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PubMed1996

Evolutionary adaptationism: another biological approach to criminal and antisocial behaviour.

Although in a sense "genetic', the conceptual framework of evolutionary psychology, behavioural ecology and sociobiology is distinct from that of behaviour genetics. Considerable confusion has resulted from failures to recognize the distinctions. These disciplines are primarily concerned with the characterization of evolved adaptations, which are usually species-typical and environmentally contingent, so theory and research in these fields mainly concerns environmental rather than genetic sources of behavioural variation. Heritable behavioural variation is in general neither predicted by nor supportive of adaptationist theories. One might even say that substantial heritability of an apparently consequential attribute is a datum that challenges the tenets of adaptationism. Behaviour genetics and evolutionary adaptationism have had only limited mutual influence, but increasing knowledge of the processes by which genotypes affect behavioural phenotypes should facilitate development of a more synthetic approach.

Adaptation, Psychological↗
PubMedDate not supplied

The effects of neonatal exposure to testosterone on the development of behaviour in female marmoset monkeys.

Experimental investigations of sexual differentiation in primates have been mainly confined to the rhesus monkey, a highly polygamous species with marked anatomical and behavioural sexual dimorphism. The marmoset is a monogamous monkey which shows little anatomical or behavioural sexual dimorphism, and both sexes exhibit positive feedback in response to the administration of oestradiol. This monkey has a relatively short gestation period of 144 days and usually gives birth to dizygotic twins. These share a common placental circulation and hence develop as haematopoietic chimaeras. However, a female with a male co-twin is not adversely affected as a result of this and the freemartin condition does not occur. Since the newborn male experiences raised testosterone levels soon after birth it is possible that the 'critical period' for sexual marmosets were implanted with 25 mg of testosterone for 50 days after birth. After removal of the implants their genitalia remained partly masculinized and they initiated more masculine rough-and-tumble play than their controls. After puberty they exhibited a mixture of male and female sexual behaviour when presented with unfamiliar normal males and females during 15-minute behavioural trials. Four of the implanted females have also ovulated. Neonatal administration of testosterone therefore has had an organizing effect on female behaviour. Whether the marmoset is exceptional in this respect, or whether other primates which exhibit a male neonatal testosterone surge, such as man and the rhesus monkey, also undergo some postnatal behavioural differentation, remains to be seen.

Animals↗
PubMed2002

Personality disorders in prisoners and their motivation for dangerous and disruptive behaviour.

OBJECTIVES: To examine the associations between DSM-III, axis II, personality disorder, motivation and disruptive behaviour in prisoners. METHOD: Interviews were carried out with 81 prisoners in prison special units in England using research diagnostic instruments and an item sheet measuring disruptive behaviours and their motivations. Independent associations were established using logistic regression. RESULTS: Specific associations were established between psychopathy and axis II disorders with violent and disruptive behaviour and motivations for these behaviours. CONCLUSIONS: The study supported a cognitive model explaining the functional association between personality disorder and antisocial behaviour. Personality disorders act as predisposing factors influencing the development of motivations and subsequently facilitate the enactment of disordered behaviour, in a linear progression. Assessment of personality disorder should be routine in disruptive and dangerous prisoners.

Adult↗
PubMed1987

Dynamics of behaviour during neuronal morphogenesis in culture.

We report a developmental sequence in the type and frequency of behaviours of neurons differentiating in vitro. We characterised these changes with extensive analysis of time-lapse sequences from both the continuing cell line pheochromocytoma PC12 and primary mixed cell culture of cat and mouse central nervous system. PC12 cells activated by nerve growth factor (NGF) differentiate in a uniform and synchronous manner. This allowed the first quantification of changes in different neuron behaviours during morphogenesis. Shortly after NGF activation, PC12 cells are highly labile in morphology and exhibit a large variety of morphological behaviours. During the first week of differentiation, the frequency of these behaviours declines, and gross morphology becomes more stable. The frequency of neurite initiation after 1 week in NGF is one-seventh what it was after 2 days in NGF. Over the same period, neurite retraction declines to one-third, and somal migration ceases altogether. Growth-cone activity does not decline during development. These behaviour changes correlate with published data on the differentiation of the neurite cytoskeleton. A qualitatively similar ontogeny was noted in the differentiation of CNS neurons in mixed cell culture. Major differences occur in the relative timing of changes in behaviours. Mature, stable morphology is not detected in these cultures until 7 weeks in vitro.

