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 five stages in Maslow's hierarchy of needs in order from lowest to highest level include physiological, safety, social (love and belonging), esteem, and self-actualization. Each need must be met from lowest (physiological) to highest (self-actualization).