When one of our authors (Kelvin Seifert) was growing up, he was provided with piano lessons. Daily practice was a staple of childhood— 365 days a year, and in a home that was deliberately kept quiet to facilitate practice. Music— especially the piano— defined a major part of his emerging self-identity. Altogether he studied piano for 13 years, from age 4 to the end of high school, with only occasional interruptions.
At any one time, Kelvin witnessed small changes in his skills. He performed a simple piece a bit better than he had the previous week, or he played more of it from memory. There were direct, obvious connections between his skills at one moment and at the moment just before or after. Back then, if you had asked him what accounted for the changes, he would have stated without hesitation that they were because he was "learning" specific piano pieces.
Across broader spans of time, however, he noticed changes that were more dramatic. Kelvin learned much more complex pieces than he had several years earlier, for example. He also played with significantly more "finesse", sensitivity and polish than as a young child. He was even listening to classical music on the radio some of the time! Kelvin's musical talent became transformed over the long term, and in some sense he did not have the "same" talent that he had had as a beginner.
If you had asked what accounted for these longer-term changes, he would have had a harder time answering than when asked about the short-term changes. He might have said simply and a bit vaguely: "I have been getting better at piano." If you ask the same question now, however, he would say that his music skills had developed, that their development had been slow and gradual, and that the changes resulted not just from simple practice, but also from becoming more widely skilled about music in general.
Development refers to long-term personal changes that have multiple sources and multiple effects. It is like the difference between Kelvin's music at age fifteen compared to his music at age five, rather than the difference between his music one week and his music the next. Some human developments are especially broad and take years to unfold fully; a person's ever-evolving ability to "read" other's moods, for example, may take a lifetime to develop fully. Other developments are faster and more focused, like a person's increasing skill at solving crossword puzzles. The faster and simpler is the change, the more likely we are to call the change "learning" instead of development. The difference between learning and development is a matter of degree. When a child learns to name the planets of the solar system, for example, the child may not need a lot of time, nor does the learning involve a multitude of experiences. So it is probably better to think of that particular experience— learning to name the planets— as an example of learning rather than of development (Salkind, 2004; Lewis, 1997)