18 Developmental Psychology: The Divide and Conquer Strategy
Remember and Understand
By reading and studying Module 18, you should be able to remember and describe:
- Agenda setting by major theories in (developmental) psychology: Piaget and Erikson
- The divide and conquer strategy in psychology research
- Dividing and conquering in developmental psychology: development as a perspective, division by topics, division by chronology
- Problems with dividing and conquering
- Closing the loop: relationship between cognitive and social development, Vygotsky’s sociocultural theory of cognitive development
Because Developmental Psychology encompasses all of the other subfields (just from a developmental perspective, we do not have any new additions to our house of psychology for you now. Instead, let us think of this as reinforcing the structure so our house will be solid. Our reinforcements illustrate scientific process by showing how some theories guide an entire subfield for a period of time, and how most researchers carve out a small piece of the overall puzzle (working on a tiny section of the whole house, so to speak).
Developmental Psychology, like several of the other subfields and the field of psychology as a whole, has progressed in an odd-seeming direction. You might expect that progress would occur by building up small theories into larger ones. One psychologist develops a theory about children’s memory, another about children’s problem solving, and a theory about childhood cognition in general emerges from an integration of these and other theories. You might recognize this process as analogous to bottom-up processing in perception, through which we recognize objects by building up, or integrating, individual features (Module 13). Instead, the early influential theories were often quite broad, attempting to explain fully some major aspect of psychology. These major theories then functioned as frameworks, setting the research agenda for later psychologists to follow—analogous to the way that top-down processing in perception guides our recognition of particular objects.
The two most famous developmental psychologists are cases in point. Jean Piaget formulated a comprehensive theory of cognitive development, and Erik Erikson, one of psychosocial development. Piaget sought to explain how a child’s understanding of and reasoning about the entire world develop, and Erikson’s theory was intended to show how challenges and crises that we encounter throughout life profoundly influence all of our future social interactions and developments. Many observers consider Piaget the first true developmental psychologist. Child development researchers prior to Piaget devoted themselves to cataloging the developmental milestones that were expected in normal children (Hunt, 2007). But the contributions of these earlier psychologists, because they were not guided by theories, are largely forgotten today. Although Piaget was not the first psychologist to study children, he was the first to offer a comprehensive theory of a major aspect of development. Nearly all research in cognitive development since Piaget’s time has been a reaction to his work. We have little doubt that one of the key aspects of Erik Erikson’s work that has led to his lasting influence is, similarly, the fact that he was the first psychologist to propose a theory of development that spanned the entire life (Hunt, 2007).
This “agenda setting” characteristic of early major theories is a key element of a psychologist’s lasting influence. Consider the big-name researchers and thinkers from early psychology, such as Piaget, B.F. Skinner, Erikson, and Sigmund Freud. Many of their theories are not currently accepted, but they set the research agendas that still guide much of the current work in psychology. For instance, it seems unlikely that James Marcia would have thought to examine what happens during the search for identity and whether the search occurs exclusively in adolescence had Erikson not proposed identity formation as a key task of adolescence. Once the search for identity was a legitimate topic of psychological inquiry, researchers like Jean Phinney could examine important questions about specific aspects of identity, such as ethnicity. The contributions of these later researchers are part of the incremental process through which scientific theories are refined and sometimes replaced (Module 14).
Starting with comprehensive theories works well because it helps individual researchers choose questions to examine that others will find interesting. For a scientist, it is not enough to conduct good research. You also have to conduct research that other scientists will want to read. If each researcher randomly chooses a topic to examine, there will be very little common ground for researchers with different specific interests to talk about. On the other hand, if two researchers begin with alternative explanations for Piaget’s observation that three-year olds have difficulty taking someone else’s perspective, they automatically have something to talk (or argue) about. The two explanations may compete with each other or they may complement each other to form a more accurate explanation of phenomena originally covered by Piaget’s theory. But this creative tension can only happen if Piaget’s theory already exists.
The Divide and Conquer Strategy in Psychology Research
Many students, when they try to generate their own research ideas in their psychology classes, often begin by thinking like Piaget and Erikson. They try to propose research that can answer every question about some complex phenomenon. As faculty members, we appreciate their interest and ambition, but the truth is most research does not proceed that way. Instead, researchers use a strategy that can be called divide and conquer to progress from a comprehensive, agenda-setting theory to an actual research project that they can reasonably complete. Individual researchers choose small elements from a broad theory or from a complex phenomenon, and they develop research ideas that pertain to those specific elements. They may then conduct entire programs of research, interrelated sets of studies that span years or decades, that are in-depth examinations of small chunks of the complex phenomena and theories.
