Attitudinal and demographic predictors of breast-feeding and bottle-feeding behavior by mothers of six-week-old infants

The demographic and attitudinal characteristics of 42 bottle feeding and 41 breast feeding mothers of 6 week old infants were compared. The women were patients of private physicians in Nashville, Tennessee. Data was obtained from self-administered questionnaires distributed through the physicians' offices. The women were primarily middle class whites and one-half of the women were multiparous and one-half were primiparous. On the basis of the information obtained in the questionnaires respondents were given scores on 13 demographic and family history characteristics and on 16 attitudinal scales which measured the mothers' preceptions of family life, child rearing, and breast feeding. Discriminant function analysis was used to assess the differences in the mean scores on each of the 29 variables for the 2 groups of mothers. Major findings were: 1) breast feeding mothers were significantly more educated and had significantly more breast feeding friends than bottle feeding mothers; 2) breast feeding mothers viewed their husbands as significantly more supportive of their feeding method than bottle feeding mothers; 3) bottle feeding mothers perceived more conflict in their marriages than breast feeding mothers; 4) bottle feeding mothers tended to favor accelerating the development of their infants more than the other mothers; and 5) breast feeding mothers had more positive attitudes toward breast beeding than bottle feeding mothers. Most of the women in both groups decided on their method of feeding prior to delivery, and complications during and following delivery did not alter their plans significantly. The 2 groups did not differ significantly in the degree to which they: 1) fostered dependency in their infants; 2) felt possessive toward their infants; 3) rejected the housewife role; and 4) were secluded at home.     

Effects of chronic social stress during lactation on maternal behavior and growth in rats

Maternal mood disorders such as depression and chronic anxiety can negatively affect the lives of not only mothers, but also of partners, offspring, and future generations. Chronic exposure to psychosocial stress is common in postpartum mothers, and one of the strongest predictors of postpartum depression is social conflict. The objective of the current study was to evaluate the effects of chronic social stress (CSS) during lactation on the maternal behavior (which consists of maternal care and aggression toward a novel conspecific) of lactating rats, as well as on the growth of the dams and their offspring. It was hypothesized that chronic daily exposure to a novel male intruder would alter the display of maternal behavior and impair growth in both the dam and offspring during lactation due to the potentially disruptive effects on maternal behavior and/or lactation. The data indicate that CSS during lactation attenuates maternal care and the growth of both dams and pups, and increases self-grooming and maternal aggression toward a novel male intruder. These results support the use of CSS as a relevant model for disorders that impair maternal behavior and attenuate growth of the offspring, such as postpartum depression and anxiety.     

The impact of breastfeeding on mothers' attentional sensitivity towards infant distress

Background

Maternal response towards infant distress has an important impact on infant development. In animals it is established that lactation and pup suckling plays an important role in maintaining maternal responses. Previous research suggests that breastfeeding is associated with sensitive maternal responses in human mothers. However, this may be because women who are more sensitive to their infant choose to breastfeed. The current study investigated the attentional sensitivity towards infant distress in women who went on to breast or formula feed during pregnancy as well as after birth. We hypothesised that differences in breast and formula feeding mothers would only emerge after birth once feeding had commenced.

Method

Women were recruited during pregnancy through community midwives as part of a longitudinal study. 51 women were seen during late pregnancy and between 3 and 6 months after birth (27 were breast and 24 were formula feeding). Sensitivity to infant distress was measured as the extent of women's attentional bias towards infant distress stimuli.

Results

After birth, we found that our index of attentional bias towards infant distress was 37 ms (0.5 S.D.s) (CI; 6-69, p = 0.021) higher in breastfeeding compared to formula feeding mothers. However, mothers who went on to breastfeed did not show greater attentional bias towards infant distress already during late pregnancy.

Conclusions

Our results suggest that the act of breastfeeding may influence mothers’ attentional sensitivity towards infant distress. Previous research suggests breastfeeding is indicative of sensitive parenting. The current findings may suggest a mechanism by which breastfeeding and/or associated infant interaction could contribute to this sensitivity.     

