Mirror-mediated responses of California scrub jays (Aphelocoma californica) during a caching task and the mark test

Mirror self-recognition, as an index of self-awareness, has been proposed as a precursor for more complex social cognitive abilities, such as prosocial reasoning and cooperative decision-making. Indeed, evidence for mirror self-recognition has been shown for animals possessing complex social cognitive abilities such as great apes, dolphins, elephants and corvids. California scrub jays (Aphelocoma californica) have provided strong evidence that non-human animals are capable of mental state attribution. For instance, scrub jays are reported to use their experience stealing the food of others to infer that other birds may similarly intend to steal from them. If a concept of “self” is required for such complex social cognitive abilities, then scrub jays might be expected to show mirror self-recognition. Thus, we examined whether California scrub jays are capable of mirror self-recognition using two experimental contexts: a caching task and the mark test. During the caching task, we compared the extent to which scrub jays protected their food after caching alone, in the presence of a conspecific and in the presence of a mirror. The birds did not engage in more cache protection behaviours with a mirror present than when caching alone, suggesting scrub jays may have recognized their reflection and so did not expect cache theft. Alternative explanations for this behaviour are also discussed. During the mark test, the scrub jays were surreptitiously marked with a red or plumage-coloured control sticker. The scrub jays showed no evidence of mirror self-recognition during the mark test, as the birds did not preferentially attempt to remove the red mark in the presence of a mirror. Together, the results provide mixed evidence of the mirror self-recognition abilities of California scrub jays. We highlight the need to develop alternative approaches for evaluating mirror self-recognition in non-human animals to better understand its relationship with complex social cognition.     

The Social Facilitation of Drinking: What is Facilitated,and Who is Affected?

The effect of a drinking companion on conspecifics was investigated using domestic hens (Callus gallus domesticus). The two aims of the investigation were firstly to see whether drinking is sensitive to social facilitation, and if so, to see whether it follows the same pattern as that of feeding, i.e. whether it acts primarily on the drinking behaviour rather than the amount ingested. The second aim was to see whether differences in how influenced the birds were by a drinking companion correlated with one or more social or non-social traits. Social facilitation was measured by comparing the intake and number of ‘head-ups’ (i.e. swallowing) of an individual in the presence of a thirsty or non-thirsty companion. The traits measured were as follows: the rank within each pair, social dependence/fear, reaction to a novel object, reaction in a feeding-inhibition test, and finally weight (as a possible index of the overall rank of the birds in the group). Social facilitation of drinking occurs but acts primarily on drinking behaviour (number of ‘head ups’); birds do not swallow as much per ‘head up’ as when they themselves are thirsty. The lightest (possibly most subdominant) birds were also the ones most influenced by the drinking conspecific. Furthermore, the heaviest (possibly most dominant) individuals were the ones with the shortest social distance and the longest latency in approaching a novel object. This meant that the birds that were most influenced by a drinking companion were also the individuals that were least fearful and showed the highest degree of exploration.     

Contingency checking and self-directed behaviors in giant manta rays: Do elasmobranchs have self-awareness?

Elaborate cognitive skills arose independently in different taxonomic groups. Self-recognition is conventionally identified by the understanding that one’s own mirror reflection does not represent another individual but oneself, which has never been proven in any elasmobranch species to date. Manta rays have a high encephalization quotient, similar to those species that have passed the mirror self-recognition test, and possess the largest brain of all fish species. In this study, mirror exposure experiments were conducted on two captive giant manta rays to document their response to their mirror image. The manta rays did not show signs of social interaction with their mirror image. However, frequent unusual and repetitive movements in front of the mirror suggested contingency checking; in addition, unusual self-directed behaviors could be identified when the manta rays were exposed to the mirror. The present study shows evidence for behavioral responses to a mirror that are prerequisite of self-awareness and which has been used to confirm self-recognition in apes.     

