Large language models have shown strong potential as role-playing agents for real individuals, yet faithful impersonating remains challenging. Existing in-context learning-based methods fail to capture how individuals react under different situations. In addition, LLM-based evaluation is difficult for obscure individuals. To address these challenges, we propose Situation--Internal state--Behavior Persona method to incorporate situation-dependent behavioral strategies. We further design an evaluation protocol that provides LLM evaluators with references about the impersonated individual. We evaluate our approach on a newly constructed dataset for the task of generating replies on social media. Experimental results show that our proposed method outperforms state-of-the-art ICL-based baselines, while our evaluation protocol achieves moderate correlation with human judgment. Besides, experiments on fictional-character benchmarks demonstrate that our proposed method is applicable beyond the social media setting. These findings suggest that incorporating behavioral information broadly improves the fidelity of role-playing for real individuals on social media or fictional characters.
Figures & tables
Figure 1: In the social media comment-replying scenarios between influencers and followers, replies involve short texts where behavioral strategy is more important for determining the fidelity of impersonation.
Dataset
Public
Identifiable Individual History
#Individual
Comment- Reply Structure
Avg. Posts per Individual
Avg. Comment-Reply Pairs per Individual
Max Posts per Individual
Max Comment-Reply Pairs per Individual
BuzzFace Santia and Williams (2018)
✗
-
-
-
-
-
-
-
TWON Münker et al. (2026)
✗
-
-
-
-
-
-
-
BluePrint Bück-Kaeffer et al. (2025)
✓
✗
-
-
-
-
-
-
SYNTHIA Rahimzadeh et al. (2026)
✓
✗
-
-
-
-
-
-
PersonalDialog Zheng et al. (2019)
✓
✗
-
-
-
-
-
-
Persona-Chat Zhang et al. (2018)
✓
✗
-
-
-
-
-
-
Table 1: Feasibility of existing datasets for studying role-playing of real individuals on social media reply generation. ”-” indicates that the corresponding information is not applicable under our comparison criteria. Since our research goal is to impersonate influencers across diverse interaction situations, we construct a dataset centered on a small number of influencers with rich historical interactions.
Figure 2: Overview of the SIBPersona method. The upper part illustrates the process of extracting data-variant persona from historical data. The lower part presents reply generation process: retrieving the most relevant dimensional documents based on the comment enables the RPA to generate a high-fidelity reply.
Methods
GPT-5.2
Gemini-3-flash
DeepSeek-V3.2
Claude-Opus-4.6
Average
M
T
RP
M
T
RP
M
T
RP
M
T
RP
M
T
RP
Naive
97.50
46.40 ‡
67.53 ‡
94.70
42.47 ‡
69.27 ‡
95.13
48.93 ‡
70.83 ‡
96.77
46.93 ‡
76.87 ‡
96.03
46.18 ‡
70.78 ‡
CoT
97.47
44.93 ‡
70.73 ‡
95.83
41.17 ‡
69.53 ‡
96.27
49.23 ‡
71.47 ‡
97.33
47.00
77.33 ‡
96.73
45.58 ‡
72.27 ‡
IMPersona
96.07
47.50 ‡
71.93 ‡
94.90
44.60 ‡
70.10 ‡
96.00
50.80 ‡
72.50 ‡
97.43
48.67 ‡
78.13 ‡
96.10
47.89 ‡
73.17 ‡
Vanilla RAG
97.33
49.43 ‡
73.20 ‡
93.77
53.20
71.50 ‡
94.23
58.37 ‡
73.43
96.70
56.93
77.70 ‡
95.51
54.48 ‡
73.96 ‡
SIBPersona
96.90
54.33
77.63
93.77
56.47
75.50
94.83
63.67
76.43
96.93
62.77
81.93
95.61
59.31
77.88
Table 2: Performance on Influencer A . Bold : the best results; ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Methods
Deepseek-V3.2
Gemini-3-flash
M
T
RP
M
T
RP
Naive
92.10 ± 3.04
42.03 ‡ ± 8.43
68.48 ‡ ± 5.86
92.50 ± 2.32
43.33 ‡ ± 7.35
70.64 ‡ ± 7.37
CoT
92.17 ± 3.03
43.92 ‡ ± 8.13
69.83 ‡ ± 6.14
92.15 ± 2.54
44.05 ‡ ± 7.08
70.48 ‡ ± 6.40
IMPersona
91.60 ± 2.21
45.54 ‡ ± 5.86
71.14 ‡ ± 6.02
91.42 ± 1.94
45.21 ‡ ± 6.40
71.56 ‡ ± 7.19
Vanilla RAG
91.39 ± 3.23
57.05 ‡ ± 2.43
72.43 ‡ ± 5.06
92.19 ± 2.46
53.43 ‡ ± 4.92
72.59 ‡ ± 4.79
SIBPersona
92.14 ± 3.26
61.09 ± 1.66
75.84 ± 4.90
92.21 ± 2.20
57.34 ± 3.20
76.48 ± 5.08
Table 3: Results on other five influencers. Bold indicates the better scores. ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Methods
M
T
RP
SIBPersona
92.67 ± 3.18
61.60 ± 1.82
75.96 ± 4.49
w/o I
92.61 ± 2.49
60.30 ± 2.37
75.44 ± 3.61
w/o RP
92.83 ± 2.44
57.82 ‡ ± 2.51
73.36 ‡ ± 4.64
Table 4: Dimension ablation study using DeepSeek-V3.2 on the six influencer. Bold : the best results; ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Methods
M
T
RP
Avg.
