Solitary Conditions Research Articles

No evidence for the melanin desiccation hypothesis in a larval Lepidopteran

Water regulation is an important physiological challenge for insects due to their small body sizes and large surface area to volume ratios. Adaptations for decreasing cuticular water loss, the largest avenue of loss, are especially important. The melanin desiccation hypothesis states that melanin molecules in the cuticle may help prevent water loss, thus offering protection from desiccation. This hypothesis has much empirical support in Drosophila species, but remains mostly untested in other taxa, including Lepidoptera. Because melanin has many other important functions in insects, its potential role in desiccation prevention is not always clear. In this study we investigated the role of melanin in desiccation prevention in the white-lined Sphinx moth, Hyles lineata (Lepidoptera, Sphingidae), which shows high plasticity in the degree of melanin pigmentation during the late larval instars. We took advantage of this plasticity and used density treatments to induce a wide range of cuticular melanization; solitary conditions induced low melanin pigmentation while crowded conditions induced high melanin pigmentation. We tested whether more melanic larvae from the crowded treatment were better protected from desiccation in three relevant responses: i) total water loss over a desiccation period, ii) change in hemolymph osmolality over a desiccation period, and iii) evaporation rate of water through the cuticle. We did not find support for the melanin desiccation hypothesis in this species. Although treatment influenced total water loss, this effect did not occur via degree of melanization. Interestingly, this implies that crowding, which was used to induce high melanin phenotypes, may have other physiological effects that influence water regulation. There were no differences between treatments in cuticular evaporative water loss or change in hemolymph osmolality. However, we conclude that osmolality may not sufficiently reflect water loss in this case. This study emphasizes the context dependency of melanin’s role in desiccation prevention and the importance of considering how it may vary across taxa. In lepidopteran larvae that are constantly feeding phytophagous insects with soft cuticles, melanin may not be necessary for preventing cuticular water loss.

Active avoidance recruits the anterior cingulate cortex regardless of social context in male and female rats.

Actively avoiding danger is necessary for survival. Most research has focused on the behavioral and neurobiological processes when individuals avoid danger alone, under solitary conditions. Therefore, little is known about how social context affects active avoidance. Using a modified version of the platform-mediated avoidance task in rats, we investigated whether the presence of a social partner attenuates conditioned freezing and enhances avoidance learning compared to avoidance learned under solitary conditions. Rats spent a similar percentage of time avoiding during the tone under both conditions; however, rats trained under social conditions exhibited greater freezing during the tone as well as lower rates of darting and food seeking compared to solitary rats. Under solitary conditions, we observed higher levels of avoidance in females compared to males, which was not present in rats trained under social conditions. To gain greater mechanistic insight, we optogenetically inactivated glutamatergic projection neurons in the anterior cingulate cortex (ACC) following avoidance training. Photoinactivation of ACC neurons reduced expression of avoidance under social conditions both in the presence and absence of the partner. Under solitary conditions, photoinactivation of ACC delayed avoidance in males but blocked avoidance in females. Our findings suggest that avoidance is mediated by the ACC, regardless of social context, and may be dysfunctional in those suffering from trauma-related disorders. Furthermore, sex differences in prefrontal circuits mediating active avoidance warrant further investigation, given that females experience a higher risk of developing anxiety disorders.

Surface colonization by Flavobacterium johnsoniae promotes its survival in a model microbial community.

Microbial communities direct key environmental processes through multispecies interactions. Understanding these interactions is vital for manipulating microbiomes to promote health in human, environmental, and agricultural systems. However, microbiome complexity can hinder our understanding of the underlying mechanisms in microbial community interactions. As a first step toward unraveling these interactions, we explored the role of surface colonization in microbial community interactions using The Hitchhikers Of the Rhizosphere (THOR), a genetically tractable model community of three bacterial species, Flavobacterium johnsoniae, Pseudomonas koreensis, and Bacillus cereus. We identified F. johnsoniae genes important for surface colonization in solitary conditions and in the THOR community. Understanding the mechanisms that promote the success of bacteria in microbial communities brings us closer to targeted manipulations to achieve outcomes that benefit agriculture, the environment, and human health.

