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4.1: Study of Development- Explanation- Experimental Designs- Lab and Field

  • Page ID
    10341
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    If you have decided to organize and conduct your developmental research program by connecting the dots provided by this textbook, you will, after reading the previous section, have completed the descriptive portion of your work. We congratulate you on many fronts. You have attended zealously to recruiting and maintaining samples that are representative of their age grades, going beyond standard recruiting strategies to find those participants who are typically overlooked. You have mentally interviewed your participants, settings, and times about how they got together, how long they have been involved with each other, and whom they ended up excluding. You have assessed the heck out of your participants on all manner of selection variables (but not all of your participants, so you can check whether your assessment battery has done any permanent damage). You have all manner of devices ready (e.g., Facebook pages, birthday cards, and pizza parties) to keep your participants in the study, and you stand ready to add new participants, if any old ones should slip through your fingers.

    You have been through the wringer with your measurement decisions, building a “developmentally-friendly” conceptualization as a frame to help you figure out who is going to be the duck on the surface and who is going to be the changing propulsion devices (and you dedicated a whole meeting of your research team in order to discuss metaphors like ducks and icebergs and what it means to measurement to “put your finger” on something to hold it still for a minute). You have figured out which constructs are parts and which are wholes (for the time being) and you knew that you could not show your face around here without including the measurement of some proximal processes. You have wrestled with the meaning of “function” and “adaptive function” and “functional theories,” and ended up taking a brisk walk around the block to clear your head.

    You have made peace with the idea that you and your team are unlikely to conduct a 70- year longitudinal study, and are convinced that there is no shame in starting with a crosssectional study, especially if your “cohorts” are one year apart. You identified some potential time windows where interesting age/cohort differences seem to be hovering, and noted that these locations happen to coincide with some age ranges that seem to be seismically active (e.g., the 5- to-7 year shift or early adolescence) and some time points that include transitions (e.g., starting school or transitioning to middle school) as well as some (e.g., third grade and age 15) that seem to be out in the middle of nowhere. Following our instructions, you have conducted a series of short-term longitudinal studies across these time windows and have in your possession some of the most beautiful data known to developmentalists—patterns of intra-individual change that differ across your participants. You know where you are—you are at Grand Central Station— your participants have come from somewhere and are going somewhere, you get it, but you were able to track them for a little while and you can see how they are changing. If your measures allow you to, you can see them as trajectories, as growth curves, one for each participant, some of them improving, some declining, some staying the same, kind of jumbled. If your measures permit, you may also see some transformations—differentiations, integrations, or reorganizations.

    You have muscled and cogitated your way through “Description” and your reward is more hard work-- now you have been promoted to “Explanation.”

    What is the difference between “description” and “explanation” again?

    As we mentioned in the first chapters of the book, description is the task of depicting, portraying, or representing patterns of development in the target phenomena, including patterns of normative age-graded changes and continuities, as well as the variety of different quantitative and qualitative pathways. (Have another look at Figure 2.1.) In contrast, explanation refers to an account of the causes that together are necessary and sufficient to produce the patterns of changes and stability that we have described: What sets of factors cause, influence, or produce these different patterns of normative and differential change or stability over time? Explanation focuses on the weighty question of “Why?”. Brace yourself. We have reached the thorny problem of “causality” (Pearl, 2009).