I'm obsessed with measurement, particularly of psychological phenomena that are really hard to pin down. How exactly have researchers eeked out why and how (and how much) people like one another?
Our fearless researcher Hannah sums up the basic techniques nicely. If you must know, I'm a fan of the behavioural tells.
MEASUREMENT OF ATTRACTION
Numerous behavioural measures have been used to assess levels of interpersonal attraction (often referred to as 'positiveness of the attitude'). Most have used the 'Interpersonal Attraction Judgment Scale', developed by Donn Byrne, which requires subjects to rate target persons on dimensions such as intelligence, knowledge of current events, morality, adjustment, likability and desirability as a work partner, usually by use of a self-report questionnaire.
Thurstone (1928) was one of the first to investigate interpersonal attraction in a quantifiable way. He proposed a method of attitude-scale construction, wherein a number of finely honed attitude statements were presented, from 1 – 20, expressing a wide range of possible attitudes toward a person or object. Subjects could then be asked whether they agreed or disagreed with each of the 20 statements, and to what extent they did so.
OTHER BEHAVIOURAL DEVICES
While questionnaire scales are the most commonly used attitude-measuring devices, other means have been used to measure the positiveness of a subject's attitude toward another person, as, when a subject is forced to consider what his own attitudes are, many researchers held that his introspection may cause him to change his attitude in the process of describing it.
Other techniques include:
Eye-contact: When two people are engaged in conversation, they look one another in the eye intermittently and for short periods. Argyle (1967) found that the amount of time individuals look at one another varies from 30 percent to 60 percent. One determinant of how long individuals gaze at one another appears to be interpersonal attraction. The frequency of glances has been found to correlate positively with an individual's liking for another, and with the extent to which he desires to initiate or maintain his interaction with the other.
Physical Proximity: Although there are cultural differences in how close people feel it is polite to stand (one study observed a conversation, during which one visiting professor slowly backed another down the full length of a college corridor, one small step at a time), distance between those conversing can also be used to measure attraction. In general, we stand closer to those we like than to those we do not.
Sociometric choices: It is generally assumed that the more we like someone, the more anxious we will be to associate with him. Thus one's choices as to whom he will associate with have been used as measures of liking in several experiments.