When 12-year-old Jack saw an old man lying on the sidewalk in apparent discomfort, he prepared to offer help. But when he noticed several adults walk past the man, he concluded that the man did not need any help. His reaction most clearly illustrates one of the dynamics involved in
a. the mere exposure effect.
b. the fundamental attribution error.
c. social loafing.
d. the bystander effect.
Answer: d