For example, Renee Baillargeon, among her other research programs, has been publishing research on infants’ understanding of object permanence since 1985. Her early research demonstrated that infants have at least a primitive understanding of object permanence, realizing that unseen objects existed much earlier than Piaget proposed, at five or even three and a half months (Baillargeon et al., 1985; Baillargeon, 1987). As her research progressed, it demonstrated that infants as young as five months old have a solid understanding of object permanence, or at least one that lasts for 6 – 7 minutes (Luo et al., 2003). Recently, theories based on her research have begun to explain why infants retain some knowledge about unseen objects– for example, that impossible events like one object passing through another cannot occur, but do not retain knowledge about other aspects– for example, when the number of unseen objects changes (Stavans et al., 2019).
Casual observers might believe that focusing on such a limited phenomenon is boring or, worse, trivial. What these people fail to realize is that we have gained a far more thorough understanding of the important concept of object permanence through Baillargeon’s work through the years than if she had not persisted in examining this small piece of the puzzle.
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In a similar way, most modern researchers opt for depth over breadth, choosing to become an expert about a very limited set of phenomena. If there are enough researchers throughout psychology becoming experts in their own small sections of the field, the result is a rich, detailed research literature that ends up covering the whole field. In essence, you get breadth, not from a single researcher, but from all of the researchers.
When you join the ranks of scientific researchers in psychology, you have several decisions you must make that relate to dividing and conquering. The first choices are made when you apply to graduate school. As we like to tell our students, no one has a PhD in psychology. Students earn a PhD in ___ psychology, where the blank is filled in with one of the subfields. Along the way to earning the degree, you become an expert in that specific subfield and not necessarily in any others. Many students are surprised to discover that someone can earn a PhD in cognitive psychology and know very little about clinical psychology, for example. Instructors of General Psychology, by the way, are an important exception. New teachers learn a great deal about the subfields that they may have neglected as a graduate student when they begin to teach General Psychology. Unfortunately, not everyone has the opportunity to teach General Psychology, however, and many psychologists remain relatively uninformed about topics outside of their area of expertise.
Other choices you would make as a psychology researcher are related to how the subfields themselves are organized. Developmental psychology may be the most complex subfield, with many different organizing schemes possible. Psychology subfields are usually divided according to topics. For example, a social psychologist studies topics that are related to the ways that people think about, influence, and relate to one another (Unit 5). A cognitive psychologist examines topics that are related to the use, understanding, and communication of knowledge (Unit2). Developmental psychology is a little bit different. Although we tend to think of it as a subfield, it really is more of a perspective, in other words, a way of looking at any topic in psychology (Module 1) Whereas a cognitive psychologist may choose to study problem-solving, and a social psychologist may choose to study aggression, a developmental psychologist might choose either topic and examine how it changes or develops through different points in the lifespan. Any specific topic, then, maybe examined developmentally. Indeed, if you examine a textbook in Developmental Psychology, you will find many topics that are also covered in other textbooks. This is not redundancy; it is a difference in perspective, the distinction between what a phenomenon is versus how it develops.
A good example of that difference in this book is the different treatment of identity and self-concept. There are psychologists who talk about identity and those who talk about self-concept. You might very well wonder whether there is a difference between the two. Both refer to people’s sense of self, their knowledge and beliefs about what the essential aspects of their attitudes, characteristics, and behaviors are. The difference between the two concepts is one of focus and perspective. Psychologists who refer to “identity” are more likely to focus on how it emerges, following the groundbreaking work of Erik Erikson. Thus, they tend to examine identity from a developmental perspective. They are also likely to focus on the adolescent years because that is when Erikson proposed people formed their identities. Psychologists who refer to “self-concept” are more likely to be social psychologists; their focus is less on how it develops, and more on what it contains. Because this unit has been about developmental psychology, we have focused on the development of identity for now. Later, in Module 26, we will return to these ideas in the context of social psychology and talk more about the contents of people’s self-concepts.
Once the subfield is chosen, a budding researcher narrows their focus by selecting specific topics to specialize in. For example, a cognitive psychologist may choose to do research on problem-solving, reasoning, or memory (among other topics). A developmental psychologist may choose to do research on attachment, identity, or object permanence. There is really no end to researchers’ opportunities to specialize and sub-specialize. For example, an identity researcher might decide to focus on the negative effects of early adoption of an ethnic/racial identity in Asian American adolescent girls.
