Sandy has a huge crush on Casey. When he is nearby, Sandy doesn't pay attention to anything or anyone else. Psychologist Donald Broadbent explained that we selectively attend to the most important information in model he developed.

The most important information in this model he developed is the "filter theory."

Explanation:

Filter theory is a description of desirability planned by Kerchoff and Davies (1962). This concept proposes that individuals advance associations by smearing a sequence of filters, such as resemblance of communal demographic issues and arrogance and complementary of wants to slender down the pool of obtainable candidates. Filter theory is a sociological theory concerning dating and mate selection. It proposes that social structure limits the number of eligible candidates for a mate. Most often, this takes place due to homogamy, as people seek to date and marry only those similar to them.