This summer I looked closely at the books on my bookshelf to  rekindle my affection with these old flames. One book that stood out was written by Morton Deutsch and Robert M. Krauss (1965) simply titled “Theories in Social Psychology”. The first chapter has a section labelled “The Nature of Theory”. In my opinion it is still very relevant today and is a must read for social and personality psychologists. I will quote from this section a little as I paraphrase the main points:

1. Theories in the physical sciences often make definitive hypotheses that are logical extensions of the theory in question.

– For example (my example, not one used by Deutsch & Krauss), Einstein’s General Theory of Relativity made a specific hypothesis regarding how much light should be observed to bend around large objects (among other hypotheses of course). Everyone that understood the theory could derive the same specific hypothesis regarding the effects of gravity on the bending of light.*

2. Theories in Social Psychology do not typically make definitive hypotheses that are logical extensions of the theory in question. Instead, “…the ‘derivations’ from most of the theories in social psychology are usually not unequivocal, or strictly logical, for they skip steps, they depend on unexpressed assumptions, and they rest on the criterion of intuitive reasonableness or plausibility rather than on formal logical criteria of consistency.” (p. 7). As they go on to say on page 11, most theoretically derived hypotheses in social psychology are plausible inferences that can be made from an understanding of the theory rather than logical deductions dictated by the theory itself.

– This was not meant as slight to social psychological theories, but was rather pointed out as a reflection of the nascent state of our theories that does not allow for specific, definitive hypotheses to be derived. As theories are rigorously tested over time, some hypotheses should (hopefully) consistently replicate, others not so much, and a better understanding of the nomological network will emerge (Cronbach & Meehl, 1955).

As Feynman discusses in his Cornell lectures (https://www.youtube.com/watch?v=EYPapE-3FRw), using the scientific method we compute the consequences of new laws/theories, and then compare these consequences with observations. If the observations are not as predicted, then the theory is not confirmed (or as he says in this lecture, they are “wrong”). But as Deutsch and Kraus point out, computing the consequences of social psychological theories is not as straightforward as it is for theories in the physical sciences. Given this fact, it is likely that at times experts could derive discordant, yet plausible, hypotheses from the same social psychological theory. Theory testing and theory building in social psychology is therefore challenging.

Then I ran this simple thought experiment (N =1): imagine asking 20 research teams with expertise on, say, adult attachment theory to independently make specific hypotheses regarding the association between, for example, scores on anxious attachment and avoidant attachment with feelings of acceptance from a romantic partner across three experimental conditions: (1) control (no intervention), (2) relationship threat (e.g., when one partner does not want to spend time with the target participant), and (3) relationship boost (e.g., when one partner does want to spend time with the target participant). Next, have a team of coders rate the similarity of generated hypotheses. How similar would they be? How many different, plausible hypotheses would be put forward? My guess is that there would be some consistency across research teams, and some variability as well. I can generate what I feel are plausible, yet discordant, hypotheses all on my own. Feel free to conduct this thought experiment with your theory of choice. Not every expert, considering the same body of information, will generate the same hypotheses.

I am not blaming the theory for not being to make definitive hypotheses at all times. But it does seem that building theory would benefit from more truly confirmatory research being conducted that tests specific, plausible, and pre-registered hypotheses, with the results published regardless of the outcomes. Because as Feynman also says in the lecture linked to above, vague theories can accommodate almost any result, making them rather useless as theories.

* at this point it is obvious I am not a physicist, p < .00000000000001.

Cronbach, L.J., & Meehl, P.E. (1955). Construct validity in psychological tests. Psychological Bulletin, 52, 281-302.

Deutsch, M., & Krauss, R.M. (1965). Theories in social psychology. New York: Basic Books Inc..