Stephen E. G. Lea

Foraging and reinforcement schedules in the pigeon: Optimal and non-optimal aspects of choice

Abstract Pigeons were trained in a Skinner box on a reinforcement schedule that simulated a foraging situation. Pecks on a central key occasionally illuminated a side key which, if pecked, led to food reward after a delay that varied with the side key colour. Reward durations, post-reward detention intervals, the probability of occurrence of the two side-key colours, and the time between side-key illuminations were all varied between conditions. The schedule allowed the pigeons to accept or reject any reward: they always accepted the side-key colour associated with less pre-reward delay, but accepted the other colour with a probability that varied between conditions. These variations were qualitatively but not quantitatively consistent with predictions from optimal foraging theory.

Psychological factors in consumer debt: Money management, economic socialization, and credit use

A postal survey study of factors correlated with consumer debt investigated several psychological variables which have been suggested as causes or effects of debt. The survey was conducted with the help of a public utility company, and questionnaires were sent to three groups with different debt histories over the preceding two years: Non-Debtors (no debt to the company), Mild Debtors (late payment to the company), and Serious Debtors (sued for debt recovery by the company). Economic and demographic factors predicted debt category well, supporting previous results. Further variance between groups was accounted for by peoples money management skills and facilities, by measures of their time horizons, and by aspects of their consumer behaviour. Non-debtors had more money management facilities (e.g. bank accounts) than debtors, and rated their abilities at money management more highly. Debtors had shorter time horizons than non-debtors. Debtors were more likely to buy cigarettes and Christmas presents for children than non-debtors. No group differences were found for attitudes to debt or locus of control. There were significant group differences for measures of economic socialization, social comparisons, use of credit, and other aspects of consumer behaviour, but these differences were not independently significant on multivariate analysis. Conclusions must be qualified because of low return rates, but the results suggest that a complex of psychological and behavioural variables affect debt and are affected by it. It is argued that these variables are linked to the psychology of poverty.

Money as tool, money as drug: The biological psychology of a strong incentive

Why are people interested in money? Specifically, what could be the biological basis for the extraordinary incentive and reinforcing power of money, which seems to be unique to the human species? We identify two ways in which a commodity which is of no biological significance in itself can become a strong motivator. The first is if it is used as a tool, and by a metaphorical extension this is often applied to money: it is used instrumentally, in order to obtain biologically relevant incentives. Second, substances can be strong motivators because they imitate the action of natural incentives but do not produce the fitness gains for which those incentives are instinctively sought. The classic examples of this process are psychoactive drugs, but we argue that the drug concept can also be extended metaphorically to provide an account of money motivation. From a review of theoretical and empirical literature about money, we conclude that (i) there are a number of phenomena that cannot be accounted for by a pure Tool Theory of money motivation; (ii) supplementing Tool Theory with a Drug Theory enables the anomalous phenomena to be explained; and (iii) the human instincts that, according to a Drug Theory, money parasitizes include trading (derived from reciprocal altruism) and object play.

The economic psychology of consumer debt

Questionnaires were distributed to groups of people with either no debt, mild debt, or serious debt to a public utility company. Serious debtors were found to differ from the Non-debtor group on economic, sociological, and psychological variables: economic resources, economic need, social support, attitude forming variables and attitudes all made independent contributions to the prediction of group membership and the extent of self-reported debt. Mild debtors were generally intermediate between Non-debtors and Serious debtors. Debt was strongly correlated with economic factors. Many results indicated that debt is a consequence of adverse family economic conditions: Serious debtors were of lower socioeconomic class, had lower incomes, were less likely to own their own homes (and much less likely to own them outright), had more children and were more likely to be single parents. They were also younger. Social and psychological factors were also found to be related to debt: Serious debtors were less likely to claim Nonconformist, Agnostic or Atheist religious views, and they had slightly more permissive attitudes towards debt, although no group showed a general tendency to approval of debt. They knew more other people who were in debt, and they were less likely to think that their friends or relations would disapprove if they knew they were in debt. Multivariate analyses showed that economic, social and psychological variables all had independent correlation with debt. These results suggest that debt is stronly influenced by adverse economic circumstances, but that social and psychological factors are also important. The conditions for the development of a self-sustaining ‘culture of debt’ do exist.

