Causal Models and Diagrammatic Representations of the Operation of Causal Processes
Path diagrams are used to portray relationships among variables at the aggregate or group level and, as such, they do not provide a clear illustration of how a particular causal chain operates within a particular couple's relationship; that is, variations within a sample in one variable are shown in path diagrams to account for variations in the sample in regard to a second variable. When a diagram shows a connection between "compatibility" and the "affective quality of interaction," the diagram proposes that couples who are highly compatible (compared to those who are less compatible) are more likely to express affection and less likely to experience conflict and negativity. It is sometimes useful to think through the implications of your causal model by applying it to a particular hypothetical case.
The following example (taken from Kelley et al., 1983) shows how it might be done. Imagine you were an omniscient observer of two individuals - Person P and Person O - who are similar in their attitudes. Attitude similarity, coupled with the opportunity to interact (propinquity), sets the stage for their interaction. Events are numbered P1-P10 in the order that they occur for Person P, and are numbered O1-O10 for the other person O.
| Person P (Person) | Person O (Other) |
| P1: expresses opinion | O1: finds P agrees with own opinion O2: feels positive affect |
| P2: sees O feel good | O3: O expresses agreement |
| P3: finds other supports own opinion | |
(P and O now have a shared perception of similarity) |
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| P4: feels positive affect | O4: observes that P perceives and likes the agreement |
| P5: moves toward O - makes eye contact and smiles | O5: thinks "P seems to like me," O6: feels positive affect |
| P6: expects further support and P7: discloses further attitude |
O7: finds P agrees with own opinion, and O8: makes supportive comment |
| P8: thinks O might be good supportive friend, and P9: says "let's get together tomorrow" |
O9: responds "OK; where and when?" |
| P10: suggests time and place | O10: agrees |
(Another opportunity for propinquity has occurred) |
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The exchange is affectively positive and free of conflict and tension. If the participants were to have dissimilar attitudes, the course of the exchange would likely develop quite differently. It is important to recognize that "attitude similarity" refers to the extent of similarity between partners on a variety of attitudinal issues. The more similar a pair is, the more likely they will, on average, agree with each other's verbalizations. Moreover, attitude similarity, conceived as a variable that distinguishes pairs of people within a population, accounts for the probability that particular kinds of scenarios will develop during an interaction.
The example captures an important way in which attitude similarity might account, in part, for the affective quality of the relationship. It is easy to extend the illustration and imagine how attitude similarity might come to affect satisfaction within the relationship. In creating diagrammatic representations, it is important to recognize that such representations capture only one of what may be many possible causal paths. It is possible, for example, that attitude similarity may affect harmony/conflict even when participants do not verbalize their attitudes. This might happen, for example, when a person performs a particular activity that reflects particular attitudes (e.g., does the dishes, attends church, takes a hike, volunteers for some activity). If the activity reflects the person's actual attitudes, then similarity in attitudes may create good feelings and encourage harmony rather than conflict.
Once you start developing your diagrammatic representations, you will begin to elaborate and refine your model. The narrative explicating your reasoning might run 2-3 single-spaced pages, depending on the complexity of your argument. Such an explication frames your question and provides you with some ideas concerning the scope of literature on courtship and marriage you will need to consider. You are now in a position to read the theoretical, methodological, and empirical literature with a more critical eye than before.
