The effect of infant fetal alcohol syndrome facial features on adoption preference

Infant facial characteristics may affect discriminative parental solicitude because they convey information about the health of the offspring. We examined the effect of Fetal Alcohol Syndrome (FAS) infant facial characteristics on hypothetical adoption preferences, ratings of attractiveness, and ratings of health. As expected, potential parents were more likely to adopt “normal” infants, and they rated the FAS infants as less attractive and less healthy. Cuteness/attractiveness was the best predictor of adoption likelihood. This study formed part of the first author’s undergraduate honors thesis at Queen’s University conducted under the supervision of the third author. This research was supported by an Ontario Mental Health Foundation Senior Research Fellowship and a research contract from the Kingston Providence Continuing Care Centre to the third author. Katherine L. Waller is a Ph.D. candidate in psychology at Queen’s University. Her research focuses on health psychology and behavior in close relationships. Anthony Volk is a Ph.D. candidate in psychology at Queen’s University. His research focuses on evolutionary psychology and parental investment. Vernon L. Quinsey is a professor of psychology and psychiatry at Queen’s University. His research focuses on forensic and evolutionary psychology.     

Prolactin responses to infant cues in men and women: effects of parental experience and recent infant contact

We used a longitudinal design to test whether parental experience differentially affects the development of prolactin responses to infant cues in men and women. Couples provided two blood samples at three tests, one test just before their babies were born, and two tests during the early postnatal period (n=21). Nine couples repeated the tests near the birth of their second babies. In the 30 min between the two samples, couples listened to recorded infant cries at the prenatal test and held their baby (fathers) or a doll (mothers) at the postnatal tests. Blood samples were analyzed for prolactin concentrations. Prolactin values were then related to sex and parity differences as well as to questionnaire data concerning emotional responses to infant cries and previous infant contact. We found that (1) prior to the birth of both the first and second babies, women's prolactin concentrations increased after exposure to infant stimuli, whereas men's prolactin concentrations decreased; postnatal sex differences varied with parity; (2) women's prolactin reactivity did not change significantly with parental experience; (3) the same men's prolactin concentrations decreased after holding their first newborns but increased after holding their second newborns; this change was not gradual or permanent; (4) men reporting concern after hearing recorded infant cries showed a different postnatal pattern of prolactin change after holding their babies than men not reporting concern; and (5) men who had little contact with their babies just prior to testing had a more positive prolactin response than men who had recently held their babies for longer periods. Although parental experience appears to affect men's prolactin responses, differences in reactivity were also related to patterns of recent infant contact and individual differences in responses to infant cues.     

The development of behavioural sex differences in infant rhesus macaques (Macaca mulatta)

Studies of infant rhesus macaques have generally reported sex differences in the frequency of expression of some behaviour patterns, such as rough-and-tumble play and socio-sexual mounting. In contrast, sex differences in other behaviour patterns, such as proximity to the mother, have been less consistantly reported. Using data on the behavioural development of infant rhesus macaques living in captive social groups, we have attempted to provide further evidence for, or against, sex differences in behaviour and to investigate the possible influence of maternal rank and parity on sex differences in infant behaviour and mother-infant interactions. The behaviour of 14 male and 20 female infants and their mothers was studied during the first six months of life, including measures of play behaviour socio-sexual mounting, and mother-infant interactions. Our data reveal that, on average, male infants exhibited more rough-and-tumble play and mounting than female infants, and also exhibited stationary play, chasing play, and initiated play more frequently than females. Such sex differences appear to be robust in macaques and have been reported in a variety of housing conditions. male and female infants did not differ in the amount of time spent at particular distances from their mothers, and mothers were not found to behave differently towards sons and daughters, using measures of restraint, rejection, and grooming. These results are in contrast to previous studies on singly-housed mother-infant pairs but similar to those on free-ranging populations. Mothers did behave differently towards their infants depending upon the mother's rank and previous number of offspring. These maternal characteristics may have significant consequences for the behavioural development of both male and female infant primates.     

Parental preferences for the facial traits of their offspring's partners can enhance parental inclusive fitness

Physical appearance provides a wealth of information concerning an individual's biological fitness and reproductive quality, but we do not know whether parents make use of this information when evaluating potential partners for their offspring. This is critical to our understanding of human mate choice, because parents frequently influence their offspring's mating decisions, either directly, for instance through arranged marriages, or indirectly, through manipulating their offspring's partner choice. Here, we used facial images that varied in attractiveness, masculinity, health, and symmetry to assess both reproductively-aged daughters' and their parents' preferences in potential mates for the daughters. In line with our predictions, both daughters and their parents had clear preferences for markers of genetic quality, although the daughters showed significantly stronger preferences for these markers than their parents. Contrary to previous research, parents and daughters did not have stronger preferences for markers of genetic quality if they perceived the daughter to be more attractive. Parents' preferences for the facial markers of genetic quality in their offspring's partner may help maximize inclusive fitness.     