Adrenal Gland Neoplasms↗
PubMed2003

A retrospective study of the behavioural and psychological symptoms of mid and late phase Alzheimer's disease.

AIM: To document the behavioural and psychological symptoms in patients with a diagnosis of established Alzheimer's disease (AD) for at least 3 years. METHODS: Patients with a > or =3 year history of AD (NINCDS/ADRDA) were recruited from old age psychiatrist and elderly care memory clinics. Information regarding duration of symptoms and non-cognitive symptomatology was obtained during interview with a carer or next-of-kin who had contact with the patient at least 3 times a week and for at least 3 years. MMSE, FAST and NPI including caregiver distress, were used to assess cognition, function and behavioural/psychological disturbance respectively. With each non-cognitive symptom the carer was asked to estimate its onset. RESULTS: The mean age of patients was 77 years and duration of illness 87 months. Mean MMSE was 8/30 and FAST score 6d. Of the psychological symptoms occurring at any stage, depression (56%), delusions (55%) and anxiety (52%) were most common, with hallucinations, elation and disinhibition occurring less frequently. In general, behavioural changes were more common with apathy occurring in 88% of patients, motor behaviour in 70%, aggression in 66%, irritability and appetite changes in 60% and sleep disturbance in 54%. All symptoms except apathy became less common when the carer was asked if they were still present in the last month. Mean onset of psychological symptoms was 47 months. Mean onset of behavioural symptoms was 48 months. Behavioural disturbance seemed to cause more care-giver distress than psychological change. CONCLUSION: The results show behavioural and psychological symptoms in AD are common and distressing for carers. They appear to require a consistent period of neurodegeneration in order to emerge.

Aged↗
PubMed2004

A comparison of the effects of Snoezelen and reminiscence therapy on the agitated behaviour of patients with dementia.

BACKGROUND: Behavioural disturbance, such as agitation, is a common feature of dementia, and causes significant problems and distress for carers. Snoezelen is increasingly used with people who have dementia, but there is limited evidence of its efficacy. OBJECTIVE: This crossover randomised controlled study aimed to evaluate the effect of Snoezelen on the mood and behaviour of patients with dementia, in comparison to the effect of an established and accepted intervention, reminiscence therapy. METHODS: Twenty patients with dementia and significant agitated behaviour, received three sessions each of Snoezelen and reminiscence. The effects were assessed using measures of observed agitated behaviour and heart rate over the course of the sessions, and mood and behaviour during the sessions. RESULTS: Both interventions had a positive effect. Snoezelen was no more beneficial than reminiscence in terms of effecting a significant reduction in agitated behaviour or heart rate. There was considerable variation in the way individuals responded to each intervention. Snoezelen may have a more positive effect than reminiscence, but due to the observed differences between the interventions being small, and the small number of subjects, this advantage was not demonstrated statistically. CONCLUSIONS: Further research, with larger numbers of subjects, and an appropriate control is required to establish the benefits of Snoezelen for people at different stages of dementia, and to identify any benefits additional to those derived from increased staff attention.

Aged↗
PubMed2003

Behavioural disturbances in dementia patients and quality of the marital relationship.

OBJECTIVES: To investigate the relationship between behavioural problems in patients with dementia and changes in the marital relationship. METHODS: Fifty-three spouse caregivers of patients with dementia participated in the study. Questionnaires and interviews were used to examine caregiver perception of changes in the quality of their relationship. Behavioural disturbances in the patient were measured with the NeuroPsychiatric Inventory (NPI). RESULTS: Caregivers experienced a deterioration of their relationship, yet at the same time most felt closer to their spouse now than in the past. Regression analysis revealed that patient behavioural problems were, independent of patient cognitive status or functional impairment, associated with deterioration in the quality of the relationship between patient and caregiver. Patient apathy rather than depressive mood was associated with this deterioration. Apathy diminished the amount and reciprocity of interactions between partners. CONCLUSIONS: These results show that passive behaviour rather than excessive behaviour has most impact on the deterioration of the marital relationship. Intervention programmes should target relationship problems when problem behaviour, especially apathy, is present in patients with dementia.

Aged↗
PubMed2007

Correlated response in yolk testosterone levels following divergent genetic selection for social behaviour in Japanese quail.

