Changes In Parental Behavior Research Articles

Effects of stress on parental care are sexually dimorphic in prairie voles

The effects of stress on parental care are poorly understood, especially in biparental species where males also display care. Data from previous studies in prairie voles, as well as parallels with pair-bonding behavior, suggest the hypothesis that a stressful experience might facilitate parental care in males but not in females. In the present study, male and female prairie voles were exposed to either a 3-min swim stressor or no stressor; 45 min later each animal was tested in a parental care paradigm. Following the parental care test, blood samples were collected and assayed for corticosterone (CORT). After the stressor males, but not females, showed significant changes in parental behavior including significantly more time in kyphosis (arched-back huddling), and a tendency to spend more time licking and grooming pups. In males, CORT levels measured following the parental care test were inversely related to licking and grooming but positively correlated with retrievals. These findings support earlier studies suggesting that the neuroendocrine substrates of parental behavior, as well as the effects of stressors, are sexually dimorphic in this species.

The importance of microclimate variation in determining size, growth and survival of avian offspring: experimental evidence from a cavity nesting passerine

Organisms are expected to balance energy allocation in such a way that fitness is maximized. While much research has focussed on allocation strategies of reproducing parents, in particular birds, relatively little attention has been paid to how nestlings allocate energy while in the nest. Nestling birds are faced with a trade-off between devoting energy to growth or to thermoregulation, and in altricial species it is likely that the thermal environment of the nest site influences the nature of this trade-off. Here, we experimentally investigate how altering the microclimate of nests affects the growth, size and survival, as well as cell-mediated immune (CMI) response, of nestling tree swallows (Tachycineta bicolor) in a temperate environment. We place air-activated heating pads in nests of swallows when young were between 4 days and 16 days of age, and compared performance of offspring to control nests. Our manipulation raised temperatures of heated nests by approximately 5 degrees C compared to control nests. Offspring in heated nests had enhanced survival while in the nest, and we also found that they were heavier and had longer ninth primary feathers at 16 days of age. In addition, heating nest boxes resulted in significantly faster growth of primaries, and there was a trend for growth rates of mass to also be higher in heated nests. There were no significant differences between heated and control nests in growth rate or size of tarsus at age 16 days, and we speculate that this lack of response to elevated nest temperatures may be due to growth of skeletal structures being limited by other factors such as calcium availability. We also found no difference between heated and control nests in CMI response. Nonetheless, our results show overall that increasing temperatures of nests has significant benefits that enhance the fitness of offspring. As provisioning rates to offspring did not differ between heated and control nests, we suspect that the beneficial effects of heating were not the consequence of changes in parental behaviour. Our results provide insight into factors, other than food supply, that have important consequences in determining reproductive success of birds breeding in temperate environments.

Medical Homes for At-Risk Children: Parental Reports of Clinician-Parent Relationships, Anticipatory Guidance, and Behavior Changes

Family-centeredness, compassion, and trust are 3 attributes of the clinician-parent relationship in the medical home. Among adults, these attributes are associated with patients' adherence to clinicians' advice. The objectives were (1) to measure medical home attributes related to the clinician-parent relationship, (2) to measure provision of anticipatory guidance regarding injury and illness prevention, (3) to relate anticipatory guidance to parental behavior changes, and (4) to relate medical home attributes to anticipatory guidance and parental behavior changes. A cross-sectional study of data collected among at-risk families when children were 1 year of age, in a randomized, controlled trial of a home-visiting program to prevent child abuse and neglect, was performed. Modified subscales of the Primary Care Assessment Survey were used to measure parental ratings of clinicians' family-centeredness, compassion, and trust. Parental reports of provision of anticipatory guidance regarding injury and illness prevention topics (smoke alarms, infant walkers, car seats, hot water temperature, stair guards, sunscreen, firearm safety, and bottle propping) and behavior changes were recorded. Of the 564 mothers interviewed when their children were 1 year of age, 402 (71%) had a primary care provider and had complete data for anticipatory guidance items. By definition, poverty, partner violence, poor maternal mental health, and maternal substance abuse were common in the study sample. Maternal ratings of clinicians' family-centeredness, compassion, and trust were fairly high but ranged widely and varied among population subgroups. Families reported anticipatory guidance for a mean of 4.6 +/- 2.2 topics relevant for discussion. Each medical home attribute was positively associated with parental reports of completeness of anticipatory guidance, ie, family-centeredness (beta = .026, SE = .004), compassion (beta = .019, SE = .005), and trust (beta = .016, SE = .005). Parents' perceptions of behavior changes were positively associated with trust (beta = .018, SE = .006). Analyses were adjusted for potential confounding by randomized, controlled trial group assignment, receipt of >or=5 well-child visits, and baseline attributes. Among at-risk families, we found an association between parental ratings of the medical home and parental reports of the completeness of anticipatory guidance regarding selected injury and illness prevention topics. Parents' trust of the clinician was associated with parent-reported behavior changes for discussed topics.

