The key to remembering is their noses. It is estimated that dogs can smell somewhere between 1,000 to 10,000 times better than humans. A study by Pacific Standard found that there is a specific area in a dog’s brain that will light up when it smells a familiar human.
The Telegram have published an article talking about a similar study published in the science journal; Behavioural Processes where they test 12 dogs of various breeds who underwent brain scans while five different scents where placed before them. The resulted showed that responses were significantly higher for the scents of familiar humans. Not only did the dogs recognise their humans' scents, but they also got more excited.
Dr Berns said: "This suggested that not only did the dogs discriminate the familiar human scent from the others, they had a positive association with it."
Dogs also have associated memory which mean they can in fact remember people based on their experiences associated with them. Your dog may have a memory of you leaving the house and due to the strong positive association with you mean they’ll celebrate when you get home.
Animal Cognition journal published a study that examined the facial recognition in domestic dogs, using pictures of faces on a computer screen. The study included 23 pet dogs and 8 kennel dogs.
The result of the study found that dogs that live with families were more responses to human faces, and were more observant of familiar rather than unfamiliar human faces. It was concluded from this study that dogs are capable of facial recognition.
Looks like there is no need to worry that you dog will forget you!