Maslow's Hierarchy of Needs
Abraham Maslow's pyramidal "Hierarchy of Needs" model is a highly-influential way of organizing human needs from the most "basic" to the most advanced. Maslow's argument is that the most basic needs must be met before people can move "up" to the more advanced needs. It's important to note, however, that Maslow did not argue that each person must have met 100% of each need in order to "move up." For example, a learner can be a little hungry and still learn, but chronic hunger is a problem.
From the bottom up, the needs Maslow advances in this theory are: physiological, safety, love and belonging, esteem, and self-actualization. The needs can be grouped into two categories: "deficiency needs" and "growth needs." Most of the pyramid consists of "deficiency needs." These needs are ones that grow worse over time, and as the need gets stronger, the person's motivation to meet the need gets stronger too. Again, someone can be a little hungry and wait for dinner, but a starving person will eat anything and find it to be delicious. Self-actualization, on the other hand, is a "growth need." This is a type of need that isn't characterized by the "lack" of something. Instead, our need for self actualization is intrinsic, and self-actualization itself can be a seen as a cluster of related "growth needs" that can be individual to each person.
Over the course of a lifetime, and even within the confines of a single day, learners can move up and down Maslow's pyramid. For example, a young student may come to class hungry, eat a school breakfast and do very well in class until an incident with a peer threatens their sense of safety or esteem. By the end of the day, the social pressures may have been addressed by an attentive teacher or caregiver, but the child then is not given dinner at home, and they go to bed hungry. Adults can have their needs disrupted too, both by mundane causes like dieting (!) or more serious disruptions like being the victim of a crime or going through a divorce.
The following short video provides more information and examples about Maslow's Hierarchy of Needs: