This chapter explains the methods of researching : observation and experience …show more content…
The most common disadvantage is time. The authors also note that longitudinal studies took a long time to finish, and it may not guarantee all babies' parents cooperation at the end because " stressed families are more likely to drop out." Some babies may drop out of this program because parents think that "repeated testing can affect behavior,” or in some case babies may passed away during this program. The last disadvantage of longitudinal studies is it’s "extremely expensive in the term of time and resources" (Bornstein, Arterberry & Lamb, 2014). With these reasons the cross- sectional take place; however this study still has advantage, and disadvantage as well. The advantages are short time, not expensive to investigate as longitudinal, and parents can cooperate at the end without stress. However, the authors reveal that cohort effects of different ages and different behaviors the problem is " do not help identify developmental …show more content…
This method is related to the brain and spinal cord. The principal electrophysiological techniques has involved the cortical event -related potential ( ERP). For example, placing an electrode is attached to the scalp with wires on the baby’s head.The purpose is helps the researchers record brain response, so they can predict the infant's memory, cognition, speech and learning language. According to Biocka 2015 “An Electroencephalogram is a test used to evaluate the electrical activity in the brain. Brain cells communicate with other through electrical impulses. An EEG can be used t help detect potential problems.” this method is safe, not harm babies , and the test is useful to allow doctor diagnose brain disorders easily when the electrodes show brain signal to the computer abnormal patterns. Positron emission tomography (PET) another technique. This test allows researchers to check and diagnose the areas rain regions where higher level of brain activity. The author reveals that “ to measure the release of position that results from the decay of radioactive glucose previously injected into the bloodstream (Bornstein, Arterberry & Lamb 2014.) Ethics is an important part of infancy researcher because babies are human beings and the principles is to inform the infant’s parents and obtain consent from the infant participants or their families. The researcher follows the rule to avoid anything that can harm the babies either physically