&gt; &quot;It’s the minimum human response time to anything...It’s the time that runners take to respond to a starting pistol—and that&#x27;s just a simple signal&quot;<p>i.e. the gap is typically exactly as long as it takes for us to react to the &quot;simple signal&quot; that the other person has stopped speaking and now it is our turn.<p>It does prove that we must be planning our response before the other person has finished speaking, but I wonder if that&#x27;s such a surprising thing to prove: words and sentences take a lot longer to say out loud than they do to comprehend.