Maternal effects are a powerful tool that parents can use to modify the phenotype of their offspring. In birds, the amount of androgens that females deposit in their eggs has been shown to influence early development and adult behavioural phenotypes. Differences in such behavioural strategies have been used as the target of artificial selection programmes with a view to improve animal welfare. In this study, we tested whether artificial selection for divergent social behaviour in Japanese quail had resulted in correlated changes in yolk androgen levels. We used lines that had been selected at the chick stage for high and low motivation to regain contact with a group of conspecific chicks. This procedure has led to important behavioural differences in the high and low line in a suite of behavioural correlates of sociality. We found that eggs laid by the line selected for high motivation for social reinstatement contained more than twice the amount of yolk testosterone of eggs laid by females from the low line, while the unselected line laid eggs with intermediate levels. This finding strongly suggests a functional link between these two traits, and underlines the possible role of yolk androgen modulation in promoting the evolution of behavioural syndromes.

Animals↗
PubMed1997

Rhesus monkey behaviour under diverse population densities: coping with long-term crowding

A popular view is that high population density promotes behavioural pathology, particularly increased aggression. In contrast, according to a coping model, some primates have behavioural mechanisms (e.g. formal displays, reconciliation and grooming) that regulate social tensions and control the negative consequences of crowding. Seven captive rhesus monkey groups, Macaca mulattawere observed over a wide range of population densities where high-density groups were over 2000 times more crowded than low-density free-ranging groups. As density increased, male rhesus monkeys increased grooming and huddling but did not increase rates of aggression. Females increased all categories of behaviour examined (heavy aggression, mild aggression, formal bared-teeth displays, grooming and huddling), but the increases were not distributed uniformly to all classes of partners. Females increased only grooming, huddling and appeasement displays to males, increased only aggression and huddling with kin and increased all categories of behaviour to non-kin adult females. There were no differences in the percentage of aggressive conflicts reconciled across density conditions. Increased density had different effects on particular relationships. Relationships between females and males were characterized by a coping pattern in which animals modified their behaviour in ways that may decrease aggression under crowded conditions. Female relationships with kin and non-kin were characterized by increases in both aggression and friendly interactions as density increased. The different patterns of response to higher density may reflect different strategies depending on the strength and stability of relationships and the potential consequences if certain relationships are disrupted.1997The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1997

Courtship behaviour in male red-backed salamanders: the ESS dating game

Social interactions in red-backed salamanders, Plethodon cinereusare complex and often depend upon the sex and reproductive status of individuals. In the population at Mountain Lake Biological Station, Virginia, adult males outnumber sexually active (gravid) females by approximately 2:1, because males court annually while females accept mates only biennially. Field observations of male P. cinereus suggest that males maintain feeding territories and allow non-gravid (not sexually active) females access to their territories for foraging, whereas they defend their territories against intrusion by males. We used a game-theoretic analysis of models of male fitness to examine conditions that would favour the evolution of this 'permissive' behaviour. Under a series of increasingly realistic behavioural assumptions, we found that the critical factor in the evolution of male permissive behaviour is female preference for permissive males. If non-gravid females are more likely to return to mate with a male that allows access to his territory, then permissive behaviour is likely to evolve. Furthermore, the evolution of permissive behaviour is facilitated when energetic losses due to territorial defence exceed those due to allowing females to forage.1997The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1998

Habitat-contingent reproductive behaviour in radio-implanted salamanders: a model and test.

All tiger salamanders, Ambystoma tigrinum, entering a small pond in New York state were given radio-implants and tracked throughout breeding to determine whether reproductive behaviour in nature differs from that described in laboratory studies. I formed an extended model of adult reproductive behaviour that included male and female strategies and differential use of habitat components in the breeding pond, and then tested four key predictions regarding adult movement using the sequence of positions of all salamanders between pond entry and exit. An unexpected, female-biased sex ratio during most courtship activity led to departures from the predicted behaviour, but in all other respects the behaviour of the males and females followed from the predictions. Apparent mate scanning in clear water, and weather assessment in pond-edge shallows just prior to emergence, are new indications for caudate amphibians. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Social inhibition of territorial behaviour in yearling male collared lizards, Crotaphytus collaris.

In central Oklahoma, collared lizard males display age-dependent differences in social behaviour, whereby sexually mature first-year (yearling) males adopt subordinate tactics, and males 2 years and older establish and defend all-purpose territories. We tested the hypothesis that the social activities of adult males inhibit the expression of territorial tactics in yearling males by recording the behaviour of yearlings in the presence of adult males, when all adult males were removed from study plots for 4 days, and then again when adult males were returned to their territories. The rates of yearling male patrol, display and intrasexual encounters increased during removals, especially during the last 2 days, following which the rates of these behaviour patterns declined when adult males were replaced. Yearling males also increased the frequency with which they interacted with females when adult males were removed. Moreover, the duration of intersexual encounters during the last 2 days of removal was over twice that during the first 2 days of removal, suggesting that females became more receptive to yearling males the longer adult males were absent. Our results suggest that the stable age-related behavioural differences in male collared lizards is governed by social feedback, where sexually mature yearling males are capable of displaying territorial behaviour patterns but are inhibited from doing so by the activities of adult males. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Pitfalls in the categorization of behaviour: a comparison of dolphin whistle classification methods.

