Magnus Enquist

Magnus Enquist
Stockholm University | SU · Department of Zoology

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126
Publications
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Introduction
Skills and Expertise

Publications

Publications (126)
Chapter
Evolution of Learning and Memory Mechanisms is an exploration of laboratory and field research on the many ways that evolution has influenced learning and memory processes, such as associative learning, social learning, and spatial, working, and episodic memory systems. This volume features research by both outstanding early-career scientists as we...
Preprint
Human language is unique in its compositional and sequential form. Language evolution is often explained by advantages of communication. However, it has proven challenging to identify an evolutionary trajectory from a world without language to a world with language, especially while at the same time explaining why such an advantageous trait has not...
Article
A specific goal of the field of cultural evolution is to understand how processes of transmission and selection at the individual level lead to population-wide patterns of cultural diversity and change. Models of cultural evolution have typically assumed that traits are independent of one another and essentially exchangeable. But culture has a stru...
Article
Full-text available
Cultural evolution theory has long been inspired by evolutionary biology. Conceptual analogies between biological and cultural evolution have led to the adoption of a range of formal theoretical approaches from population dynamics and genetics. However, this has resulted in a research programme with a strong focus on cultural transmission. Here, we...
Preprint
A specific goal of the field of cultural evolution is to understand how processes of transmission and selection at the individual level lead to population-wide patterns of cultural diversity and change. Models of cultural evolution have typically assumed that traits are independent of one another and essentially exchangeable. But culture has a stru...
Preprint
Full-text available
Cultural evolution theory has long been inspired by evolutionary biology. Conceptual analogies between biological and cultural evolution have led to the adoption of a range of formal theoretical approaches from population dynamics and genetics. However, this has resulted in a research programme with a strong focus on cultural transmission. Here, we...
Article
We present a new mathematical formulation of associative learning focused on non-human animals, which we call A-learning. Building on current animal learning theory and machine learning, A-learning is composed of two learning equations, one for stimulus-response values and one for stimulus values (conditioned reinforcement). A third equation implem...
Article
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A widely accepted view in the cultural evolutionary literature is that culture forms a dynamic system of elements (or ‘traits’) linked together by a variety of relationships. Despite this, large families of models within the cultural evolutionary literature tend to represent only a small number of traits, or traits without interrelationships. As su...
Article
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Social transmission of information is a key phenomenon in the evolution of behaviour and in the establishment of traditions and culture. The diversity of social learning phenomena has engendered a diverse terminology and numerous ideas about underlying learning mechanisms, at the same time that some researchers have called for a unitary analysis of...
Data
Supplementary materials for “Social learning through associative processes: A computational theory”
Article
A defining feature of Pavlovian conditioning is that the unconditioned stimulus (US) is delivered whether or not the animal performs a conditioned response (CR). This has lead to the question: Does CR performance play any role in conditioning? Between the 1930s and 1970s, a consensus emerged that CR acquisition is driven by CS–US (CS, conditioned s...
Preprint
Full-text available
Social transmission of information is a key phenomenon in the evolution of behavior and in the establishment of traditions and culture. The diversity of social learning phenomena has engendered a diverse terminology and numerous ideas about underlying learning mechanisms, at the same time that some researchers have called for a unitary analysis of...
Preprint
A defining feature of Pavlovian conditioning is that the unconditionedstimulus (US) is delivered whether or not the animal performs aconditioned response (CR). This has lead to the question: Does CRperformance play any role in learning? Between the 1930's and 1970's,a consensus emerged that CR acquisition is driven by CS-USexperiences, and that CRs...
Article
Full-text available
Humans stand out among animals for their unique capacities in domains such as language, culture and imitation, yet it has been difficult to identify cognitive elements that are specifically human. Most research has focused on how information is processed after it is acquired, e.g. in problem solving or ‘insight’ tasks, but we may also look for spec...
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Many questions in animal intelligence and cognition research are challenging. One challenge is to identify mechanisms underlying reasoning in experiments. Here, we provide a way to design such tests in non-human animals. We know from research in skill acquisition in humans that reasoning and thinking can take time because some problems are processe...
Article
Using conscription data and follow ups from a large representative sample of Swedish men, and in accordance with earlier studies, we found a bell shaped association between male height and the hazard for not being unmarried. The shape of this association was not affected by indicators of health and socioeconomic status and it might, instead, be due...
Article
Full-text available
Behaving efficiently (optimally or near-optimally) is central to animals’ adaptation to their environment. Much evolutionary biology assumes, implicitly or explicitly, that optimal behavioural strategies are genetically inherited, yet the behaviour of many animals depends crucially on learning. The question of how learning contributes to optimal be...
