It was assumed that the duration of working memory in dogs is around 27 seconds, however, a study on a group of dogs revealed that they were able to maintain spatial memory of an object up to 240 seconds. In our study, we looked at 50 multiple dog breeds. In experiment 1, a small ball was put in one of the 3 wooden boxes in front of the dogs. The dogs had a retention interval for 1,2,3 and 4 minutes consecutively. Then they were asked to search for the ball. In experiment 2, the same ball was put in 3 colourful boxes that were, green, blue, and purple which are distinguishable to dog vision. The retention intervals were kept the same. Our results revealed that the addition of colour has increased the dogs' likelihood of finding the ball which suggests an advancement in the duration of working memory.