# Correlation Between Co-Design and Psychological Need Satisfaction Based on fNIRs Hyperscanning
## 3 Results  
### IBS Increased in DLPFC and BROCA During Co-Design  
By integrating the 24-channel map localized by the Polhemus Patriot system with the WTC analysis results, significant consistency in the DLPFC (dorsolateral prefrontal cortex)- and BROCA (pars triangularis Broca's area)-related channels under Co-design conditionscan be observed as shown in below Table 1. Among them, \"Channel\" represents the channel name, \"No.\" represents the brain area number, \"Brain area\" represents the corresponding brain area name, and \"PR\" stands for Precision Recall, and their corresponding t-values, \(p\)-values, and Cohen's d indicating the magnitude of the effect. After conducting the WTC analysis in MATLAB, it was found that the users and designers exhibited a higher level of synchronization during co-design sessions. Within this dataset, we observed an increase in consistency which was also observed in the other channels covering DLPFC and BROCA (CH2, 3, 4, 11, and 24). If we take the CH4 pair as an example, which consisted of DLPFC and BROCA (CH4: 45 pars triangularis Broca's area, 0.11594, 46 Dorsolateral prefrontal cortex, 0.88406), the results are as shown in Figure 6.  
During the aggregated data collected from the overall experiment, encompassing the Exp, Com, and Draw blocks, significantly higher coherence levels were identified within the temporal period range of 12.8 to 51.2 s (visually represented in red), suggesting that the enhanced neural synchronization observed within this specific time window is functionally associated with task-related variables. Firstly, it can be observed that even within the same subjects performing the same design task, there are differences in coherence between blocks conducted at different times. Specifically, the later blocks exhibit higher coherence compared to the earlier ones, indicating an improved level of collaboration. Secondly, when comparing the two task modes, it is evident that co-design exhibits a higher and more significant level of coherence than traditional design, as previously \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Channel** & **No.** & **Brain Area** & **PR** & **t** & **_p_** & _Cohen’s d_ \\ \hline CH2 & 44 & pars opercularis, part of Broca’s area & 0.086 & 2.288 & 0.036 & 0.418 \\  & 45 & pars triangularis Broca’s area & 0.914 & & & \\ CH3 & 45 & pars triangularis Broca’s area & 0.901 & & & \\ CH4 & 46 & Dorsolateral prefrontal cortex & 0.099 & & & \\ CH4 & 45 & pars triangularis Broca’s area & 0.116 & & & \\ CH11 & 46 & Dorsolateral prefrontal cortex & 0.884 & 3.540 & 0.005 & 0.646 \\  & 9 & Dorsolateral prefrontal cortex & 0.912 & & & \\ CH11 & 46 & Dorsolateral prefrontal cortex & 0.088 & 2.665 & 0.018 & 0.486 \\  & 45 & pars triangularis Broca’s area & 0.807 & & & \\ CH24 & 46 & Dorsolateral prefrontal cortex & 0.193 & 4.290 & 0.005 & 0.783 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Table of significant channel data related to DLPFC and BROCA. Figure 6: The CH4 IBS increases in the DLPFC and BROCA during traditional and co-design rounds: (**a**) traditional; (**b**) co-design. mentioned. Furthermore, Fisher Z-transform was performed on the difference in IBS between the traditional and co-designs of the same subjects, and a single-sample \(t\)-test was performed. It was found that channels 2 and 3 showed a significant increase in IBS compared to the traditional during co-design (CH2: t = 2.309, \(p\) = 0.029, [PERSON]'s d = 0.429; CH3: t = 2.333, \(p\) = 0.010, [PERSON]'s d = 0.433). Finally, to quantify the changes in coherence among all the participants and investigate the levels of collaboration and synchronization across the different contextual phases of the various design modes for the subsequent correlation analysis and discussion, the t-values for interactive blocks under both traditional design and co-design tasks were further calculated. These blocks included \"Traditional Com\", \"Co-design Com\", \"Traditional Draw\", and \"Co-design Draw\".