Stephen Edmund Gillam Lea

University of Exeter | UoE · Department of Psychology

A recent study on the diving behaviour of European shags (Gulosus aristotelis (L.)) foraging in kelp forests off rocky coasts of Norway suggests surface durations are related only to the duration of the preceding dive, and hence are being used for respiratory recovery. These results contrast with earlier reports concerning shags foraging in highly...

At high elevations, biodiversity is at elevated risk from extinctions due to rapid environmental changes. In the most of its range in Himalayas, the red panda, an endangered species, is struggling to survive in the wild, and a global captive breeding programme has been launched to conserve the species. Because captivity can have negative impacts on...

A number of different phenomena in pigeon visual cognition suggest that pigeons do not immediately recognize two identical objects in different locations as being "the same." To examine this question directly, pigeons were trained in an absolute go/no-go discrimination between arbitrary selections from sets of 16 images of paintings by Claude Monet...

Everyday financial behaviour involves inter-temporal choices, between saving, spending, and debt. Consumers do not always take these decisions to their best advantage. Ainslie's analysis of the means to willpower as suppression, resolve, and habit is potentially applicable to understanding and improving the decisions that consumers make. Some relev...

Habitat characteristics and microhabitat of organisms pose a number of choices to foraging species, for example where and how to search for prey, which prey to select and what foraging technique to employ. Predators can enhance the profitability of foraging by adapting their strategies flexibly in relation to prey characteristics and environmental...

This paper reviews psychological studies of real‐life use of credit, debt, and overindebtedness, with the aim of making policy recommendations that could reduce the damage done by debt to both individuals and society. The overall level of debt in society is heavily influenced by the level of economic inequality and social insecurity, and no psychol...

This paper aimed to explore and clarify the concept of behavioral flexibility. A selective literature review explored how the concept of behavioral flexibility has been used in ways that range from acknowledging the fact that animals’ behavior is not always bounded by instinctual constraints, to describing the variation between species in their cap...

Inhibitory control enables subjects to quickly react to unexpected changes in external demands. In humans, this kind of behavioral flexibility is often used as an indicator of an individual’s executive functions, and more and more research has emerged to investigate this link in nonhuman animals as well. Here we explored the value of a recently dev...

Inhibiting learned behaviours when they become unproductive and searching for an alternative solution to solve a familiar but different problem are two indicators of flexibility in problem solving. A wide range of animals show these tendencies spontaneously, but what kind of search process is at play behind their problem-solving success? Here, we i...

In many cognitive tasks where humans are thought to rely on executive functioning, pigeons' behavior can be explained by associative processes. A key form of executive functioning is inhibiting prepotent responses, often investigated in humans by means of "Stop-Signal" or "Change-Signal" procedures. In these procedures, execution of a well-practice...

The great increase in the study of dog cognition in the current century has yielded insights into canine cognition in a variety of domains. In this review, we seek to place our enhanced understanding of canine cognition into context. We argue that in order to assess dog cognition, we need to regard dogs from three different perspectives: phylogenet...

Behavioural and cognitive processes play important roles in mediating an individual's interactions with its environment. Yet, while there is a vast literature on repeatable individual differences in behaviour, relatively little is known about the repeatability of cognitive performance. To further our understanding of the evolution of cognition, we...

Two experiments investigated what makes it more likely that pigeons’ behavior will come under the control of multiple relevant visual stimulus dimensions. Experiment 1 investigated the effect of stimulus set structure, using a conditional discrimination between circles that differed in both hue and diameter. Two training conditions differed in whet...

Behavioural flexibility has been argued to be an evolutionarily favourable trait that helps invasive species to establish themselves in non-native environments. Few studies, however, have compared the level of flexibility (whether considered as an outcome or as a process) in mammalian invaders and related native species. Here, we tested whether fle...

In human participants, 2 paradigms commonly assumed to measure the executive-control processes involved in response inhibition are the stop-signal and change-signal tasks. There is, however, also considerable evidence that performance in these tasks can be mediated by associative processes. To assess which components of inhibitory response control...