The Process and Causes of Fledging in a Cavity‐Nesting Passerine Bird, the House Wren (Troglodytes aedon)

AbstractLittle is known about the process or causes of fledging or nest‐leaving in passerine birds because researchers can rarely predict when fledging will occur in a given nest. We used continuous videotaping of nests to both document the process of fledging in the house wren, Troglodytes aedon, a small, cavity‐nesting songbird, and test hypotheses as to what might cause fledging to begin. Fledging began any time from 14 to 19 d after hatching commenced. Slower‐developing broods fledged later than faster‐developing broods. Fledging typically began within 5 h of sunrise and over 80% of all nestlings fledged before noon. All nestlings fledged on the same day at 65% of nests and over two consecutive days in most other nests. We found no evidence that fledging was triggered by changes in parental behaviour. Parental rate of food delivery to nestlings did not decline during a 3‐h period leading up to the first fledging, nor was the rate of feeding just prior to the first fledging lower than the rate at the same time the day before. Moreover, parents did not slow the rate of food delivery to nests after part of the brood had fledged. Hatching is asynchronous in our study population which creates a marked age/size hierarchy within broods. At most nests, the first nestling to fledge was the most well‐developed nestling in the brood or nearly so (as measured by feather length). This suggests that fledging typically begins when the most well‐developed nestlings in the brood reach some threshold size. However, at about one‐fifth of nests, the first nestling to fledge was only moderate in size. At these nests, severe competition for food may have caused smaller, less competitive nestlings to fledge first to increase their access to food. We found no strong support for the suggestion that the oldest nestlings delay fledging until their least‐developed nestmate reaches some minimum size, although further experimental work on this question is warranted.

The role of childhood asthma in altering parental smoking behavior

Rationale To determine if a diagnosis of asthma in children altered parental smoking behavior towards a reduction in environmental tobacco smoke exposure. Methods In 2002/03, a survey was sent to 12556 households of children born in 1995 in Manitoba, Canada. Parents were asked whether their 7-year-old child had asthma, and whether smokers were present in the home in 1995 and/or currently. The likelihood (odds ratio, OR) of a change in parental smoking behavior was determined according to the presence of asthma in their child, a family history of asthma, location of residence (rural/urban) and socioeconomic status. Results 3564 (28.4%) of the surveys were returned. The overall prevalence of parental smoking in 1995 and 2002/03 was 32.2% and 23.4% respectively (31.9%/23.4% and 32.3%/23.5% in rural and urban environments respectively). Parents were not more likely to quit smoking (OR=1.01, 95%CI=0.66-1.54) or smoke outside (OR=1.02, 95%CI=0.56–1.83) if their child developed asthma. Parental behavior (quit smoking or smoked outside) did not change if there was a positive family history of asthma (OR=1.06, 95%CI=0.80–1.40), if they lived in a rural or urban location (OR=0.93, 95%CI=0.71–1.23) or if they were from a low or high income household (OR=1.11, 95%CI=0.84–1.46). Conclusions The likelihood of altering parental smoking behaviour occurred independently of the diagnosis of asthma in their child, a family history of asthma, location of residence, or socioeconomic status.

Changes in parental risk behaviour after an information campaign against sudden infant death syndrome (SIDS) in Norway

To assess parental risk behaviour before and after a sudden infant death syndrome (SIDS) information campaign with special emphasis on associations with maternal age, education, marital status and birth order. Data from questionnaires sent to all mothers who gave birth in Norway during a period before the campaign were compared with corresponding data obtained after the campaign. Prevalence of non-supine sleeping position decreased from 33.7% to 13.6% while changes in smoking, non-breastfeeding and co-sleeping were disappointing. Risk factors were particularly prevalent in young mothers, but also in mothers with a minimum period of education, non-cohabitation and at birth order 2+. Non-supine sleeping decreased to a level that has never been reported before. In future campaigns, subgroup-specific measures may be needed.

