dogs raised their inner eyebrows more and at higher intensities than wolves.
"More" and "at higher intensities" does not make sense
because it says the same thing two times.
I think the original work might have said:
|Based on dissections of dog and wolf heads, we show that the
|levator anguli oculi medialis, a muscle responsible for raising
|the inner eyebrow intensely, is uniformly present in
|dogs but not in wolves.
|Behavioral data, collected from dogs and wolves, show that
|dogs produce the eyebrow movement significantly more often
|and with higher intensity than wolves do, with highest-
|intensity movements produced exclusively by dogs.
This clearly means: plus souvent et avec plus d'intensité.