reported that blood pressure significantly
decreased and concentrations of β-endorphin, oxytocin,
prolactin, β-phenylethylamine, and dopamine increased when dogs
in a novel environment were stroked by people who lived permanently
with them. Another study of dogs undergoing clinical
examinations found that their heart rates were significantly lower
when they were in the presence of people who lived permanently
with them (Palestrini et al., 2005). Similarly, cortisol levels did not
increase if dogs were exposed to a novel environment in the presence
of people who lived permanently with them (Tuber et al.,
1996).