Adaptationist Research Articles

Evolutionary Psychology as Computational Theory in the Cognitive Sciences

Scarcely a decade old, evolutionary psychology (EP) has developed a high profile within the cognitive sciences. EP's niche involves what David Marr (1982) called “computational theories:” functional descriptions of what information processing devices, including brains, are designed to do. Such theories constrain and inform the search for cognitive and neural descriptions of the device. EP is characterized by primary commitments to modularity of mind, the use of evolutionary biology's adaptationist program to generate hypotheses regarding mental modules, and the use of cognitive science's methods for testing such hypotheses. It is also characterized by a number of secondary commitments and positions on important issues that are not necessitated by the evolutionary approach. These are defensible within the broader fields of human behavior and cognition, and by tertiary commitments that are logically unrelated to the EP program but nonetheless characteristic of the field (i.e., anti-theistic biases and other strong reductionisms). EP has much to offer. Combining the conceptual methods of evolutionary biology and the empirical methods of the cognitive sciences seems genuinely promising, but it's rhetoric is strong for an immature discipline and its reductionism pits it against disciplines with which it might productively coexist. The primary (and even secondary) commitments are not antithetical to an orthodox Christian faith, but the anti-theistic and anti-religious tendencies of some vocal protagonists represent a challenge.

“Spandrels of the night?”

Vertes & Eastman argue against the popular idea that dreams promote memory consolidation and suggest instead that REM provides periodic endogenous stimulation during sleep. Although we suspect that much of the debate on the function of dreams reflects a too eager acceptance of the “adaptationist program,” we nonetheless support the position of the authors and propose a specific advantage of periodic REM activity.[Vertes & Eastman]

Evolutionary Psychology

Evolutionary psychology (EP) presents a new, integrated approach to human behavior, by explaining how the mental programs, designed by evolutionary selection, guide our social behavior. It claims that cognitive and emotional processes—that is domain-specific algorithms—have been selected in our evolutionary environment as devices of solving particular adaptive problems faced by the Pleistocene hunter-gatherers. Evolutionary psychologists can develop testable explanations that focus on aspects and mechanisms of behavior that cannot readily be explained with current psychological theories. An adaptationist approach provides a powerful explanatory framework that helps us to eliminate the old dichotomies from our thinking, such as innate and learned, universality and diversity, etc. At the same time, however, evolutionary psychology implies several problems and difficulties that should be solved in the future in order to avoid useless confrontations with psychologists. The message of Darwinism to psychology is that the analysis of the evolution of mental capacities and the explanation of the adaptive mechanisms of behavior are crucial contributions to forming an integrated view of ourselves.

The fall and rise of Dr Pangloss: adaptationism and the Spandrels paper 20 years later

Twenty years have passed since Gould and Lewontin published their critique of ‘the adaptationist program’ – the tendency of some evolutionary biologists to assume, rather than demonstrate, the operation of natural selection. After the ‘ Spandrels paper’, evolutionists were more careful about producing just-so stories based on selection, and paid more attention to a panoply of other processes. Then came reactions against the excesses of the anti-adaptationist movement, which ranged from a complete dismissal of Gould and Lewontin’s contribution to a positive call to overcome the problems. We now have an excellent opportunity for finally affirming a more balanced and pluralistic approach to the study of evolutionary biology.

Adaptationism and the Power of Selection

Adaptationism and the Power of Selection

Literary study and evolutionary theory : A review essay.

Several recent books have claimed to integrate literary study with evolutionary biology. All of the books here considered, except Robert Storey's, adopt conceptions of evolutionary theory that are in some way marginal to the Darwinian adaptationist program. All the works attempt to connect evolutionary study with various other disciplines or methodologies: for example, with cultural anthropology, cognitive psychology, the psychology of emotion, neurobiology, chaos theory, or structuralist linguistics. No empirical paradigm has yet been established for this field, but important steps have been taken, especially by Storey, in formulating basic principles, identifying appropriate disciplinary connections, and marking out lines of inquiry. Reciprocal efforts are needed from biologists and social scientists.

The Partner‐Specific Investment Inventory: An Evolutionary Approach to Individual Differences in Investment

This research advances an evolution‐based model of the function and content of investment in romantic relationships. In developing this model, theory testing has proceeded concurrently with the validation of a multidimensional measure of partner‐specific investment (PSI). Ten strategies of investment were identified through factor analysis and scaled to form the PSI Inventory. These scales form a diverse set of investment measures that are reasonably independent, internally consistent, and reliable across raters. Both gender and sociosexual orientation predict use of specific PSI strategies. Overall PSI scores correlate positively with partner’s feelings of love and felt security in the relationship, correlate negatively with degree of sexualizing of others by partner, and do not correlate with the self’s performance of mate retention behaviors. It is concluded that the PSI Inventory possesses adequate psychometric properties and satisfactory convergent, discriminant, and incremental validity, thus suggesting that it constitutes a viable means of assessing individual differences in investment. These investigations show how a multidimensional, adaptationist approach to investment can further our understanding of these individual differences.