On the impact of sex and birth order on contact with kin

Previous research indicates that birth order is a strong predictor of familial sentiments, with middleborns less family-oriented than first- or last-borns. In this research, effects of sex and birth order on the actual frequency of contact with maternal and paternal kin were examined in two studies. In Study 1, one hundred and forty undergraduates completed a questionnaire relating to the amount of time they spent in contact with specific relatives, while in Study 2, one hundred and twelve undergraduates completed the same questionnaire with the addition of two questions relating to the subjects’ parents’ birth orders. Subjects were more likely to have frequent contact with maternal, as opposed to paternal, kin and women experienced more frequent contact than men with relatives in general. The birth order of subjects did not appear to have a significant influence on contact but the birth order of the subjects’ parents did, with the offspring of middleborn mothers having relatively little contact with maternal grandparents and the offspring of middleborn fathers having relatively little contact with paternal grandparents. These sex and birth order differences are discussed in relation to possible differences in how women and men use kinship ties and in terms of how birth order may influence parental solicitude. Catherine Salmon recently received her Ph.D. in psychology from McMaster University in Hamilton Ontario. Her interest in kinship and family relationships has grown out of her own large extended family and many visits to Utah as well as exposure to evolutionary thinking about the family in the lab of Martin Daly and Margo Wilson. Her other current research interests focus on female sexuality and the evolutionary study of literature.     

The effects of habitat- and diet-based cues on association preferences in three-spined sticklebacks

A number of recent articles have investigated the potentialof familiarity preferences to influence group membership infree-ranging animals. However, it is not clear to which extentindividual recognition or a more general recognition of a groupodor is responsible for familiarity preferences. First, we testedthe sensory basis of the recognition of familiars in stickleback.When allowed to choose between a familiar and a nonfamiliarstimulus shoal on the basis of both visual and chemical communication,visual communication only, and chemical communication only,the preference of focal fish for familiars was shown to dependon the presence of chemical cues. We subsequently investigatedthe effects of recent habitat and diet on shoaling preferencesin the three-spined stickleback (Gasterosteus aculeatus). Experimentalfish were divided into four treatment groups consisting of twowater treatments (saline and freshwater) and two diet treatments(Daphnia spp. and bloodworm). Focal fish subsequently showedsignificant association preferences for groups of nonfamiliarfish that had undergone the same water or diet treatment asthemselves. These data indicate that individual recognitionis not a prerequisite for the expression of association preferences.     

The effects of residential locality on parental and alloparental investment among the Aka foragers of the central African Republic

In this paper I examine the intracultural variability of parental and alloparental caregiving among the Aka foragers of the Central African Republic. It has been suggested that maternal kin offer higher frequencies of allocare than paternal kin and that maternal investment in infants will decrease when alloparental assistance is provided. Behavioral observations were conducted on 15 eight- to twelve-monthold infants. The practice of brideservice and the flexibility of Aka residence patterns offered a means to test the effect of maternal residence on parental and alloparental investment. There was significant variation in the frequency of investment and who supplied care to infants depending on whether mothers resided with their kin or their husbands’ kin. However, in spite of the variation in allocare, when all categories of caregivers were examined collectively, infants received similar overall levels of care. Courtney L. Meehan is a Ph.D. student in cultural anthropology at Washington State University. Her research interests include parenting, alloparenting, female social networks, and female-female cooperation and competition.     

The effect of perceived cultural and material threats on ethnic preferences in immigration attitudes

This paper shows that cultural and material threats exist side by side, serving different psychological functions, and that they manifest in differential attitudes towards immigrants from different ethnic or racial origins. While culturally threatened individuals prefer immigrants akin to themselves, as opposed to those from different races and cultures, the materially threatened prefer immigrants who are different from themselves who can be expected not to compete for the same resources. We test our hypotheses using multilevel structural equation modelling, based on data from twenty countries in the 2002 wave of the European Social Survey. The disaggregation of these two types of perceived threat reveals responsiveness to the race of immigrants that is otherwise masked by pooling the two threat dimensions.     