Monkeys with mirrors: Some questions for primate psychology

Monkeys do not appear to recognize themselves in mirrors but display social responses to the reflection. This article comprehensively reviews the literature concerning monkeys’ reactions to mirrors, describing the interest shown in reflections, the reinforcing effects of mirror-image stimulation, the social responses of the monkeys, their interpretation of objects reflected in a mirror, and their performance in tests of self-recognition. In all cases limitations of the methods employed restrict conclusions about the monkeys’ behavior. Detailed behavioral observations coupled with comparisons of the psychological properties of mirrors with those of other stimuli promise to reveal more useful information about cognitive mechanisms and abilities of monkeys and other primates.     

Mirror-image reactions in a tool-using,adult male Macaca tonkeana

This study examined reactions to mirror-image stimulation in a wild- reared adult male monkey (Macaca tonkeana) which had spontaneously developed a form of tool-use, namely the use of plant stems to reach mucus inside the nose. Initial intense social responsiveness to the mirror was followed by habituation, although some social responding persisted. Mirror- induced social facilitation of drinking was demonstrated, the first record of such an effect in a nonhuman primate. Rather than enhancing the subject's tool-using activity, the presence of the mirror disrupted tool-use. Finally, an objective test for the presence of self-recognition failed to obtain any evidence of self-recognition in the subject, lending support to the view that the capacity for self-recognition may be lacking in monkeys.     

Social Control and Physiological Cost of Cheating in Status Signalling Male House Sparrows (Passer domesticus)

Flock-forming passerines often use plumage characteristics to signal their social dominance. While the benefits to signal dominance seem obvious, costs associated with status signalling are ambiguous. The social control hypothesis predicts that individuals of high social status – with large badges – are involved in more social interactions with individuals of similar badge size. Cheaters are therefore exposed to increased risk of fighting with high quality individuals and the costs associated with enhanced fights with dominant males are supposed to outweigh the benefits of cheating. We tested the social control hypothesis in male house sparrows ( Passer domesticus ), by observing social interactions in captive flocks and determining dominance relationships. Two low status individuals within each flock had the size of their badge experimentally increased and the interactions involving experimental and control birds were recorded. We also assessed the potential physiological cost of cheating in terms of enhanced levels of the stress hormone, corticosterone. Dominance was significantly positively correlated with badge size, but not with other morphological traits. We found little support for the social control hypothesis. Birds did not have significantly more interactions with individuals of similar badge size, before the manipulation. Similarly, after the experimental increase in badge size, experimental birds did not tend to have more encounters with large-badged males. Experimental birds with enlarged badges won more fights compared with prior to the manipulation, suggesting that badge size is used as a signal of social dominance even in small and stable flocks. Finally, corticosterone levels in the blood did not increase significantly after the manipulation of badge size, suggesting that there is no measurable cost, resulting from stress, in cheaters.     

Mirror reactions in a zoo colony of Cebus monkeys

The extensive research investigating the reactions of a number of species of nonhuman primates to their mirror images has revealed that monkeys have never been observed to react with self-directed behaviors, as have some species of higher apes. The intermittent exposure of captive Cebus monkeys to a mirror over a 5-week period produced species-specific social reactions to the mirror, supporting the suggestion that at least in some instances the monkeys were viewing their mirror image as a conspecific. The variability in the duration and expression of mirror-directed behaviors observed in the study appeared to be related to the age and past experience of the monkeys. The duration of mirror viewing of subadults was over twice that of the adults, while the young, hand-reared animals exhibited more manipulative and fewer social behaviors than did the young animals raised in the zoo. The average viewing time of the zoo colony decreased substantially over the course of the study but the monkeys were still spending an appreciable time at the mirror after 5 weeks.     

