Frank S. answered • 08/18/20
Chemistry and Physics Shaped By 15 Years’ Experience and Love
This is a very important question. It gets at the fundamental nature of what science is, and why psychology is a real science like chemistry or physics and not some trick we just made up: just like those other subjects, psychology can and does use the scientific method.
In a scientific experiment there is a presumed relationship between two phenomena; in other words you've made some observations about the world, and you've noticed that two things seem to "go together" or be connected in some way.
You also believe that you understand how those things are connected; at least well enough to make a TESTABLE, FALSIFIABLE prediction about the relationship. This sort of "educated guess" is called a hypothesis; it at least makes sense on paper, and you've talked it over with colleagues and checked the literature for anything that might ruin the idea out of hand.
But crucially, hypotheses are usually expressed as a predictive "if...then... statement." In other words, you want to be able to say, "If I do this, then we should observe that."
This construction allows you to design an experiment that allows you to literally "do this" and check to see if you really do "observe that." Remember the two phenomena I mentioned? The two things you thought were related? You're literally going to manipulate one (so, literally "do this") and then you're going to observe the other (literally "observe that.")
The one you manipulate is called the independent variable, and the one you observe is called the dependent variable.
Critically, there can only be those two variables in the experiment, while all other things are held constant; if there are extra variables, any results you observed are meaningless because you can't quite be sure which of the variables caused the things you observed. These potential snags are called confounding variables, and it is a major challenge of psychology research to design an experiment that can remove or minimize them all.
So lets say you perform your experiment and it turns out that your predictions were wrong. Great, you've demonstrated that the dependent and independent variable are not connected in the way you thought, so you document your results and publish your paper anyway so other people don't waste resources going down the same blind alley. You've falsified your hypothesis, so you head back to the drawing board.
But what if you do observe things to be the way you've predicted! Great! Now you repeat the experiment several times and publish the results. Peers in your subject will (or are supposed to, anyway) replicate the experiment as well to make sure it's not just you that gets these results, and then it's time to generalize-- test the same connection in a new way with a new experiment. If your hypothesis survives this experiment too, you just might have found new psychology theory.
A theory is therefore not just an opinion or a guess... it is a powerful scientific model for how a system works that has stood up to some substantial testing. The muggles... I mean, laypeople often get this wrong, either out of legitimate ignorance, or, sadly, out of arrogance.
And so science does not determine truth directly; instead it tests and exposes lies, one at a time. The body of scientific knowledge-- all of it, not just in psychology-- has been built up like this over the past four hundred or so years, often at great peril to those to have contributed.
Like children on the beach we are, with our tiny shovels and pails, patiently digging our way to a better world, one shovelful at a time.
