Question

葉音

in which の　inがどこから発生したのかわかりません。
教えてください！

[01
Traditionally, listening was viewed as a passive process, in
which our ears were receivers into which information was
poured, and all the listener had to do was passively
register the message. Today we recognize that listening is
an 'active' process, and that good listeners are just as active
when listening as speakers are when speaking.
Active listening is also an interpretive process. 2 Listening
used to be thought of as the exact decoding of the message.
3 In fact, listening involves subtle interpretation.
(福島大)

Answer 1

ののののの

関係代名詞は、基本的に先行詞と同じものを指しています。
この文の場合、先行詞はa passive processですから、
in a passive process ということです。

in which our ears were receivers〜　と言ってますから、
a passive process（受動的なプロセス・受け取るプロセス）"においては"、我々の耳はレシーバーだ

ってことです。