One way of testing cognitive abilities (or intelligence”) is by using so-called “means-end” tests, where the desired outcome can only be achieved by utilising some means to that end. Pulling a piece of food that is out of reach into reach with the help of an attached string is one of these means-end tasks. The ability of dogs to solve this problem...

When animals encounter a task they have solved previously, or the same problem appears in a different apparatus, how does memory, alongside behavioural traits such as persistence, selectivity and flexibility, enhance problem-solving efficiency? We examined this question by first presenting grey squirrels with a puzzle 22 months after their last exp...

Behavioural flexibility allows animals to adjust their behaviours according to changing environmental demands. Such flexibility is frequently assessed by the discrimination-reversal learning task. We examined grey squirrels' behavioural flexibility, using a simultaneous colour discrimination-reversal learning task on a touch screen. Squirrels were...

Are the mechanisms underlying variations in the performance of animals on cognitive test batteries analogous to those of humans? Differences might result from procedural inconsistencies in test battery design, but also from differences in how animals and humans solve cognitive problems. We suggest differentiating associative-based ( learning ) from...

In order to test how flexibly animals are able to behave when making trade-offs that involve assessing constantly changing risks, we examined whether wild Eastern grey squirrels showed flexibility of behavioral responses in the face of variation in 2 conflicting risks, cache pilferage, and predation. We established that cache pilferage risk decreas...

This chapter explores how the economic model of individual behavior can be improved by incorporating a number of insights from evolutionary theory and complex systems theory. Insights from psychology, the neurosciences, and the behavioral strand of economics may be better understood from an evolutionary and complexity perspective. It takes an integ...

This chapter explores how the economic model of individual behavior can be improved by incorporating a number of insights from evolutionary theory and complex systems theory. Insights from psychology, the neurosciences, and the behavioral strand of economics may be better understood from an evolutionary and complexity perspective. It takes an integ...

‘‘Moralistic’’ punishment of free riders can provide a beneficial reputation, but the immediate behavior is costly to the punisher. In Study 1, we investigated whether variation in status would be perceived to offset or mitigate the costs of punishment. One hundred and nineteen participants were presented with a vignette describing a punishment sce...

Human performance in task-switching paradigms is seen as a hallmark of executive-control processes: switching between tasks induces switch costs (such that performance when changing from Task A to Task B is worse than on trials where the task repeats), which is generally attributed to executive control suppressing one task-set and activating the ot...

We tested pigeons' acquisition of a conditional discrimination task between colored grating stimuli that included choosing 1 of 2 response keys, which either appeared as white keys to the left and right of the discriminative stimulus, or were replicas of the stimulus. Pigeons failed to acquire the discrimination when the response keys were white di...

To fully understand how problem-solving ability provides adaptive advantages for animals, we should understand the mechanisms that support this ability. Recent studies have highlighted several behavioural traits including persistence, behavioural variety and behavioural/cognitive flexibility that contribute to problem-solving success. However, any...

Humans can spontaneously create rules that allow them to efficiently generalize what they have learned to novel situations. An enduring question is whether rule-based generalization is uniquely human or whether other animals can also abstract rules and apply them to novel situations. In recent years, there have been a number of high-profile claims...

Learning allows individuals to adapt their behaviors flexibly to a changing environment. When the same change recurs repeatedly, acquiring relevant tactics may increase learning efficiency. We examined this relationship, along with the effects of proactive interference and other interference information, in a serial spatial reversal task with 5 gra...

Comparative studies of primate personality offer informative insights into the evolutionary origins of personality structure in primate species. Primate personality research has, however, focused on a limited number of species. We investigated personality in three relatively understudied species: Sulawesi black crested macaques (Macaca nigra), Barb...

Eurasian oystercatchers (Haematopus ostralegus) feed on at least 15 different prey species in different habitats along the NW European coast. In each habitat, they specialise mostly on a single molluscan prey and within that prey type, they use various strategies to make foraging more profitable depending upon a number of internal and external fact...

Pigeons were trained to discriminate photographs of cat faces from dog faces, using either high- or low-pass spatial frequency filtered stimuli. Each pigeon was trained with multiple exemplars of the categories, but only with either high-pass or low-pass filtered stimuli. Not all pigeons reached the discrimination criterion. Successful pigeons were...