The effects of social context and opportunity cost on the behavioral economic value of cannabis.

Behavioral economics suggest that cannabis reinforcing value (cannabis demand) may be influenced by external, contextual factors such as the social reward that might accompany cannabis use and the presence of opportunity costs (e.g., a next-day responsibility that cannabis use might adversely impact). The present study examined the effect of social context and opportunity cost on cannabis demand and explored whether relations were moderated by cannabis use severity. Adults with past-week cannabis use recruited from Amazon's Mechanical Turk (N = 310; 53.5% female, 79.4% White) completed four purchase tasks, in which participants reported how much cannabis they would purchase across escalating prices, to index cannabis demand under varying contexts: (a) solitary, typical responsibilities; (b) social, typical responsibilities; (c) solitary, substantial responsibilities; and (d) social, substantial responsibilities. The presence of peers significantly increased demand intensity (consumption at zero price) and Omax (maximum expenditure) relative to the solitary conditions. Substantial responsibilities significantly decreased intensity, breakpoint (price at which consumption is fully suppressed), and Pmax (price at which maximum expenditure occurs) and increased elasticity (greater price sensitivity). Demand was most inelastic in the social, typical responsibilities condition relative to other conditions. Cannabis use severity was associated with less elastic demand in the solitary, typical responsibilities condition. Those with higher cannabis use severity reported larger differences in demand intensity and Omax between solitary and social conditions, and in demand elasticity between typical and substantial responsibility conditions. Results are consistent with previous research illustrating social and opportunity costs as determinants of cannabis use behavior. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Response of Cucumis sativus to Neighbors in a Species-Specific Manner

Plants exhibit various behaviors of growth and allocation that play an important role in plant performance and social interaction as they grow together. However, it is unclear how Cucumis sativus plants respond to different neighbors. Here, we performed 5 neighbor combinations with C. sativus as the focal species. The selected materials of C. sativus responded to neighbors and exhibited different behavior strategies in a species-specific manner. All competition treatments reduced the growth of C. sativus seedlings to a certain extent, but only the Eruca sativa neighbor treatment reached a significant level in total root length and shoot biomass. Compared with growing under solitary conditions, focal plants avoided, tended to and did not change their allocation to their nearby plants. The larger the biomass of their neighbors, the stronger the inhibition of the focal plants. In addition, no significant correlations between growth and allocation variables were found, suggesting that growth and allocation are two important aspects of C. sativus behavioral strategies. Our findings provide reference and support for agricultural production of C. sativus, but further research and practice are still needed.

Habituation and Behavioural Response of Confinement-Induced Anxiety Conditions in a Zebrafish Model

The zebrafish model is an emerging model for the study of the complex behavioural patterns noted in depression and neurological disorders. Confinement and memory loss are linked with cognition and mental health impairment, where confinement paradigms are assessed using other behavioural responses based on novel tanks or T tanks. Since zebrafish are exploratory animals, the impact during confinement cannot be evaluated using a novel tank or T tank. The present study investigates the response of the zebrafish to acute confinement and assesses its memory-based learning behaviour through parameters such as movement, swimming speed, and time spent inside the confined space. The movement and swimming speed of the fishes in confinement showed no significant difference. When confined inside a space, the fish showed their anxiety with erratic movements or bouts of freezing, which declined by 83%, during the six days of confinement and the escape time from the confinement space also decreased by 58%. The impact of anxiety, resulting in clockwise and counter-clockwise movement, also reduced after three days. Our results summarise that the decrease in anxiety can help the fish in habituating itself to a forced condition. This experiment on zebrafish behavioural biology is used to assess the cognitive behaviour against confinement, and it emphasizes the learning of behavioural adaptions under both crowded and solitary conditions.

Shifting thermal regimes influence competitive feeding and aggression dynamics of brook trout (Salvelinus fontinalis) and creek chub (Semotilus atromaculatus).