IMPersona
2.92 ‡
2.40 ‡
2.67 ‡
2.67 ‡
Vanilla RAG
3.68
3.72
3.62
3.67
SIBPersona
3.78
3.64
3.62
3.68
Table 5: Human evaluation results comparing our framework with the baseline. Bold : better results; ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Conditions
M
T
RP
Uninterpretable
3.03
3.00
2.87
Interpretable
4.13 †
3.97 †
4.00 †
Table 6: Human evaluation scores for Interpretable (n=20) and Uninterpretable (n=10) groups. Bold : better results; † : significant improvement with p<0.05 .
Methods
CA
RA
CK
CP
IMPersona
2.94
2.43
2.25
2.38
SIBPersona
3.28 †
2.66 †
2.32 †
2.69 †
Fine-tuned CoSER
3.35
2.61
2.28
2.68
Table 7: Results on CharacterEval. CA : Conversational Ability, RA : Role-Playing Attractiveness, CK : Character Consistency–Knowledge, and CP : Character Consistency–Persona. Bold : the best results; † : significant improvement with p<0.05 .
Methods
CA
RA
CK
CP
SIBPersona
3.28
2.66
2.32
2.69
w/o T
3.33
2.69
2.31
2.74
w/o I
3.28
2.66
2.31
2.68
w/o RP
3.16 ‡
2.61
2.30
2.62 ‡
w/o RP & T
3.05 ‡
2.54 ‡
2.28
2.57 ‡
Table 8: Component ablation study on CharacterEval. Bold : the best results; ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Appendix figures & tables36 assets
Supplementary material from the paper’s appendix.
Appendix
Influencer
Persona Score
A
B
C
D
E
F
High
50
50
50
35
50
9
Medium
50
50
50
50
22
39
Low
50
50
50
50
12
50
Appendix
Table 9: Number of data in the test samples.
Influencer
Post Length
Comment Length
Reply Length
High (%)
Med (%)
Low (%)
A
467.92 ± 471.09
17.58 ± 25.37
8.46 ± 9.69
13%
29%
58%
B
367.39 ± 231.62
30.70 ± 57.55
10.01 ± 10.54
12%
35%
53%
C
952.74 ± 740.92
66.83 ± 105.54
33.65 ± 28.14
34%
36%
53%
D
355.21 ± 508.89
14.20 ± 15.24
9.56 ± 10.17
16%
25%
59%
E
271.65 ± 221.00
27.54 ± 28.06
9.52 ± 10.21
5%
8%
87%
F
860.21 ± 574.41
26.53 ± 29.41
11.82 ± 10.39
8%
33%
60%
Appendix
Table 10: Dataset diversity statistics across the six influencers, including text lengths and the proportion of comment–reply pairs across high, medium, and low persona-score levels.
Models
M
T
RP
GPT-5.2
6,064
1,410
970
Gemini-3-flash
5,755
1,050
861
Deepseek-V3.2
5,143
1,022
749
Claude-Opus-4.6
2,307
407
703
Appendix
Table 11: Number of dimensional documents of Influencer A .
Influencer
M
T
RP
B
12,358
8,162
6,701
C
6,179
2,982
4,049
D
8,914
4,935
3,811
E
10,087
2,393
2,378
F
2,587
446
398
Appendix
Table 12: Number of dimensional documents of Influencer B-F extracted from Deepseek V3.2 .
Influencer
M
T
RP
B
13360
8253
6911
C
5296
3321
3643
D
10102
4839
4053
E
10309
3536
3287
F
2363
515
449
Appendix
Table 13: Number of dimensional documents of Influencer B-F extracted from Gemini-3-flash .
Figure 3: t-SNE projection of the embeddings of mpjk , spjk , and bjk generated by Claude-Opus-4.6 .
