Professor Ross Flom conducted two experiments where he looked at the frequency in which dogs followed a pointing gesture to locate a hidden reward. Those gestures were paired with either positive or negative behaviors from the person pointing. Positive behaviors included smiling and speaking in a pleasant tone. Negative behaviors included frowning, a furrowed brow and speaking in a harsh tone.
The main finding of the study is that dogs use human emotions in determining how quickly or how slowly they’re going to go and explore an unfamiliar location. While positive behaviors didn’t improve response time from the control group, negative behaviors, which simulated emotions closely tied to anger, delayed the response time.
The bottom line: your dog doesn’t trust you when you’re angry.
DoggyMom.com 
Thank you 🙂 There’s similar research from University of Lincoln (and I remember there’s more about it in some Eötvös Lóránd University supported study). Here’s a link to another article: https://www.sciencedaily.com/releases/2016/01/160112214507.htm
Research involving dogs is a particular interest of mine; here’s a link from January about the Lincoln research: https://doggymom.com/2016/01/16/study-shows-dogs-can-recognise-human-emotions/
Thank you 🙂 My personal little obsession is animal communication 🙂