I have known a number of dogs, and I have known a number of people. And I have noticed quite a few personality traits that individuals of the two species have in common.
We could probably draw a diagram, with one axis showing systematic differences between the two species, and the other axis showing variations in personality common to humans and dogs. I suspect this second axis would be very rich in parallels.
I wonder whether there is some quality in evolution of mammals that promotes a particular range of personality types — confident, shy, neurotic, calculating, trusting of strangers, and so forth. Many psychological qualities that we think of as “human” are probably shared across a wide range of species.
It would be interesting to study the gamut of personality traits in a way that does not privilege humans in particular, but rather takes other species into account. I wonder whether this has been tried.