Models of conditioned reinforcement and abnormal behaviour in captive animals.

Abnormal behaviours are common in captive animals, and despite a lot of research, the development, maintenance and alleviation of these behaviours are not fully understood. Here, we suggest that conditioned reinforcement can induce sequential dependencies in behaviour that are difficult to infer from direct observation. We develop this hypothesis using recent models of associative learning that include conditioned reinforcement and inborn facets of behaviour, such as predisposed responses and motivational systems.

A Comparison of Individual Learning and Social Learning in Zebrafish Through an Ethorobotics Approach.

Social learning is ubiquitous across the animal kingdom, where animals learn from group members about predators, foraging strategies, and so on. Despite its prevalence and adaptive benefits, our understanding of social learning is far from complete. Here, we study observational learning in zebrafish, a popular animal model in neuroscience.

Social learning through associative processes: a computational theory.

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 social learning in terms of associative processes. Leveraging previous attempts and a recent computational formulation of associative learning, we analyse the following learning scenarios in some generality: learning responses to social stimuli, including learning to imitate; learning responses to non-social stimuli; learning sequences of actions; learning to avoid danger.

A model of contact-induced language change: Testing the role of second language speakers in the evolution of Mozambican Portuguese.

Language change is accelerated by language contact, especially by contact that occurs when a group of speakers shifts from one language to another. This has commonly been explained by linguistic innovation occurring during second language acquisition. This hypothesis is based on historical reconstructions of instances of contact and has not been formally tested on empirical data.

On the role of responses in Pavlovian acquisition.

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 stimulus) experiences, and that CRs play a minimal role, if any. Here we revisit the question and present 2 new quantitative methods to evaluate whether CRs influence the course of learning.

Generosity pays: Selfish people have fewer children and earn less money.

Does selfishness pay in the long term? Previous research has indicated that being prosocial (or otherish) rather than selfish has positive consequences for psychological well-being, physical health, and relationships. Here we instead examine the consequences for individuals' incomes and number of children, as these are the currencies that matter most in theories that emphasize the power of self-interest, namely economics and evolutionary thinking. Drawing on both cross-sectional (Studies 1 and 2) and panel data (Studies 3 and 4), we find that prosocial individuals tend to have more children and higher income than selfish individuals.

Birth Intervals and Health in Adulthood: A Comparison of Siblings Using Swedish Register Data.

A growing body of research has examined whether birth intervals influence perinatal outcomes and child health as well as long-term educational and socioeconomic outcomes. To date, however, very little research has examined whether birth spacing influences long-term health. We use contemporary Swedish population register data to examine the relationship between birth-to-birth intervals and a variety of health outcomes in adulthood: for men, height, physical fitness, and the probability of falling into different body mass index categories; and for men and women, mortality.

Social learning may lead to population level conformity without individual level frequency bias.

A requirement of culture, whether animal or human, is some degree of conformity of behavior within populations. Researchers of gene-culture coevolution have suggested that population level conformity may result from frequency-biased social learning: individuals sampling multiple role models and preferentially adopting the majority behavior in the sample. When learning from a single role model, frequency-bias is not possible.

Women's rights in democratic transitions: A global sequence analysis, 1900-2012.

What determines countries' successful transition to democracy? This article explores the impact of granting civil rights in authoritarian regimes and especially the gendered aspect of this process. It argues that both men's and women's liberal rights are essential conditions for democratisation to take place: providing both women and men rights reduces an inequality that affects half of the population, thus increasing the costs of repression and enabling the formation of women's organising - historically important to spark protests in initial phases of democratisation. This argument is tested empirically using data that cover 173 countries over the years 1900-2012 and contain more nuanced measures than commonly used.

Can squirrel monkeys learn an grammar? A re-evaluation of Ravignani (2013).

Ravignani et al. (2013) habituated squirrel monkeys to sound sequences conforming to an grammar ( = 1, 2, 3), then tested them for their reactions to novel grammatical and non-grammatical sequences. Although they conclude that the monkeys "consistently recognized and generalized the sequence ," I remark that this conclusion is not robust.

Using register data to deduce patterns of social exchange.