The natural distributions of freshwater fish species are limited by their thermal tolerances via physiological constraints and increased interspecific competition as temperatures shift toward the thermal optima of other syntopic species. Species may mediate stress from temperature change physiologically, behaviorally, or both; but these changes may compromise competitive advantages through effects on feeding and social behavior. In the Appalachian Mountains of North America, creek chub (Semotilus atromaculatus) are found in warm‐water and cold‐water streams and overlap in range with brook trout (Salvelinus fontinalis) across lower thermal maxima, where they compete for food and space. As stream temperatures continue to increase due to climate change, brook trout are under increasing thermal stress which may negatively affect their ability to compete with creek chub. To examine the influences of temperature on competitive interactions between these species, we observed feeding behavior, aggression, and habitat use differences at three temperatures approaching brook trout thermal maxima (18°C, 20°C, and 22°C) among dyad pairs for all combinations of species in experimental flow‐through tanks. We also examined feeding and habitat use of both species under solitary conditions. We found as temperature increased, feeding and aggression of brook trout were significantly reduced in the presence of creek chub. Creek chub pairs were more likely to occupy benthic areas and refugia while brook trout pairs used surface water more. Space use patterns significantly changed by pairing treatment. Aggression and space use shifts allowed increased exploitative and interference competition from creek chub when paired with brook trout that was not present in conspecific pairs. The decreased dominance of a top predator may lead to diverse impacts on stream community dynamics with implications for the future range restriction of brook trout and demonstrate possible mechanisms to facilitate competitive advantages of warm water generalist species under thermal stress.

Larval Crowding Did Not Enhance Adult Migration Propensity in Spodoptera frugiperda.

Simple SummaryThe fall armyworm, Spodoptera frugiperda (J. E. Smith), is a typical invasive migratory pest with a strong reproductive capacity, which has caused serious damage to crops. Larvae of S. frugiperda exhibit high levels of cannibalism associated with larval crowding. However, the response of S. frugiperda adults to such stress remains unclear. In this study, we investigated the effects of larval density on flight and reproductive parameters of S. frugiperda adults. We found that S. frugiperda reared under high-larval density conditions exhibited lower pupal and body weights, weaker flight and reproductive capacities than those reared as solitary larvae. This result was different from that of many migratory insects, where larval crowding enhanced migratory propensity of subsequent adults. In contrast, high-larval density conditions did not increase adult migration propensity in S. frugiperda. These findings enhance our understanding of migratory and reproductive behaviors of S. frugiperda in response to larval density.Reproduction and flight are two major adaptive strategies to cope with environmental stress in migratory insects. However, research on density-mediated flight and reproduction in the global migratory agricultural pest Spodoptera frugiperda is lacking. In this study, flight and reproductive performances in response to larval crowding were investigated in S. frugiperda. We found that larval crowding significantly reduced the pupal and body weights of S. frugiperda. Adults reared under the highest density of 30 larvae/jar had the minimum wing expansion, which was significantly smaller than that of larvae reared under solitary conditions. Larval crowding also significantly increased the pre-oviposition period (POP) and period of first oviposition (PFO) but decreased the lifetime fecundity, flight duration and flight distance. Our results showed that S. frugiperda reared under solitary conditions exhibited higher pupal and body weights and stronger reproductive and flight capacities than those reared under high-density conditions. Larval crowding did not enhance the migration propensity in S. frugiperda adults. In conclusion, larval crowding may not be a major factor affecting FAW migration due to high levels of cannibalism. These findings provide new insights into the population dynamics of S. frugiperda under larval crowding conditions.

