This must be devastating to some.
Dogs are wonderful creatures. Our dogs recognize me and are always happy to see me. Dogs are also smart and successful creatures. Our dogs have learned several cute tricks. But dogs (and other non-human animals) are missing something we take for granted: episodic memory. Dogs don't remember what happened yesterday and don't plan for tomorrow.
In defining episodic memory, Endel Tulving argued that it is unique to humans. Experience influences all animals. Most mammals and birds can build complex sets of knowledge or semantic memory. You and I also remember the experience of learning these complex sets of information. Dogs don't.
Episodic remembering is mental time travel and depends on a few crucial cognitive capabilities. First, in order to experience episodic remembering, an individual must have a sense of self. Most non-human animals have a dramatically different experience of self than we do. For example, most animals (and young humans) fail to identify themselves in mirrors. If I look in a mirror and see that I have something stuck between my teeth, I try to correct the problem. (I also wonder why my friends didn't tell me I had something stuck between my teeth.) In contrast, put a red dot on a child's forehead, put the child in front of a mirror, and watch what happens. Young children are more likely to reach for the baby in the mirror than for their own foreheads. Dogs treat the dog in the mirror as another dog; not as themselves. Most animals fail at the red dot mirror task.
https://www.psychologytoday.com/blog...-dont-remember