What type of experiment is conducted in a natural environment where the researcher manipulates the independent variable and measures its effect on the dependent variable?

A field experiment is the correct choice as it takes place in a natural environment, allowing researchers to manipulate the independent variable while observing its effect on the dependent variable. Unlike laboratory experiments, which are conducted in controlled settings and may not accurately reflect real-world dynamics, field experiments integrate the experimental design into everyday situations. This setup enhances ecological validity, making the findings more applicable to real life and providing insights that would be difficult to obtain in a lab setting.

In a field experiment, researchers can maintain some level of control over variables while still being exposed to the complexities of a natural environment. This method is especially useful in psychological research where behaviors and interactions are influenced by external factors that can alter how the independent variable affects the dependent variable. By utilizing this approach, researchers can gain a deeper understanding of the relationships they are studying in a context that participants are familiar with.