Figure 4: t-SNE projection of representative memory documents generated by DeepSeek-v3.2 .
Figure 5: t-SNE projection of representative speaking style documents generated by DeepSeek-v3.2 .
Figure 6: t-SNE projection of representative reaction process documents generated by DeepSeek-v3.2 .
Methods
Reciprocal Ranking score
IMPersona
0.42 ‡
SIBPersona
0.71
Ground Truth
0.71
Appendix
Table 14: Human comparison evaluation reciprocal scores. Bold indicates the best score. ‡ : significant degradation compared to SIBPersona ( p<0.05 )
M
T
RP
Rater 1 & 2
0.364
0.429
0.406
Rater 1 & 3
0.417
0.506
0.508
Rater 2 & 3
0.426
0.495
0.487
Appendix
Table 15: Inter-rater agreement among the three annotators.
Pass Rate
95% CI
Rater 1
0.80
[0.67, 0.89]
Rater 2
0.84
[0.72, 0.92]
Rater 3
0.92
[0.81, 0.97]
Total
0.94
[0.84, 0.98]
Appendix
Table 16: Extraction faithfulness evaluated by the three annotators. The Total column reports the pass rate of by applying majority-vote across all annotators.
Method
# Tokens
Vanilla RAG
593.51 ± 456.37
IMPersona
1972.64 ± 816.14
SIBPersona
1630.83 ± 812.02
Appendix
Table 17: Average number of tokens inserted into the prompt per test query across six influencers using DeepSeek-V3.2 .
Method
M
T
RP
Naive
95.89
46.43 ‡
70.85 ‡
CoT
96.58
45.73 ‡
72.33 ‡
IMPersona
95.94
48.10 ‡
73.20 ‡
Vanilla RAG
95.32
54.12 ‡
73.68 ‡
SIBPersona
95.46
59.22
77.81
Appendix
Table 18: Evaluation results on Influencer A averaged over four models after excluding overlapping test instances. ‡: significant degradation compared to SIBPersona (p < 0.05).
Methods
M
T
RP
Naive
97.28
46.48 ‡
77.33 ‡
CoT
97.61
47.93 ‡
78.08 ‡
IMPersona
97.14
48.63 ‡
78.80 ‡
Vanilla RAG
97.02
58.93 ‡
79.18 ‡
SIBPersona
96.69
62.37
81.52
Appendix
Table 19: Results on Influencer A averaged over four models using evaluator references extracted from the demonstration source. ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Reference Format
Source of Reference
Pearson
Spearman
Raw comment–reply pairs
Test candidate pool
0.355
0.409
SIBPersona document
Demonstration source
0.448
0.462
SIBPersona document
Test candidate pool (Ours)
0.561
0.530
Appendix
Table 20: Correlation between different evaluator configurations and human judgments.
Methods
Deepseek-V3.2
Gemini-3-flash
M
T
RP
M
T
RP
Naive
91.34 ± 3.24
42.63 ‡ ± 9.19
70.83 ‡ ± 5.49
92.18 ± 2.83
44.21 ‡ ± 10.84
68.91 ‡ ± 7.71
CoT
91.06 ± 3.35
46.65 ‡ ± 7.36
71.56 ‡ ± 4.79
92.14 ± 1.71
45.57 ‡ ± 8.63
68.53 ‡ ± 7.39
IMPersona
91.43 ± 2.61
48.44 ‡ ± 5.61
73.04 ‡ ± 5.20
91.34 ± 2.36
46.32 ‡ ± 8.20
69.88 ‡ ± 7.94
Vanilla RAG
91.30 ± 3.24
59.18 ‡ ± 4.58
74.30 ‡ ± 4.26
92.37 ± 2.60
56.47 ‡ ± 3.07
72.49 ‡ ± 3.97
SIBPersona
92.01 ± 3.53
62.96 ± 4.27
77.18 ± 4.44
92.29 ± 2.48
59.48 ± 3.00
75.60 ± 5.10
Appendix
Table 21: Evaluation results across the other five influencers using references extracted from the demonstration source. ‡ : significant degradation compared to SIBPersona ( p<0.05 ).
Influencer
Split
Data type
A
B
C
D
E
F
Demonstration
Post
1955
2716
713
2903
2130
453
Demonstration
Comment-Reply pair
1361
15240
5553
6087
4383
705
Test Candidates
Post
652
285
54
192
287
84
Test Candidates
Comment-Reply pair
547
1719
361
227
261
120
Appendix
Table 22: Number of data in the training set and the test candidate pool.
Influencers
Models
M
T
RP
All
Rep.
All
Rep.
All
Rep.