The categorization of behaviour patterns into separate classes is crucial to the study of animal behaviour. Traditionally researchers have classified behaviour patterns through careful observation by eye. Recently this method has been increasingly replaced by computer methods. While the definition and fine scale analysis that can be achieved with computers is desirable, only a few studies have actually looked at how these methods perform in comparison with human observation. I compared the classification of bottlenose dolphin, Tursiops truncatus, whistles by human observers with the performance of three computer methods: (1) a method developed by McCowan (1995, Ethology, 100, 177-193); (2) a comparison of cross-correlation coefficients using hierarchical cluster analysis; and (3) a comparison of average difference in frequency along two whistle contours also using hierarchical cluster analysis. The whistle sample consisted of 104 randomly chosen whistles from a group of four captive bottlenose dolphins recorded both during periods when one was separate from the rest of the group and while they all swam in the same pool. The sample contained five individual-specific signature whistles and several nonsignature whistles. Five human observers, without knowledge of the recording context, were more likely than the computer methods to identify signature whistles that were used only while an animal was isolated from the rest of the group. I discuss the limitations of methods commonly used for pattern recognition in communication studies. The discrepancies between methods show how crucial it is to obtain an external validation of the behaviour classes used in studies of animal behaviour. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

Human evolutionary psychology and animal behaviour.

Homo sapiens is increasingly being studied within the evolutionary (adaptationist, selectionist) framework favoured by animal behaviour researchers. There are various labels for such work, including evolutionary psychology, human behavioural ecology and human sociobiology. Collectively, we call these areas 'human evolutionary psychology' (HEP) because their shared objective is an evolutionary understanding of human information processing and decision making. Sexual selection and sex differences have been especially prominent in recent HEP research, but many other topics have been addressed, including parent-offspring relations, reciprocity and exploitation, foraging strategies and spatial cognition. Many HEP researchers began their scientific careers in animal behaviour, and in many ways, HEP research is scarcely distinguishable from other animal behaviour research. Currently controversial issues in HEP, such as the explanation(s) for observed levels of heritable diversity, the kinds of data needed to test adaptationist hypotheses, and the characterization of a species-typical 'environment of evolutionary adaptedness', are issues in animal behaviour as well. What gives HEP a distinct methodological flavour is that the research animal can talk, an ability that has both advantages and pitfalls for researchers. The proper use of self-reports and other verbal data in HEP might usefully become a subject of future research in its own right. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1999

The effect of group size on the foraging behaviour of juvenile coho salmon: reduction of predation risk or increased competition?

Animals often increase their apparent willingness to incur risk when foraging in groups, presumably because group membership reduces an individual's risk of predation. As group size increases, however, competition for resources may also increase, resulting in a decrease in the quantity of resources available to each member of the group. When resources are scarce, individuals might be expected to increase their foraging effort in an attempt to increase their share. Such increases in effort will often appear to increase an individual's risk of predation. Thus, increased competition may contribute to the frequently observed relationship between risk-taking behaviour and group size. To date, no experimental assessment of the relative importance of these two mechanisms exists. We argue that to differentiate between the hypotheses of 'risk reduction' and 'increased competition', it is necessary to quantify the effect of predation risk on the form of the relationship between group size and risk-taking behaviour, and thus, to manipulate both group size and predation risk. We conducted an experiment to determine the relative importance of risk reduction and increased competition to the foraging decisions of juvenile coho salmon, Oncorhynchus kisutch. We recorded the foraging behaviour of 18 focal individuals in the presence and absence of a predator, and in the company of zero, one and three conspecifics. As group size increased from one to four, focal fish captured more prey items, ventured closer to the feeder (and predator) to intercept them, and decreased their use of cover. Furthermore, although focal individuals captured fewer prey items and intercepted them further from the feeder in the presence of the predator than in its absence, the form of the relationship between risk-taking behaviour and group size was not affected by the level of predation risk. The results of our experiment are consistent with the interpretation that increases in risk-taking behaviour with group size occurred primarily as a consequence of increased competition for scarce resources. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2000

Behavioural isolation between two closely related Hawaiian Drosophila species: the role of courtship.