The emergence of gonadal hormone influences on dopaminergic function during puberty

Adolescence is the developmental epoch during which children become adults—intellectually, physically, hormonally and socially. Brain development in critical areas is ongoing. Adolescents are risk-taking and novelty-seeking and they weigh positive experiences more heavily and negative experiences less than adults. This inherent behavioral bias can lead to risky behaviors like drug taking. Most drug addictions start during adolescence and early drug-taking is associated with an increased rate of drug abuse and dependence.The hormonal changes of puberty contribute to physical, emotional, intellectual and social changes during adolescence. These hormonal events do not just cause maturation of reproductive function and the emergence of secondary sex characteristics. They contribute to the appearance of sex differences in non-reproductive behaviors as well. Sex differences in drug use behaviors are among the latter. The male predominance in overall drug use appears by the end of adolescence, while girls develop the rapid progression from first use to dependence (telescoping) that represent a female-biased vulnerability. Sex differences in many behaviors including drug use have been attributed to social and cultural factors. A narrowing gap in drug use between adolescent boys and girls supports this thesis. However, some sex differences in addiction vulnerability reflect biologic differences in brain circuits involved in addiction. The purpose of this review is to summarize the contribution of sex differences in the function of ascending dopamine systems that are critical to reinforcement, to briefly summarize the behavioral, neurochemical and anatomical changes in brain dopaminergic functions related to addiction that occur during adolescence and to present new findings about the emergence of sex differences in dopaminergic function during adolescence.     

Mate preferences and choices for facial and body hair in heterosexual women and homosexual men: influence of sex,population, homogamy,and imprinting-like effect

Recent research has reported that male body and facial hair influence women's mate preferences. However, it is not clear whether such preferences are typical for women or for individuals who prefer males as sexual partners. Here we explored body and facial hair in preferred and actual partners among men and women who prefer men as sexual partners. Including homosexual individuals provides a unique opportunity to investigate whether evolved mating psychologies are specific to the sex of the individual or sex of the partner. Based on an online survey of 1577 participants from Brazil and the Czech Republic, we found that, on average, homosexual men preferred hairier stimuli than heterosexual women, supporting past findings that homosexual men have strong preferences for masculine traits. Preferences for facial and body hair appear to be influenced less by sex of the preferred partner than sex of the individual, pointing to a possible sex-specific mating psychology. Further, Brazilians preferred bigger beards than Czechs, which was positively associated with the self-reported amount of beardedness in Brazil, suggesting that familiarity effects underpin cross-cultural differences in preferences for facial hair. Moreover, homosexual men preferred a self-similar degree of beardedness, and Czech women preferred a similar degree of beardedness as their fathers had during their childhood. However, these effects were not associated with the level of facial hair in their actual partners; in general, mate preferences and actual mate choices for facial and body hair differed. Thus, individual differences in some self-reported characteristics, cultural factors, and aspects of personal experience may modulate differences in preferences for masculine traits.     

The role of male visual and chemical cues on the activation of female courtship behaviour in the sex-role reversed peacock blenny

Chemical cues during courtship in peacock blenny Salaria pavo did not add significantly to the response of visual stimuli and females did not court when a male was not visible. The results showed that female S. pavo courtship behaviour was elicited exclusively by male visual features and not by a multicomponent signal in different sensory modalities. The time spent by females courting the male and exhibiting the nuptial colouration during visual trials correlated with the size of the male's crest, suggesting a signalling function for this trait. Alternative hypothesis for the function of the putative pheromones released by the male's anal gland are discussed. Evidence that female sexual motivation decreases towards the end of the breeding season is also provided, which should be considered in future mate choice experiments.     

The impact of friend-or-foe cues and survival pressure on trust in the investment game

Prior research has shown that people place more trust in a counterpart referred to as a “partner” than as an “opponent” in a bargaining game. This is thought to be because the appellations “partner” or “opponent” serve as subtle cues activating a postulated friend-or-foe (FOF) mental module. However, no research has investigated the association between FOF cues and trust in an investment game from an evolutionary perspective. The present research demonstrates the effect of FOF cues on trust among Chinese samples in an actual investment game (Study 1) and in a hypothetical investment game (Study 2), and further demonstrates the moderating role of survival pressure on the association between FOF cues and trust—FOF cues influence trust in a scenario involving survival pressure but not in a scenario lacking survival pressure (Study 3). These findings are consistent with the existence of an adaptive FOF mental mechanism used by human beings to solve survival challenges.     

