[topherclay]

The novelty is that they tested this one theory instead of just proposing it as an explanation.

The introduction of this paper lists some other explanations that you may or may not have seen in the past and it says some have been disproven and some have not yet been tested.

[LudwigNagasena]

The paper lists some other explanations and references the papers that analyzed them. Maybe the paper presents a novel convincing technique, but it is not like they are the first to study the behavior.