Good question. Lots of tournament fisherman have made a good living catching bass behind another tournament angler who left the bass after catching one. The thinking that the bass are spooked is uaually not the issue. There will always be at least one bass that is more agressive then the others and you catch that fish first, on a reaction bite. The bigger bass, more than likely if you caught a smaller fish, have already moved a little deeper when you caught that first bass.
Try fishing over your shoulder a little deeper and a lot slower and your success rate should improve. The biggest mistake most fisherman make is leaving active bass that are feeding to move onto greener pastures and focusing their efforts toward the shoreline.
WRB