Three-month-old Jefferson will probably listen longer to __________ than to __________.

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.

Correct Answer: D

Rationale: Cross-sectional studies can be threatened by cohort effects because different age groups may have experienced different historical or social contexts, influencing the results. This disparity can lead to invalid comparisons between age groups, confounding the study's findings. Option A, practice effects, refer to changes in participants' behavior due to repeated testing, not a specific threat to cross-sectional studies. Participant dropout (Option B) is a threat related to attrition in longitudinal studies, not cross-sectional studies. Sequential timing (Option C) does not pose a threat to cross-sectional studies; instead, it refers to the order of tasks in a study design.

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: D

Rationale: The correct answer is D because investigators who study development aim to identify the factors that influence consistencies and transformations in people from conception to death. This goal encompasses various domains such as physical, cognitive, emotional, and social development, highlighting the comprehensive nature of developmental research. Choices A, B, and C are incorrect as they do not align with the overarching goal of developmental researchers, which is to understand the factors influencing individuals throughout their lifespan, rather than focusing solely on genetic factors, environmental factors related to disease, or abnormal development in specific age groups.

Correct Answer: D

Rationale: In this scenario, the researchers randomly assigned adolescents to either a single-grade classroom or a mixed-age classroom, which is an example of a field experiment. A field experiment involves manipulating independent variables in a natural setting to observe the effects on participants. This design allows for more control over variables compared to naturalistic observation, case studies, or natural experiments. Naturalistic observation involves observing subjects in their natural environment without manipulating any variables. A case study focuses on in-depth analysis of a single individual or a small group. A natural experiment involves observing naturally occurring events without intervention or manipulation by the researcher.

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: B

Rationale: The major strength of the clinical interview is that it can provide a large amount of information in a fairly brief period. This allows researchers to gather detailed data about an individual's thoughts, feelings, and behaviors efficiently. Choice A is incorrect because the clinical interview focuses on gathering information from individuals rather than comparing their responses. Choice C is incorrect as clinical interviews are primarily aimed at understanding individuals rather than cultures or social groups. Choice D is incorrect as it describes a strength of naturalistic observations, not clinical interviews.

Correct Answer: B

Rationale: Dr. Dias's research findings indicate a correlation between the death of a spouse and a decline in the surviving partner's physical health. This correlation suggests a relationship between the two variables, but it does not necessarily imply a direct cause-and-effect relationship. Therefore, the correct conclusion supported by this study is option B - 'The death of a spouse is related to a decline in the surviving partner's physical health.' Option A is too direct in its causation claim, which is not proven by correlation alone. Option C reverses the cause and effect relationship suggested by the research. Option D introduces an unrelated third variable, which is not supported by the study's findings.

Correct Answer: C

Rationale: According to psychosexual theory, developed by Sigmund Freud, how parents manage their child's sexual and aggressive drives in the first few years is crucial for healthy personality development. This theory suggests that personality development is heavily influenced by a child's experiences during early stages of development, particularly related to handling sexual and aggressive impulses. Choices A, B, and D are incorrect as they do not align with the core principles of psychosexual theory, which focuses on the importance of early childhood experiences, especially in the context of sexual and aggressive drives.