<P> The most fundamental and basic four layers of the pyramid contain what Maslow called "deficiency needs" or "d - needs": esteem, friendship and love, security, and physical needs . If these "deficiency needs" are not met--with the exception of the most fundamental (physiological) need--there may not be a physical indication, but the individual will feel anxious and tense . Maslow's theory suggests that the most basic level of needs must be met before the individual will strongly desire (or focus motivation upon) the secondary or higher level needs . Maslow also coined the term "metamotivation" to describe the motivation of people who go beyond the scope of the basic needs and strive for constant betterment . </P> <P> The human brain is a complex system and has parallel processes running at the same time, thus many different motivations from various levels of Maslow's hierarchy can occur at the same time . Maslow spoke clearly about these levels and their satisfaction in terms such as "relative", "general", and "primarily". Instead of stating that the individual focuses on a certain need at any given time, Maslow stated that a certain need "dominates" the human organism . Thus Maslow acknowledged the likelihood that the different levels of motivation could occur at any time in the human mind, but he focused on identifying the basic types of motivation and the order in which they should be met . </P> <P> Physiological needs are the physical requirements for human survival . If these requirements are not met, the human body cannot function properly and will ultimately fail . Physiological needs are thought to be the most important; they should be met first . </P> <P> Air, water, and food are metabolic requirements for survival in all animals, including humans . Clothing and shelter provide necessary protection from the elements . While maintaining an adequate birth rate shapes the intensity of the human sexual instinct, sexual competition may also shape said instinct . </P>

Maslow hierarchy of needs which is most important