“ASSESSING A MULTILEVEL CAUSALITY MODEL IN THE EVOLUTION OF COGNITION” MSc in Brain and Cognitive Sciences Behavioral Neuroscience track By: Vanessa Del Pozo Sánchez Student no: 11104066 First assessor: mw. dr. Federica Russo Second assessor: dhr. dr. Hein van den Berg Date: 28/June/2017 Abstract Cognition is the mechanism by which an organism is able to acquire, process, and retain information through senses and experiences. To this day, there is no agreement regarding its evolutionary explanation. The literature describes a wide range of methods in order to understand components such as motor behavior, thought, consciousness, memory, perception, and language, among others. This is done with the aim of complementing the origin of the evolutionary processes of cognition. However, none of these approaches has considered the evolution of cognition as a result of a network of complex interactions at different levels of organization. In this thesis, we introduce a multilevel causality model for the understanding of the adaptationist idea of cognition. The model is built by integrating three evolutionary processes: ontogeny, phylogeny, and Evo-devo. The model allowed us to fill the failures that evolutionary processes presented. Thus, we can conclude that with more detailed studies of multilevel causality in the biological systems of cognition, we can develop complete explanations of evolutionary mechanisms that occur at certain level, and observe their consequences at other levels. 1 Index General introduction 3 1. Historicity of cognition and Dennett’s adaptationist approach of cognition 4 1.1 History of cognition from Lamarck onwards 5 1.2 Cognition: an adaptationist property according to Daniel Dennett 10 1.3.1 Evolution of simple entities by Dennett 11 1.3.2 From simple replicators to the nervous system 11 1.3.3 Phenotypic variation and the understanding of cognition 13 2. Ontogeny and the “theory of neuronal group selection” in the understanding of cognition. 15 2.1 Introduction 15 2.2 Edelman and the variation and selection within neural populations 15 2.2.1 The three main tenets of the theory of neuronal group selection. 16 2.2.2 Degeneracy and value 18 2.3 Edelman’s theory applied to the immune system 19 3. Evo-Devo: an extension to cognition 20 3.1 Introduction 20 3.2 Evolutionary developmental biology theory 21 3.2.1 The neural system from an Evo-Devo perspective. 22 3.2.1.1 Types of constraints 23 3.3 Evo-devo and cognition 24 4. Multilevel causality models and cognition 26 4.1 Introduction 26 4.2 The understanding of adaptation 26 4.3 Difficulties in the explanation of cognition by the adaptationist approach. 27 4.3.1 Difficulties in Dennett’s approach and ontogeny 27 4.3.2 Analysis of Edelman and Dennett’s theories: differences and similarities. 30 4.4 Multilevel causality 31 4,4,1 Types of multilevel causality 31 4.4.1.1 Bottom-up causality for the understanding cognition. 32 4.4.1.2 Top-Down causality and cognition 34 4.5 Integration of types of multilevel causality model to understand cognition 36 Conclusions 38 References 40 2 Introduction Evolution refers to the process by which species respond and adapt to the environment as a result of maximizing their fitness. Changes occur at all levels -from protein synthesis to behavior- in order to predict and even manipulate environmental regularities. One category of such mechanisms of response and adaptation is cognition: the process by which an organism is capable to acquire, process, and retain information through senses and experiences. Therefore, cognitive capacities in animals -including the human being- can be studied as phenotypic traits within evolutionary biology. The general objective of this work is both to show how cognition develops and to address those of its elements that allow an adaptive explanation. We focus on evolutionary processes through ontogeny, phylogeny, and evolutionary developmental biology, all of which deal with the development of cognition in animals with a central nervous system. Then, by combining the study of these evolutionary processes, we can apply the multilevel causality model as a tool to understand the evolution of cognition in the adaptational approach. This work will be structured in the following manner: - To identify the epistemically significant features of cognition, it is necessary to know the philosophical and historical approaches by which it has been studied. In the Chapter 1, we present how the understanding of cognition has developed trough time, and then we include an analysis of the main ideas of one of the ultra-Darwinian authors in adaptation of cognition: Daniel Dennett. - In Chapter 2, we describe an evolutionary take on cognition from the ontogenetic perspective. We analyze the theoretical arguments of neural Darwinism given by the neurobiologist Gerald Edelman, the essence of whose argument is based on an analogy of evolution by Darwinian natural selection at the cellular level. Edelman argues that a selection process is carried out at the level of neural groups in the nervous system of some mammals. With this, he explains the emergence of such cognitive phenomena as perception, memory, and consciousness. 