Do synactors simulate human actors convincingly?

Synactors are required most often to play humans and alien lifeforms in games. It is hard to judge performances depicting alien life forms objectively without any alien lifeform so far being discovered and observed; judgement is made against conventional standards of performance: how have aliens been depicted in the past and is the present depiction better or worse than other examples, in the viewer's opinion.

One thing to bear in mind when playing an alien lifeform is that many human players make anthropomorphic assumptions about aliens: they assume that aliens think and express themselves in human-like ways if they resemble humans outwardly, or at least they will understand them and their part in the story if they do.

Equally, an alien lifeform that resemble an earthly lifeform might be expected to behave in a way similar to how the earthly lifeform is know to behave. Cartoon characters also might be expected often to fulfill anthropomorphic expectations.