Changes in parental risk behaviour after an information campaign against sudden infant death syndrome (SIDS) in Norway

Aim: To assess parental risk behaviour before and after a sudden infant death syndrome (SIDS) information campaign with special emphasis on associations with maternal age, education, marital status and birth order. Methods: Data from questionnaires sent to all mothers who gave birth in Norway during a period before the campaign were compared with corresponding data obtained after the campaign. Results: Prevalence of non-supine sleeping position decreased from 33.7% to 13.6% while changes in smoking, non-breastfeeding and co-sleeping were disappointing. Risk factors were particularly prevalent in young mothers, but also in mothers with a minimum period of education, non-cohabitation and at birth order 2+. Conclusions: Non-supine sleeping decreased to a level that has never been reported before. In future campaigns, subgroup-specific measures may be needed.

Informal construction of contingencies in family-based interventions for oppositional defiant behavior.

Clinical Behavior Analysis (CBA) and Applied Behavior Analysis (ABA) are distinguished by target-population and technology. Two brief case-reports illustrate how CBA can be relevant for a problem-category that is typically associated with ABA, and to document the fluid borders between the two approaches. In both cases improved parental behavior was shaped and maintained through sources of reinforcement under control of the child in the family's natural environment. A concern with the pitfalls of instructional control and functional implications of interpersonal relations are highlighted as well as the reliance on naturalistic observation of the family and its interaction with the therapist (therapeutic relationship) during the sessions as a unit of analysis. Analog functional analysis guided the construction of treatment in the first case, while the parent's discussions with the therapist guided the second. Both therapies produced parental mediator behavior parallel to improvement of the child's target-behavior. In both cases changes in parental behavior and in child-behavior interlocked in the construction of new interpersonal contingencies at home. Key words: Clinical Behavior Analysis; Instructional Control; Naturalistic Environment; Interpersonal Contingencies. ********** Applied Behavior Analysis (ABA) is traditionally identified with practices of direct contingency management guided by functional analysis under controlled experimental conditions, while Clinical Behavior Analysis (CBA) refers to the application of contextual behaviorism to outpatient talk-therapy in outpatient settings, with an emphasis on rule-governance, language and interpersonal relations (Dougher and Hayes, 2000; Kohlenberg, Bolling, Kanter and Parker, 2003). Oppositional and aggressive children (whether verbally capable or not) are a traditional subject-group for ABA, even when the analyst personally has no control over the relevant environment. From its early days on, ABA adapted itself well to this challenge, by training parents to directly manage relevant contingencies at home, enlisting them as actual behavior engineers (e.g. Wahler, Winkel, Peterson and Morrison, 1965). Similar strategies are difficult to imagine for instance with the typical adult outpatient who suffers from an anxiety disorder or interpersonal distress. One of the features that is said to distinguish CBA is that it targets exactly the latter population: verbally capable clients whose daily life contingencies the therapist cannot directly control. The focus of CBA on adult outpatients suggest that behavior analytic treatment of children's problems should only interest ABA, a claim that is not in dissonance with most of the relevant literature. The present article pretends to illustrate that treatment of children's problems in a nonresearch setting can have more or less of the above mentioned features that define CBA. Two cases are shortly discussed to bring to the foreground the fuzzy boundary between applied and clinical behavior analysis in work with families that seek help for child behavior problems. Case one: Jenny was a developmentally normal three year old, only child of a young couple that sought guidance at an outpatient clinic concerning the handling of her tantrums which according to them had always existed: the child had bouts of crying until turning blue when it was only a few months old, had bitten its mother frequently, and generally interacted in coercive ways until the present day. Weekly sessions happened at the clinic with the entire family. In the first interview, both parents expressed intense despair, about their inability to control their child's behavior and the severe social exclusion they had fallen victim to in their village because of this. They reported having seen several physicians whose advices they had followed without result, that two types of prescribed medication had provoked paradoxical effects and that a one year long psychological treatment had brought no relief. …

Reproductive Abnormalities, Teratogenicity, and Developmental Problems in American Kestrels (Falco sparverius) Exposed to Polychlorinated Biphenyls