Intimate sexual relations in prehistory: Lessons from the Japanese macaques

The goal of this paper is to discuss the implications of research on female homosexual behaviour in Japanese macaques (Macaca fuscata) for reconstructing intimate sexual relations in prehistory. I argue that an adaptationist approach to sex formulated within the context of sexual selection theory has dictated, by and large, how prehistorians envision these relationships. I demonstrate how studies of female homosexual behaviour in Japanese macaques challenge many of our most basic assumptions about this topic. The concept of sexual pleasure is presented as an important framework for understanding intimate sexual relations in prehistory. Finally, I discuss the role of sexual pleasure in human bio‐cultural evolution, particularly in relation to the evolution of material culture.

Speedbumps for Adaptationism

Adaptation. MICHAEL R. ROSE and GEORGE V. LAUDER, Eds. Academic Press, San Diego, 1996. xiv, 511 pp., illus. $69.95 or £52, ISBN 0-12-596420-x; paper, $34.95 or £24.95, ISBN 0-12-596421-8.

An adaptationist view of apoptosis.

A cell's decision whether to undergo apoptosis (cell suicide) is examined here from an adaptationist perspective, rather than a mechanistic one. External and internal inputs to the cell's protein-based information processing network are used in making this decision, with the cell factoring in its replaceability. A system in which each cell takes primary responsibility for deciding its own fate has great adaptive value because it harnesses each cell's self-knowledge rather than waiting for external cues to be recognized by other cells. Cell self-destruction can be an important selective mechanism, potentially leading to better performance of tissues over time. However, reliance on cells to monitor themselves has a flaw, since cells may incur selfish mutations that impair their apoptotic responsibility. The tight control exerted over somatic cells serves to check selfish genes involved in neoplasia and viral infections. Germ cells appear to be similarly monitored, both by other germ cells and by supporting follicular or Sertoli cells, thus maintaining the advantages offered by an apoptotic system. The adaptationist approach views the limited replacement of neurons and cardiac myocytes as likely to have net survival value. The linkage of these cells into a network with their neighbors throughout a lifetime allows for a precisely functioning team of cells expected to compensate for gradual declines in individual cell functionality. Replacement of apoptotic cells with naive cells might decrease brain functionality and might risk upsetting the conduction of cardiac impulses. The evolutionary viewpoint lends itself to new hypotheses, but only the boldest speculator would have predicted a system in which cells are given primary responsibility for deciding whether to kill themselves when they deem it beneficial to the organism.

Testing Adaptationism: A Comment on Orzack and Sober

Testing Adaptationism: A Comment on Orzack and Sober

How to Formulate and Test Adaptationism

How to Formulate and Test Adaptationism

Darwinian adaptation, population genetics and the streetcar theory of evolution.

This paper investigates the problem of how to conceive a robust theory of phenotypic adaptation in non-trivial models of evolutionary biology. A particular effort is made to develop a foundation of this theory in the context of n-locus population genetics. Therefore, the evolution of phenotypic traits is considered that are coded for by more than one gene. The potential for epistatic gene interactions is not a priori excluded. Furthermore, emphasis is laid on the intricacies of frequency-dependent selection. It is first discussed how strongly the scope for phenotypic adaptation is restricted by the complex nature of 'reproduction mechanics' in sexually reproducing diploid populations. This discussion shows that one can easily lose the traces of Darwinism in n-locus models of population genetics. In order to retrieve these traces, the outline of a new theory is given that I call 'streetcar theory of evolution'. This theory is based on the same models that geneticists have used in order to demonstrate substantial problems with the 'adaptationist programme'. However, these models are now analyzed differently by including thoughts about the evolutionary removal of genetic constraints. This requires consideration of a sufficiently wide range of potential mutant alleles and careful examination of what to consider as a stable state of the evolutionary process. A particular notion of stability is introduced in order to describe population states that are phenotypically stable against the effects of all mutant alleles that are to be expected in the long-run. Surprisingly, a long-term stable state can be characterized at the phenotypic level as a fitness maximum, a Nash equilibrium or an ESS. The paper presents these mathematical results and discusses - at unusual length for a mathematical journal - their fundamental role in our current understanding of evolution.

Explanatory pluralism in evolutionary biology

The ontological dependence of one domain on another is compatible with the explanatory autonomy of the less basic domain. That autonomy results from the fact that the relationship between two domains can be very complex. In this paper I distinguish two different types of complexity, two ways the relationship between domains can fail to be transparent, both of which are relevant to evolutionary biology. Sometimes high level explanations preserve a certain type of causal or counterfactual information which would be lost at the lower level; I argue that this is central to the proper understanding of the adaptationist program. Sometimes high level kinds are multiply realised by lower level kinds: I argue that this is central to the understanding of macroevolution.

