Social learning theory suggests that four sub-processes are believed to govern skill acquisition. these are:

They are: (1) Attention (2) Retention (3) Motor Reproduction (4) Motivation

The changes to agriculture in the united states since 1900 is that increased mechanization has increased food production, thereby increasing the need for labor. there has been an increased need for higher speeds of food production due the fact that the population in the united states continues to rise.