Code
This package contains simulation code accompanying the paper "The power of associative learning and the ontogeny of optimal behavior," by Magnus Enquist, Johan Lind, and Stefano Ghirlanda. The package contains code to reproduce all simulations in the paper, and documentation on how the code works.
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Full-text available
We have carried out an empirical study of long-term change in European cookery to test if the development of this cultural phenomenon matches a general hypothesis about cultural evolution: that human cultural change is characterized by cumulativity. Data from seven cookery books, evenly spaced across time, the oldest one written in medieval times (...
Article
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Here we present an analytical technique for the measurement and evaluation of changes in chronologically sequenced assemblages. To illustrate the method, we studied the cultural evolution of European cooking as revealed in seven cook books dispersed over the past 800 years. We investigated if changes in the set of commonly used ingredients were mai...
Article
We performed a meta-analysis of over 90 data sets from delayed matching-to-sample (DMTS) studies with 25 species (birds, mammals, and bees). In DMTS, a sample stimulus is first presented and then removed. After a delay, two (or more) comparison stimuli are presented, and the subject is rewarded for choosing the one matching the sample. We used data...
Article
Open Access link below: http://rspb.royalsocietypublishing.org/content/royprsb/281/1779/20132561.full.pdf Correlations in family size across generations could have a major influence on human population size in the future. Empirical studies have shown that the associations between the fertility of parents and the fertility of children are substanti...
Article
Full-text available
We use the term regulatory traits to indicate traits that both regulate cul-tural transmission (e.g., from whom to learn) and are themselves culturally trans-mitted. In the first part of this contribution we study the dynamics of some of these traits through simple mathematical models. In particular, we consider the cultural evolution of traits tha...
Article
Across many taxa, intriguing positive correlations exist between intelligence (measured by proxy as encephalization), behavioral repertoire size, and lifespan. Here we argue, through a simple theoretical model, that such correlations arise from selection pressures for efficient learning of behavior sequences. We define intelligence operationally as...
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Full-text available
Humans have genetically based unique abilities making complex culture possible; an assemblage of traits which we term "cultural capacity". The age of this capacity has for long been subject to controversy. We apply phylogenetic principles to date this capacity, integrating evidence from archaeology, genetics, paleoanthropology, and linguistics. We...
Article
Full-text available
We explore the impact of age on cultural change through simulations of cultural evolution. Our simulations show that common observations about the relationship between old and young naturally emerge from repeated cultural learning. In particular, young individuals are more open to learn than older individuals, they are less effective as cultural mo...
Chapter
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Det kan framstå som nästan mirakulöst att det existerar någonting så intrikat och komplicerat i universum som en blomma eller en katt. Hur kan sådan komplexitet uppkomma och fungera? Från att ha varit ett av bevisen för en guds existens har vi nu tack vare Charles Darwin och forskarna i hans efterföljd en godvetenskaplig förståelse fö r hur det gåt...
Article
Full-text available
Many cultural traits exhibit volatile dynamics, commonly dubbed fashions or fads. Here we show that realistic fashion-like dynamics emerge spontaneously if individuals can copy others' preferences for cultural traits as well as traits themselves. We demonstrate this dynamics in simple mathematical models of the diffusion, and subsequent abandonment...
Data
Equilibrium values of preferences. Frequency of the preference for a trait at the end of a fashion cycle ( in equation 15 (Model S1) as a function of initial frequency of the preference, . All parameters as in Figure S2. (TIF)
Data
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Derivation and analysis of Model 1. (PDF)
Data
Sample model trajectories. Sample model trajectories in the plane of the simplified system in equations 6–7 (Model S1), for different initial frequencies of the preference, , and initial frequency of the trait . Trajectories start at the closed circle and end at the open diamond. The dashed line is the line , which delimits the state space together...
Data
Maximum frequency attained during a trait's fashion cycle. Maximum frequency attained during a trait's fashion cycle, as a function of initial preference, , and system parameters, . Initial frequency is . (TIF)
Data
Examples of frequency-preference dynamics in simulations of the multi-trait preference model. (A) The preference (red) for a trait rises in the population, which causes a rise in frequency (blue). As the trait becomes common, the preference falls and eventually the trait declines in frequency. See main text for discussion. (B) Another example of th...
Data
Full-text available
Model 1 transitions. (PDF)
Data
Distribution of trait lifespans in the multi-trait models of fashion. Distribution of trait lifespans for the preference, status and neutral models for the simulations described in the main text. (TIF)
Data
Goodness of simplified model. Absolute difference between trait frequency () according to the full Model 1 (equations 1–4 in the main text) and the simplified model in equations (6,7,9) as a function of initial preference, , and for different combinations of and parameters (). Trait frequency in the simplified model lies within 2% of the frequency...
