Our pet dogs seem to be good at knowing that it’s time to run over when we say “treat”, but that’s a word they hear – hopefully, from their vantage point – every day. How is their longer-term memory for certain names, though? A new study finds it could persist for years, even if they haven’t heard it in a while.

Research recently published in the journal Biology Letters investigated how well dogs were able to recall the names of toys they hadn’t seen in two years. These weren’t just any old pet dogs, though. They were gifted word learners, which are dogs that have demonstrated a vocabulary of object labels, or, essentially, they have shown the ability to quickly learn the names of things.

The five dogs in this study – all gifted word learner border collies – had learned the names of 12 toys within a week in December 2020. Those toys were then stowed away. A month later, they were asked to retrieve six of the 12 toys. A month after that, they were asked to retrieve the other six. In the first experiment, they chose correctly an overall average of 70% of the time, while their success rate was 55% in the second month. After that, the toys were hidden from view for two years.

At the two-year mark, the border collies were quizzed on the names again. Due to the very common pet owner experience of toys being misplaced, one dog was only tested on 11 toys and one on only five. This time around, though, when they were asked to retrieve the toys in similar experiments, they were still right an average of 44% of the time. For four of the five dogs, the correct toy was retrieved at least once between three and nine times, showing that these dogs may have remembered their old friends, at least for now.

The authors write, “When comparing the dogs’ group performance in the present 2-year memory test, with that of the one- and two-month memory tests, it appears that there was no significant reduction in their recall of the labelled objects. However, the fact that there was a trend towards significance in the comparison between the 2-year and one-month memory tests, raises the possibility that larger sample sizes may reveal a reduction in the dogs’ recall over such a long timeframe.”

Despite that disclaimer, the findings show that dogs may have a longer-term object name recall capability, though researchers do say that this may not necessarily be the case with your own pooch. Most family dogs have not shown they have a strong ability to learn object labels.

However, it shows certain long-term memory recall may not just be a human thing, and it provides an opportunity to see what else may be going on in the minds of non-speaking animals.

The researchers explain, “In humans, high performance in verbal memory tasks has been associated with high-performance in other memory tasks, such as visuospatial memory and autobiographical memory, and other cognitive domains, such as executive functioning. [Gifted word learner] dogs provide a unique opportunity to examine whether such correlations may also exist in a species that does not possess language.”

You can read the whole study here.