Why do I get 0.167s of vocal_RT even when I run the word_naming demo without any response?

Builder
1

Dear all，
Why is it that whenever I run the word_naming demo without any response, I also get almost 0.167s of vocal_RT?

QQ截图20201009200313

OS (e.g. Win10): Win10
PsychoPy version (e.g. 1.84.x): v2020.1.3
**What are you trying to achieve?:**word naming

2

Dear all, I have similar questions about the vocal_RT. First, I didnt get the difference between rt “while recording” and “during playback”. Also, is this RT triggered by the first sound captured by the microphone? If so, is it possible to adjust thresholds?
best,
ricardo