# Discrimination Accuracy of Sequential Versus Simultaneous Vibrotactile Stimulation on the Forearm
## 4 Results
### Learning Effects  
An additional finding is that participants' average accuracy in recognizing vibrotactile patterns increased throughout the course of the six experimental blocks, showing a clear learning effect over time (see Figure 7). An ANOVA analysis revealed significant differences in accuracy among the six experimental blocks (F (5, 168) = 2.91; \(p\) = 0.015), showing how pattern reproduction improved as the experiment progressed.  
Figure 5: Accuracy for the two different stimulus presentation methods (sequential and simultaneous).  
Figure 6: (**a**) Accuracy as a function of serial position of each individual vibrotactile stimulation during sequential presentation for short (2–3 actuators) and (**b**) long patterns (4–5 actuators).  
This emphasizes the importance of considering training schedules for sensory substitution devices, in light of the considerable improvement that we see over only a 35 min. long experiment. Training should, therefore, be considered in addition to presentation methods and pattern lengths when designing experiments on the recognition of vibrotactile patterns, but even more importantly, it should be considered when sensory substitution devices are designed. Adequate training ensures that participants have the necessary knowledge and skills to perform the tasks or recognize the patterns that are being tested.  
Without proper training, experimental results may be influenced by participants' lack of familiarity with the task in each case. The finding of a learning effect over a relatively short experiment duration emphasizes the dynamic nature of vibrotactile pattern recognition and the potential for rapid performance improvement. This knowledge is valuable for designing effective training schedules and optimizing the usability of sensory substitution devices. When planning experiments on vibrotactile pattern recognition, it is therefore essential to factor in not only training but also the potential for skill development over time, along with other variables such as presentation methods and pattern length.  
Overall, Table 3 provides insights into how the performance indicators in this study differed in terms of their presentation methods, accuracy rates, pattern lengths, stimulation times, learning effects, serial position effects, and user feedback in the context of cognitive tasks.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Performance Indicators** & **I** & **II** \\ \hline Presentation Method & Sequential & Simultaneous \\ Accuracy Rate & High (93.24\%) & Low (26.15\%) \\ Pattern Length & Short patterns (2–3)/Long & Short patterns (2–3)/Long \\  & patterns (4–5) & patterns (4–5) \\ Stimulation Time & 500 ms with a 450 ms interval & 1000 ms \\ Learning Effects & Positive & Positive \\ Serial Position Effects & Primacy and recency & - \\  & observed & \\ User Feedback & Positive & Negative \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of performance indicators in this study.  
Figure 7: Performance across the six experimental blocks. The figure shows a clear learning effect over time (the 6 experimental blocks) for both presentation methods (simultaneous and sequential) and different pattern lengths (short (A) versus long (B) patterns). The error bars show the standard deviation within each group for each block.