Foreword: Early Printed Responses to the Closing of London's Playhouses, 1641–43

ForewordEarly Printed Responses to the Closing of London's Playhouses, 1641–43 Christopher Highley (bio) in one of early modern england's most unlikely volte-faces, the notorious antitheatricalist William Prynne penned a tract defending the public stage. Published in 1649, Mr William Prynn His Defence of Stage-Plays reversed the same author's landmark denunciation of theater in his Histrio-mastix. The Players Scourge, or, Actors Tragædie (1633).1 Prynne's reference in the earlier work to "Women-Actors, notorious whores"2 was widely seen as glancing at Henrietta Maria's participation in court plays; as a result, he was quickly condemned by the court of Star Chamber to stand in the pillory and have his ears "trimmed." Prynne's outrage in the 1630s at what he considered the growing authoritarianism of the king, and the threats from bishops and a Catholic queen, had turned by 1649 into alarm at "a Tyrannical, abominable, lewd, schismatical [and] hæretical Army"3 that not only held the king captive but also controlled Parliament following Pride's Purge of its moderate members in December 1648. The specific occasion for Prynne's defense of the stage was the removal of the "Players from their Houses"4 by groups of overzealous soldiers. For [End Page 11] Prynne, this was a violation of the king's prerogative, an attempt to silence Charles I's allies in the theater and to deny him a form of royal solace. From the beginning of hostilities in 1642, Prynne had upheld royal authority and worked for a reconciliation of king and commons in defiance of more radical voices, many of which emerged from the army. In retrospect, Prynne regretted his earlier comparison of Charles I to Nero for "loving of Stage-playes," as well as his attack on Henrietta Maria "with the bitter and cruell words of whore and strumpet" for performing in plays. He now recognized that "Playes are lawfull things, and are to be allowed as recreations for honest men." Prynne claimed that when he wrote Histrio-mastix, he was unaware of the nature of the plays "as were written and acted in England of late, for the Recreation of our most gracious King and Queen, and many of their best friends."5 Although Prynne remained hostile to "lewd" plays, he recognized that "honest Playes may be tolerated," and he even disavowed his earlier objections to cross-dressing on stage.6 By 1649, then, Prynne had come to the startling conclusion that, as Sir William Davenant later put it, "they that would have no King, would have no Play."7 Mr William Prynn His Defence of Stage-Plays is one of a few printed defenses of the stage in the years between 1642 and 1660. In this essay, I examine defenses of the stage in the years immediately after the playhouses were shut, a period when we might expect a flurry of protests to this unprecedented parliamentary action. Here again, defenses of the stage are rare, although The Actors Remonstrance, or Complaint: For the silencing of their profession is one notable and well-known exception (January 1643). In particular, I want to suggest that in order to gauge resistance to the closure, we need to look beyond formal defenses of the stage. I will argue that the republication in 1643 of Thomas Randolph's play The Muses Looking-Glasse is part of a counteroffensive against the ban on plays that also reveals something about the role of local politics in motivating the parliamentary prohibition.8 There are several possible reasons why no printed defenses of playing appeared before The Actors Remonstrance of January 1643. This absence is all the stranger when [End Page 12] we recall that a tract called The Stage-Players Complaint, published in 1641 shortly before the official closure, offered a precedent and template of sorts for theater supporters and personnel. The Stage-Players Complaint is a "pleasant Dialogue between Cane of the Fortune, and Reed of the Friers" in which the two actors lament "the sad and solitary conditions for want of Imployment . . . [during] this heavie and Contagious time of the Plague in London." Whereas Cane, the pessimist, thinks that public...

Intraspecific variation in longevity of Drosophila prolongata (Diptera: Drosophilidae) under solitary and group conditions

AbstractConsiderable variations in behavior and physiology exist among sexes and strains of species. The amount and allocation of energy resources can affect the health and survival of individuals. If an individual devotes a large amount of energy to interact with other conspecifics, the resources may become too scarce to maintain their physical condition, which could reduce longevity. In this study, I examined the interactive effects of sex, strain, and the presence of conspecifics on adult longevity using four strains of Drosophila prolongata. This species shows a large intraspecific variation in behavior and morphology among isofemale strains. Under solitary conditions, longevity was significantly different among strains for both sexes. The effects of same‐sex conspecifics on adult longevity were also highly variable between the sexes and among strains. When exposed to conspecifics, the longevity of males of a hyper‐aggressive strain was more notably decreased than that of females of the same strain or either sex of other less aggressive strains. These results indicate that differences in the balance of costs and benefits of social interactions lead to differences in adult longevity under group conditions between the sexes and among strains within the same species.

