Given that field experiments are high in external validity,why is it that social psychologists still rely on laboratory studies?

Question

Quizplus · Accepted Answer

Laboratory studies allow for greater control of extraneous variables, which increases internal validity. This control is often necessary, particularly when testing causal relationships between variables. While field experiments have higher external validity, they can be more difficult to control for variables, which can make it harder to draw causal conclusions.

Given That Field Experiments Are High in External Validity,why Is