Third party punishment can be evolutionarily stable if there is heterogeneity in the cost of punishment or if punishers receive a reputational benefit from their actions. A dominant position might allow some individuals to punish at a lower cost than others and by doing so access these reputational benefits. Three vignette-based studies measured pa...

It is widely accepted in European culture that magpies (Pica pica) are unconditionally attracted to shiny objects and routinely steal small trinkets such as jewellery, almost as a compulsion. Despite the long history of this folklore, published accounts of magpies collecting shiny objects are rare and empirical evidence for the behaviour is lacking...

This chapter provides a historical and personal account of the development of our understanding of the psychology of money over the past 30 years. Classical psychological theories (such as those of Freud and Skinner) are briefly considered, as is the characteristics approach to money before our more recent attempt to propose a tool/drug theory of m...

Scholars from psychology, neuroscience, economics, animal behavior, and evolution describe the latest research on the causes and consequences of overconsumption. Our drive to consume—our desire for food, clothing, smart phones, and megahomes—evolved from our ancestors' drive to survive. But the psychological and neural processes that originally evo...

The recent financial crisis has affected most countries. With cutbacks in business, trade and government spending, millions world-wide have lost their jobs, with young people disproportionately affected. This paper synthesizes the thoughts expressed during an interdisciplinary discussion held in July 2013 among economists and psychologists from a v...

Why do so many people all over the world, so often, react to completely worthless scam offers? In two questionnaire studies, one of which included the distribution of an experimentally manipulated simulated scam, we investigated differences between respondents who did and did not report past compliance with scams. We found that the principal differ...

Humans can perform several different tasks on the same set of stimuli in rapid alternation. Each task, signaled by a distinct task cue, may require the classification of stimuli using a different stimulus attribute. However, such "task switching" performance comes at a cost, as expressed by weaker performance when switching rather than repeating ta...

Pigeons were trained to discriminate photographs of cat faces from dog faces. They were then presented with test stimuli involving high- and low-pass spatial filtering. Discrimination was maintained with both types of filtered stimuli, though it was increasingly impaired the more information was filtered out, and high-pass filtering impaired discri...

There is considerable controversy about what is encoded when primates produce alarm calls to an external event. Results are often compatible with multiple explanations, such as differences in a caller's perceived level of threat, direction of attack or category of predator. Using acoustic predator models, we investigated how male blue monkeys', Cer...

Social psychologists have established various psychological mechanisms that influence perception of risk and compliance in general. The empirical investigation in this paper focused on how those mechanisms apply to complying with scams. A scale of susceptibility to persuasion was developed, validated and then applied to the phenomena of scam compli...

This chapter summarizes the major findings of two decades of ongoing survey research probing the psychology of debt amongst the United Kingdom's most severe, as well as more moderate debtor populations. It shows that peoples' lay understandings of the concept of “debt” differs dramatically from that of an economist or accountant, with the categoriz...

Recent years have seen increased cooperation between psychologists and economists. This is mirrored in interdisciplinary journals (like the Journal of Economic Psychology or the Journal of Socio-Economics) as well as in interdisciplinary conferences. During one of these conferences, The IAREP/SABE conference in Cologne in 2010, a group of scholars...

How can animals learn the prey densities available in an environment that changes unpredictably from day to day, and how much effort should they devote to doing so, rather than exploiting what they already know? Using a two-armed bandit situation, we simulated several processes that might explain the trade-off between exploring and exploiting. They...

This volume aims to show what psychologists have to say on the evolution of mind. This book begins with a thorough overview of what is known of the non-primate mind and its evolution. Following this, an international range of experts discuss in temporal sequence the human mind at various stages of evolution, beginning with the pre-hominids of 20 mi...

Predators are able to identify fine characteristic features of prey and use them to maximise the profitability of foraging. Oystercatchers Haematopus ostralegus select thin-shelled mussels Mytilus edulis to hammer through because they are easier to crack than thick-shelled mussels. But mussel shells are composite structures, so we need to ask what...