This study found abnormalities in multiple reproductive stages in captive American kestrels (Falco sparverius) when exposed to polychlorinated biphenyls (PCBs) through dietary and in ovo exposure. American kestrels laid eggs with environmentally relevant total PCB levels (34.1 μg/g whole egg wet weight) when consuming PCB-spiked (Aroclor 1248:1254:1260) food (5–7 μg/g body weight per day) for 100 d only in 1998. In 1999, the same adults laid eggs with estimated total PCBs of 23 μg/g. Effects of maternal (only female exposed) and paternal (only male expose d) in ovo PCB exposure were investigated. Maternal F1 eggs contained predicted total PCB concentrations of 0.34 μg/g. Specific abnormalities occurred more frequently during dietary F0 exposure, particularly aggressive courtship interactions, clutch abandonment, occurrences of cracked eggs, and developmental effects. Multiple developmental effects were more pronounced during than after dietary PCB exposure of adults, and although these effects were limited, nevertheless they occurred in the F1 maternal and F1 paternal pairs. However, the incidence of multiple deformities throughout the breeding season increased dramatically from 1998 (13%) to 1999 (56%) in F0 PCB-exposed pairs. Developmental abnormalities were unlikely to be attributed to the extrinsic factors of disease, genetics, or nutritional (vitamin D3) deficiencies, but rather to adverse changes in parental behavior and intrinsic factors involving altered genetic material and PCB exposure. Readily cleared PCB congeners may induce specific types of behavioral and developmental abnormalities, but persistent congeners and metabolites are likely producing (1) odd laying patterns, (2) developmental effects including embryonic underdevelopment and edema, and (3) increased incidences of multiple deformities within a clutch.

Parent interaction course in order to enhance communication skills between parents and children following pediatric cochlear implantation

Objective: To assess the effect of a parent interaction training course on the communication skills of parents of young implanted children. The training course was designed to help parents to be less controlling in their interactions with their deaf children and to facilitate the development of spoken language. Study design: Prospective study comparing the communication skills of parents of deaf children fitted with cochlear implants before and after a parent interaction training course. Setting: Pediatric tertiary referral center for cochlear implantation. Methods: Video samples were taken of parents interacting with their children 1 month before the course (ranging from 15 days to 2 months) and after the course (ranging from 15 days to 1 month). Video samples were then transcribed orthographically and parents' turns in the interaction were assigned to one of two categories: (a) initiations—the parent initiates conversation or introduces a new topic and (b) responses—the parent responds to the child's previous turn. 12 months after completion of the course, the process was repeated in order to establish the relative permanence of changes in behavior. Hypothesis: The parents' turns would shift from a predominance of initiations to a predominance of responses as a result of attendance on the course. This would demonstrate that the parents were less controlling of their children in communication and were exhibiting more contingent behavior—responding to their child's initiations rather than expecting the child to respond to theirs. Patients: The study involved 17 parents of 11 implanted children. The mean age at implantation was 4 years (range: 2.2–6.3 years). The implant experience of the children ranged from 2 to 23 months at the time of the study. All children used total communication. Results: The post-course initiations were half those of the pre-course ones (median from 14 decreased to 7) and the responses were almost double following the course (median from 8 increased to 14). Both differences were statistically significant ( P<0.05). 12 months after the course, the responses score remained high with a median score of 16.5. However, a slight but significant increase in the initiation scores was also noted (median from 7 to 8.5). Parental satisfaction of the course was found to be high as no families failed to attend on any of the occasions despite the great distances some of them had to travel. Conclusion: The format of the parent interaction training course was found to be highly acceptable to the parents and the components covered proved to be effective in promoting positive changes in parental communication behavior. Clinicians need to provide a responsive environment for implanted deaf children and help others to do the same. The training course provided a very useful forum to share insights and skills and to evaluate ways of enhancing the communication between parents and children following cochlear implantation.

