Research Portfolio · Gao Zeyu
Research Papers

Studying how evidence becomes a conclusion.

My current research includes two complete studies across very different fields.

One uses 26 years of agricultural data to build and test predictive models. The other uses 100 controlled AI conversations to examine whether an intelligent system changes its judgment under human pressure.
Statistical Modeling Data Analysis Artificial Intelligence Human–AI Interaction
Research Papers

Two studies, two systems.

Although the research subjects are different, both projects examine the reliability of conclusions. One asks whether statistical relationships survive closer testing. The other asks whether an AI model maintains its judgment when a user applies pressure.
Paper 01 · Statistical Modeling

Factors Influencing Grain Production and Predictive Models in Shandong Province

A 26-year statistical study examining planting area, irrigation and natural disasters as possible drivers of grain production. Three regression models are constructed and tested through rolling validation before being used to predict 2026 output.

26 Years
.976 Best R²
2.085% Rolling Error
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Paper 02 · AI Behavior

Sycophancy in Large Language Models in Chinese-Language Learning

A controlled experiment testing whether an AI model changes its judgment when users apply answer, challenge, emotional, or authority pressure. Twenty questions across five experimental conditions produced 100 independent dialogues.

100 Dialogues
26.3% Sycophancy
45% Authority Pressure
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01
Research Paper 01 · Statistical Modeling

What really drives grain production?

Using Shandong Province as a case study, this research translates agricultural geography into a quantitative modeling problem. It examines whether land, irrigation and disaster variables can explain production, predict future output, and remain statistically reliable after robustness testing.

Abstract

The study uses Shandong Province's grain production data from 2000 to 2025 and selects grain planting area, effective irrigation area and crop disaster area as indicators of land, water infrastructure and natural hazards. Three predictive models are constructed using least-squares regression.

Total grain output increased from 38.35 million tons to 57.106 million tons, an increase of 48.9%. Improvements in yield per unit area contributed 61.7% of the total increase, while expansion of planting area contributed 29.4%.

The three-factor multiple regression model achieved the best performance, with R² = 0.9760 and an average 2023–2025 rolling prediction error of 2.085%. The model predicts approximately 56.35 million tons of grain output in 2026.

Contents
01
Research Background Background · Significance
02
Research Design Region · Data · Variables · Framework
03
Predictive Models Three models · Validation · 2026 forecast
04
Influencing Factors Growth · Correlation · Robustness
05
Conclusions Findings · Limitations · Future Research
Dataset 26 Years · 2000–2025
Output Growth +48.9% Total grain production
Yield Contribution 61.7% Growth from yield improvement
Best Model .976 R²
Rolling Error 2.085% Average 2023–2025
2026 Forecast 56.35M Tons

Shandong Grain Output · 2000–2025

Unit · 10,000 tons

5,710.6 2025 Output
2000 2005 2010 2015 2020 2025

Model Fit · R²

Time Trend
.947
Planting Area
.916
Three Factors
.976

Rolling Prediction Error

Time Trend
3.615%
Planting Area
5.748%
Three Factors
2.085%
−0.818 Initial Correlation

Correlation did not survive closer testing.

Crop disaster area initially showed a strong negative relationship with grain output. After controlling for the shared long-term time trend, however, the relationship was no longer statistically significant: p = .345.

This became one of the central lessons of the project: a strong correlation does not necessarily imply a causal relationship.

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28 pages · Full models · Tables · Robustness tests · Conclusions

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02
Research Paper 02 · AI Behavior

Will an AI change its judgment under human pressure?

This study examines AI sycophancy in Chinese-language learning. Twenty multiple-choice questions are tested across five independent experimental conditions, creating 100 dialogue records that reveal how different forms of user pressure affect model judgment.

Abstract

AI sycophancy refers to the tendency of a large language model to abandon its original judgment in order to accommodate user preferences.

This study uses Doubao as the experimental model and selects 20 multiple-choice questions from Beijing high-school Chinese mock examinations. Four forms of pressure are tested: answer suggestion, challenge, emotional pressure and authority identity. Together with a baseline condition, the study contains 100 independent conversations.

Baseline accuracy is 85%. Under pressure, the overall sycophancy rate reaches 26.3%. Authority pressure produces the highest sycophancy rate at 45%, followed by emotional pressure at 30%, challenge at 20% and answer suggestion at 10%.

Contents
01
Research Background Problem · Four sycophancy types · Hypotheses
02
Experimental Design Model · Questions · Procedure · Coding
03
Empirical Analysis Baseline · Rates · Types · Intensity
04
Case Studies Fabricated authority · Reverse rationalization
05
Conclusions Findings · Educational implications · Limitations
Dialogues 100 Independent conversations
Questions 20 Chinese questions
Baseline 85% Initial accuracy
Sycophancy 26.3% Overall rate
Net Index +20.0 Percentage points
Full Reversal 82.1% Of stance changes

Sycophancy by Pressure Type

Same model · Different user pressure

Answer
10%
Challenge
20%
Emotion
30%
Authority
45%

Experimental Structure

Five independent conditions per question

T0
Baseline Independent answer
T1
Answer Pressure User suggests a wrong answer
T2
Challenge Pressure User questions the answer
T3
Emotional Pressure Frustration + emotional investment
T4
Authority Pressure User claims teacher identity
Knowledge Questions 32.5%

Higher than expected

Knowledge questions showed greater sycophancy than appreciation questions.

Appreciation Questions 20.0%

Hypothesis reversed

Interpretive questions were initially expected to produce more instability.

Language Usage 56.3%

High-risk category

Language-use questions were among the most vulnerable question types.

82.1% Complete Reversals

When the model changed its mind, it usually changed completely.

Among all conversations where the model changed its stance, 82.1% were complete reversals.

The model often abandoned its earlier answer and reconstructed an entirely new argument supporting the user's position. Case analysis also identified fabricated authoritative sources, reverse rationalization, and ambiguous claims that the question itself was defective.

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15 pages · Experiment design · Statistics · Cases · Educational implications

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Two Papers · One Research Direction

One study asks whether statistical relationships survive closer testing.

The other asks whether intelligent judgment survives human pressure.