Shrunken Social Brains? A Minimal Model of the Role of Social Interaction in Neural Complexity.

The social brain hypothesis proposes that enlarged brains have evolved in response to the increasing cognitive demands that complex social life in larger groups places on primates and other mammals. However, this reasoning can be challenged by evidence that brain size has decreased in the evolutionary transitions from solitary to social larger groups in the case of Neolithic humans and some eusocial insects. Different hypotheses can be identified in the literature to explain this reduction in brain size. We evaluate some of them from the perspective of recent approaches to cognitive science, which support the idea that the basis of cognition can span over brain, body, and environment. Here we show through a minimal cognitive model using an evolutionary robotics methodology that the neural complexity, in terms of neural entropy and degrees of freedom of neural activity, of smaller-brained agents evolved in social interaction is comparable to the neural complexity of larger-brained agents evolved in solitary conditions. The nonlinear time series analysis of agents' neural activity reveals that the decoupled smaller neural network is intrinsically lower dimensional than the decoupled larger neural network. However, when smaller-brained agents are interacting, their actual neural complexity goes beyond its intrinsic limits achieving results comparable to those obtained by larger-brained solitary agents. This suggests that the smaller-brained agents are able to enhance their neural complexity through social interaction, thereby offsetting the reduced brain size.

Substrate-borne vibration and sound production by the land hermit crab Coenobita compressus during social interactions

Despite the diversity of sound production in crustacea, sounds produced by the land hermit crabs (Coenobitidae) are not well understood. Here, sound and substrate-borne vibration production by the tropical species Coenobita compressus was characterized in relation to shell architecture and social context. Sound production rates were compared between group and solitary conditions. Chirps were measurable in the air (peak frequency 800-8400 Hz) and within the sediment (40-1120 Hz). On average, chirp pulses were 0.08 s, spaced 0.41-0.92 s apart, and had trains composed of 4-6 pulses. There were significant correlations between the shell architecture and chirp vibroacoustics. Notably, a correlation between the substrate-borne peak frequency and shell wall thickness was found, indicating that the shell remodeling process which crabs undertake (shell wall thinning) impacts the vibroacoustics of the chirps. Chirp production was significantly linked to sociality during increased individual proximity and shell contests; hence, the function is hypothesized to be intraspecific communication relative to personal space and defense. Although there have been anecdotal observations of chirping in the Coenobitidae, this paper provides a full characterization of C. compressus, which produces chirps in two sensory modes, indicating the potential of being a seismic signaler.

Poor mental health and uptake of disability benefits

Background with rationale Disability related social security benefits were introduced to help off-set the additional costs incurred by people with disability and to help them better integrate into society. However, there are concerns that not everyone with a disability is receiving the benefits to which they are entitled.
 Aim To undertake a record-linkage study to compare levels of benefit uptake Disability Living Allowance (DLA) according to disability type and severity as reported in the Northern Ireland 2011 Census.
 Data/methods The linked data sources were the 2011 census records and all DLA records for calendar year 2011. The main comparison was of DLA receipt amongst those reporting chronic mobility difficulties (MD) and those with chronic poor mental health (PMH) (both yes/no) with the addition of limitation of daily activities (none, a little, a lot), which was used as a proxy for severity and DLA eligibility.
 Results Most people with disability had multiple disabilities but here the analysis is primarily amongst people with solitary conditions to avoid potential confounding. Approximately 20,000 people in the population reported either only MD or only PMH, though 68% of MD had their daily activities limited a lot compared to 55% of those with PMH. Overall, 71.8% of people with MD and daily activities limited a lot were on DLA compared to only 57.5% of similarly affected people with PMH the relative odds ratio being (OR 0.53 95%CI 0.50, 0.56).
 Conclusion It appears that people with poor mental health are less likely to receive disability benefits compared to those with mobility problems. This may be because they are less able to prove their eligibility for these benefits under the current assessment processes.