Another important organizational distinction, one that applies only to developmental psychology, is between a chronological and a topical division of the subfield. Individual researchers in developmental psychology tend to select both topics and ages to study. For example, you may choose to study working memory in infancy, childhood, adolescence, or adulthood. Some researchers specialize even further, focusing on infants under 6 months old or young adults between 25 and 40, for example. Others broaden their view by examining changes as individuals move from one age group to another, or even throughout the lifespan.
Problems with the Divide and Conquer Strategy
So, the divide and conquer strategy affords researchers the opportunity to make incremental scientific progress and creates enclaves of psychologists who have common interests. You may have picked up on a danger associated with dividing and conquering, however. Recall that by becoming an expert in one area of psychology, researchers might end up relatively uninformed about other areas. In order for the divide and conquer strategy to be completely successful, we need to remember that it is only part of the process. After dividing and conquering individual areas, we need to close the loop, so to speak, by looking for ways to reintegrate the divided areas. Unfortunately, however, reintegrating is extremely difficult for several reasons.
Few Psychologists Work at Closing the Loop
Earlier, we presented divide and conquer as if researchers freely chose the strategy. Although it is true that how you divide is a choice, whether you divide is not. Quite simply, it is necessary to divide and conquer. The subject matter of psychology is too large and complex to be tackled all at once. The overwhelming quantity that makes dividing necessary is precisely what makes reintegrating an imposing prospect.
It is a full-time job for a researcher in psychology to study their piece of the puzzle. It is no one’s full-time job to assemble the individual pieces. Reintegration requires a researcher to look beyond their own research area and keep current by reading research produced in other areas. Let us show you how unrealistic that task can be. The American Psychological Association maintains a database of descriptions of scholarly work in psychology, comprising journal articles, edited and authored books, and book chapters reporting research. The database is called PsycINFO; if you do not learn about it in your General Psychology course, you almost certainly will if you take additional classes in psychology. In June 2020, PsycINFO covered over 1,700 different journals. Each journal publishes from 3 to 12 issues per year, and each issue has several research articles. Using conservative estimates of four issues per year and six articles per issue, it works out to almost 41,000 journal articles published in psychology every year. On top of that, there is research presented at scientific conventions and in many scholarly books, and recently, researchers have been sharing their research on pre-print servers (brand new research that has not been peer-reviewed yet). It is, we are sure you will agree, an overwhelming quantity of research.
If a researcher tries to read even 1% of the journal articles published per year, they would need to finish more than one article per day, every day of the year. Psychology researchers who are employed as college professors, as the very large majority are, are paid to produce research and to teach, so the reading has to take place during their spare time. Suffice it to say that no one is able to keep up with more than a very small portion of current research. Because it is a full-time job to produce and keep up with research in your own corner of the field, there are relatively few opportunities to communicate with people outside of your area.
Other Viewpoints are Neglected
When researchers are not careful about reintegrating, a divide and conquer mentality can lead to serious oversights. In essence, divide and conquer sometimes becomes divide and conquer and forget about the rest. For example, throughout most of its history, the psychology of religion has really been closer to the psychology of Christianity (Hood et al., 2018). Viewpoints from other religious traditions have all too often been overlooked.
The subfields of psychology are not immune to the dangers of neglect and oversight. Over the years, many cognitive psychologists have simplified their research by excluding social factors. For example, a researcher who is interested in problem-solving from a purely cognitive point of view would likely focus on things like the speed with which the problem was solved and the way the answer was determined and not pay attention to whether or not a problem solver was anxious. Many researchers conduct studies and never consider how they know that their research participants are motivated to complete their projects. By focusing too closely on the “topic” of the research study, we might leave out important details that could affect the interpretation of the results.
One key oversight that has taken place throughout the history of psychology is culture. Many researchers through the years have focused solely on psychological processes within a single culture; in some cases, researchers have devoted an entire career to studying phenomena by doing experiments with students at a single college. What if people from somewhere else are different? The cross-cultural differences that I have outlined throughout this book just scratch the surface of the differences among people across the world. You should realize that there are entire courses on cross-cultural psychology, and many psychologists who do not focus on this approach are not well informed about the findings. This can be an enormous oversight, by the way. Whenever there are large differences between Western and Non-Western cultures, for example, it is worth keeping in mind that there are many more Non-Westerners than Westerners in the world. China and India alone account for over one-third of the world’s population (2.8 billion out of 7.8 billion in 2020). Anything that is true of people in the US alone can hardly be called a truth about human psychology. Critics have charged that psychology has, for far too long, been WEIRD– based on research participants from Western, Educated, Industrialized, Rich, and Democratic societies (Heinrich et al., 2010).