Transgenerational effects of maternal immune challenge in tree swallows (Tachycineta bicolor)

The fact that avian eggs contain antibody of maternal origin is well documented, but only recently has this phenomenon been considered in an ecological context. We used tree swallows (Tachycineta bicolor) to examine the possibility of transgenerational immunity and its effect on nestling growth and immune development. We measured cell-mediated immunity with a delayed-hypersensitivity assay and antibody-mediated immunity with a hemagglutination test with sheep red blood cells (SRBCs). We tested for differences in immunocompetence and growth between nestlings from females who had been exposed to a novel antigen prior to egg laying and nestlings from unexposed females. To determine whether the effect, if any, resulted from something transferred to the eggs prior to egg laying or from subsequent changes in parental behaviour, nestlings were exchanged so that at each nest half the nestlings were from females who had been injected with SRBCs and half were from females who had not been exposed to SRBCs. Finally, brood sizes were independently manipulated to either 4 or 6 nestlings. We failed to detect maternal antibodies in any nestlings, and whether a female was exposed to SRBCs or not had no effect on the growth or cell-mediated immunity of her brood. However, nestlings in smaller broods grew better than nestlings in larger broods, though we did not find the expected differences in cell-mediated immunity. Furthermore, within each nest, nestlings whose mothers had been exposed to SRBCs grew better than nestlings whose mothers had not been exposed. These results are contrary to the idea of a simple trade-off in the allocation of resources between parasite protection and reproduction; however, they support the idea that exposure of females to parasites prior to egg laying leads to better nestling growth, and are congruous with the possibility of mithridatic parental care.

Does teaching scald burn prevention to families of young children make a difference? A pilot study

This article reports a pilot project designed to ascertain what scald burn prevention practices parents of young children used and whether teaching would lead to implementation of burn-related home-safety practices. The sample (n = 49) was followed up longitudinally, and participants completed a survey during two home interviews conducted at 4-week intervals. There was a statistically significant change in the number of scald burn prevention measures (p < .001) implemented by parents after public health nurses provided teaching. Changes in parental behavior were correlated with ethnicity (p < .05). The results have implications for teaching families effective scald burn prevention strategies. Copyright © 2001 by W.B. Saunders Company

Maternal care, gene expression, and the development of individual differences in stress reactivity.

The quality of family life influences the development of individual differences in vulnerability to illness throughout later life. As adults, victims of childhood physical or sexual abuse are at considerably greater risk for mental illness, as well as for diabetes and heart disease (e.g., Refs. 1–3). Children need not be beaten to be compromised. Persistent emotional neglect or conditions of harsh, inconsistent discipline serve to increase the risk of depression and anxiety disorders to a level comparable to that observed in cases of abuse. 4 Indeed, for certain outcomes, the consequences of persistent neglect exceed those of abuse. 5,6 More subtle relationships exist. Low scores on parental bonding scales, reflecting cold, distant parent–child relationships, significantly increase the risk of depression and anxiety in later life (e.g., Refs. 7,8). And the risk is not unique to mental health. Russak and Schwartz 9 found that by midlife those individuals who, as undergraduate students, rated their relationship with parents as cold and detached, had a fourfold greater risk of chronic illness, including depression and alcoholism as well as heart disease and diabetes. Parental factors also serve to mediate the effects of environmental adversity on development. For example, the effects of poverty on emotional and cognitive development are mediated by parental factors, to the extent that if such factors are controlled, there is no discernible effect of poverty on child development. 10,11 Moreover, treatment outcomes associated with early intervention programs are routinely correlated with changes in parental behavior: In cases where parental behavior proves resistant to change, treatment outcomes are seriously limited. These findings suggest that variations in parental care mediate, in part at least, the effects of environmental adversity on child development. One of the more common findings here is that maternal depression associated with environmental conditions not only compromises parent–child interactions, but also limits the efficacy of early intervention programs.

Phylogenetic constraint on male parental care in the dabbling ducks

Phylogenetic constraint and inertia, i.e. limitations on future evolutionary trajectories imposed by previous adaptation, are often invoked to explain behavioural, morphological and physiological traits that defy explanation in an adaptive context. We reconstructed historical changes in male parental care behaviour in the dabbling ducks (family: Anatidae; tribe: Anatini) using a phylogeny based on mitochondrial DNA sequences. Male parental care is observed in many tropical and Southern hemisphere dabbling ducks but is lacking in all Northern hemisphere species. Southern hemisphere species that are very recently derived from Northern hemisphere ancestors, however, are exceptions to this general pattern. Lack of male parental care in these species can be attributed to phylogenetic constraint.