Mirror-Directed Social Behaviors of Garnett's Greater Bush Baby (Otolemur garnettii)

Many diurnal anthropoid species direct social behaviors toward their own mirror-image as though viewing a conspecific. To determine whether a nocturnal prosimian species would behave similarly, we videotaped social responses of 45 Garnett's greater bush babies (Otolemur garnettii) observing mirror-images for the first time, scored them for frequency and duration, and compared them with the same behaviors directed elsewhere in the test apparatus. Males scentmarked more than females did, principally with the hindfoot, and most when in immediate proximity to the mirror. Bush babies displayed bipedal posture and threat gestures when oriented directly toward a mirror from a near position. Orientation toward the mirror also increased the frequency of arched-back postures; however, this behavior was not contingent on proximity to the mirror or visibility of the mirror-image. The differential expression of specific behaviors toward mirror-images by male and female bush babies supports the view that this nocturnal prosimian, thought to be dependent on olfaction and audition for communication, is capable of specific recognition by visual cues alone.     

The role of early life experience and species differences in alcohol intake in microtine rodents

Social relationships have important effects on alcohol drinking. There are conflicting reports, however, about whether early-life family structure plays an important role in moderating alcohol use in humans. We have previously modeled social facilitation of alcohol drinking in peers in socially monogamous prairie voles. We have also modeled the effects of family structure on the development of adult social and emotional behaviors. Here we assessed whether alcohol intake would differ in prairie voles reared by both parents compared to those reared by a single mother. We also assessed whether meadow voles, a closely related species that do not form lasting reproductive partnerships, would differ in alcohol drinking or in the effect of social influence on drinking. Prairie voles were reared either bi-parentally (BP) or by a single mother (SM). BP- and SM-reared adult prairie voles and BP-reared adult meadow voles were given limited access to a choice between alcohol (10%) and water over four days and assessed for drinking behavior in social and non-social drinking environments. While alcohol preference was not different between species, meadow voles drank significantly lower doses than prairie voles. Meadow voles also had significantly higher blood ethanol concentrations than prairie voles after receiving the same dose, suggesting differences in ethanol metabolism. Both species, regardless of rearing condition, consumed more alcohol in the social drinking condition than the non-social condition. Early life family structure did not significantly affect any measure. Greater drinking in the social condition indicates that alcohol intake is influenced similarly in both species by the presence of a peer. While the ability of prairie voles to model humans may be limited, the lack of differences in alcohol drinking in BP- and SM-reared prairie voles lends biological support to human studies demonstrating no effect of single-parenting on alcohol abuse.     

Absence of social facilitation of courtship in the wolf spider, Schizocosa ocreata (Hentz) (Araneae: Lycosidae)

Males of many animal species are reproductively limited by the difficulty and time costs of finding mates. Males of such species should be selected to take advantage of any cues that might reveal the location of prospective mates. Cues to female location are not restricted to those produced by females, but might also include the highly apparent courtship displays of males that have already found a female. By “eavesdropping” on these courting rivals, initiating sexual displays when courting rivals are detected (i.e., social facilitation of displays); males might effectively exploit the mate-searching efforts of their rivals. We tested the possibility that male Schizocosa ocreata wolf spiders exhibit social facilitation of courtship behaviors using a combination of live behavioral trials and video playback with single stimulus presentations. When exposed to visual cues from another male, male S. ocreata can discern the presence of another individual whether that individual is courting or not. However, we found no evidence of social facilitation of courtship or chemoexploratory behaviors in response to seismic or visual cues presented in isolation or combined. While complex, multimodal, male courtship signals are important in mate choice by female S. ocreata, males do not appear to use these cues to socially facilitate their own courtship.     

Mirror agnosia.

