Blackwell and Colleagues Conducted an Experiment on Seventh Graders in a New

Multiple Choice

Blackwell and colleagues conducted an experiment on seventh graders in a New York City school to assess whether teaching students that intelligence was a malleable rather than a fixed trait could improve students' classroom motivation and mathematical performance.This experiment is an example of a

A) laboratory experiment.
B) field experiment.
C) population-based survey experiment.
D) natural experiment.