Parental and First Generation Effects of Exogenous 17β-Estradiol on Reproductive Performance of Female Zebra Finches (Taeniopygia guttata)

Steroids hormones have numerous “activational” effects in adult birds, regulating sexual behavior, and more recently maternal androgens have been shown to have potentially important “organizational” effectsin ovo,influencing offspring growth, development, and behavior. In this study I investigated parental and first-generation effects of exogenous estrogens on female reproduction in zebra finches (Taeniopygia guttata). 17β-Estradiol (E2; 1.2 μg/g, 4 daily injections i.m.) elevated plasma levels of the yolk precursors, vitellogenin (VTG) and very low-density lipoprotein (VLDL), in nonbreeding females to levels similar to those of breeding females. However, E2-treatment of breeding females caused no significant change in plasma VTG or VLDL levels compared to control birds (measured at the 1-egg stage), and there was no difference in reproductive performance between groups (egg size, clutch size, timing of laying). E2-treated females produced significantly more daughters than sons (21F:8M) at fledging, compared to control females (18F:19M). Nestling mortality was significantly higher in broods of E2-treated females, suggesting that the skewed sex ratio may have resulted from differential mortality of male chicks. The pattern of chick mortality in E2-broods was not consistent with this being caused by estrogen-mediated changes in parental behavior (e.g., provisoning). Mean egg mass of daughters of E2-treated females was typical of experienced, adult breeders, and larger than normal, first-time breeders or control offspring (0.947 vs 0.850 g). There was no treatment effect on offspring clutch size or laying interval. These results suggest that early exposure to maternal estrogensin ovomight be involved in establishing intraindividual variation in female-specific phenotypic traits, as has previously been demonstrated for androgens and male behavioral traits (e.g., aggression).

Roles of estrogen receptor-alpha gene expression in reproduction-related behaviors in female mice.

The role of gene expression of the estrogen receptor-alpha form (ER alpha) in the regulation of female reproductive behavior was investigated in estrogen receptor knockout (ERKO) mice, deficient specifically for the ER alpha, but not the ER beta, gene. Estrogen- or estrogen- plus progesterone-treated gonadectomized ERKO mice did not show any lordosis response. Detailed behavioral analysis revealed that ERKO females were also deficient in sexual behavioral interactions preceding the lordosis response. They were extremely rejective toward attempted mounts by stud male mice, which could not show any intromissions. During resident-intruder aggression tests, gonadally intact ERKO females were more aggressive toward female intruder mice than wild-type (WT) mice. Gonadectomy did not influence the levels of aggressive behavior, and their genotype differences when mice were tested both before and after gonadectomy. However, when mice were tested after gonadectomy for the first time, very few ERKO mice showed aggression. In contrast to aggression, male-type sexual behavior shown by resident mice toward female intruder mice during aggression tests was not different between ERKO and WT mice and was completely abolished after gonadectomy of the resident mice. Finally, it was also found that ERKO females showed greatly reduced levels of parental behavior toward newborn pups placed in their home cage. These changes in parental behavior were not influenced by gonadectomy. ERKO females retrieved significantly fewer numbers of pups with longer latencies compared with wild-type (WT) or heterozygous (HZ) littermates when they were tested as gonadally intact or 20-65 days after gonadectomy. In addition, during parental behavior tests, a significantly higher percentage of ERKO mice exhibited infanticide compared with WT and HZ mice, which rarely showed infanticide. Taken together, these findings suggest that ER alpha gene expression plays a key role in female mice, not only for sexual behavior but also for other interrelated behaviors, such as parental and aggressive behaviors. In addition, persistence of genotype differences in parental and aggressive behavior after gonadectomy indicates that ER alpha activation during neural developmental processes may also be involved in the regulation of these behaviors.

Charadriiform Birds in Antarctica: Behavioral, Morphological, and Physiological Adjustments Conserving Reproductive Success

Birds colonizing different climates must alter some aspect of their breeding biology to maintain successful reproduction. Comparative analyses were used to elucidate the changes in parental behavior and in the rate of development of the young associated with successful breeding of charadriiform birds in Antarctica. The species studied, the kelp gull Larus dominicanus, the South Polar skua Catharacta maccormicki, and the greater sheathbill Chionis alba, represent three of the four independent colonizations of Antarctica by charadriiform birds. Antarctic species brooded their young two to five times longer than did their temperate relatives. The Antarctic young had greater tolerance to hypothermia, which suggests that, historically, parental care failed to protect the young from selection by low temperatures. Antarctic hatchlings were neither larger nor metabolically more mature than their relatives. Despite presumed selection on the young by low temperatures and the presence of individual variation in development, the young did not attain homeothermy significantly earlier than did their temperate relatives. Growth rates over the entire nestling period were also similar for Antarctic and temperate species. The Antarctic young did grow faster to a moderate size more favorable for thermoregulation and showed coordinately faster development of resting metabolic rate. South Polar skuas, from the oldest Antarctic lineage, further diverged in having accelerated development of thermogenesis, which substantially reduced their reliance on parental brooding. Evolutionary changes in physiological development of the young have resulted in improved abilities to tolerate hypothermia and in lower costs, relative to peak metabolic rates, to maintain homeothermy.

