Patrick Bateson

How do sensitive periods arise and what are they for

Abstract The general issue of sensitive periods in development is discussed. In the particular case of imprinting, onset of sensitivity is influenced by a specific change in state. Sensitivity ends because imprinting narrows preferences to familiar objects. The first preferences to be established are in part protected by responses such as escape from novel objects. Since these protective devices can be overcome, existence of a descriptive sensitive period can be reconciled with modification of the preferences later in development. When filial and sexual imprinting normally occur at different stages of development, the different evolutionary pressures operating on the timing mechanisms can be attributed to quite different biological roles in kin recognition. Lessons rather than general principles are drawn from the studies reviewed here.

Environmental influences during development and their later consequences for health and disease: implications for the interpretation of empirical studies

Early experience has a particularly great effect on most organisms. Normal development may be disrupted by early environmental influences; individuals that survive have to cope with the damaging consequences. Additionally, the responses required to cope with environmental challenges in early life may have long-term effects on the adult organism. A further set of processes, those of developmental plasticity, may induce a phenotype that is adapted to the adult environment predicted by the conditions of early life. A mismatch between prediction and subsequent reality can cause severe health problems in those human societies where economic circumstances and nutrition are rapidly improving. Understanding the underlying mechanisms of plasticity is, therefore, clinically important. However, to conduct research in this area, developmental plasticity must be disentangled from disruption and the adverse long-term effects of coping. The paper reviews these concepts and explores ways in which such distinctions may be made in practice.

Towards a new developmental synthesis: adaptive developmental plasticity and human disease

1focusing mainly on short-term outcomes such as infant survival and stunting. 2 However, the longer term eff ects on adult health 3 of a poor start to life suggest a further perspective. Developmental eff ects have been viewed traditionally in the context of major disruptions such as caused by teratogens, prematurity and growth retardation, but there is increasing appreciation of the role of developmental plasticity, which provides individuals with the fl exibility to adjust their trajectory of development to match their environment. Plasticity operates across the entire range of environment, from undernutrition to excessive nutritional environments associated with gestational diabetes or maternal obesity, 4,5

Organization and ontogeny of alternative tactics

Abstract This paper considers the ways in which substantial discontinuous variation in behaviour (called alternative tactics) arise during the course of the lives of individuals. First, it considers a scheme into which examples of alternative tactics can be placed. This scheme reveals specific assumptions that are frequently made about alternative tactics and the problems involved in their measurement. The paper then discusses the shortcomings of dichotomizing alternative tactics into discrete categories, focusing particularly on the genes/environment distinction. Developmental phenomena that can give rise to discontinuous variation in behaviour are then related to specific examples from species that show alternative tactics. Several developmental phenomena are likely to be involved in the origins of any particular case of intraspecific variation in behaviour. Factors in development may have canalizing effects, facilitating effects, or they may maintain variation in behaviour. They may also enable alternative tactics to occur or initiate their appearance in either juveniles or adults. Three aspects of the processes involved in generating such variation in behaviour are also discussed. These are the interactions between genetic and environmental influences, alternative routes in development, and learning. However, in no case is a particular developmental phenomenon or process likely to be solely responsible for a particular example of discontinuous variation in behaviour; new ontogenetic analyses are required to uncover the multiple influences.

A method for rating the individual distinctiveness of domestic cats

Abstract Fourteen adult female domestic cats were watched by two observers for 3 months. Ratings of 18 aspects of each cats behavioural style were obtained independently from each observer. Correlations between observers were statistically significant for 15 of the 18 aspects and seven of the correlation coefficients were greater than 0·7. The ratings were compared with results of direct recording methods, where equivalent measures were available and, in five out of six cases, the results of the ratings and direct methods were significantly correlated. The rating method is, therefore, generally reliable and can be adequately validated. Some assessments of observer ratings which are not obviously and easily related to direct recordings may prove particularly useful in developmental studies of alternative modes of behaviour and the origins of individual differences.

Effects of restricted lesions of the chick forebrain on the acquisition of filial preferences during imprinting

The effects of placing bilateral lesions in that part of the chick brain (IMHV) which was previously been implicated in imprinting, was studied in young domestic chicks. Twenty-four dark-reared chicks were matched in pairs on the basis of their approach activity during a 30 min period of exposure to one of two visual imprinting stimuli. Both members of the chick pair were then anaesthetized and bilateral lesions were made by radio-frequency coagulation in the IMHV of one chick; the other chick served as a sham-operated control. On the following day each chick was exposed for 2.5 h to the imprinting stimulus to which it had previously been exposed. After training, the preferences of all chicks were measured by comparing their approach to the training stimulus with that to the second stimulus. Sham-operated chicks showed a strong preference for the training stimulus; lesioned chicks showed none. Subsequently the latency of each chick to approach and accurately peck a shiny rod was measured. The two groups of chicks did not differ significantly in this test of visuomotor coordination. The area of tissue damaged by the lesion was reconstructed: IMHV was severely damaged with relatively little damage to other areas of the brain.

