It refers a few paragraphs earlier, i.e.: “I originally had two justifications for putting this in. (1) Provine found that laughter was 30× less frequent when people were alone; (2) Evolutionarily, there’s no point in emitting communicative signals when there’s no one around to hear them.” (Sorry that’s unclear, I’ll reword.)
What are (1) and (2) referring to?
It refers a few paragraphs earlier, i.e.: “I originally had two justifications for putting this in. (1) Provine found that laughter was 30× less frequent when people were alone; (2) Evolutionarily, there’s no point in emitting communicative signals when there’s no one around to hear them.” (Sorry that’s unclear, I’ll reword.)