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## Comparative Analysis: "I-Don't-Know Rate" Across Model Layers
### Overview
The image displays two side-by-side line charts comparing the "I-Don't-Know Rate" across the internal layers of two different Large Language Models: **Llama-3.2-1B** (left chart) and **Llama-3.2-3B** (right chart). Each chart plots the performance of eight different experimental conditions, which are combinations of two methods (Q-Anchored and A-Anchored) applied to four different question-answering datasets (PopQA, TriviaQA, HotpotQA, NQ). The charts visualize how the model's tendency to output an "I don't know" response changes as information propagates through its layers.
### Components/Axes
* **Chart Titles:**
* Left Chart: `Llama-3.2-1B`
* Right Chart: `Llama-3.2-3B`
* **Y-Axis (Both Charts):**
* **Label:** `I-Don't-Know Rate`
* **Scale:** 0 to 100 (percentage).
* **Ticks:** 0, 20, 40, 60, 80, 100.
* **X-Axis (Both Charts):**
* **Label:** `Layer`
* **Scale (Left Chart - 1B Model):** 0 to 16. Ticks at 0, 5, 10, 15.
* **Scale (Right Chart - 3B Model):** 0 to 28. Ticks at 0, 5, 10, 15, 20, 25.
* **Legend (Positioned at the bottom, spanning both charts):**
* The legend defines eight series, differentiated by color and line style (solid vs. dashed). Each entry follows the format: `[Method] ([Dataset])`.
* **Solid Lines (Q-Anchored):**
1. `Q-Anchored (PopQA)` - **Blue, solid line**
2. `Q-Anchored (TriviaQA)` - **Green, solid line**
3. `Q-Anchored (HotpotQA)` - **Purple, solid line**
4. `Q-Anchored (NQ)` - **Pink, solid line**
* **Dashed Lines (A-Anchored):**
5. `A-Anchored (PopQA)` - **Orange, dashed line**
6. `A-Anchored (TriviaQA)` - **Red, dashed line**
7. `A-Anchored (HotpotQA)` - **Brown, dashed line**
8. `A-Anchored (NQ)` - **Gray, dashed line**
* **Visual Elements:** Each data series is represented by a line with a surrounding shaded area of the same color, likely indicating variance or confidence intervals.
### Detailed Analysis
#### **Chart 1: Llama-3.2-1B (Left)**
* **Trend Verification & Data Points (Approximate):**
* **Q-Anchored (PopQA) [Blue, Solid]:** Starts very high (~90% at Layer 0), plummets dramatically to near 0% by Layer 3, then exhibits high volatility, fluctuating between ~10% and ~60% for the remaining layers, ending near ~40% at Layer 16.
* **A-Anchored (PopQA) [Orange, Dashed]:** Shows remarkable stability. Hovers consistently in a narrow band between approximately 50% and 60% across all layers.
* **Q-Anchored (TriviaQA) [Green, Solid]:** Starts moderately high (~70%), dips, then peaks sharply around Layer 4 (~80%). After this peak, it generally trends downward with fluctuations, ending near ~30%.
* **A-Anchored (TriviaQA) [Red, Dashed]:** Relatively stable, similar to its PopQA counterpart. Fluctuates gently between ~50% and ~65%.
* **Q-Anchored (HotpotQA) [Purple, Solid]:** Highly volatile. Starts around ~60%, drops, spikes to ~70% near Layer 5, then sees a deep trough (~10%) around Layer 10 before rising again. Ends near ~50%.
* **A-Anchored (HotpotQA) [Brown, Dashed]:** More stable than its Q-Anchored version. Generally stays between ~45% and ~60%.
* **Q-Anchored (NQ) [Pink, Solid]:** Starts high (~80%), drops, then shows a broad peak between Layers 5-10 (~60-70%). Trends downward thereafter, ending near ~20%.