Injury control in pre-school children: a review of parental safety measures and the behavioural determinants

Safety education directed at parents of pre-school children may be an important tool in reducing injuries of pre-school children at home. However, many studies on educational programmes directed at parents have shown little evidence of success in terms of changes in parental safety behaviour and childhood injuries. These programmes may have been affected, among other factors, by a typical kind of ‘programme failure’ due to a lack of empirical information on at-risk behaviour and the deterinants of that behaviour prior to the educational development of programmes. We tried to get an indication of the extent to which previous safety educational programmes had grounded their activities on an empirical basis. Therefore, a review of literature was carried out on empirical studies on (i) parental safety measures—the form of parental safety behaviour that is supposed to be very important in preventing injuries to pre-school children—and (ii) the behavioural determinants of those safety measures. It appeared that information on these topics is scarce and this suggests that previous programmes may indeed have suffered from such programme failure. Recommendations are made for enlarging the body of knowledge essential for the development of effective safety education directed at parents of pre-school children. Finally, some recommendations are presented for safety practitioners.

Review of Research on Home Visiting for Pregnant Women and Parents of Young Children

In this paper, David Olds and Harriet Kitzman review the results of the experimental literature concerning the effectiveness of home visiting programs in improving the lives of children and families. Their extensive review concentrates on randomized trials, that is, those most methodologically rigorous studies of all in which families are randomly assigned to two groups, typically to receive either (1) home visiting services (the experimental group) or (2) care as usual (the control group). Olds and Kitzman further focus on just those studies in which the effects of home visiting can be teased apart from the effects of other sorts of services (for example, medical care and child care). Thus, their review does not include some of the studies that are mentioned by other authors (for example, Powell and Weiss) in their articles for this journal issue or described in the Appendix (page 205). Nevertheless, the review is very comprehensive. The authors summarize results of 31 home visiting programs that have focused on preventing preterm delivery and low birth weight; improving the outcomes of infants born preterm or low birth weight; or serving low-income families or families at risk for child maltreatment. Tables 2, 3, and 4 depict the results of studies on outcomes including changes in parental behavior, home environment, child development and behavior, child abuse, rates of preterm and low birth weight births, and health care utilization. The authors conclude that home visiting is a promising approach, but all too often the promise has not been clearly demonstrated. Indeed, results suggest that home visiting programs in the past have benefited some families but not others and have improved some outcomes but not others. Olds and Kitzman suggest that these differences in effectiveness may be the result of several characteristics of the home visiting programs, including their comprehensiveness of purpose and goals, level of staffing, frequency of visits, and the populations they are designed to serve. In general, the authors suggest that programs which are comprehensive in focus, have frequent visits, are staffed by well-trained professionals, and serve families that are initially at elevated risk for poor outcomes are more likely to demonstrate success. The authors conclude that carefully designed home visiting programs should continue to receive support.

Parent Training Using Videotape Self-Modeling

Mothers with 4- to 7-year-old male children with behavior problems related to noncompliance and aggression were recruited to participate in a parent training study. Each mother-child dyad was observed and videotaped over fifteen 15-minute laboratory sessions. Resulting videotapes were edited to show only examples of three targeted parental behaviors: selective attention, issuing direct and clear commands, and praise contingent on child compliance. One baseline, one attention control, and three treatment conditions made up the within subject multiple baseline design. During treatment conditions, mothers viewed the edited tapes depicting the respective target behavior. The data analysis indicated that videotape self-modeling did not significantly alter parental or child behavior with the exception of the final phase in which parents issues more direct and concise commands and the children became more compliant. However, a follow-up exploration in which variables such as parental comprehension and motivation were manipulated produced robust changes in parental behavior. Potential explanations for the results and recommendations for future research are made.