Normal people rarely confuse the mirror image of an object with a real object so long as they realize they are looking into a mirror. We report a new neurological sign, ''mirror agnosia'', following right parietal lesions in which this ability is severely compromised. We studied four right hemisphere stroke patients who had left visual field ''neglect''. i.e. they were indifferent to objects in their left visual field even though they were not blind. We then placed a vertical parasagittal mirror on each patients'' right so that they could clearly see the reflection of objects placed in the (neglected) visual field. When shown a candy or pen on their left, the patients kept banging their hand into the mirror or groped behind it attempting to grab the reflection; they did not reach for the real object on the left, even though they were mentally quite lucid and knew they were looking into a mirror. Remarkably, all four patients kept complaining that the object was ''in the mirror'', ''outside my reach'' or ''behind the mirror''. Thus, even the patients'' ability to make simple logical inferences about mirrors has been selectively warped to accommodate the strange new sensory world that they now inhabit. The finding may have implications for understanding how the brain creates representations of mirror reflections.     

Mirror responses in a group of Miopithecus talapoin

Studies of non-human primate self-recognition in mirrors demonstrate variation both within and between species. This study applied a rigorous methodology that took into account habituation of subjects to the mirror as an object and to the experimental situation. The species observed in our study was Miopithecus talapoin, which has been little studied in the wild or in captivity. Although this species shows several interesting characteristics, including complex social organisation and a high encephalization index, the talapoin monkeys in the study did not pass the mark test; however, they showed a prerequisite for self-recognition, namely comparing their body parts to the image of these in the mirror.     

No Plastic Responses to Experimental Manipulation of Sperm Competition per se in a Free‐Living Flatworm

In the absence of sperm competition evolutionary theory predicts low mating rates and low ejaculate expenditure per mating, and sex allocation theory for simultaneous hermaphrodites predicts a strongly female‐biased sex allocation. In the presence of sperm competition a shift towards a more male‐biased sex allocation and a higher ejaculate expenditure are predicted. The free‐living flatworm Macrostomum lignano has been shown to respond plastically in mating rate, testis size, and sperm transfer to manipulation of the social group size, a proxy of the strength of sperm competition. However, manipulation of social group size may manipulate not only sperm competition, but also other factors, such as food supply and metabolite concentration. In this study we therefore manipulated sperm competition per se by repeatedly exposing individuals to partners that have either mated with rivals or not, while keeping the social group size constant. Our results suggest that M. lignano does not have the ability to detect sperm competition per se, as worms experimentally exposed to the presence or absence of sperm competition did not differ in sex allocation, sperm transfer or mating behavior. A response to our manipulation would have required individual recognition, the ability to detect self‐referencing tags, or tags or traces left by rivals on or in the mating partners. We first discuss the possibility that highly efficient sperm displacement may have decreased the difference between the treatment groups and then propose three alternative cues that may allow M. lignano to respond plastically to the social group size manipulation used in earlier studies: assessment of the mating rate, chemical cues, or tactile cues.     

Mirror inspection varies with age and tool-using ability in tufted capuchin monkeys (Cebus apella)

We examined mirror inspection in tufted capuchin monkeys (Cebus apella). Capuchins were presented with a non-reflective surface for 30 minutes and then a mirror for 3 hours. Inspection of the non-reflective surface did not vary significantly as a function of tool-using ability, age, or sex. Mirror inspection was lowest in older animals, and was greater in animals that used tools than in animals that did not use tools. Mirror-aided self-inspection was not observed. These results indicate that mirror inspection varies with age and tool-using ability in tufted capuchin monkeys. We hypothesize that psychological capacities associated with mirror inspection correspond with those related to the use of tools, and that these capacities facilitate the emergence of self-recognition in some primate species.     