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Darwinian processes should favour those individuals that deploy the most effective strategies for acquiring information about their environment. We organized a computer-based tournament to investigate which learning strategies would perform well in a changing environment. The most successful strategies relied almost exclusively on social learning (...
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We investigated whether a sexual preference for smoking can be related to past experiences of parental smoking during childhood, as predicted by the theory of sexual imprinting, but also by sexual conditioning theory. In a sample of over 4000 respondents to five Internet surveys on sexual preferences, we found that parental smoking correlates with...
Article
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Previous work on mathematical models of cultural evolution has mainly focused on the diffusion of simple cultural elements. However, a characteristic feature of human cultural evolution is the seemingly limitless appearance of new and increasingly complex cultural elements. Here, we develop a general modelling framework to study such cumulative pro...
Article
Several theories, including psychodynamic theories, sexual imprinting and early conditioning have been formulated to explain sexual development. Empirical data, however, remain insufficient for a thorough evaluation of these theories. In this study, we test the hypothesis that a critical period exists for the acquisition of sexual preferences, as s...
Article
The ability to acquire knowledge and skills from others is widespread in animals and is commonly thought to be responsible for the behavioural traditions observed in many species. However, in spite of the extensive literature on theoretical analyses and empirical studies of social learning, little attention has been given to whether individuals acq...
Article
We consider models of the interactions between human population dynamics and cultural evolution, asking whether they predict sustainable or unsustainable patterns of growth. Phenomenological models predict either unsustainable population growth or stabilization in the near future. The latter prediction, however, is based on extrapolation of current...
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Full-text available
Social learning (learning through observation or interaction with other individuals) is widespread in nature and is central to the remarkable success of humanity, yet it remains unclear why copying is profitable and how to copy most effectively. To address these questions, we organized a computer tournament in which entrants submitted strategies sp...
Article
Full-text available
We present a model of cultural evolution in which an individual's propensity to engage in social learning is affected by social learning itself. We assume that individuals observe cultural traits displayed by others and decide whether to copy them based on their overall preference for the displayed traits. Preferences, too, can be transmitted betwe...
Article
Full-text available
Although genetic information is acquired only once, cultural information can be both abandoned and reacquired during an individual's lifetime. Therefore, cultural evolution will be determined not only by cultural traits' ability to spread but also by how good they are at sticking with an individual; however, the evolutionary consequences of this as...
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Bird and Emery (1) showed that rooks (Corvus frugilegus) can learn to manufacture and use tools to obtain food. They suggest that these behaviors emerge through insight and the authors touch upon a fundamental question in the study of animal intelligence: How can insight learning be separated from shaping?
Article
In a species capable of (imperfect) social learning, how much culture can a population of a given size carry? And what is the relationship between the individual and the population? In the first study of these novel questions, here we develop a mathematical model of the accumulation of independent cultural traits in a finite population with overlap...
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Full-text available
Historical records show that culture can increase exponentially in time, e.g., in number of poems, musical works, scientific discoveries. We model how human capacities for creativity and cultural transmission may make such an increase possible, suggesting that: (1) creativity played a major role at the origin of human culture and for its accumulati...
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Alan Rogers (1988) presented a game theory model of the evolution of social learning, yielding the paradoxical conclusion that social learning does not increase the fitness of a population. We expand on this model, allowing for imperfections in individual and social learning as well as incorporating a “critical social learning” strategy that tries...
Article
A demographic transition is a change in the pattern of growth of a population. Human history records several kinds of such transitions, e.g., from stability to growth or between different kinds of growth. Culture is often implied as the main fuel of demographic transitions, but theorizing is so far limited to verbal arguments. Here we study two sim...
Article
Because culture requires transmission of information between individuals, thinking about the origin of culture has mainly focused on the genetic evolution of abilities for social learning. Current theory considers how social learning affects the adaptiveness of a single cultural trait, yet human culture consists of the accumulation of very many tra...
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Full-text available
We show that a simple network model of associative learning can reproduce three findings that arise from particular training and testing procedures in generalization experiments: the effect of (i) 'errorless learning', (ii) extinction testing on peak shift, and (iii) the central tendency effect. These findings provide a true test of the network mod...
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Existing mathematical models suggest that gene-culture coevolution favours a conformist bias in social learning, that is, a psychological mechanism to preferentially acquire the most common cultural variants. Here we show that this conclusion relies on specific assumptions that seem unrealistic, such as that all cultural variants are known to every...