The role of field-collected cues in the host recognition of twig girdlers (Oncideres rhodosticta) on honey mesquite (Prosopis glandulosa)

Conspecific gravid females integrate volatile organic compounds (VOCs) to exploit potential oviposition sites; the role of VOCs has not been examined on twig girdlers, Oncideres rhodosticta, and honey mesquite, Prosopis glandulosa. To examine the host selection behavior of female twig girdlers, we examined the preference and searching time between healthy and girdled twigs of honey mesquites in New Mexico, USA. Among 21 different volatile organic compounds, female twig girdlers reacted to six chemical compounds from girdled twigs and four from healthy twigs. While females responded to Heptanal, (E)-2-Heptenal, and Linalool oxide on both healthy and girdled twigs, they also reacted to one healthy specific compound and two girdled specific compounds. Female twig girdlers distinguished healthy twigs over girdled twigs with faster searching time. Our finding demonstrates VOCs in the genus Oncideres for the first time, providing additional empirical information to help decide on the biological control potential of possible agents during the pre-release risk assessment.     

The impact of water pH on association preferences in fish

Acidification of lakes and rivers, as a consequence of anthropogenic interference, can cause fundamental changes to biological and ecological processes. One of the main consequences of a reduction in water pH for aquatic organisms is the disruption of their chemosensory abilities, as the detection of chemical cues underpins a wide range of decision‐making processes; for example, a reduction to low pH has been shown to interfere with predator avoidance and the detection of foraging cues. Moreover, aquatic organisms are known to make widespread use of chemical information to inform their social behaviour, although we have a comparably poor understanding of how this is impacted by water acidification, especially their shoaling behaviour. Using a standard behavioural assay, we therefore investigated the impact of low water pH on the social interactions mediated by diet‐derived chemical cues in three‐spined sticklebacks (Gasterosteus aculeatus), by quantifying social behaviour in water that varied either experimentally or naturally in pH. In both cases, we predicted that association patterns would be disrupted by low pH conditions, as reduced pH has shown to interfere with the perception of chemical cues in other non‐social contexts. Consistent with this prediction, our results demonstrate that an acute, short‐term reduction in water pH caused a breakdown in the diet‐mediated social interaction patterns seen in more alkaline water, although, interestingly, the pattern of associations for fish tested in naturally acidic water was both more complex and in a direction that was precisely contrary to our predictions. Overall, the findings provide insights into the potential effects of an acute reduction in water pH on fish communication and social interaction patterns, which may have implication for various individual, group, population and community‐level processes.     

The effect of ostensive cues on dogs’ performance in a manipulative social learning task

In contrast to animal social learning (e.g. dogs learning from observing another dog), humans typically teach by attracting the attention of the learner. Also during the training of dogs, humans tend to attract their attention in a similar way. Here, we investigated dogs’ ability to learn both from a dog and a human demonstrator in a manipulative task, where the models demonstrated which part of a box to manipulate in order to get a food reward. We varied the communicative context both during the dog and during the human demonstration comparably: a second experimenter directed the attention of the subjects to the model (dog/human ostensive demonstration) or remained silent (dog/human non-ostensive demonstration). Moreover, we investigated whether the training level of the dogs (well-trained vs. untrained) affected how the dogs performed in the manipulative tasks after the different demonstrations.We found that better trained dogs showed significantly better problem solving abilities. They paid more attention to the human demonstration than to the dog model, whereas such a difference in attentiveness of the less trained dogs was not found. Despite slight differences in paying attention to the different demonstrators, the presence of human or the dog demonstrators exerted equally effectiveness on the test performance of the dogs. However, the effectiveness of the demonstrations was significantly reduced if ostensive cues were given during the demonstrations by a second experimenter. Analysis of attentiveness and activity of the observer dogs during the demonstrations indicates that the reason for this negative effect was a combination of distracted attention paid to the demonstration and a higher level of excitement in the ostensive than in the non-ostensive demonstrations.This study suggests that third party communication during demonstration attracts dogs’ attention to the communicator instead of paying close attention to the model. We suggest that precise timing and synchronization of attention-calling and demonstration is necessary to avoid this distracting effect.     