This paper presents a novel method for deducting propensities for social exchange between individuals based on the choices they make, and based on factors such as country of origin, sex, school grades and socioeconomic background. The objective here is to disentangle the effect of social ties from the other factors, in order to find patterns of social exchange. This is done through a control-treatment design on analysing available data, where the 'treatment' is similarity of choices between socially connected individuals, and the control is similarity of choices between non-connected individuals.

Memory for stimulus sequences: a divide between humans and other animals?

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.

Time Does Not Help Orangutans Solve Physical Problems.

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.

The power of associative learning and the ontogeny of optimal behaviour.

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 behaviour is largely open.

Cooperation and Shared Beliefs about Trust in the Assurance Game.

Determinants of cooperation include ingroup vs. outgroup membership, and individual traits, such as prosociality and trust. We investigated whether these factors can be overridden by beliefs about people's trust.

A novel method to analyze social transmission in chronologically sequenced assemblages, implemented on cultural inheritance of the art of cooking.

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 mainly gradual or subject to fashion fluctuations.

What games support the evolution of an ingroup bias?

There is an increasing wealth of models trying to explain the evolution of group discrimination and an ingroup bias. This paper sets out to systematically investigate the most fundamental assumption in these models: in what kind of situations do the interactions take place? What strategic structures - games - support the evolution of an ingroup bias? More specifically, the aim here is to find the prerequisites for when a bias also with respect to minimal groups - arbitrarily defined groups void of group-specific qualities - is selected for, and which cannot be ascribed to kin selection. Through analyses and simulations of minimal models of two-person games, this paper indicates that only some games are conducive to the evolution of ingroup favouritism.

Modeling the genealogy of a cultural trait.

The mathematical study of genealogies has yielded important insights in population biology, such as the ability to estimate the time to the most recent common ancestor (MRCA) of a sample of genetic sequences or of a group of individuals. Here we introduce a model of cultural genealogies that is a step toward answering similar questions for cultural traits. In our model individuals can inherit from a variable, potentially large number of ancestors, rather than from a fixed, small number of ancestors (one or two) as is typical of genetic evolution.

Animal memory: A review of delayed matching-to-sample data.

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.

Dog movie stars and dog breed popularity: a case study in media influence on choice.

Fashions and fads are important phenomena that influence many individual choices. They are ubiquitous in human societies, and have recently been used as a source of data to test models of cultural dynamics. Although a few statistical regularities have been observed in fashion cycles, their empirical characterization is still incomplete.

How feedback biases give ineffective medical treatments a good reputation.

Background: Medical treatments with no direct effect (like homeopathy) or that cause harm (like bloodletting) are common across cultures and throughout history. How do such treatments spread and persist? Most medical treatments result in a range of outcomes: some people improve while others deteriorate. If the people who improve are more inclined to tell others about their experiences than the people who deteriorate, ineffective or even harmful treatments can maintain a good reputation.

Lord's paradox in a continuous setting and a regression artifact in numerical cognition research.

In this paper we review, and elaborate on, the literature on a regression artifact related to Lord's paradox in a continuous setting. Specifically, the question is whether a continuous property of individuals predicts improvement from training between a pretest and a posttest. If the pretest score is included as a covariate, regression to the mean will lead to biased results if two critical conditions are satisfied: (1) the property is correlated with pretest scores and (2) pretest scores include random errors.

Fashion vs. function in cultural evolution: the case of dog breed popularity.

We investigate the relationship between characteristics of dog breeds and their popularity between years 1926 and 2005. We consider breed health, longevity, and behavioral qualities such as aggressiveness, trainability, and fearfulness. We show that a breed's overall popularity, fluctuations in popularity, and rates of increase and decrease around popularity peaks show typically no correlation with these breed characteristics.

Editorial decisions may perpetuate belief in invalid research findings.

Social psychology and related disciplines are seeing a resurgence of interest in replication, as well as actual replication efforts. But prior work suggests that even a clear demonstration that a finding is invalid often fails to shake acceptance of the finding. This threatens the full impact of these replication efforts.

When does intimate partner violence continue after separation?

Over their lifetime, approximately 10% of all women become victims of postseparation stalking or assault. We use a nationally representative survey of separated Swedish women to examine whether men who strive to control their partners during their relationships are more likely to stalk or assault their ex-partners after separation. The empirical analysis shows that basic measures of control behaviors explain 18% of the variance in stalking victimization and 8% of the assault victimization.