Two experiments examined whether pigeons discriminate polymorphous categories on the basis of a single highly predictive feature or overall similarity. In the first experiment, pigeons were trained to discriminate between categories of photographs of complex real objects. Within these pictures, single features had been manipulated to produce a high...

© National Research Council of Canada 2002. Published version reproduced with the permission of the publisher. European Oystercatchers (Haematopus ostralegus) were highly selective towards mussels between 35 and 50 mm in length, and fewer than 5% of mussels taken were below 35 mm or above 50 mm. The oystercatchers selected ventrally thin-shelled mu...

The present research investigated whether the tendency to prefer decision-consistent to decision-inconsistent information after making a preliminary choice would vary during the sequential process of searching for additional pieces of decision-relevant information. Specifically, it was tested whether decision makers would be more confirmatory in th...

The effects of picture manipulations on humans' and pigeons' performance were examined in a go/no-go discrimination of two perceptually similar categories, cat and dog faces. Four types of manipulation were used to modify the images. Mosaicization and scrambling were used to produce degraded versions of the training stimuli, while morphing and cell...

Predators are able to identify fine characteristic features of prey and use them to maximise the profitability of foraging. Oystercatchers Haematopus ostralegus select thin-shelled mussels Mytilus edulis to hammer through because they are easier to crack than thick-shelled mussels. But mussel shells are composite structures, so we need to ask what...

Questionnaire research was carried out to identify factors that may encourage problem debtors to take the first steps towards getting out of debt. Consumers with debt problems were identified with the aid of creditor organisations and Her Majesty’s Court Service for England and Wales. Responses were also sought from non-debtors from the same consum...

Associations between the sun exposure and sun protective behaviours of adolescents and their friends were examined along with the role played by authoritative parenting and other family and peer socialisation factors. Four hundred and two adolescents (198 males, 204 females) participated in the research. It was found that these adolescents and thei...

An economics that doesn't take real-world human behaviour into account has no chance of getting us out of the hole we're in

This chapter reviews evidence for conceptual learning in nonprimate mammals. It shows that there can be no reasonable doubt that highly complex stimuli in the visual, olfactory, and auditory domains can all be reliably discriminated by mammals from a range of groups. The evidence that such discrimination is at the conceptual level (i.e. that discri...

Book synopsis: Human adults appear different from other animals in their ability to form abstract mental representations that go beyond perceptual similarity. In short, they can conceptualize the world. This apparent uniqueness leads to an immediate puzzle: WHEN and HOW does this abstract system come into being? To answer this question we need to e...

This chapter presents some concluding thoughts from the authors. It argues that there is nothing unique about the distinct components that contribute to the making of human concepts, when these are considered individually. What is unique is their combined presence in a single species. Of particular note is the long developmental period that allows...

Human adults appear different from other animals in their ability to form abstract mental representations that go beyond perceptual similarity. In short, they can conceptualize the world. When and how does this abstract system come into being? To answer this question we need to explore the origins of adult concepts. When does the developing child a...

Why would we carry out experiments in which pigeons are trained to discriminate between sets of photographs of real-world objects? Weisman and Spetch (2010) suggest a number of possible reasons. Three that play a particularly important role in the discussion are: (a) To discover whether birds can discriminate between the corresponding categories of...

Behavioural observations are vital to furthering our knowledge of species' ecology. Determining a method for formalising the length of behavioural observation time (coined Behaviour Discovery Curve) is practical for both reducing disturbance to the animals observed and limiting costs to the researcher. This paper suggests a method of calculating be...

Pigeons (Columba livia), gray squirrels (Sciurus carolinensis), and undergraduates (Homo sapiens) learned discrimination tasks involving multiple mutually redundant dimensions. First, pigeons and undergraduates learned conditional discriminations between stimuli composed of three spatially separated dimensions, after first learning to discriminate...

Pigeons and undergraduates learned conditional discriminations involving multiple spatially separated stimulus dimensions. Under some conditions, the dimensions were made available sequentially. In 3 experiments, the dimensions were all perfectly valid predictors of the response that would be reinforced and mutually redundant; in 2 others, they var...