Sensory control of maternal aggression in Rattus norvegicus

Female rats become aggressive toward adult conspecifics during lactation. This change in social affect is dependent on the presence of the offspring, because maternal aggression disappears when the pups are removed. It was found that a similar decline occurs when the litter is placed in a glass flask while remaining in the home cage. In contrast, maternal aggression persists following placement of the pups in a nylon mesh bag. The pups did not vocalize while being in the mesh bags, so it appears that olfactory cues from the offspring constitute a critical element in the maintenance of maternal aggression in the rat. It has been suggested that the odor not only of the pups but also of the intruder may contribute to eliciting aggressive behavior in lactating rodents. In line with this proposal, it was found that mother rats spend about one third of the time preceding the first attack sniffing the body of the intruder. In contrast to findings in mice, housing of the prospective intruder behind a double wire mesh partition in the lactating female's home cage failed to reduce her aggressiveness toward him. Rats, then, may require more intimate contact with an individual than do mice for the aggression-reducing effect of familiarization to be observed.     

Differential Effects of Short- and Long-Term Early Maternal Separation on Subsequent Maternal Behavior in Rats

Female Sprague-Dawley pups were separated from mothers every other day for 8 hr (long-term separation/LTS), 4 hr (short-term separation/STS), or 0 hr (no separation/NS) from postnatal day 2–20. In adulthood, they were mated and tested for maternal behaviors during two lactations. It was expected that females separated from mothers as pups would show deficits in maternal behavior as adults. Contrary to expectations, LTS showed better nest building and grouped young faster during both lactations. LTS were first to display aggression and displayed more aggression during the second lactation. Notably, while some measures decreased from first to second lactation in NS and STS, LTS maintained levels of maternal care. These results suggest that extended periods of maternal separation may exaggerate some aspects of maternal behavior.     

Lactation and stress: protective effects of breast-feeding in humans

Whilst most research on breast-feeding has been designed to assess its importance for infant health or to find a human nutrient replacement for infant formula, the effects of breast-feeding on maternal health have received little scientific attention. In several animal studies lactation has been shown to be associated with a marked blunting of physiological and behavioral responses to physical and psychological stress. However, the literature on the effects of lactation on stress in humans remains limited. This review focuses primarily on recent findings on the effects of breast-feeding on neuroendocrine and behavioral responses to acute stress exposure in lactating women. The available data suggest that breast-feeding suppresses the hypothalamic-pituitary-adrenal (HPA) axis response to physical and psychosocial stress. However, lactation in women, in contrast to lactating rats, does not seem to result in a general restraint of the endocrine stress response during the whole period of lactation. Recent data strongly suggest that the blunted HPA axis response to stress in women seems to be counterbalanced if the acute stressor, at least when of a psychosocial nature, occurs later than 1 h after suckling. Further elucidation of the underlying psychobiological mechanisms involved in suppressed stress responses during lactation will no doubt lead to new insights into improved health sequelae of breast-feeding in women and to a better understanding of the psychobiology of human stress protection in general.     

Effects of septal-forebrain lesions on maternal aggression and maternal care

Septal-forebrain lesions significantly increased the defensive reactions of lactating Long-Evans rats (n = 13) relative to nonlesioned control females. The lesions greatly enhanced defensive behaviors on a number of standard tests (e.g., responsiveness to humans and anesthetized conspecifics) while abolishing aggression toward intruding male conspecifics. The lesions also produced a striking disruption in maternal behavior as evidenced by absence of nest building, reduced litter weights, failure to retrieve, lick, or nurse pups, and increased cannibalization. While these results cannot be interpreted as indicating that maternal aggression is equivalent to offense, they are congruent with such a view. Certainly they are not supportive of a view that maternal aggression is primarily defensive. The lesion-induced abolition of maternal attack may have resulted from an inhibition of offensive tendencies by heightened defensiveness and/or reduced pup stimulation. There was no evidence that the lesion-induced impairment in maternal behavior resulted from a failure to sequence the individual behavioral acts comprising maternal behavior. Rather, all features of maternal care seemed to be greatly attenuated.     

