In contrast to animal social learning (e.g. dogs learning from observing another dog), humans typically teach by attracting the attention of the learner. Also during the training of dogs, humans tend to attract their attention in a similar way. Here, we investigated dogs' ability to learn both from a dog and a human demonstrator in a manipulative task, where the models demonstrated which part of a box to manipulate in order to get a food reward. We varied the communicative context both during the dog and during the human demonstration comparably: a second experimenter directed the attention of the subjects to the model (dog/human ostensive demonstration) or remained silent (dog/human non-ostensive demonstration). Moreover, we investigated whether the training level of the dogs (well-trained vs. untrained) affected how the dogs performed in the manipulative tasks after the different demonstrations. We found that better trained dogs showed significantly better problem solving abilities. They paid more attention to the human demonstration than to the dog model, whereas such a difference in attentiveness of the less trained dogs was not found. Despite slight differences in paying attention to the different demonstrators, the presence of human or the dog demonstrators exerted equally effectiveness on the test performance of the dogs. However, the effectiveness of the demonstrations was significantly reduced if ostensive cues were given during the demonstrations by a second experimenter. Analysis of attentiveness and activity of the observer dogs during the demonstrations indicates that the reason for this negative effect was a combination of distracted attention paid to the demonstration and a higher level of excitement in the ostensive than in the non-ostensive demonstrations. This study suggests that third party communication during demonstration attracts dogs' attention to the communicator instead of paying close attention to the model. We suggest that precise timing and synchronization of attention-calling and demonstration is necessary to avoid this distracting effect.