Why Are Modern Families Small? Toward an Evolutionary and Cultural Explanation for the Demographic Transition

As societies modernize, they go through what has become known as “the demographic transition;” couples begin to limit the size of their families. Models to explain this change assume that reproductive behavior is either under individual control or under social control. The evidence that social influence plays a role in the control of reproduction is strong, but the models cannot adequately explain why the development of small family norms always accompanies modernization. We suggest that the widening of social networks, which has been found to occur with modernization, is sufficient to explain the change in reproductive norms if it is assumed that (a) advice and comment on reproduction that passes among kin is more likely to encourage the creation of families than that which passes among nonkin and (b) this advice and comment influence the social norms induced from the communications. This would, through a process of cultural evolution, lead to the development of norms that make it increasingly difficult to have large families.

Dogs (Canis lupus familiaris) fail to show understanding of means-end connections in a string-pulling task.

Domestic dogs (Canis lupus familiaris) were tested in four experiments for their understanding of means-end connections. In each of the experiments, the dogs attempted to retrieve a food treat that could be seen behind a barrier and which was connected, via string, to a within-reach wooden block. In the experiments, either one or two strings were present, but the treat was attached only to one string. Successful retrieval of the treat required the animals to pull the appropriate string (either by pawing or by grasping the wooden block in their jaws) until the treat emerged from under the barrier. The results showed that the dogs were successful if the treat was in a perpendicular line to the barrier, i.e. straight ahead, but not when the string was at an angle: in the latter condition, the typical response was a proximity error in that the dogs pawed or mouthed at a location closest in line to the treat. When two strings that crossed were present, the dogs tended to pull on the wrong string. The combined results from the experiments show that, although dogs can learn to pull on a string to obtain food, they do not spontaneously understand means-end connections involving strings.

Gambling in young adolescents

A questionnaire was used to investigate gambling in British adolescents. Responses from fifty 13- to 14-year-olds were analyzed. Gambling was found to be very pervasive (90% of subjects reported at least some gambling activity). Males gambled more than females, both in absolute terms and as a proportion of income. Income was found to have some influence on gambling behavior, but the effects of intelligence and social class were nonsignificant. Slot machines were the commonest form of gambling in both sexes.

Perception of object unity in chicks: A comparison with the human infant☆

Abstract Newly hatched chicks (Gallus gallus) were imprinted on a display consisting of two rod pieces that moved above and below a central occluder. On test trials, the chicks approached a complete rod in preference to two rod pieces. This finding, supported by those from control coditions, suggests that chicks, soon after hatching, perceive object unity. The results are compared with those from human infants.

The unacceptability of money as a gift

Abstract In four studies, subjects were asked whether money was an acceptable gift. In the first study, students stated that they would find it less acceptable to give their mothers a cheque than a gift token or a selected present; and that if they had to send a cheque they would spend more than twice as much on it as on the other sorts of gift. The second study confirmed these results on a larger, non-student sample of young adults, and also showed that it made no difference whether a cheque or cash was specified. In the third study, students were asked about the reasons why they would find it unacceptable to give or receive a cheque as a present. The most important reasons focused on the time and effort that ought to be spent on selecting a present, and the possibility that money sent as a gift might be used for mundane purchases. In the final study, mothers of students were asked about the kinds of presents they would find it acceptable to receive: they indicated that a cheque would be less acceptable than a selected present of a gift token, but they did not expect more to be spent on a cheque than on other gifts. Taken together, these results strongly confirm casual impressions that money is unacceptable as a gift in some contexts, implying both that the element of social exchange is crucially important in gift-giving, and that even in modern societies money is not a universally acceptable medium of exchange.

Images of conspecifics as categories to be discriminated by pigeons and chickens: Slides, video tapes, stuffed birds and live birds

Four experiments investigated the discrimination of images of conspecifics by pigeons; in Experiment 1, chickens were also used as subjects, and images of allospecifics were also used as discriminative stimuli. In Experiment 1, chickens were successfully trained to discriminate slides of pigeons, pictures of one bird being positive stimuli and pictures of another bird being negative; and pigeons were similarly trained to discriminate slides of chickens. However, an attempt to train pigeons to discriminate slides of pigeons only succeeded with one bird out of six. Pigeons were slower to learn chicken slides, and chickens were slower to learn pigeon slides, than chickens were to learn chicken slides in a previous experiment. In Experiment 2, a dishabituation technique was used to demonstrate that pigeons readily discriminate individual live pigeons. In Experiment 3, an attempt was made to test habituation to life-size moving video images of pigeons, but these images did not elicit any natural social responses from the subject pigeons. In Experiment 4 pigeons were trained in a discrimination in which the objects to be discriminated were two different stuffed pigeons. No pigeon learned this discrimination. The experiments give some evidence that chickens are better at discriminating images of individuals than pigeons. No single feature seems to be sufficient for pigeons to discriminate between conspecifics, but the combination of features that is required remains unknown.