Our Divisions Might Be Arbitrary
Perhaps when we separate phenomena and study them individually, the division changes the way the phenomena work. Let us illustrate by analogy. Imagine that you are a parent that has recently begun giving your two school-aged children an allowance contingent on their getting ready for school on time every day. A divide and conquer strategy would dictate that you consider each child separately, as the problem might not be equally bad for each child. You might be tempted to conclude that one child will need a larger reward (i.e., a bigger allowance) than the other will in order to motivate them to get ready. How do you think that individualized strategy will work out in the real world, though? You might discover that the other child judges the unequal allowances to be unfair, and they would likely end up less motivated to comply.
In a similar way, if we follow the typical division of subfields in psychology and separate phenomena such as cognitive development from the social contexts in which they occur, we may discover that when we return to the real world, we have missed something important.
This book, like every other psychology book we have ever seen, separates cognitive and social development. Each individual topic must fit neatly into one or the other. Attachment is a social development, and language is a cognitive development, for example. But the real-world phenomena that these theories attempt to explain do not observe the boundaries between cognition and social development that we have drawn. The phenomena are integrated wholes in which cognitive and social processes interact.
The artificial separation that may come from dividing and conquering can lead to a false dichotomy, an oversimplification based on seeing a phenomenon in either-or terms (Module 1). Researchers may harbor beliefs about the supremacy of cognition over social processes, or vice versa. Or, when researchers who focus exclusively on biological correlates of behavior have little contact with those who examine environmental impacts on development, the resulting research articles seem to be proposing that either nature or nurture is the explanation, not that both might work together (Harris, 1998; Maccoby, 2002).
Closing the Loop
As you have seen, dividing and conquering is both necessary and beneficial for progress in psychology, but it can lead to serious problems. Psychologists need to be vigilant about the short-sightedness and errors that can follow from a rigid adherence to the strategy. We must close the loop by encouraging approaches that cross boundaries or by choosing unconventional ways of dividing and conquering.
Fortunately, many psychologists are vigilant. Even when they cannot become experts in multiple areas of the field, they can appreciate the contributions of research that comes from different perspectives. In addition, there are striking success stories in which discoveries have crossed the traditional boundaries, as well as some general principles that can be, and in many cases, are followed to minimize the dangers associated with unchecked dividing and conquering.
When researchers reintegrate phenomena, putting back together concepts that had previously been divided, such as cognitive and social development, the results are very elegant. For example, the realization that the cognitive abilities of newborns and infants allow important social developments, such as attachment, is striking (Bowlby, 1982; Flavell & Miller, 1998). The fact that a newborn baby, despite poor vision and muscle control, is already equipped to look at the face of their mother and can recognize their mother’s voice reveals how finely tuned and closely related cognitive and social development really are.
The work of the Russian psychologist Lev Vygotsky (1978) is an excellent example of a psychological approach that has not observed the typical separation between the cognitive and the social. Although Vygotsky’s research was originally done in the 1930s, it was unpublished and unknown in the US for many years. After its discovery, the work has steadily gained in influence. Vygotsky’s contribution is called the sociocultural theory of cognitive development and it shows how cognitive developments are embedded in the social world in which we live. The young child is seen as an apprentice of sorts.
Their development takes place not by itself, but under the guidance of older people. In other words, the social activity of a parent or older sibling teaching a skill to a young child is an integral part of the child’s cognitive development.
The key concept that revealed the level of development that a child had reached was something Vygotsky called the zone of proximal development. This is the level at which a child can perform while being helped by someone else. For example, a 7-year old might not be able to multiply yet. However, if a teacher guides them through a problem while explaining it along the way, they may come up with the correct answer. The skill is within their zone of proximal development. It indicates that the child is closer to being able to multiply than another child who cannot understand it even when someone guides them. For Vygotsky, that process of being guided by another person is the key that leads to cognitive developments.
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In general, we can continue to encourage and value other boundary-crossing approaches, such as cross-cultural research and interdisciplinary efforts. Even if only a small number of researchers and thinkers in psychology take active roles in these endeavors, they can act as catalysts. Psychology in general can progress in its typical divided and conquered fashion while we develop an integrated understanding of psychology that comes from crossing boundaries.
