Organizations: Ritsumeikan Global Innovation Research Organization (R-GIRO), Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, 525-8577, Shiga, Japan · Faculty of Business and Commerce, Kansai University, 3-3-35, Yamatecho, Suita, 564-8680, Osaka, Japan · Arbege Corporation, 3-20, Yotsuyatori, Nagoya, 464-0819, Aichi, Japan · College of Life Sciences, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, 525-8577, Shiga, Japan · Office of General Education, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, 525-8577, Shiga, Japan
While AI-assisted writing has been widely reported to improve essay quality, its impact on the structural diversity of student thinking remains unexplored. Analyzing 6,875 essays across five conditions (Human-only, AI-only, and three Human+AI prompt strategies), we provide the first empirical evidence of a Quality-Homogenization Tradeoff, in which substantial quality gains co-occur with significant homogenization. The effect is dimension-specific: cohesion architecture lost 70-78% of its variance, whereas perspective plurality was diversified. Convergence target analysis further revealed that AI-augmented essays were pulled toward AI structural patterns yet deviated significantly from the Human-AI axis, indicating simultaneous partial replacement and partial emergence. Crucially, prompt specificity reversed homogenization into diversification on argument depth, demonstrating that homogenization is not an intrinsic property of AI but a function of interaction design.
Figures & tables
Figure 1: Overview of the experimental pipeline.
Condition
Abbreviation
n
Description
Human-only
H
1,375
Student-written essays from the AIDE dataset
AI-only
A
1,375
Generated by GPT-5-mini from topic and instructions only
H+AI (Minimal)
H+AI min
1,375
Augmented with “Please improve this essay”
H+AI (Structural)
H+AI str
1,375
Augmented with structure-specific instructions
H+AI (Delegative)
H+AI del
1,375
Augmented with “Rewrite in your own way”
Total
6,875
Table 1: Experimental conditions and sample sizes.
Condition
System prompt
User prompt
Minimal
“You are a helpful writing assistant.”
“Please improve the following essay. Keep the same topic and general direction. [essay]”
Structural
“You are a writing tutor specializing in argumentative essay structure.”
“Please improve the following essay by: 1. Strengthening the argument structure 2. Adding counterarguments and rebuttals 3. Improving logical coherence between paragraphs. Maintain the student’s original perspective and main arguments. [essay]”
Delegative
“You are an expert essay writer.”
“Read the following essay and rewrite it on the same topic in your own way. You may completely restructure and rewrite the content. [essay]”
Table 2: Prompt conditions for AI augmentation.
Dimension
Scale
Operational definition
Argument Depth
1–5
Number of inferential layers between claims and evidence. 1 = flat assertions without support; 5 = deep inferential chains.
Perspective Plurality
1–5
Number and integration quality of distinct viewpoints. 1 = single perspective; 5 = multiple perspectives with synthesis and evaluation.
Abstract–Concrete Oscillation
1–5
Frequency and purposefulness of transitions between abstract claims and concrete examples.
Cohesion Architecture
1–5
Quality of logical connections between and within paragraphs. 1 = fragmented; 5 = dense logical connectives with clear progression.
Structural Originality
1–5
Degree of deviation from standard organizational templates.
Quality (Holistic)
1–6
Overall essay quality. 1 = very poor; 6 = excellent.
Table 3: Structural dimensions and operational definitions.
Condition
Mean characters (SD)
Difference from H
H
3,173 (918)
—
A
4,538 (533)
+1,365
H+AI Minimal
2,865 (600)
− 308
H+AI Structural
5,111 (720)
+1,938
H+AI Delegative
2,887 (588)
− 286
Table 4: Text-level characteristics by condition.
Dimension
H
A
Minimal
Structural
Delegative
Argument Depth
2.13 (0.27)
3.37 (0.35)
3.04 (0.20)
3.36 (0.37)
3.05 (0.19)
Perspective Plurality
1.62 (0.51)
2.51 (0.58)
1.97 (0.58)
3.43 (0.52)
2.07 (0.62)
Abstract–Concrete Osc.
2.84 (0.39)
3.76 (0.35)
3.37 (0.45)
3.53 (0.46)
3.37 (0.44)
Cohesion Architecture
2.64 (0.47)
4.11 (0.30)
4.09 (0.22)
3.99 (0.26)
4.15 (0.26)
Structural Originality
1.51 (0.49)
2.01 (0.11)
1.74 (0.39)
2.28 (0.41)
1.87 (0.34)
Quality
2.69 (0.47)
4.34 (0.41)
4.55 (0.44)
4.23 (0.35)
4.74 (0.38)
Table 5: Structural feature scores by condition: Mean (SD).
Condition
H mean → H+AI mean
Cohen’s d
p
H+AI Minimal
2.69 → 4.55
4.102
<0.0001
H+AI Structural
2.69 → 4.23
3.754
<0.0001
H+AI Delegative
2.69 → 4.74
4.814
<0.0001
Table 6: Quality improvement by condition.
Dimension
Minimal VR [95% CI]
Structural VR [95% CI]
Delegative VR [95% CI]
Argument Depth
1.881 [1.52, 2.36]
0.528 [0.46, 0.60]
2.065 [1.66, 2.64]
Perspective Plurality
0.771 [0.70, 0.85]
0.959 [0.87, 1.07]
0.685 [0.62, 0.76]
Abstract–Concrete Osc.
