# Predicting Architectural Space Preferences Using EEG-Based Emotion Analysis: A CNN-LSTM Approach
## 3 Materials and Methods
### Pilot Experiment  
Preliminary Validation  
Before conducting the main experiment, we performed a pilot experiment with eight architecture majors to verify the suitability of stimulus presentation and data analysis procedures. Participants watched multiple architectural images while EEG was recorded, focusing in particular on ERP components (N100/N200, P300, and LPP) [129,130]. Figure 3 illustrates example ERP patterns in parietal and occipital channels, confirming the experimental design was appropriate for measuring emotional responses.  
From the pilot experiment, parietal channels showed more negative amplitudes (N100/N200 range) and sustained positive amplitude in the LPP range for 'like' (preferred) stimuli, indicating robust initial sensory processing and prolonged emotional engagement. In contrast, 'dislike' (non-preferred) stimuli elicited a higher positive amplitude near the P300 range, suggesting a deeper cognitive processing of negative stimuli. Similar trends were observed in occipital channels, where preferred stimuli showed strong negative amplitudes in the 0.1-0.2 s interval, and non-preferred stimuli displayed positive amplitude increases around P300. These ERP differences reflect variations in visual and cognitive processing triggered by the emotional value of the stimuli. Table 9 summarizes the observed ERP features and interpretations for each stimulus type (like, neutral, and dislike).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Stimulus Type** & **ERP Window** & **Brain Region** & \
\begin{tabular}{c} **Amplitude** \\ **Tendency** & **Interpretation** \\ \hline \multirow{8}{*}{Like} & \multirow{3}{*}{N100/N200} & \multirow{3}{*}{Parietal} & Strong negative & Reflects a rapid and robust neural \\  & & & amplitude & reaction to the initial stimulus \\ \cline{3-5}  & & & Occipital & Strong negative & Denotes intense visual processing for \\  & & & amplitude & a preferred stimulus \\ \cline{2-5}  & & & & Low positive & Indicates minimal cognitive \\  & & & amplitude & resource allocation \\ \cline{2-5}  & & & Occipital &
\begin{tabular}{c} Low positive \\ amplitude \\ \end{tabular} & Suggests for reducing cognitive load \\  & & & & for positive stimuli \\ \cline{2-5}  & & & & Sustained positive & Demonstrates prolonged maintenance \\  & & & amplitude increase & of a positive emotional response \\ \cline{2-5}  & & & Occipital & Sustained positive & Shows an enduring reinforcement of a \\  & & & amplitude increase & favorable emotional state \\ \hline \hline \end{tabular}
\end{table}
Table 9: Event-related potential (ERP) responses by stimulus type and brain region.  
Figure 3: Event-related potential graphs: (a) parietal lobe; (b) occipital lobe.  
The pilot results indicate that this research protocol is indeed suitable for exploring emotional responses; stable EEG patterns were obtained [131; 132; 133; 134]. Building on these insights, we further investigate the potential to predict user preference and analyze architectural elements that induce affective responses in the main experiment.