Infant stumptailed macaques reared with mirrors or peers: Social responsiveness,attachment, and adjustment

Comparisons of activity toward mirrors and peers in infant macaques being reared with one of these stimuli as the primary rearing partner revealed markedly greater social responsiveness to a fully accessible cagemate than to one's own reflection. Measures of exploration, aggression, and especially play all revealed the cagemate to be the more potent social stimulus. Mirror-reared infants given additional experience of a live peer behind a transparent partition were less responsive to the mirror than were infants with no social stimulation other than a mirror. In contrast, cagemate-directed behavior of peer-reared infants was not seriously affected by additional exposure to a mirror. A fully accessible peer also elicited more social responding than a peer behind a transparent partition, and infants with experience of both a live cagemate and mirrors were generally more responsive toward the former. Greater agitation in peer-reared than in mirror-reared stumptailed monkeys during separations from their rearing partners suggests that exposure to the physically accessible partner led to stronger attachments. Infants reacted positively to a moderately unfamiliar environment but showed behavioral disruption when placed in a very unfamiliar environment. Disruption was especially evident in peer-reared infants, in which exposure to the unfamiliar environment was compounded with the absence of the attachment figure. Mirror-rearing appeared to reduce the tendency toward ‘isolation syndrome’ behaviors compared to alone-rearing, and these behaviors appear to be less common in stumptailed than in rhesus macaques.     

The responses of bonobos (Pan paniscus) to their mirror images: Evidence of selfrecognition

This research examined the responses of bonobos (Pan paniscus) to their mirror images. Nine bonobos were presented alternately with the reflective and non-reflective sides of a mirror. The apes exhibited considerable interest in the mirror, and immature animals exhibited higher frequencies of contingent action and inactive looking than did adults. four animals used the mirror to inspect parts of their bodies that were otherwise not visible to them, indicating that bonobos are capable of self-recognition.     

Social facilitation in a troop of Guinea Baboons (Papio papio) living in an enclosure

A method is described of assessing whether or not social facilitation occurred in a troop of Guinea Baboons (Papio papio) living in an enclosure. The method did not involve the removal of individuals from the troop.The study revealed an interaction between social facilitation and the quality of social relationship involved; affiliative relationships enhanced the social facilitation of leaving an experimental zone. The theoretical implications of this finding are discussed.The method also disclosed an anomaly of learning in a group: making mistakes during reversals of a discrimination problem was also subject to social facilitation. This finding corroborates Zajonc's report (1967) of several results on social facilitation of errors.     

Mark tests for mirror self-recognition in capuchin monkeys (Cebus apella) trained to touch marks

In Experiment 1, three capuchin monkeys (Cebus apella) were exposed to a mirror in their home cage for 3 days and then given food treats for touching orange marks located on the surface of an experimental chamber. Following training, a mirror was added to the chamber to see if the monkeys would use it to guide non-reinforced contacts with an orange mark on their foreheads that was only visible as a mirror reflection (mark test). Two monkeys touched the head-mark more often with the mirror present than absent, but no mark touches were emitted while looking at the mirror. In Experiment 2, the monkeys were rewarded for touching orange marks on their bodies that were directly visible, followed by another head-mark test. Again, two monkeys touched the mark more often with the mirror present than absent, but these contacts were not emitted while looking at the mirror. Since facing the mirror while mark touching was not required for reinforcement during training, Experiment 3 further tested the possibility that increased mark touching in the presence of the mirror during Experiments 1 and 2 was the result of a memorial process. For this, a final, novel mark test was conducted using an orange mark on the neck that was only visible as a reflection (Experiment 3). No monkeys passed this test. These are the first mark tests given to capuchin monkeys. The results are consistent with the finding that no monkey species is capable of spontaneous mirror self-recognition. The implications of sequential training and mark testing for comparative evaluations of mirror self-recognition capacity are discussed.     

Gene manipulation in mycobacteria

Gene manipulation in mycobacteria developed in two phases. In the first phase genes of mycobacteria were transferred into cells ofE. coli andStreptomyces lividans. In the second phase, heterologous genes were transferred into mycobacteria either with a shuttle phasmid or hybrid plasmids. A prerequisite for successful gene manipulation in mycobacteria was a thorough understanding of plasmids in mycobacteria. Construction of recombinant DNA molecules contributed not only to the fact that mycobacteria did not remain outside the mainstream of modern genetic research but also to their present practical importance.