Ant activity-rest rhythms vary with age and interaction frequencies of workers

Social insect colonies are highly organized systems, where communication among nestmates (i.e., social interactions) has a pivotal function for colonial organization. In order to further the understanding of social organization, the chronobiological system of social insect species, particularly their circadian rhythm, has recently attracted much attention. However, gaps still remain in our understanding of how individual active/rest rhythms are governed in various social contexts. In this study, we investigate the effects of worker-worker interactions on circadian activity rhythms, using the monomorphic ant, Diacamma sp. Continuous tracking of solitary ants elucidated circadian activity rhythms, both in young and old workers ( 70 days after eclosion, respectively). The color tag–based automatic tracking of multiple workers revealed that young-old interactions reduced circadian rhythmic activities in both young and old workers, whereas young workers retained active/rest rhythms under young-young worker interactions. Together with the analyses of worker-worker interaction frequencies, we conclude that interactions between workers in different age groups (i.e., workers with different tasks) function as different cues to alter worker active/rest patterns. We discuss the potential roles of worker-worker interactions on the chronobiological organization of the ant society. In social animals, how individual behavioral rhythms are governed by social interactions is a fundamental question towards the mechanistic understanding of complex biological systems. Using an image-based tracking system, we composed artificial ant worker groups consisting of different functions (i.e., young nurses and old foragers) and investigated whether the age composition and the resulting interactions had an effect on the active/rest rhythms of individual workers, and of the whole group. In solitary conditions, both young and old workers showed circadian activity; however, when grouped with workers from different age groups, both young and old workers turned to show weak circadian rhythmicity or around-the-clock activity. Our results suggest that even simple social cues (i.e., frequency of contact with young and old workers) could alter worker activity patterns. To our knowledge, this is the first evidence showing that specific worker-worker interaction induces weakly rhythmic and/or arrhythmic states.

Four types of vibration behaviors in a mole cricket

Vibrational communication is known in some subterranean insects. Except for their use in sexual signaling, vibration behavior has rarely been reported. We report here four distinct types of substrate-based vibration behaviors in the mole cricket, Gryllotalpa orientalis, which are not associated with sexual signaling because of the occurrence of these behaviors in nymphs: (1) scraping with the forelegs; (2) foreleg taps (tapping with the forelegs); (3) palpal taps (tapping with the maxillary palpi); and (4) tremulation (back-and-forth movement of the whole body). Scraping is hypothesized to be used for the inspection of borrows. Foreleg taps are possibly informing nearby individuals of their presence, because it is never observed in solitary conditions. Palpal taps are rarely observed and its function is unknown. Tremulation is possibly related to avoidance of conspecific individual approaching and touching. The combination of the four vibration behaviors in the mole cricket may be unique among insects.

Sociality Affects REM Sleep Episode Duration Under Controlled Laboratory Conditions in the Rock Hyrax, Procavia capensis.

The rock hyrax, Procavia capensis, is a highly social, diurnal mammal. In the current study several physiologically measurable parameters of sleep, as well as the accompanying behavior, were recorded continuously from five rock hyraxes, for 72 h under solitary (experimental animal alone in the recording chamber), and social conditions (experimental animal with 1 or 2 additional, non-implanted animals in the recording chamber). The results revealed no significant differences between solitary and social conditions for total sleep times, number of episodes, episode duration or slow wave activity (SWA) for all states examined. The only significant difference observed between social and solitary conditions was the average duration of rapid eye movement (REM) sleep episodes. REM sleep episode duration was on average 20 s and 40 s longer under social conditions daily and during the dark period, respectively. It is hypothesized that the increase in REM sleep episode duration under social conditions could possibly be attributed to improved thermoregulation strategies, however considering the limited sample size and design of the current study further investigations are needed to confirm this finding. Whether the conclusions and the observations made in this study can be generalized to all naturally socially sleeping mammals remains an open question.