The effect of gonadal hormones and gender on anxiety and emotional learning

Disorders of anxiety and fear dysregulation are highly prevalent. These disorders affect women approximately 2 times more than they affect men, occur predominately during a woman's reproductive years, and are especially prevalent at times of hormonal flux. This implies that gender differences and sex steroids play a key role in the regulation of anxiety and fear. However, the underlying mechanism by which these factors regulate emotional states in either sex is still largely unknown. This review discusses animal studies describing sex-differences in and gonadal steroid effects on affect and emotional learning. The effects of gonadal hormones on the modulation of anxiety, with particular emphasis on progesterone's ability to reduce the responsiveness of female rats to corticotropin releasing factor and the sex-specific effect of testosterone in the reduction of anxiety in male rats, is discussed. In addition, gonadal hormone and gender modulation of emotional learning is considered and preliminary data are presented showing that estrogen (E2) disrupts fear learning in female rats, probably through the antagonistic effect of ERalpha and ERbeta activation.     

The effects of social context on the hormonal and behavioral responsiveness of human fathers

We tested first-time fathers with their 22-month old toddlers to determine whether social context variables such as pre-test absence from the child and presence of the mother affected physiological measures associated with paternal responsiveness. Heart rate and blood pressure readings as well as blood samples to determine prolactin, testosterone and cortisol levels were taken before and after the 30-min father–toddler interactions. Fathers were tested on a day when they were away from their child for several hours before testing (‘without-child’ day) and on another day where they remained with their child throughout the day (‘with-child’ day). Most measures decreased over the 30-min test period but relative decreases were context-dependent. Men maintained higher prolactin levels when they were away from their children longer before testing on the ‘without-child’ day. Cortisol levels decreased during both tests and they decreased more on the ‘with-child’ day for men who had spent more time alone with their toddler before the test. Heart-rate and diastolic (but not systolic) blood pressure decreased more on the ‘with-child’ day than on the ‘without-child’ day. Fathers' testosterone levels decreased when their partners were less involved in the interactions. Compared to men with high responsiveness ratings on both days, men whose responsiveness increased after being away from their child on the ‘without-child’ day maintained higher systolic blood pressure and had a greater decrease in testosterone levels. We conclude that context may be more important in determining fathers' physiological responses to child contact than has previously been appreciated, particularly for some individuals.     

The influence of predatory fish on mayfly drift: extrapolating from experiments to nature

1. A knowledge of how individual behaviour affects populations in nature is needed to understand many ecologically important processes, such as the dispersal of larval insects in streams. The influence of chemical cues from drift‐feeding fish on the drift dispersal of mayflies has been documented in small experimental channels (i.e. < 3 m), but their influence on dispersal in natural systems (e.g. 30 m stream reaches) is unclear. 2. Using surveys in 10 Rocky Mountain streams in Western Colorado we examined whether the effects of predatory brook trout (Salvelinus fontinalis) on mayfly drift, that were apparent in stream‐side channels, could also be detected in natural streams. 3. In channel experiments, the drift of Baetis bicaudatus (Baetidae) was more responsive to variation in the concentration of chemical cues from brook trout than that of another mayfly, Epeorus deceptivus (Heptageniidae). The rate of brook trout predation on drifting mayflies of both species in a 2‐m long observation tank was higher during the day (60–75%) but still measurable at night (5–10%). Epeorus individuals released into the water column were more vulnerable to trout predation by both day and night than were Baetis larvae treated similarly. 4. Drift of all mayfly taxa in five fishless streams was aperiodic, whereas their drift was nocturnal in five trout streams. The propensity of mayflies to drift was decreased during the day and increased during the night in trout streams compared with fishless streams. In contrast to the channel experiments, fish biomass and density did not alter the nocturnal nature nor magnitude of mayfly drift in natural streams. 5. In combination, these results indicate that mayflies respond to subtle differences in concentration of fish cues in experimental channels. However, temporal and spatial variation in fish cues available to mayflies in natural streams may have obscured our ability to detect responses at larger scales.     

The effects of CO2 and chronic cold exposure on fecundity of female Drosophila melanogaster

Carbon dioxide and chilling are sometimes used to immobilise insects for laboratory research. Both of these methods are known to have short-term effects on behaviour and physiology in Drosophila, but their long-term impacts are unknown. We exposed female D. melanogaster adults to high CO₂ concentrations (4 h at 18,000 ppm) and chronic cold (72 h at 4 °C). The carbon dioxide exposure increased chill coma recovery time, but did not result in changes in offspring number, sex ratio, or size. By contrast, the cold exposure resulted in fewer, smaller offspring, and resulted in a male-biased sex ratio compared to controls. There was no significant interaction between CO₂ and cold. We conclude that although caution must be used in choosing an immobilisation method, CO₂ appears to have less long-term impact than cold.