Final answer:
The term for forgetting to search for a pencil and making a sandwich instead is called 'absentmindedness', a common memory error due to breaks in attention.
Step-by-step explanation:
The scenario described where Tim is doing homework, but after his pencil snaps and he goes to get a new one, he instead makes a sandwich due to forgetting his initial intent, is referred to as absentmindedness. This term characterizes lapses in memory that occur due to breaks in attention or focus being divided elsewhere. Absentmindedness is a common memory error that everyone experiences at times, such as when you walk into a room and forget why, or when you cannot recall if you've completed a routine task because you were distracted or preoccupied, much like Cynthia, the psychologist, who forgot if she had returned her court identification because she was worried about her sick daughter.