Physical/verbal aggression: Sex differences in style1

Two studies exploring the use of physical/verbal aggression are reported, the first using women and the second using men as subjects. Both studies allowed subjects to choose between and control the intensity of two response modes: verbal aggression (insults) and physical aggression (electric shock). Aggressive style was investigated over two levels of arousal, sex of experimenter, and sex of provocateur-victim. Results indicated that women aggressed discriminatively in the verbal mode as a function of their arousal, while men were capable of aggressing discriminatively in both the verbal and physical modes. Men who had been disagreed with and punished by a female victim-provocateur in the presence of a male experimenter or by a male victim in the presence of a female experimenter demonstrated high levels of physical aggression compared to the other groups.     

A COMPARISON OF MALE AND FEMALE DIRECTORS IN POPULAR PORNOGRAPHY: WHAT HAPPENS WHEN WOMEN ARE AT THE HELM?

Pornography is a lucrative business. Increasingly, women have participated in both its production, direction, and consumption. This study investigated how the content in popular pornographic videos created by female directors differs from that of their male counterparts. We conducted a quantitative analysis of 122 randomly selected scenes from 44 top-renting adult videos in 2005 (half male- and half female-directed). Findings revealed that all films shared similar depictions: Verbal and physical aggression was common, women were the primary targets of aggression, and negative responses to aggression were extremely rare. Compared to male-directed films, female-directed films were significantly more likely to portray women-only scenes and sexual acts. Even when controlling for main characters' gender, female-directed films showed significantly more female perpetrators aggressing against female targets and significantly more depictions of women as perpetrators of aggression. We highlight the importance of economic forces, rather than director gender, in dictating the content of popular pornography.     

Sex differences in aggressive behaviour in various strains of mice

Two nonalbino inbred (C57 BL/6 and C3H/He) and one albino strain (Swiss) of mice were compared for female aggression toward intruders: 1 in period of lactation, 2 in nonlactating state and (3) in nonlactating state but previously rubbed with urine of lactating females; and for male aggression toward familiar or unfamiliar opponents. The results showed that resident females of the C57 and Swiss strain vigorously attack lactating intruders introduced into their cages. This effect was mediated by urinary cues emitted by the latter mice. It was also shown that Swiss residents displayed aggression towards nonlactating females, irrespective of their strain. Groups of C57 residents reacted most aggressively towards Swiss females, less aggressively towards C3H intruders, but did not show any aggression towards their own nonlactating conspecifics. In contrast, none of the C3H resident female groups displayed aggression towards intruding females of any category or strain. The results also showed that the males of the three strains displayed little (Swiss and C3H) or no aggression (C57) towards familiar opponents, whereas they directed increased aggressive responses towards unfamiliar ones. Comparisons among the three strains of mice revealed that Swiss males were the most aggressive in either situation. On the other hand, the finding that C3H males showed aggressive responses suggested that male and female aggression are, in this strain, under separate genetic or hormonal control.     

Social Support in Academic Programs and Family Environments: Sex Differences and Role Conflicts for Graduate Students

We hoped to identify the sources and types of social support that are most beneficial for helping graduate students cope with stress. A second purpose of our study was to identify sex differences in stress and the most beneficial types of support. Students living in graduate student housing were surveyed to assess (a) social support in their academic programs and in their family environments, (b) recent stressful life events, and (c) depression and anxiety as psychological symptoms of stress. Women reported significantly more stress, more symptoms of stress, and significantly less support from their academic departments and family environments than did men. Family support had only buffering effects, but no direct effects on stress symptoms for women. Graduate program and family support had direct effects, but no buffering effects on stress symptoms for men. These results may indicate greater role strain for women, perhaps resulting from less support for their multiple roles and greater concerns about balancing academic and family demands.     

Beyond sex differences: Family and occupational roles' impact on women's and men's dreams

The question addressed is: do recent changes in the occupational roles of women, with their indirect influence on men's lives, have an impact on the dreams of women and men? Three groups of parents (N=96) including in equal numbers, mothers at home, wage-earning mothers and fathers, kept a dream diary from which two dreams per dreamer were content analyzed. Assuming continuity between daytime and dream experiences, it was hypothesized that differences in manifest dream content would be a function of single versus dual role enactment, rather than sex. Contrary to predictions, statistical analyses performed on selected dream variables did not yield significant differences between groups for pleasant and unpleasant emotions, friendly interactions and aggression. Dream characters, and the concerns they reflect, were found to vary, though, according to social roles. Commitment to their family was reflected above all in the mothers' at home dreams, while commitment to their profession took precedence in those of the wage-earning mothers. Comparable commitment to work and family was found among the fathers. Findings suggest that as gender differences in waking life decrease, so may differences in dreams.     