A
DeepSeek-V3.2
2424
35
446
15
274
12
Claude-Opus-4.6
1156
25
189
10
244
12
Gemini-3-flash
2477
36
419
15
318
13
GPT-5.2
2926
39
588
18
375
14
B
DeepSeek-V3.2
1786
30
851
21
758
20
Appendix
Table 23: Statistics of extracted documents and representative documents across influencers and models. All denotes the total number of dimensional documents extracted from the candidates for testing, and Rep. denotes the number of representative dimensional documents selected from the corresponding dimensional corpus.
Figure 7: Examples of three level of data for Influencer A .
Figure 8: Correlation matrix between LLM and human evaluations. *** p<0.001 , ** p<0.01 , * p<0.05 .
Methods
B
C
D
E
F
M
T
RP
M
T
RP
M
T
RP
M
T
RP
M
T
RP
Deepseek v3.2
Naive
97.67
45.60 ‡
78.07 ‡
88.97
52.00 ‡
69.57 ‡
91.59
37.22 ‡
60.93 ‡
90.24
26.85 ‡
64.17 ‡
90.66
40.97 ‡
66.22 ‡
CoT
97.87
45.63 ‡
79.80 ‡
89.57
53.00 ‡
71.43
90.89
43.96 ‡
62.22 ‡
90.30
28.15 ‡
65.30 ‡
90.82
40.87 ‡
66.48 ‡
IMPersona
95.77
46.47 ‡
81.43 ‡
89.70
54.43 ‡
71.67
90.70
42.44 ‡
64.63 ‡
90.65
36.73 ‡
66.19 ‡
90.20
42.35 ‡
67.81
Vanilla RAG
97.33
60.50
81.33 ‡
88.20
55.43 ‡
70.83
90.81
58.41 ‡
70.44 ‡
89.82
53.87
69.70
89.34
55.10
66.33 ‡
Appendix
Table 24: Results of Influencer B–F . Bold : best results; ‡ : significant degradation compared to SIBPersona p<0.05 .
LLM penalty-based evaluation
Pair-wise Evaluation
Tasks
Methods
M
T
RP
Win
Tie
Lose
General
IMPersona
75.32
65.10
71.15
-
-
-
General
SIBPersona
76.64
66.75 †
73.97 †
0.43
0.32
0.25
Summary
IMPersona
75.28
62.37
70.44
-
-
-
Summary
SIBPersona
78.94 †
63.83
73.12 †
0.34
0.39
0.27
Appendix
Table 25: Experimental results on RoleAgentBench, comparing our method with the baseline. Bold indicates the better score between the two methods. † denotes a result that is significantly better than its counterpart ( p<0.05 ).
Figure 9: An example where both human and LLM evaluators assign high scores, while traditional metrics assign low scores.
Figure 10: Example of top-1 dimensional document retrieval. The influencer names in the text are anonymized and replaced with "Influencer".
Figure 11: English translation of the example for top-1 dimensional document retrieval. The influencer names in the text are anonymized and replaced with "Influencer".
Figure 12: Qualitative examples where our method performs well. The influencer names in the text are anonymized and replaced with "Influencer".
Figure 13: Qualitative examples where our method performs poorly. The influencer names in the text are anonymized and replaced with "Influencer".
Figure 14: English translation of the persona scoring prompt used in our dataset.
Figure 15: Recognition prompt used in RoleAgentBench. All datasets share the same prompt except that the few-shot examples are replaced with the examples from the corresponding dataset.
Figure 16: Memory extraction prompt used in RoleAgentBench. All datasets share the same prompt except that the few-shot examples are replaced with the examples from the corresponding dataset.
Figure 17: Speaking style extraction prompt used in RoleAgentBench. All datasets share the same prompt except that the few-shot examples are replaced with the examples from the corresponding dataset.
Figure 18: Reaction Process extraction prompt used in RoleAgentBench. All datasets share the same prompt except that the few-shot examples are replaced with the examples from the corresponding dataset.
Figure 19: Evaluation prompt used in RoleAgentBench. All datasets share the same prefix prompt except for the data input format (question, model reply, and correct reply triplet).
Figure 20: Evaluation rubrics used for all datasets
Figure 21: Reply generation prompt used in RoleAgentBench. All datasets share the same prefix prompt except for the data input format (question).
Large language model-based role-play simulation creates interactive agents that portray people, characters, or users for training, testing, and research.
Faculty of Computer and Information Science, University of Haifa, Israel · School of Therapy, Counseling and Human Development, University of Haifa, Israel · The PhD Program of Hermeneutics and Culture, Interdisciplinary Studies Unit, Bar-Ilan University, Israel +1