Previous laboratory studies on social learning suggest that some animals can learn more readily if they first observe a conspecific demonstrator perform the task unsuccessfully and so fail to obtain a food reward than if they observe a successful demonstrator that obtains the food. This effect may indicate a difference in how easily animals are abl...

Scatter-hoarding animals transport food away from its source before storing it to maximize the likelihood that the cache will survive for use at a later time. However, the more time animals spend transporting and storing the food the less time they have for food collection. Previous studies suggest that the time animals spend on caching depends to...

Oystercatchers Haematopus ostralegus periodically pause while handling mussels Mytilus edulis to make visual scans. This paper presents evidence that scanning is associated with the high incidence of intra-specific food stealing among mussel-eating Oystercatchers. Scanning increased in frequency as bird density - and the risk of being attacked for...

The diet and feeding behaviour of Cercopithecus preussi in montane forest on Kilum Mountain, Cameroon, was studied over a period of 15 months and compared with that of Cercopithecus mitis observed over a similar period in montane forest on the Zomba Plateau, Malawi. Cercopithecus preussi was found to eat fruit with a similar frequency to C. mitis ,...

Mature leaves from two Afro-montane forests in widely separated parts of Africa were compared for protein and acid detergent fibre content, major factors in their potential as food items for members of Cercopithecus spp. which inhabit both forests. Leaves from Kilum Mountain Forest in Cameroon, which grows on volcanic soils, had a much higher prote...

Psychologists have been observing and interpreting economic behaviour for at least fifty years, and the last decade, in particular, has seen an escalated interest in the interface between psychology and economics. The Cambridge Handbook of Psychology and Economic Behaviour is a valuable reference resource dedicated to improving our understanding of...

This review focuses on the success and survivorship of captive-born versus wild-caught carnivores used in reintroductions. Previous reviews have suggested that reintroduction projects using captive-born animals are less likely to be successful than projects translocating wild-caught animals. The purpose of this paper is to examine this statisticall...

The Individual Behaviour Based Model developed using Oystercatchers (Haematopus ostralegus) as a model species is successful in predicting the impacts of environmental changes in aquatic ecosystems. At its heart is a food depletion model which assumes that consumers will tend to starve in highly depleted areas and seasons. Since dorsal hammering Oy...

Many naturally occurring categories vary across multiple stimulus dimensions (e.g. size, color, texture). When humans cat- egorize multidimensional stimuli on the basis of a single dimension this has been taken to indicate use of a rule that could be verbalized. Sorting on the basis of all the stimulus dimensions ('overall similarity' or 'family re...

Poverty is an economic, social and psychological condition. It is not as obvious as it might seem precisely what that condition is: the definition of poverty occupies a large section of any academic treatment of the subject. One reason for this is that poverty means different things within the discourse of different academic disciplines, and econom...

Farm animals are confronted with major changes in their environment as they go through different phases of the production system. Examples include introduction to a new housing system, provision of a new type of feed, mixing with unfamiliar conspecifics or being exposed to new human handlers. Learning processes that reduce uncertainty in such situa...

The cultural norms of traditional societies encourage behavior that is consistent with maximizing reproductive success but those of modern post-demographic transition societies do not. Newson et al (2005) proposed that this might be because interaction between kin is relatively less frequent in modern social networks. Assuming that people's evaluat...

Insects, birds, and mammals have been shown capable of encoding spatial information in memory using multiple strategies or frames of reference simultaneously. These strategies include orientation to a goal-specific cue or beacon, to the position of the goal in an array of local landmarks, or to its position in the array of distant landmarks, also k...

Until a few generations ago, humans made their living by foraging, like other animals. We have therefore inherited genes that allowed our ancestors to thrive as hunters and gatherers. Thriving in a modern economy requires very different behaviours but we cope because the human brain evolved to be flexible with the ability to form cooperative networ...

The shell thickness and strength of the mussel, Mytilus edulis L. were investigated across the season on the Exe estuary, SW England. Collection and measurements of mussels across the season showed that the average ventral thickness of their shells increased from end of September to mid-November and stayed constant till early December, and then sig...