The soft plastic jig catches more bass for me than any other lure. Old reliable continues to perform time after time. In the spring trying to imitate a crayfish is a good starting point. In the fall maybe a shad color is best. Bait color definitely attracts interest, but movement and behavior are equally important in actually fooling the fish.
Plastic jigs are a package deal with color, size, action and presentation equally important.
What really happens is that the fish sees and feels the bait in the water and then natural curiosity takes over. Fortunately, bass are more curious than a pup with baby teeth trying to decide what to chew on next. Springtime is marked by a slow metabolism on the part of the fish, cool temperatures, overcast skies and scarcity of food. Fish are trying to get active, move shallow and find nest sites. A soft plastic jig fished on the bottom fits right in, fulfilling the needs of the bass.