A phenomenon, in a scientific context, is something that is observed to occur or to exist. This meaning contrasts with the understanding of the word in general usage, as something extraordinary or outstanding.
Phenomena are categorized in a number of ways. Here are a few of the many possibilities, with examples:
- Natural phenomena are those that occur or manifest without human input. Examples of natural phenomena include gravity, tides, biological processes and oscillation.
- Social phenomena are those that occur or exist through the actions of groups of humans. Six degrees of separation, for example, is a phenomenon that is demonstrated in social networking.
- Psychological phenomena are those manifested in human behaviors and responses. The sunk cost effect, for example, is the tendency for humans to continue investing in something that clearly isn’t working. Another psychological phenomenon, the Hawthorne effect is demonstrated by an improvement in human behavior or performance as a result of increased attention from superiors, clients or colleagues.
- Visual phenomena include optical illusions, such as the peripheral drift illusion in which people perceive movement in static images like Kitaoka Akiyoshi's rotating snakes (See the image in our definition of the peripheral drift illusion).
The word phenomenon is derived from the Greek verb phainein, which means to show, shine, appear, to manifest or to be manifest.