3 - In Chapter 3, we review the explanations from developmental evolutionary biology (Evo-Devo) regarding the origin of the variations for which natural selection applies. In order to understand the weight those variations have in an adaptive explanation of cognition, we also examine the role of natural selection itself in the arguments of the Evo-Devo. - In Chapter 4, we develop a multilevel causality model. To do this, it is essential to understand what a multilevel causality model is and how does it work. After that, we construct a model of cognition that integrates ontogeny, phylogeny, and evolutionary developmental biology. Our motivation stems from the idea that biological systems are organized hierarchically in levels, which range from molecules to ecosystems. Lower levels limit the higher ones, but these in turn also influence the first in a reciprocal causal dependence. Finally, in the last section, we present the conclusions of our work. 4 1. Historicity of cognition and Dennett’s adaptationist approach of cognition 1.1 History of cognition from Lamarck onwards Even though there have been many attempts to categorize living beings, from Aristotle to Cuvier, it was not until the early nineteenth century that the French naturalist Jean B. Lamarck –in his work Philosophie Zoologique (1809)– created a classification of the animal kingdom based on the degree of intelligence that each animal presents. As such, Lamarck can be seen as the first one to study cognition with an evolutionary approach (Atran 1993). The classification proposed by Lamarck was based on functional correlations of brain structure, and it rendered three large groups: apathetic, sensitive, and intelligent. Within the apathetic group, we could find cnidarians, sponges, and worms. Crustacean mollusks, insects, arachnids, echinoderms, and myriapods were part of the sensitive group. Finally, the intelligent class was made up of all vertebrates. Based on his classification, Lamarck divided the animals into evolutive stages. He devised a new system –the system of “perfection”–, where the simplest existing animals rose progressively to the most complex or “perfect” animals. Just as in the “Scala naturae” of Aristotle, the highest level in this stepwise process was occupied by humans. Only at the highest level did the organisms display psychological functions such as memory, judgment, attention, and thinking (Papini 2009). In the 1870’s, Charles Darwin, another revolutionary figure of the natural world, published two books that referred to the evolution of the mind. His work “The Descent of Man and Selection in Relation to Sex” (1871) established that mental characteristics –including moral and social instincts in humans– are inherited in the same manner as physical characteristics, namely by variation and Natural Selection (NS). In the other book, entitled “The Expression of Emotion in Man and Animal” (1872), Darwin brought into discussion the concept of emotion. He claimed that emotions are just like any other characteristic, so that they too undergo adaptations and evolve. He compared facial expressions of some primates against humans’ facial expressions, finding out that facial expressions were sometimes caused by desires and sensations unleashed by the nervous system. 5 Lamarck and Darwin were revolutionary naturalists that both gave way to a new paradigm that featured ideas we now associate with cognition. In fact, Alfred Giard, an important zoologist who published his findings during the 1880’s, considered that Lamarckism and Darwinism were actually complementary theories, and he supported this idea with studies on evolutive convergence. For example, he put forward a classification of organisms based on their behavior in their natural environment, and did this with a Lamarckian approach (Peláez del Hierro et al., 2002). Carrying on with our chronological review, we must mention Douglas Spalding, who is regarded as one of the founders of ethology and who published his first work, entitled “On instinct”, in 1872. His overall studies brought him to the conclusion that instincts are a guide for learning and for inherited capacities (Thorpe, 1979; Gray, 1967). Similarly, George Romanes, an evolutionary biologist and psychologist who set the foundations of comparative psychology, proposed general principles for the evolution of the mind based on psychological capacities rather than physical relationships between animals. He presented them in his book “Animal Intelligence” (1882). Karl Lashley, a behaviorist from Virginia, carried out studies on intelligence, behavior, and the neuronal basis of certain cognitive processes as of the 1920’s. He focused on brain physiology and psychology, trying both to find the locus of specific memory traces and to describe the behavior of the mind with mathematical and physical concepts. His contributions to the study of cognition were based on the different types of tests that he ran throughout his life.