Correct Answer: B

Rationale: One challenge associated with longitudinal research is that participants may relocate or drop out of the study over time. This can result in missing data and potential biases in the findings, impacting the study's overall validity and reliability. Furthermore, it can present difficulties for researchers in accurately monitoring and analyzing changes in individuals over an extended period. Options A, C, and D are incorrect because longitudinal research can indeed allow for inferences about cause-and-effect relationships, findings can be generalized to the real world with appropriate design and sampling, and it is suitable for studying individual developmental patterns.

Correct Answer: C

Rationale: A case study would be the best method for Dr. Bigelow to study musical prodigies. In a case study, the researcher can closely examine and analyze the unique characteristics, abilities, and behaviors of individual subjects. This method allows for in-depth exploration of a specific phenomenon, making it ideal for investigating exceptional cases such as musical prodigies. Naturalistic observation involves observing subjects in their natural environment without interference, which may not provide the detailed insights needed for studying musical prodigies. Clinical interviews focus on gathering information through structured questioning, not ideal for studying unique talents. Structured interviews involve asking a set of predetermined questions, which may not allow for the depth of exploration required for studying musical prodigies.

Correct Answer: B

Rationale: Central to Piaget's theory is the concept of adaptation, which refers to the process by which individuals adjust to new information and experiences by modifying their existing cognitive structures. Piaget believed that this process of adaptation involved two key components: assimilation, where individuals incorporate new information into their existing schemas, and accommodation, where individuals adjust their schemas to fit new information. This concept highlights the dynamic nature of cognitive development and the importance of interaction between individuals and their environment in shaping intellectual growth. Choice A, 'imitation,' is incorrect as Piaget's theory focuses on how individuals actively construct their understanding of the world through their interactions with it, rather than simply imitating others. Choice C, 'self-efficacy,' is not the central concept in Piaget's theory; self-efficacy is a concept from Bandura's social cognitive theory. Choice D, 'scaffolding,' is associated with Vygotsky's sociocultural theory, not Piaget's theory.

Correct Answer: D

Rationale: In an experimental study examining whether the way angry encounters end affects children's emotional reactions, the dependent variable would be the children's emotional reactions. The dependent variable is the outcome being measured or tested in an experiment. In this study, the researchers are trying to understand how the way angry encounters end influences children's emotions. Therefore, the emotional reactions of the children would be the dependent variable that is being studied and measured in relation to the way angry encounters end. Choices A, B, and C are not the dependent variable in this scenario. While they may be related factors, the main focus of the study is on how the way angry encounters end impacts children's emotional reactions, making children's emotional reactions the dependent variable.

Correct Answer: C

Rationale: Three-month-old Jefferson will likely listen longer to human speech compared to nonspeech sounds because infants have a natural preference for speech sounds. This preference is believed to be attributed to their biological readiness to learn language and communicate with others. Choice A is incorrect because voices are a form of human speech, which is preferred over pure tones. Choice B is incorrect as noises do not necessarily engage infants' attention as effectively as human speech. Choice D is incorrect because Jefferson is more likely to listen longer to his native language rather than a foreign language at this early age.