The Adaptionist Approach Has Limits

The Adaptionist Approach Has Limits

Evolutionary Psychology: Adaptationist, Selectionist, and Comparative

structure and reciprocity in social dilemmas. Journal of Experimental Social Psychology, 29, 252-267. Kramer, R. M., & Brewer, M. B. (1984). Effects of group identity on resource use in a simulated commons dilemma. Journal of Personality and Social Psychology, 46, 1044-1057. McClintock, M. K. (1987). A functional approach to the behavioral endocrinology of rodents. In D. Crews (Ed.), Psychobiology of reproductive behavior: An evolutionary perspective (pp. 176203). Englewood Cliffs, NJ: Prentice-Hall. Oyama, S. (1985). The ontogeny of information. New York: Cambridge University Press. Trivers, R. L. (1972). Parental investment and sexual selection. In B. Campbell (Ed.), Sexual selection and the descent of man 18711971 (pp. 136-179). Chicago: Aldine. Turner, J. C., Hogg, M., Oakes, P., Riecher, S., & Wetherell, M. (1987). Rediscovering the social group: A self-categorization theory. Oxford, England: Blackwell. Williams, G. C. (1966). Adaptation and natural selection. Princeton, NJ: Princeton University Press. Wilson, D. S., & Sober, E. (in press). Re-introducing group selection to the human behavioral sciences. Behavioral and Brain Sciences.

Labor and the Rise of Complex Hunter-Gatherers

In recent years, an explosion of interest in the causes of cultural complexity, particularly the rise of complex hunter-gatherers, has generated an exciting intellectual exchange. Existing models of the emergence of middle-range societies depend on notions of population growth, risk management and stress, political manipulation, and conflict. In order to understand the appearance of complex foraging—collecting societies, there is a need to synthesize rather than polarize aspects of these perspectives, particularly the political and adaptationist approaches to modeling cultural evolution. I suggest that the emergence of chiefly politics and ascribed power is ultimately contingent on the development of elite control over labor. Specific opportunities for rising leadership to manipulate household labor may emerge from a range of conditions of sociopolitical or environmental stress.

Mode, tempo and pattern of evolution in subterranean mole rats of the Spalax ehrenbergi superspecies in the quaternary of Israel

The Spalax ehrenbergi superspecies in Israel involves 4 chromosomal species (2n = 52, 54, 58 and 60) displaying active ecological speciation throughout the Quaternary, matching climatic diversity. The mode of speciation was presumably peripatric, initiated chromosomally in small peripherally isolated populations. The emergence of the new chromosomal species was followed by a gradual genic accumulation of positive assortative mating, based on premating ethological species-specific isolating mechanisms involving olfaction, vocalization, seismic (vibrational), aggression and mating (through bacular variation) cues. Speciation was gradual, not punctuational, budding sequential daughter species with increasing chromosome numbers and heterozygosity, in a trend along an ecological gradient of increasing aridity towards the desert. The adaptationist programme is indispensable in understanding the evolution of Spalax ehrenbergi. The evolution of Spalax links micro- and macroevolution, corroborating the Synthetic Theory of Evolution. The evolutionary model of Spalax is potentially rich and its future advancement can enrich evolutionary theory.

Equivalence and the adaptationist program

Equivalence guarantees comparison. Thus, one may make a legitimate comparison of all species which, if responding, are adapted to a certain condition with all species which, if not adapted, do not respond to this condition. Several ways in which this theme is elabored are presented. An insight into the way in which equivalence works is illustrated as follows. When an eastern woodchuck has a low elevation habitat, has a long growing season, has sexual maturation in the second year, has annual reproduction, and has an aggressive intolerant social system, this bundle of traits is adaptive of, maximizes the fitness of, woodchuck x. And the equivalent to ‘If x has the woodchuck bundle of traits, then this bundle is adaptive of x ′ is ‘If this bundle is not adaptive of x, then x does not have the woodchuck bundle of traits’. So, there are two steps wherein x stays the same: x has the woodchuck bundle; x does not have the woodchuck bundle. But there is a third step wherein an Olympic marmot as a different ‘ x’ has an opposite bundle of traits and thus does affirm the second equivalent ‘if the woodchuck bundle is not adaptive of x, then x does not have this bundle’. The process of adaptation, as when bird, adapted for flight, came from reptile, not adapted for flight, is really a three step process: x is adapted for flight, the same x is conceived as not adapted for flight, a different x (reptile) really is not adapted for flight. But this evolutionary metamorphosis of ‘adapted’ from ‘not adapted’ rests squarely on the mechanics of an equivalence, just like the one just mentioned for the woodchuck-marmot case. The adaptationist program says this: “each aspect of an organism's morphology, physiology and behavior has been molded by natural selection as a solution to a problem posed by the environment”. But the “wholesale reconstruction of a reptile to make a bird is considered a process of major adaptation by which birds solved the problem of flight”. The first quoted sentence says that each organism (or group of organisms) solved a problem and thus endorses only affirmation of ‘adapted’. The equivalence analysis behind the second quote endorses both affirmation and denial of ‘adapted’ in the process of adaptation. Thus, there is contradiction in the presentation of the adaptationist program by Lewontin.

Rape: The perfect adaptationist story

Rape: The perfect adaptationist story