I personally believe that lab experiments are useful and an effective way to test and gather data. Even though they can often lack ecological validity and mundane realism they can easily be replicated and results can be retested, helping to prove/disprove data, ultimately leading to the creation of practical applications.
That psychologist can make statements about cause and effect because they involve the deliberate manipulation of one variable while trying to keep the other variables constant, unlike non-experimental methods.
Lab experiments can also be replicated due to the standardised procedures and measures, ultimately making it easier to check the reliability of the research/results and prove/disprove results if the research is conducted by another researcher.
