An externality is a cost or benefit of an economic activity experienced by an unrelated third party. Positive externality is a benefit from an economic activity experienced by an unrelated third party. Examples of positive externalities include: 1. Individual education. The increased levels of an individual`s education can also raise economic productivity and reduce unemployment levels. 2. Vaccination. Vaccination benefits not only the person vaccinated but other people in the community because the probability of being infected decreases. The majority of externalities are negative. A negative externality is a negative consequence of an economic activity experienced by an unrelated third party. Examples of negative externalities are: 1. Air pollution. A factory burns fossil fuels to produce goods. The people living in the nearby area and workers of the factory suffer from the deteriorating air quality. 2. Noise pollution. People living near a large airport suffer from high noise levels.
ervention based on their own interest, and receives the reinforce when the child attempts to follow the instructor’s prompt. Incidental teaching is also an intervention that promotes lasting and impactful results because it is an intervention that is early, it also can be done in a variety of settings with different people, it can have family involvement, the procedure can include peers, and it is fun for the child since it initiated by the child (McGee et al., 1999). Since it is child selected, it drives the child’s motivation, which ultimately assists the child to learn.
Limitations
Incidental teaching is a procedure that has shown a lot of progress in children, especially in vocalization. However, the teaching procedure is mainly an intervention that focuses on verbal communication and can be limiting to certain children with ASD, especially those who are severe. McGee et al. (1983) modified the standard incidental teaching for autistic children with severe language deficits shown evident progress in the subjects. However, the setting was more contrived and it was not based on the interests of the child. In addition, many studies mentioned that it is beneficial for the child to initiate, but it becomes challenging to use incidental teaching past a certain age because then the interests start to become narrower and more depleted.
It is also difficult to find a “perfect” intervention for ASD because it is a spectrum disorder, so the signs and symptoms vary among children. Therefore, each child is at a different level of severity, and each level of severity needs more or less assistance. It is going to be easier for high functioning children with ASD to learn how to have verbal communication that is socially functional than it would be for lower functioning children with ASD. It is also dependent upon the parents and the services of the child that determines the success of an intervention. Some parents do not have as much time to practice instructional teaching at home, so the procedure may only be done once or twice a week with therapy appointments. For example, McGee et al. (1999) had a home-based component in their study where to parents did an addition ten hours a week of teaching with their child, so that is also a contributing factor to the children’s progress. In addition, if a child does not have therapists that are educated adequately for the procedure, then the child will not have as much progress. This procedure, like many others in the field of ASD