Behavioural isolation plays a critical role in several recent models of speciation. A detailed understanding of the process of speciation requires analysis of taxonomic groups that have not completed reproductive isolation. We studied D. silvestris and D. heteroneura because they are still in the process of divergence: behavioural isolation between them is incomplete, and neither postzygotic nor ecological isolation has been detected. Behavioural isolation is due to the failure of courtships between male D. silvestris and female D. heteroneura: there is no postzygotic isolation from either parental species. The F1 hybrids are as successful in courtship with parental individuals as same-species pairs, which suggests that the hybrids resemble male D. heteroneura or female D. silvestris in some behaviour patterns that are crucial to mating success. We searched for this crucial resemblance by examining courtship between F1 hybrids and the parental adults. We found that successful F1 males are somewhat more similar than unsuccessful F1 males to D. heteroneura males, but nevertheless they were intermediate between males of the two species. We also found that in both species the presence of female wings is necessary for courtship to proceed to copulation. These results reinforce an earlier report that behavioural isolation between these species is largely attributable to the decision as to whether to court at all, rather than to the details of courtship. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2000

Variation in steroid hormones associated with infant care behaviour and experience in male marmosets (Callithrix kuhlii).

We describe temporal patterns of change in paternal behaviour and urinary concentrations of the steroid hormones testosterone (T) and oestradiol (E(2)) in male black tufted-ear marmosets, Callithrix kuhlii, relative to the birth of their young, and test predictions of the hypotheses that (1) high levels of T are incompatible with paternal care and (2) levels of T and E(2)vary with a father's prior experience in his family group. After young were born, levels of urinary T and E(2)remained near prepartum concentrations and rates at which fathers carried infants were below peak levels until the approximate time that postpartum mating ordinarily occurs, suggesting a possible trade-off between readiness to mate and paternal behaviour in C. kuhlii. Infant-carrying behaviour of fathers occurred at its highest rate 3-4 weeks after parturition and coincided with significant declines in urinary levels of T and E(2), providing preliminary support for the hypothesis that these hormones are antagonistic to paternal behaviour. Urinary T and E(2)declined among fathers regardless of whether their young survived to weaning or died at birth, indicating that variation in these hormones after parturition occurs even in the absence of continued stimuli from infants. When adjusted for declines ordinarily associated with aging, urinary T tended to be lower among fathers with a great deal of prior experience caring for young compared with fathers having little or no experience, suggesting that either experience affects T levels of fathers, or that T levels influence fathers' chances of successfully rearing infants. Overall, our results suggest that in male C. kuhlii, T, and possibly E(2), play an important role in balancing the expression of paternal care with that of other reproductive behaviours. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1994

Cognitive control of eating behaviour and the disinhibition effect.

Restrained eaters have been reported to overeat following a high caloric preload, a phenomenon referred to as the disinhibition effect. However this effect has not been found when subjects were classified by the restraint subscales of the Three-Factor Eating Questionnaire (TFEQ; Stunkard & Messick, 1985) or the Dutch Eating Behaviour Questionnaire (van Strien et al., 1986). The present study investigates the disinhibition effect in 133 normal-weight young women, using a two-factorial classification including the TFEQ-restraint and the TFEQ-disinhibition scale. The subjects were requested to consume ice-cream ad libitum during a taste test following a 200-ml milkshake preload or without preload. The results show that the behavioural disinhibition effect occurs only in subjects with simultaneous high scores on both subscales. In addition, subjects with high disinhibition scores consumed more ice-cream than low disinhibition subjects irrespective of their degree of restraint. While subjects with a more rigid control of eating behaviour did not show a difference in the amount of ice-cream consumed with or without preload, subjects with a more flexible control of eating behaviour reduced their intake following the preload condition. With regard to the Revised Restraint Scale (RRS Herman & Polivy, 1980) multiple regression results show that high RRS scores may be due to either higher TFEQ-restraint or higher TFEQ-disinhibition scores. The interpretation of the results favours the renaming of the TFEQ-disinhibition scale to "susceptibility to eating problems" because high scores on this scale indicate overeating in a variety of situations without requiring prior inhibition i.e. dietary restraint. It is supposed that high susceptibility to eating problems may be caused by rigid control of eating behaviour, whereas flexible control of eating behaviour may be a less problematic strategy of long-term weight control.

Adolescent↗