The psychologist Paco Underhill He became an expert in consumer behavior in the 1990s after examining thousands of hours of images of security cameras installed in stores.
One of the strangest patterns discovered was the so-called "ass rub effect", through which the consumer seemed to depose his attitude of buying if he rubbed his ass with another person because of the hallway.
Underhill points out that by studying the behavior of buyers at points of sale we can find indications of the patterns that govern their consumption habits. The underhill theories they include the invariant right (the Americans stay on the right side of the esplanades or sidewalks), the period of downward change (they need time to slow down), the decompression zone (they don't notice the area inside the door of a store) and " petting "(customers like to handle merchandise).
One of the most curious are the friction between people. When the stores are crowded and the exhibitors of the product are very close to each other, this forces customers to squeeze to pass when another person is on their way.
The images analyzed by Underhill showed hundreds of cases in which clients had to involuntarily scrub each other. The behavior of men and women in this respect was different.
In the case of women (and to a lesser extent in men), rubbing with another person was the reason they tended to stop looking and they left the store without having bought anything.
But what really caused the consumer to leave the store? The discomfort? The physical contact with strangers? None of that, because customers were not aware that they reacted to these frictions, as he explains Adam Alter in his book Irresistible:
They knew they had left the store, but they almost always said it had nothing to do with the presence of other customers. Sometimes they gave solid reasons that justified their departure (they were late for a meeting or had to go look for the children at school), but the pattern was too obvious to deny their existence. What Underhill had identified was a detention rule, that is, a signal that led consumers to stop buying.