Motor skill
A motor skill is a function that involves specific movements of the body's muscles to perform a certain task. These tasks could include walking, running, or riding a bike. In order to perform this skill, the body's nervous system, muscles, and brain have to all work together. The goal of motor skill is to optimize the ability to perform the skill at the rate of success, precision, and to reduce the energy consumption required for performance. Performance is an act of executing a motor skill or task. Continuous practice of a specific motor skill will result  in a greatly improved performance, which leads to Motor Learning. Motor learning is a relatively permanent change in the ability to perform a skill as a result of continuous practice or experience. Types of motor skills. Motor skills are movements and actions of the muscles. There are two major groups of motor skills: Both Gross and fine motor skills can become weakened or damaged. Some reasons for these impairments could be caused by an injury, illness, stroke, congenital deformities (an abnormal change in the size or shape of a body part at birth), cerebral palsy, and developmental disabilities. Problems with  the brain, spinal cord, peripheral nerves, muscles, or joints can also have an effect on these motor skills, and decrease control over them. Development. Motor skills develop in different parts of a body along three principles: In children, a critical period for the development of motor skills is preschool years (ages 3–5), as fundamental neuroanatomic structure shows significant development, elaboration, and myelination over the course of this period. Many factors contribute to the rate that children develop their motor skills. Unless afflicted with a severe disability, children are expected to develop a wide range of basic movement abilities and motor  skills around a certain age. Motor development progresses in seven stages throughout an individual's life: reflexive, rudimentary, fundamental, sports skill, growth and refinement, peak performance, and regression. Development is age-related but is not age dependent. In regard to age, it is seen that typical developments are expected to attain gross motor skills used for postural control and vertical mobility by 5 years of age. There are six aspects of development: In the childhood stages of development, gender differences can greatly influence motor skills. In the article "An Investigation of Age and Gender Differences in Preschool Children's Specific  Motor Skills", girls scored significantly higher than boys on visual motor and graphomotor tasks. The results from this study suggest that girls attain manual dexterity earlier than boys. Variability of results in the tests can be attributed towards the multiplicity of different assessment tools used. Furthermore, gender differences in motor skills are seen to be affected by environmental factors. In essence, "parents and teachers often encourage girls to engage in [quiet] activities requiring fine motor skills, while they promote boys' participation in dynamic movement actions". In the journal article "Gender Differences in Motor Skill Proficiency From Childhood to Adolescence" by  Lisa Barrett, the evidence for gender-based motor skills is apparent. In general, boys are more skillful in object control and object manipulation skills. These tasks include throwing, kicking, and catching skills. These skills were tested and concluded that boys perform better with these tasks. There was no evidence for the difference in locomotor skill between the genders, but both are improved in the intervention of physical activity. Overall, the predominance of development was on balance skills (gross motor) in boys and manual skills (fine motor) in girls. Stages of motor learning. Motor learning is a change, resulting from practice . It often involves improving the accuracy of movements both simple and complex as one's environment changes. Motor learning is a relatively permanent skill as the capability to respond appropriately is acquired and retained. The stages of motor learning are the cognitive phase, the associative phase, and the autonomous phase. Law of effect. Motor-skill acquisition has long been defined in the scientific community as an energy-intensive form of stimulus-response (S-R) learning that results in robust neuronal modifications. In 1898, Thorndike proposed the law of effect, which states that the association between some action (R) and some  environmental condition (S) is enhanced when the action is followed by a satisfying outcome (O). For instance, if an infant moves his right hand and left leg in just the right way, he can perform a crawling motion, thereby producing the satisfying outcome of increasing his mobility. Because of the satisfying outcome, the association between being on all fours and these particular arm and leg motions are enhanced. Further, a dissatisfying outcome weakens the S-R association. For instance, when a toddler contracts certain muscles, resulting in a painful fall, the child will decrease the association between these muscle contractions  and the environmental condition of standing on two feet. Feedback. During the learning process of a motor skill, feedback is the positive or negative response that tells the learner how well the task was completed. Inherent feedback: after completing the skill, inherent feedback is the sensory information that tells the learner how well the task was completed. A basketball player will note that he or she made a mistake when the ball misses the hoop. Another example is a diver knowing that a mistake was made when the entry into the water is painful and undesirable. Augmented feedback: in contrast  to inherent feedback, augmented feedback is information that supplements or "augments" the inherent feedback. For example, when a person is driving over a speed limit and is pulled over by the police. Although the car did not do any harm, the policeman gives augmented feedback to the driver in order for him to drive more safely. Another example is a private tutor for a new student in a field of study. Augmented feedback decreases the amount of time to master the motor skill and increases the performance level of the prospect. Transfer of motor skills: the gain or loss in  the capability for performance in one task as a result of practice and experience on some other task. An example would be the comparison of initial skill of a tennis player and non-tennis player when playing table tennis for the first time. An example of a negative transfer is if it takes longer for a typist to adjust to a randomly assigned letter of the keyboard compared to a new typist. Retention: the performance level of a particular skill after a period of no use. The type of task can have an effect on how well the motor skill  is retained after a period of non-use: Brain structures. The regions of the frontal lobe responsible for motor skill include the primary motor cortex, the supplemental motor area, and the premotor cortex. The primary motor cortex is located in the precentral gyrus and is often visualized as the motor homunculus. By stimulating certain areas of the motor strip and observing where it had an effect, Penfield and Rassmussen were able to map out the motor homunculus. Areas on the body that have complex movements, such as the hands, have a bigger representation on the motor homunculus. The supplemental motor  area, which is just anterior to the primary motor cortex, is involved with postural stability and adjustment as well as coordinating sequences of movement. The premotor cortex, which is just below the supplemental motor area, integrates sensory information from the posterior parietal cortex and is involved with the sensory-guided planning of movement and begins the programming of movement. The basal ganglia are an area of the brain where gender differences in brain physiology is evident. The basal ganglia are a group of nuclei in the brain that is responsible for a variety of functions, some of which include movement . The globus pallidus and putamen are two nuclei of the basal ganglia which are both involved in motor skills. The globes pallid-us is involved with the voluntary motor movement, while the putamen is involved with motor learning. Even after controlling for the naturally larger volume of the male brain, it was found that males have a larger volume of both the globus pallidus and putamen. The cerebellum is an additional area of the brain important for motor skills. The cerebellum controls fine motor skills as well as balance and coordination. Although women tend to have better fine motor skills , the cerebellum has a larger volume in males than in females, even after correcting for the fact that males naturally have a larger brain volume. Hormones are an additional factor that contributes to gender differences in motor skill. For instance, women perform better on manual dexterity tasks during times of high estradiol and progesterone levels, as opposed to when these hormones are low such as during menstruation. An evolutionary perspective is sometimes drawn upon to explain how gender differences in motor skills may have developed, although this approach is controversial. For instance, it has been suggested that men were the  hunters and provided food for the family, while women stayed at home taking care of the children and doing domestic work. Some theories of human development suggest that men's tasks involved gross motor skill such as chasing after prey, throwing spears and fighting. Women, on the other hand, used their fine motor skills the most in order to handle domestic tools and accomplish other tasks that required fine motor-control.