Gender differences in the relation between stressful life events and adjustment among school-aged children

The study evaluated gender differences in the relation between stressful life events and adjustment among elementary school children. In Study I, anxiety, aggression, submissive withdrawal, and life event questionnaires were completed by 63 Israeli children. The frequency of life events was associated with increased anxiety and trends toward heightened withdrawal and aggression among boys, but not girls. In Study II, 80 Israeli mothers of elementary school children completed parallel questionnaires regarding their child. As in Study I, life events were associated among boys, but not girls, with increased anxiety and a trend toward heightened withdrawal. No gender difference arose in the association for aggression. Discussion focused on the possible roots of these findings in differential patterns of stress sensitivity, resilience, and coping, and on their ramifications for the study of cross-situational gender differences.     

70-kHz vocalizations by male mice do not inhibit aggression in lactating mice

Two experiments investigated the relationship between adult male 70-kHz vocalizations and aggression by lactating female mice (Mus domesticus). Intact, vocalizing males, surgically devocalized males, and naturally nonvocalizing males were used to assess the effects of high frequency vocalizations on maternal aggression. The emission of high frequency vocalizations promoted aggressive behavior by the females. In both experiments, lactating females attacked the vocalizing males more rapidly and showed a higher incidence of aggressive behaviors toward these males than they did to the nonvocalizing male. We suggest that these vocalizations are only one of many situational cues that the female uses to determine her final behavioral response.     

Lactation deficit in OFA hr/hr rats may be caused by differential sensitivity to stress compared with Wistar and Sprague Dawley rats

OFA hr/hr (OFA) rats present a major lactation deficit that impairs offspring survival. To explore whether abnormal stress responsiveness causes this deficit, we compared their hormonal (prolactin, progesterone, and corticosterone) responses to stress (room change and 2-min ether exposure) with those of Wistar and Sprague Dawley (SD) rats. We tested responses during the estrous cycle, pregnancy, lactation, after ovariectomy, and ovarian steroid hormone priming, and responses to suckling. We evaluated hypothalamic expression of receptors for prolactin (PRLRlong) and the isoforms of receptors for progesterone (PRA and B) and estrogen (ERα and β) in late pregnancy. We tested whether administration of an anxiolytic (diazepam) improved lactation. Ether exposure increased circulating levels of the three hormones in the three strains of rats, cycling and ovariectomized, but was less effective in pregnancy and lactation. Elevated estrogen level (estrus and estradiol-treated ovariectomized rats) potentiated the prolactin response more in SD and OFA rats than in Wistar rats. Elevated progesterone level (late pregnancy, lactation, progesterone-treated ovariectomized rats) inhibited the prolactin response less in OFA than in SD or Wistar rats. Ether exposure inhibited the prolactin and oxytocin responses to suckling only in OFA rats. Diazepam treatment increased pup survival rate and the prolactin response to suckling. Hypothalamic total PR mRNA content, assayed by RT-PCR, was higher in pregnant OFA rats compared with SD and Wistar rats, but the PRB/PRA protein ratio determined by Western blot was lowest in Wistar rats, intermediate in OFA rats, and highest in SD rats. The heightened sensitivity to stress of lactating OFA rats may contribute to their lactational deficit and be caused by a combination of hypoprolactinemia and reduced inhibitory capacity of progesterone.     

Stress exposure and affective modulation of aggressive behavior in men and women

To study differences in the effects of stress exposure and affective responding on aggression in men and women, the authors examined the effects of an acute stressor (air blast) on subsequent aggressive behavior, measured as the intensity of shocks men and women delivered to a putative employee. The authors measured participants' affective responding using the startle reflex. Results showed that although men and women did not differ in their startle responses to the actual stressor, high stress led to contrasting patterns of subsequent aggressive behavior. Women under high stress responded with less aggression than women under low stress, whereas men exposed to high stress exhibited increases in aggression relative to those under low stress. Affective responding during the stressor differentially modulated aggression in men and women: Startle responses predicted increasing levels of aggression in men and less aggression in women. These findings suggest that although men and women show similar basic affective processing in response to stressors, the behavioral profiles associated with stress differ in men and women. These findings have implications for understanding gender differences in the prevalence of internalizing and externalizing psychopathology.     

