Final answer:
Sara's reaction of shifting her attention when hearing her name in another conversation demonstrates inattentional blindness.
Step-by-step explanation:
The perceptual effect demonstrated by Sara shifting her attention when hearing her name in another conversation is called inattentional blindness. Inattentional blindness refers to the failure to notice something that is completely visible because attention is focused on something else. An example of inattentional blindness is the famous gorilla experiment conducted by Simons and Chabris, where participants were so focused on counting basketball passes that they completely missed a person in a gorilla costume walking through the scene.