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The aim of this study was to estimate the relative frequency of Fetishes in a large sample of individuals. Using the Internet as a data source, we examined 381 discussion groups. We estimate, very conservatively, that at least 5000 individuals were targeted. The relative frequency of each preference category was estimated considering (a) the number...
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In the human sciences, cultural evolution is often viewed as an autonomous process free of genetic influence. A question that follows is, If culture is not influenced by genes, can it take any path? Employing a simple mathematical model of cultural transmission in which individuals may copy each other's traits, we show that cultural evolution favor...
Article
The rapid increase in the understanding of biological communication has been largely theory driven. Game-theoretical models have completely changed how behavioural biologists think about communication. These theories are widely cited, but much of the theoretical work remains only vaguely understood by the wide majority of those who make use of it....
Article
Many signals found in nature seem exaggerated, for instance in size or colour. According to the receiver bias hypothesis such signal features evolve as a consequence of nonfunctional response biases in receivers. In this study we tested this hypothesis using chickens, Gallus gallus domesticus, in a virtual evolution experiment testing the potential...
Book
How can we make better sense of animal behavior by using what we know about the brain? This is the first book that attempts to answer this important question by applying neural network theory. Scientists create Artificial Neural Networks (ANNs) to make models of the brain. These networks mimic the architecture of a nervous system by connecting elem...
Article
It is common to find spatially repetitive patterns in animal visual signals. The evolution of such patterns is not well explained by existing theories of signal evolution. In this paper, we suggest that the evolution of signals with spatial repetition may be due to specific recognition problems and receiver biases. The logics of our hypotheses are...
Article
Animals tend to respond more strongly to signals that are more colourful and such signals are also common in nature. This is the first study to explore experimentally the possibility that response biases arising in an animal's recognition mechanisms can explain these findings. We trained domestic fowls, Gallus gallus domesticus, to respond by pecki...
Article
We review data from both ethology and psychology about generalization, that is how animals respond to sets of stimuli including familiar and novel stimuli. Our main conclusion is that patterns of generalization are largely independent of systematic group (evidence is available for insects, fish, amphibians, reptiles, birds and mammals, including hu...
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Full-text available
In studies of both animal and human behaviour, game theory is used as a tool for understanding strategies that appear in interactions between individuals. Game theory focuses on adaptive behaviour, which can be attained only at evolutionary equilibrium. We suggest that behaviour appearing during interactions is often outside the scope of such analy...
Article
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Organisms can learn by individual experience to recognize relevant stimuli in the environment or they can genetically inherit this ability from their parents. Here, we ask how these two modes of acquisition affect signal evolution, focusing in particular on the exaggeration and cost of signals. We argue first, that faster learning by individual rec...
Article
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We trained chickens to react to an average human female face but not to an average male face (or vice-versa). In a subsequent test, the animals showed preferences for faces consistent with human sexual preferences (obtained from university students). This suggests that human preferences arise from general properties of nervous systems, rather than...
Article
This experiment provides the first empirical evidence that symmetry preferences may arise as a by-product of animals' recognition mechanisms. We used a computer touch screen to train domestic fowl, Gallus gallus domesticus, to discriminate between rewarding and nonrewarding stimuli. The rewarding stimuli consisted of two slightly asymmetrical cross...
Chapter
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We explore the extent to which learning and memory mechanisms can explain variation in facial attractiveness. We suggest that two general mechanisms are in operation, and work together in determining attractiveness. Both can be understood in terms of general principles of learning, memory and generalization. One mechanism is related to the problem...
Article
We studied response biases to visual stimulation using a new experimental technique. The subjects (hens, Gallus gallus domesticus) were confronted with several rewarding and non-rewarding patterns on a computer screen. In contrast with standard discrimination tasks the rewarding patterns were not identical and varied in a dimension differentiating...
Article
The study of threat displays has long been an area in which theory and empirical work have each spurred the other forward. Communication is currently the focus of great interest and effort on the part of modellers. A great deal that classical ethologists have accurately described about threat displays still lacks adequate explanation. Here we revie...
Article
Females in monogamous species tend to be more sexually active than females in species with other mating systems. In this paper we consider the possibility that female sexuality has evolved because more sexually active females have received more male assistance. We develop a model in which there is no direct cue available to males indicating whether...
Article
We assume that parents use the signalling intensity of their young to determine how much food they bring to the nest, and that the pattern of food allocation is determined by the signalling intensity and by the intensity of other nonsignalling behaviours that are not perceived by the parents. We explore different ways in which signalling, nonsignal...