The Unsolvable Problem Task

Control dogs were in less experimenter proximity, this could be because shelter dogs have had more frequent interactive situations with unknown individuals such as caretakers or visitors. As rehomed dogs have previously been relinquished and adopted by a new owner, it means that they also might have had a lot of interactions with strangers and eventually even formed an attachment bond to a new owner.

Shelter dogs had less eye contact with owner or the caretaker. It is known that dogs tend to gaze towards the owner to ask for help when facing problems, and as shelter dogs had less eye contact, it suggests that they did not ask for help. Previous studies have found that shelter dogs can develop an attachment bond towards human beings who interact with them, but as the shelter dogs did not ask their caretakers for help, suggests that their bond is not as strong as that between a dog and its owner.

Memory test

There were no significant differences in the memory test. This test used two cups and a 60 second delay and it is possible that the test was not challenging enough. However, previous studies have used similar methods which suggests that the test protocol used in this study should be functional to measure working memory in dogs.

Eye contact test

Shelter dogs had shorter eye contact duration in the Eye Contact Test and they also had less eye contact in the Unsolvable Problem Task which suggests that the tendency to make and maintain eye contact is generally low, and this is most likely because they had caretakers instead of owners. It could also be because of social isolation, as control and rehomed dogs have had more opportunities to learn communicative responses throughout their daily interactions with humans, and shelter dogs haven’t because they tend to be more socially isolated.

Sleep patterns and hair cortisol

In previous studies, shelter dogs have been observed to have higher levels of cortisol compared to pet dogs. In this study, shelter dogs did indeed have higher levels of cortisol compared to rehomed dogs, but on the contrary, so did control dogs. The reasons for this could be many as it has previously been found that many different factors such as lifestyle, positive social interactions, breed, and size can affect cortisol levels. Hence, there could have been many reasons why control dogs had higher levels than expected in this study. The levels were however still within the normal span and control dogs did not show more stress-related behaviours than other groups.

No differences were found in sleep patterns. Previous studies have found that shelter dogs slept less over a 24-hour period, suggesting that shelter housing affects the sleep of shelter dogs. This differs from the results of this study, however, this study only analysed 4 hours and not 24 hours. The results might have been different if alternative methods were used.


This study did find some indications of both short and long-term effects of relinquishment. The short term effects such as shelter dog’s reduced ability to make and maintain eye contact, dogs might recover from once they have been adopted by a new owner. But the long-term effects, such as rehomed dogs’ contact seeking behaviour towards strangers shows that relinquishment might still have long lasting or even permanent effects on behaviour.