A "bridge" in animal training is a stimulus that bridge a correct response to a reinforcement (usually a food reward) and is almost often a vocal communication such as the sound of a clicker or praises (Good boy!). A bridge is usually an anticipation of something positive going to happen and bridging tells an animal that they did the desired behavior and a reward is on its way.
Most of what I did today was bridging and positively reinforcing my lemurs to do the behavior I want them to do. The bridge, in this instance, is the sound of a moving conveyer belt that dispenses a treat. When the lemur hears the mechanical sound of the conveyer belt, it acts as a bridge to tell them they did the right behavior and a food reward is on its way. All the lemurs that I worked with today were very cooperative. They ran right up to the apparatus and did a lot of explorative behaviors but almost immediately knows that the chute in the apparatus drops food reward because they were sitting near the chute (this might be a biased observation on my end). Hopefully, in time, they will associate the sound of the conveyer belt as the bridge.
Aside from doing training today, the trainers and me found a few issues that I need to work on with my apparatus. One of the most important thing was glare. We tried to train the lemurs outdoors and the glare made it impossible to see the tablet screen. I will be training the lemurs indoors tomorrow so hopefully the screen should be brighter (in theory it will). Some design changes were made to the phone app interface, including having a number countdown on how many food rewards were dispensed for easy rewinding, as well as incorporating haptic feedback whenever I press a button so I don't have to look down at the phone while miraculously also keeping an eye on the lemur.