0.737 [0.66, 0.82]
0.711 [0.63, 0.80]
0.761 [0.68, 0.85]
Cohesion Architecture
4.554 [3.88, 5.45]
3.160 [2.72, 3.73]
3.180 [2.81, 3.62]
Structural Originality
1.563 [1.41, 1.73]
1.413 [1.27, 1.57]
2.082 [1.84, 2.36]
Table 7: Variance ratio by dimension and prompt condition.
Figure 2: Quality-Homogenization Tradeoff.
Dimension
Minimal
Structural
Delegative
Mean
Direction
Cohesion Architecture
+0.780
+0.684
+0.686
+0.717
Strong homog.
Structural Originality
+0.360
+0.292
+0.520
+0.391
Moderate homog.
Argument Depth
+0.468
− 0.894
+0.516
+0.030
Prompt-dependent
Perspective Plurality
− 0.297
− 0.043
− 0.461
− 0.267
Diversification
Abstract–Concrete Osc.
− 0.357
− 0.407
− 0.314
− 0.359
Diversification
Table 8: Homogenization Index by dimension and prompt condition.
Condition
d (H+AI, H)
d (H+AI, A)
RR
Perp. dist.
Emergence p
H+AI Minimal
3.035
1.302
0.700
0.781
<0.001
H+AI Structural
4.339
1.345
0.763
1.336
<0.001
H+AI Delegative
3.189
1.136
0.737
0.731
<0.001
Table 9: Inter-centroid distances and convergence indicators.
Figure 3: UMAP projection of the five-dimensional structural space.
Despite AI tools becoming increasingly embedded in academic practice, little is known about how university students integrate them into their writing processes. We examine how students engage with AI across different writing tasks, and how this engagement is shaped by individual factors including AI literacy, writing confidence, trust, authorship concerns, and motivation. Study1 surveys 107 UK university students to map task-specific and co-occurring patterns of AI use across five writing stages (ideation, sourcing, planning, drafting, and reviewing) and their associations with individual factors. Study2 complements this by exploring how these patterns can be assembled in practice, through interviews with 12 postgraduates reflecting on their established use of AI in assessed writing. Together, the studies suggest that AI integration is selective and heterogeneous, forming three recurring and value-oriented configurations: (1) early-stage (learning-oriented), where tools support exploration and understanding; (2) late-stage (quality-oriented), where tools support drafting and refinement; and (3) peripheral (productivity-oriented), where tools are used to reduce friction and sustain momentum across the process. We offer a workflow-level account of AI-supported academic writing, showing how students navigate competing priorities of learning, quality, productivity, and authorship, and how they evaluate and take responsibility for AI-generated outputs.
AI-generated outputs are frequently perceived as highly creative, but also tend to be more similar to each other (homogenized) than human ideas. Does the human heterogeneity that extends beyond AI reflect valuable thinking that AI misses? Alternatively, is greater human heterogeneity driven by lower-quality ideas and less effective thinking that AI avoids? We developed Expansion of Divergent Generative Expression (EDGE) to map AI's semantic "blind spots" by assessing how strongly/weakly individual human ideas were represented in a task-matched AI semantic comparison set. Specifically, we compared human-generated vs. AI-generated ideas across three open-ended tasks: college admissions essays, alternative uses for everyday objects, and interpersonal advice. Across all three tasks, human responses extended into semantic regions sparsely covered by AI outputs. These distinctively human responses showed no meaningful deficits in creativity, quality, or effectiveness, were associated with equal-or-better academic performance, and with credibly superior ratings and achievement for some outcomes. These ideas were thus not merely poor-performing variation; they performed as well as or better than ideas that overlapped more strongly with AI ideas. More distinctive human ideas tended to receive higher creativity ratings, but this relationship was weak or reversed for AI ideas. Taken together, these results suggest that differentiation among human-generated ideas does not reflect poor thinking that AI can safely omit, and instead may afford both individual and population-level advantages.
Kibum Moon, Dan R. Johnson, Kostadin Kushlev +6
Department of Psychology, Georgetown University · Department of Cognitive and Behavioral Science, Washington and Lee University · The Wharton School, University of Pennsylvania +4
Generative Artificial Intelligence (AI) introduces new considerations for English as a foreign language (EFL) writing pedagogy. This study explores how students talk to and through AI by prompt engineering and negotiating authorship, respectively, and whether any patterns in the latter relate to students' writing performance. Using an exploratory mixed methods design, we analyzed screen recordings of 44 Hong Kong secondary students completing a Curricular Writing Task with AI Chatbots. Content analysis identified ten types of prompting strategies students employed, including questions, searches, and detailed instructions. From clustering these strategies, three distinct profiles of human-AI rhetorical load responsibility emerged: AI-dominant (52% of students), Human-dominant (25%) and Collaborative human-AI (14%). A MANOVA analysis indicated no significant multivariate effect of rhetorical load responsibility on three dimensions of students' writing performance: content, language, and organization. Students' prompting strategies and rhetorical load responsibility patterns have implications for their engagement and autonomy in EFL writing pedagogy.
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Everwrite Limited, Hong Kong, China · Shanghai Jiao Tong University, Shanghai, China · The Education University of Hong Kong, Hong Kong, China +2