Social Interaction in the Art of Acting: Forms and Phases

Abstract Creativity is here construed as an activity taking place in phases over time, one everywhere imbued with the social, whether the creator does much of the work alone as in fiction writing or with others where the creation itself is collaborative such as jazz improvisation. This paper considers the creation of theatrical roles, a domain in which some phases of the activity take place under solitary conditions and others involve face-to-face interaction. Grounded in a research review, the paper examines the phases of the creative process in scripted acting. It notes the kinds of social relationships in each, the roles of intention, reflection and spontaneity, the forms of interaction in terms of Schütz’s multiple realities and the ways in which those realities interact.

The effect of social feedback and social context on subjective affective responses to music

Previous research suggests that music listening influences individual affective responses. However, there is scant research examining how social factors might interact to influence subjective affective responses to music. This study investigates the effects of social feedback and social context on subjective affective responses to music. In a between-subjects experiment, participants (N = 120) listened to unfamiliar music from various genres either alone or with another participant. For each musical example, participants received positive and negative social feedback, derived from a pilot study, or factual album information. After listening to each musical example and reading the provided social feedback or album information, participants reported their subjective valence, arousal, subjective affective intensity, concentration, music liking and familiarity. There was no effect of social feedback on subjective valence responses. Positive and negative social feedback influenced subjective arousal responses positively and negatively, respectively. Subjective affective intensity was not influenced by social feedback. Social context did not influence subjective affective responses to the musical examples. Lower concentration was reported in social listening conditions compared to solitary conditions. Greater familiarity with the musical examples was reported when social feedback was provided. The findings of the present study suggest that social feedback can influence particular affective responses to, and familiarity with, music. However, social listening might reduce concentration, especially in the absence of social feedback. These findings highlight issues warranting consideration for how music is affectively experienced in everyday life, as well as purposely used in varied contexts.

The Experimenter Expectancy Effect: An Inevitable Component of School Science?

A medium-scale quantitative study (n = 90) found that 10–11-year-old pupils dealt with theory and evidence in notably different ways, depending on how the same science practical task was delivered. Under the auspices of a 2×2 part-randomised and part-quasi experimental design, pupils were asked to complete a brief, apparently simple task involving scientific measurement. One half of the sample carried out the task in a naturalistic whole class context; the other half worked as lone experimenters in solitary conditions where accuracy of measurement was promoted. In the whole class setting pupils exposed to an illustrative lesson displayed behaviour indicative of experimenter expectancy, tending to differentiate theory and evidence to a lesser degree than pupils who experienced an enquiry lesson. In addition, during the illustrative lesson many of the pupils were biased towards their theories in ways that lay well beyond those intended by the research design. On the other hand, in the solitary setting pupils performed equally well with both illustrative and enquiry treatments. Implications are discussed in the light of the problems of excessive pupil theory/data-ladenness. Finally, the advantages and disadvantages of exposing young learners to more authentic versions of professional science are considered.

Common marmosets show social plasticity and group-level similarity in personality.

The social environment influences animal personality on evolutionary and immediate time scales. However, studies of animal personality rarely assess the effects of the social environment, particularly in species that live in stable groups with individualized relationships. We assessed personality experimentally in 17 individuals of the common marmoset, living in four groups. We found their personality to be considerably modified by the social environment. Marmosets exhibited relatively high plasticity in their behaviour, and showed ‘group-personality’, i.e. group-level similarity in the personality traits. In exploratory behaviour this was maintained only in the social environment but not when individuals were tested alone, suggesting that exploration tendency is subjected to social facilitation. Boldness, in contrast, showed higher consistency across the social and solitary conditions, and the group-level similarity in trait scores was sustained also outside of the immediate social environment. The ‘group-personality’ was not due to genetic relatedness, supporting that it was produced by social effects. We hypothesize that ‘group-personality’ may be adaptive for highly cooperative animals through facilitating cooperation among individuals with similar behavioural tendency.