But scientific findings haven't put a dent in the popularity of online dog shaming sites like dogshaming.com and shameyourpet.com or videos like those posted on youtube.com/crackrockcandy. In the photos and videos, dogs wear humorous written "confessions" and often are surrounded by the remnants of their misdeeds. There is no question that in some photos, they look guilty of eating, drinking, chewing, licking or destroying something they shouldn't have.
Dogshaming.com was the first and is among the most popular sites. Since Pascale Lemire started it in August 2012, it has received more than 58 million page views and more than 65,000 submissions. A submission has to come with a photo showing the dog's guilty look.
Lemire, who lives in Vancouver, British Columbia, also published a book called "Dog Shaming," which hit the New York Times best-seller list in January.
"I don't think dogs actually feel shame," Lemire said. "I think they know how to placate us with this sad puppy-dog look that makes us think they're ashamed of what they've done. My guess is that their thinking is: 'Oh man, my owner is super mad about something, but I don't know what, but he seems to calm down when I give him the sad face, so let's try that again.'"
She thinks the online dog shaming memes are all in good fun.
"People come for a laugh and camaraderie," Lemire said. "They see that their dog isn't the only one who does awful things. People don't shame their dogs out of anger, they do it out of love."
Another dog owner helped get celebrities into the trend. In late 2011, Jeremy Lakaszcyck of Boston started putting shaming videos of his lemon beagle, Maymo, on YouTube. Four months later, Ellen DeGeneres ran one of them on her show and comedian Ricky Gervais tweeted it. The popularity of the videos soared, Lakaszcyck said.
He also submitted photos to Lemire for dogshaming.com, which made Maymo even more famous.
Maymo has a naturally sad or guilty face and senses something is wrong if Lakaszcyck speaks in a stern voice. "They know when their owners are angry.
"Maymo can sit for quite a while looking sad because he's a ham. It's natural, and he knows a treat is coming. His tail usually wags through the wait. It's like he's happy on one end and sad on the other," he said.
One of the first scientific studies on the "guilty dog look" was conducted in 2009 by Alexandra Horowitz, an associate professor of psychology at Barnard College in New York City. One of her books, "Inside of a Dog: What Dogs See, Smell, and Know," included the findings.
In the study, she used 14 dogs, videotaping them in a series of trials and studying how they reacted when an owner left the room after telling them not to eat a treat. When the owners returned, sometimes they knew what the dogs had done and sometimes they didn't and sometimes the dogs had eaten the treats and sometimes they hadn't.
"I found that the 'look' appeared most often when owners scolded their dogs, regardless of whether the dog had disobeyed or did something for which they might or should feel guilty. It wasn't 'guilt' but a reaction to the owner that prompted the look," Horowitz said.
"I am not saying that dogs might not feel guilt, just that the 'guilty look' is not an indication of it," she added. She also believes there is a difference between guilt and shame.
Dogs can certainly learn from bad behavior, but rewards or punishment are most effective right after the wrongdoing, said Beaver, the veterinary professor. "The farther it gets from that, the less connection is made with the behavior," she said.