Homology is the word evolutionary biologists use to refer to similarity due to common ancestry. For example, human hands, bat wings, and the flippers of seals appear quite different, but are homologous because they all evolved from the feet of a common ancestor with four limbs. The notion of homology has been enormously helpful to biologists as they have worked to organize their observations of biological traits across species. Like evolutionary biologists, who are concerned with the origins and subsequent alterations of traits across generations, developmental psychologists are concerned with the origins and subsequent alterations of psychological traits across individuals' lifetimes. Given the similar concerns in these two fields, the idea of homology should be as useful to developmental psychologists as it has been to evolutionary biologists. Nonetheless, this idea has not been used extensively in developmental psychology. The current project will be an interdisciplinary workshop that will bring together an international group of evolutionary-developmental biologists, developmental psychobiologists, philosophers of science, and traditional child developmentalists to explore how the concept of homology might aid in understanding psychological and behavioral development. There has never been a meeting devoted to work on the potential utility of the homology concept for the field of developmental psychology, and the time is right for such a meeting; recent scientific advances have created a climate in which an interdisciplinary collection of scientist-theorists will be able to make progress that will advance this field. The workshop will foster interactions that would otherwise never occur, facilitate mutual understanding of the concepts under discussion, and promote future collaborations.
All of our psychological and behavioral characteristics emerge as we develop, so understanding traits as diverse as aggressive behavior, mathematical competence, altruism, or linguistic skills requires studying the development of these traits. The entire field of developmental psychology is devoted to understanding how and why it is that each of us develops our adaptive and maladaptive behaviors and mental states. Unfortunately, developmental psychologists still have no generally accepted coherent theory for understanding how such traits emerge and change across time. This workshop will take a concept that has been productively used by biologists and import it into developmental psychology, thereby contributing to a theoretical advance in the field that is likely to have wide-ranging implications. Specifically, the workshop will facilitate developmental psychologists' formulation of novel, empirical research questions that will enhance understanding of both normal and abnormal development in a variety of psychological domains. Because the ideas generated and discussed in the workshop will be widely disseminated in a scholarly journal as well as on the internet, progress made by the workshop participants will have positive effects on the thinking and practice of students and professionals in academic disciplines as well as those in the mental health professions. Furthermore, because the origins of our psychological characteristics are of great interest to the lay public and bear on aspects of public policy such as education and our understanding of developmental disorders, this workshop will contribute to our knowledge about human development and ultimately could promote real changes in institutional practices as well.
Homology generally refers to similarity due to common ancestry. For example, a bat’s wings and a person’s hands appear different, but are homologous because they both evolved from the feet of a common ancestor. Homology has also been used in developmental biology to refer to characteristics that differentiate from the same embryonic tissue via similar developmental processes; thus, ovaries and testes in mammals are developmentally homologous. Biologists have found the concept of homology to be enormously helpful in organizing observations of diverse traits across species. In contrast, the concept of homology has been underutilized by scientists concerned with the development of behavior. The homology concept should interest developmental psychologists because of its potential ability to help us recognize when behaviors, thought processes, or emotional reactions are related to one another because of shared origins in development. Our small group workshop was held at Dalhousie University in Halifax, Nova Scotia from August 16 – 18, 2011; an international group of 13 theorists attended the workshop, including evolutionary-developmental biologists, comparative psychologists, developmental psychologists, philosophers of science, and developmental psychobiologists. The primary goal of the workshop was to bring together theorists from different disciplines to explore how the concept of homology, properly imported from biology, might aid in understanding psychological/behavioral development. In advance of the workshop, each participant prepared a synopsis of a talk to be presented in Halifax; these papers were disseminated before the meeting so the participants had a chance to think about each other’s perspective prior to the workshop. During the conference, each participant gave a half-hour talk, which was followed by a 30-minute discussion period. An additional 90-minute discussion period was scheduled for the final day of the workshop. The presentations and discussions allowed theorists who otherwise might not have had the opportunity to interact to collectively think through some of the issues involved in importing the concept of homology into developmental psychology. A meeting about homology and behavioral development had never before taken place, and because of recent advances in evolutionary-developmental biology, developmental systems theory, and molecular biology, the time was right for an interdisciplinary collection of scientist-theorists to focus on this potentially transformative concept. Although the workshop was successful because it advanced the knowledge of the participants, we also endeavored to benefit society by making the information shared at the conference available to a wider audience. We expect a variety of professionals to be interested in this work; a better understanding of behavioral development has the potential to inform our thinking about, for instance, the treatment of developmental disorders. The primary product of the workshop was a special issue of Developmental Psychobiology, which contains papers written by the participants and informed by conversations that occurred during the meeting; this issue was published in January, 2013 (volume 55, number 1), and the 11 papers in it are all freely available (i.e., they are ‘open access’). We believe this special issue will enhance scientific endeavors within developmental psychology (and, we hope) psychology more generally. The homology concept has been valuable for biologists, and can be expected to be so for psychologists, too. Psychologists have started explaining behavior using biological constructs like evolution, hormones, and genes, but the piecemeal introduction of such constructs has sometimes led to conceptual errors. We expect the papers in our special issue to ultimately aid scientists in their efforts to understand the evolutionary and developmental origins of human behaviors. In addition to disseminating the results of our work in Developmental Psychobiology, we created a permanent website containing information about the workshop and its participants, and links to the participants’ pre-meeting synopses, their presentations, and video recordings of their talks at the conference (http://pzacad.pitzer.edu/homology/). The website also contains links to all of the papers published in our special issue of Developmental Psychobiology on homology in developmental psychology. Finally, to ensure that our website will be readily found by students, graduate students, professionals interested in understanding behavioral development, and other interested members of the general public, we created a short Wikipedia entry—https://en.wikipedia.org/wiki/Homology_(psychology)—that provides an overview of the ideas discussed at the meeting, as well as a link to our developmental homology website. Through our website and our Wikipedia entry, the workshop will be able to continue contributing to the scientific education of a new generation of developmental scientists.
