auxiliary signals for contextualized user representation. From post-reply graphs, ValueGraph learns semantic and structural representations and further aligns users through relative value similarity with contrastive and clustering objectives. Rather than treating inferred values as gold psychological labels, ValueGraph uses them as soft constraints for representation learning. Experiments on stance detection and twitter bot detection show consistent gains over strong text-based, graph-based, and text-only LLM baselines, highlighting value-signal guidance as a useful inductive bias for socially informed user modeling.
Figures & tables
Figure 1: The framework of ValueGraph . In Stage 1, we construct a post-reply graph and perform GraphMAE2-based unsupervised pre-training to learn contextualized post representations by jointly modeling semantic and structural information. The resulting post embeddings are aggregated into user representations. In Stage 2, we introduce moral value signals extracted by MoralBERT and optimize user representations through value-guided contrastive learning and clustering objectives. The learned user representations are then used for downstream fine-tuning on stance detection and Twitter bot detection.
LLM
Graph Pre-training
PLM
GNN
ValueGraph
Model
Dataset
Metric
GPT-5.4
GraphCL
GraphMAE2
SimCSE
ModernBERT
Bertweet
GCN
GAT
GTN
GLAN
MT_CSD
Acc.
0.58
0.41
0.60
0.60
0.56
0.58
0.40
0.42
0.57
0.63 ∗
MacF1
0.56
0.38
0.55
0.56
0.53
0.51
0.35
0.33
0.56
0.58
BrLSTM
RumourEval19
Acc.
0.73
0.59
0.67
0.74
0.74
0.65
0.61
0.31
0.71
0.77 ∗
MacF1
0.47
0.38
0.47
0.53
0.59
0.56
0.25
0.18
0.45
0.71 ∗
Table 1: Stance detection results on MT_CSD and RumourEval19. ∗ indicates statistical significance at 99% confidence level compared with the second-best performance based on two-tailed paired Student’s t -test.
Method
Setting
Type
Accuracy
MacF1
Precision
Recall
MCC
GPT-5.4
Text-only
T
56.9 (±0.1)
52.1 (±0.1)
57.1 (±0.1)
54.9 (±0.1)
11.8 (±0.1)
RoBERTa
Baseline
T
50.7 (±0.2)
54.8 (±0.5)
48.8 (±0.1)
62.5 (±1.2)
–
ValueGraph
T
56.9 (±0.6) ∗ ∗
64.3 (±0.4) ∗ ∗
53.3 (±0.6) ∗ ∗
81.0 (±2.3) ∗
–
Baseline
UT
63.1 (±0.5)
66.2 (±0.5)
58.9 (±0.5)
75.6 (±1.4)
–
ValueGraph
UT
65.9 (±0.3) ∗ ∗
68.9 (±2.4) ∗
61.2 (±0.6)
78.7 (±1.8) ∗
–
BotGCN (T5)
Baseline
TG
56.8 (±6.0)
64.4 (±1.3)
53.7 (±5.1)
82.1 (±8.1)
17.9 (±9.7)
Table 2: Comparison of text-only GPT-5.4, baseline embeddings, and ValueGraph embeddings for twitter bot detection. * and ** indicate statistical significance at 95% and 99% confidence levels, respectively, based on two-tailed paired Student’s t -test between ValueGraph and the corresponding baseline embedding.
Figure 2: t-SNE visualization of user embeddings for Twitter bot detection. Red and grey dots represent ground-truth human and bot users, respectively.
Task
Model/data
Configuration
Accuracy
MacF1
Stance
GLAN (MT_CSD)
Only Stage 1
41.2
40.7
Stage 1 + Lcls
50.4
34.3
Stage 1 + Luser
45.3
32.6
Full
63.0
58.0
BrLSTM (RumourEval19)
Only Stage 1
53.7
55.8
Stage 1 + Lcls
62.7
52.8
Table 3: Ablation results of ValueGraph embeddings under different training settings across stance detection and Twitter bot detection tasks. For Twitter bot detection, BotGAT is evaluated in the FTUG setting.
Appendix figures & tables10 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 3: Distribution of RBF-based similarities for 100,000 randomly sampled user pairs.
Figure 4: Hyperparameter configurations used in ValueGraph training. All settings use temperature τ=0.07 , margin coefficient β=0.5 , margin m=1 , and clustering loss weight λcluster=0.05 . The three configurations vary in the number of augmented users k and the number of clusters K .
Subreddit
Comments
Politics
5,626,191
Neoliberal
2,315,326
Relationship Advice
861,704
Confession
477,353
Conservative
165,182
Worldnews
100,194
Appendix
Table 4: Statistics of the Reddit pre-training corpus.
Dataset
Posts
BEARD ( Zeng and Gao 2022 )
3,393,578
Twitter-Covid ( Lin et al. 2022 )
474,710
PHEME ( Zubiaga et al. 2016 )
59,387
Twitter16 ( Ma et al. 2016 )
1,101,985
Total
5,029,660
Appendix
Table 5: Statistics of the Twitter pre-training corpus.
Split
Label
Count
Train
Against
3,349
Favor
2,383
None
5,441
Valid
Against
710
Favor
481
None
1,115
Appendix
Table 6: Statistics for MT_CSD dataset
Split
Label
Count
Train
Comment
2,734
Deny
333
Query
330
Support
841
Dev
Comment
173
Deny
11
Appendix
Table 7: Statistics for RumourEval19
Useed+←⋃u∈Useed(u~∼kS(u)∪u^∼kD(u))
Appendix
Algorithm 1 ValueGraph Training
Model
Hidden Dim
Learning Rate
Weight Decay
Dropout
Batch Size
Max Epoch
GLAN (MT_CSD)
512
1e-5
1e-4
0.2
32
100
BrLSTM (RumourEval19)
300
1e-4
1e-4
0.5
16
100
Appendix
Table 8: Hyperparameter settings for stance detection models.
Model
Hidden Dim
Learning Rate
Weight Decay
Dropout
Batch Size
Max Epoch
RoBERTa (T)
128
1e-4
1e-5
0.5
96
60
RoBERTa (T,U)
128
1e-4
1e-5
0.5
96
60
BotRGCN (T,G)
256
5e-4
5e-5
0.5
128
300
BotRGCN (F,T,U,G)
128
5e-4
1e-3
0.3
128
300
GAT (T,G)
96
2e-4
5e-5
0.5
128
300
GAT (F,T,U,G)
96
2e-4
5e-5
0.5
256
300
Appendix
Table 9: Hyperparameter settings for Twitter bot detection models.
Task
Model/dataset
Configuration
Accuracy
F1-score
Stance Detection
GLAN (MT_CSD)
Only Stage 1
41.2
40.7
Stage 1 + Lcls
50.4
34.3
Stage 1 + Luser
45.3
32.6
Full
63.0
58.0
BrLSTM (RumourEval19)
Only Stage 1
53.7
55.8
Stage 1 + Lcls
62.7
52.8
Appendix
Table 10: Ablation results under different training configurations across two tasks: stance detection and Twitter bot detection. For Twitter bot detection, RoBERTa is evaluated in the UT setting, while BotGAT, BotGCN, and BotRGCN are evaluated in the FTUG setting.