The biology of developmental plasticity and the Predictive Adaptive Response hypothesis.

Many forms of developmental plasticity have been observed and these are usually beneficial to the organism. The Predictive Adaptive Response (PAR) hypothesis refers to a form of developmental plasticity in which cues received in early life influence the development of a phenotype that is normally adapted to the environmental conditions of later life. When the predicted and actual environments differ, the mismatch between the individuals phenotype and the conditions in which it finds itself can have adverse consequences for Darwinian fitness and, later, for health. Numerous examples exist of the long‐term effects of cues indicating a threatening environment affecting the subsequent phenotype of the individual organism. Other examples consist of the long‐term effects of variations in environment within a normal range, particularly in the individuals nutritional environment. In mammals the cues to developing offspring are often provided by the mothers plane of nutrition, her body composition or stress levels. This hypothetical effect in humans is thought to be important by some scientists and controversial by others. In resolving the conflict, distinctions should be drawn between PARs induced by normative variations in the developmental environment and the ill effects on development of extremes in environment such as a very poor or very rich nutritional environment. Tests to distinguish between different developmental processes impacting on adult characteristics are proposed. Many of the mechanisms underlying developmental plasticity involve molecular epigenetic processes, and their elucidation in the context of PARs and more widely has implications for the revision of classical evolutionary theory.

Social Enrichment during Postnatal Development Induces Transgenerational Effects on Emotional and Reproductive Behavior in Mice

Across species there is evidence that the quality of the early social environment can have a profound impact on neurobiology and behavior. In the present study we explore the effect of communal rearing conditions (three dams with three litters per cage) during the postnatal period on offspring (F1) and grand-offspring (F2) anxiety-like and maternal behavior in Balb/c mice. Females rearing pups in communal nests exhibited increased levels of postpartum maternal care and communal rearing was found to abolish sex-differences in weaning weights. In adulthood, communally reared offspring were observed to display reduced anxiety-like behavior when placed in a novel environment. When rearing their own offspring under standard conditions, communally reared females demonstrated higher levels of motivation to retrieve pups, built higher quality nests, and exhibited higher levels of postpartum care compared to standard reared females. When exposed to an intruder male, communally reared females were more subordinate and less aggressive. F2 offspring of communally reared females were observed to engage in reduced anxiety-like behavior, have larger litter sizes and an increased frequency of nursing on PND 1. Analysis of neuropeptide receptor levels suggest that a communal rearing environment may exert sustained effects on behavior through modification of oxytocin and vasopressin (V1a) receptor densities. Though Balb-C mice are often considered “socially-incompetent” and high in anxiety-like behavior, our findings suggest that through enrichment of the postnatal environment, these behavioral and neuroendocrine deficits may be attenuated both within and across generations.

The dynamics of parent-offspring relationships in mammals

Evolutionary theories about parent-offspring relationships have predicted that young will aggressively demand food and care from their parents at the time of weaning - when the parents should, in their own interests, reserve their efforts for future offspring. Detailed studies of the behavioural development of mammals have given only limited support for these expectations. Often the mother is more amenable to the needs of her offspring than evolutionary theory predicts, and often offspring are sensitive to the state of their mother, tuning the pattern of their own development accordingly. Such aggression as is seen between mother and offspring tends to occur at stages other than weaning. The mismatch between theory and evidence may arise because a mother needs to monitor her offsprings state as well as her own and respond appropriately in order to maximize her own reproductive success. Similarly, an offspring needs to monitor its mother and prepare for the world in which it will grow up, in order to maximize its chances of surviving to breed.

The Effects of Prior Exposure To Light On the Imprinting Process in Domestic Chicks

Domestic chicks were placed in isolation under a constant white light for 30 minutes. Afterwards these birds and a group previously kept in the dark were trained with a Red or a Yellow flashing light for 45 minutes. Subsequently all chicks were given a choice between familiar and unfamiliar flashing lights in some new apparatus which is described in detail for the first time. The chicks exposed to constant light showed a clear preference for the flashing light with which they had been trained whereas the Dark control chicks did not. It is suggested that the constant light activated their visual pathways enabling the Light-exposed chicks to learn more than the Dark control chicks during the imprinting procedure.