Rank these four pairs from the STRONGEST predicted attraction to the WEAKEST, combining the factors present in each.

1. Two neighbours who see each other daily, share the same interests and values, and each has learned the other likes them.
2. Two colleagues who see each other daily and share many interests, but neither knows what the other thinks of them.
3. Two people who see each other daily but disagree about almost everything.
4. Two people who have never met, live in different countries, and know nothing of each other.

The pairs have three, two, one and zero of the durable factors respectively. The instructive comparison is the third versus the fourth: daily contact despite disagreement still beats no contact at all, because proximity and mere exposure operate even without similarity - which is exactly why proximity is described as one of the strongest single predictors.