To say “dog” when seeing a fox is quite likely; to say “dog” when seeing a shetland pony for the first time is not so likely. This is because the fox has many of the relevant features that control the response “dog,” but a shetland pony has only a few of the relevant features that control the response.
Fur
Barking
Four legs
Canine teeth
Claws
Tail
Size
Color