MIDLIFE CHILDBEARING Strategies for Informed Decisionmaking

More and more women in the United States are choosing to delay mother-hood until their 30s or even 40s. Yet traditional medical advice warns against midlife pregnancy, predicting a variety of adverse reproductive outcomes associated with "advanced maternal age." Assignment to a high-risk category may result in heightened feelings of concern about pregnancy complications among midlife mothers. Because it is possible that increased emotionality during pregnancy may itself give rise to various childbearing complications, some middle-aged women may become victims of iatrogenic stress during pregnancy. This article first examines critically the medical literature describing the relationship between maternal age and pregnancy outcomes and finds little support for the medical pessimism. Next, the article describes the literature that explores the links between heightened emotionality during pregnancy and various negative outcomes and suggests that, despite serious methodological flaws, there is some evidence that fear-induced stress during pregnancy may place certain middle-aged women at higher risk for complications. Finally, strategies for improved decisionmaking and for enhancing the pregnancy experience of midlife women are proposed.     

Attack,inhibition and target of aggression

Predictions concerning aggression displacement, derived from Miller's conflict model, were investigated under conditions in which subjects' inhibitions about aggressing against an attacker were manipulated. Half of the high-attacked subjects were placed in a high-inhibition situation, designed so that strong inhibitory tendencies competed with strong aggressive tendencies; the remaining high-attacked subjects were placed in a low-inhibition situation, designed so that weak inhibitory tendencies competed with strong aggressive tendencies. Low-attacked control subjects also received the inhibition treatment. High- and low-attacked subjects were then confronted with one of four target persons, varying in similarity, toward whom they could aggress with electric shock. As expected, under high inhibition, the target most similar to the attacker received more shocks from high-attacked subjects than did either the attacker or two less similar targets. Contrary to expectation, the attacker did not receive the most shocks under low inhibition; personality evaluations of the attacker suggested that high-attacked subjects in substitute target conditions may have been unintentionally angered further by being denied the opportunity for direct retaliation.     

Effects of daily and acute restraint stress during lactation on maternal aggression and behavior in mice

A decreased reactivity to stressors during lactation might heighten the expression of maternal care (including defense of offspring) by minimizing the extent to which stress can impact maternal care. Although stressors applied during pregnancy have variable effects on maternal aggression (or defense of offspring), to date no study has examined the effects of stress applied during the postpartum period on maternal aggression. In this study, we examined the effects of both daily and acute restraint stress (30 min) applied postpartum on maternal aggression and other maternal behaviors. Daily restraint (ending 2 h before testing) did not alter any measure of maternal behavior, including nursing, licking and grooming of pups and pup retrieval, or any measure of maternal aggression. In contrast, acute stress significantly impaired total time aggressive and number of attacks, but pup retrieval was normal. c-Fos levels were significantly elevated in a number of brain regions in association with acute stress, including lateral septum (LS), caudal periaqueductal gray and medial amygdala (MeA), suggesting possible sites where stress reactivity could alter aggression. Together, the results indicate that acute restraint stress impairs maternal aggression and provide a starting point for future studies examining how stress reactivity pathways may intersect with maternal aggression pathways.     

Self-esteem, academic self-concept, and aggression at school

The present study explores the relation between academic self-concept, self-esteem, and aggression at school. Longitudinal data from a racially diverse sample of middle-school students were analyzed to explore how academic self-concept influenced the likelihood of aggressing at school and whether high self-concept exerted a different pattern of influence when threatened. Data include self-reported academic self-concept, school-reported academic performance, and parent-reported school discipline. Results suggest that, in general, students with low self-concept in achievement domains are more likely to aggress at school than those with high self-concept. However, there is a small sample of youth who, when they receive contradictory information that threatens their reported self-concept, do aggress. Global self-esteem was not found to be predictive of aggression. These results are discussed in the context of recent debates on whether self-esteem is a predictor of aggression and the use of a more proximal vs. general self-measure in examining the self-esteem and aggression relation.