This emoji was part of the proprietary / non-standardized emoji set first introduced by Japanese carriers like Softbank. These emojis became part of the Apple iPhone starting in iOS 2.2 as an unlockable feature on handsets sold in English speaking countries.
Maslow's (1943, 1954) hierarchy of needs is a motivational theory in psychology comprising a five tier model of human needs, often depicted as hierarchical levels within a pyramid. Maslow stated that people are motivated to achieve certain needs and that some needs take precedence over others.
The Work of Abraham Maslow. Psychologist Abraham Maslow described a hierarchy of needs that he argued provides a model for understanding the need for human relations in the classroom. Needs lower on the pyramid, such as physical and safety needs, must be met before an individual will consider higher-level needs.