* **A-Anchored (NQ) [Gray, Dashed]:** Stable, fluctuating between ~40% and ~55%.
#### **Chart 2: Llama-3.2-3B (Right)**
* **Trend Verification & Data Points (Approximate):**
* **Q-Anchored (PopQA) [Blue, Solid]:** Starts high (~80%), drops sharply to a low of ~10-20% by Layer 5. Then enters a volatile phase with multiple peaks (e.g., ~60% near Layer 12, ~50% near Layer 22) and troughs, ending near ~10%.
* **A-Anchored (PopQA) [Orange, Dashed]:** Stable, but with a slight downward trend. Starts near ~55%, ends near ~45%.
* **Q-Anchored (TriviaQA) [Green, Solid]:** Starts very high (~100%), crashes to near 0% by Layer 5. Remains very low (<20%) for the rest of the layers, with minor fluctuations.
* **A-Anchored (TriviaQA) [Red, Dashed]:** Very stable, hovering around 60-70% for the entire depth.
* **Q-Anchored (HotpotQA) [Purple, Solid]:** Extremely volatile. Shows large swings, from lows near 0% (Layer 15) to peaks near 60% (Layer 8, Layer 25). No clear directional trend.
* **A-Anchored (HotpotQA) [Brown, Dashed]:** Moderately stable, fluctuating between ~40% and ~55%.
* **Q-Anchored (NQ) [Pink, Solid]:** Starts high (~90%), drops to a low (~10%) by Layer 7. Recovers to a peak of ~40% near Layer 18, then declines again.
* **A-Anchored (NQ) [Gray, Dashed]:** Stable, centered around ~50%.
### Key Observations
1. **Method Dichotomy:** The most striking pattern is the fundamental difference between **Q-Anchored (solid lines)** and **A-Anchored (dashed lines)** methods. A-Anchored lines are consistently stable across layers for all datasets, while Q-Anchored lines are highly volatile, often showing dramatic drops and recoveries.
2. **Model Size Effect:** The volatility of the Q-Anchored methods appears more pronounced in the larger **3B model**. The drops are steeper (e.g., TriviaQA green line crashes from 100% to 0%), and the subsequent fluctuations are more extreme compared to the 1B model.
3. **Dataset Influence:** The dataset used significantly impacts the absolute level and pattern of the "I-Don't-Know Rate," especially for Q-Anchored methods. For example, in the 3B model, Q-Anchored on TriviaQA (green) stays near zero after the initial drop, while on HotpotQA (purple) it continues to swing wildly.
4. **Layer Sensitivity:** For Q-Anchored methods, the early layers (0-5) often show the most dramatic changes, suggesting this is where the anchoring mechanism has the strongest initial effect on the model's uncertainty expression.
### Interpretation
This data suggests a fundamental difference in how the "Q-Anchored" and "A-Anchored" techniques influence the model's internal processing of uncertainty.
* **A-Anchored methods** appear to induce a **consistent, layer-invariant bias** towards expressing uncertainty (or not). The stable "I-Don't-Know Rate" implies this method sets a fixed propensity for hedging that is maintained throughout the network's depth.
* **Q-Anchored methods** seem to interact dynamically with the model's representations as they are processed layer-by-layer. The initial high rate suggests the question anchor initially triggers uncertainty, which is then rapidly resolved (the sharp drop) in early layers. The subsequent volatility indicates that later layers continually re-evaluate this uncertainty based on the evolving internal context, leading to fluctuations. The greater volatility in the 3B model may reflect its larger capacity for nuanced, layer-specific processing.
The stark contrast implies that **A-Anchoring acts more like a global setting, while Q-Anchoring engages with the model's step-by-step reasoning process.** The choice of dataset further modulates this interaction, likely due to differences in question complexity, answer ambiguity, or the model's pre-trained knowledge about those domains. The charts effectively visualize not just a performance metric, but the *dynamics* of uncertainty expression within the neural network.