Images Of Conspecifics Research Articles

Behavioural responses to video playbacks by zebra finch males

A major problem for communication research is to provide standardized stimuli and to disentangle the relative contribution of different sensory channels to the compound signal and its effectiveness. Video techniques have frequently been used for this purpose. Fifty Hertz cathode ray tube (CRT) screens cannot be used for birds because their flicker frequency is lower than the time resolution of at least songbirds. Thin film transistor (TFT) screens have successfully been used to present video clips of behaving conspecifics. We show here that they are indeed transmitting video images in a way that enables zebra finches to react appropriately to live video images of conspecifics and that the test birds are able to detect small differences in the behaviour of the stimulus animals. Adding acoustic information strongly enhanced the reaction to the video clips.

Zebra Finches actively choose between live images of conspecifics

ABSTRACT Both auditory and visual signals are important to elicit avian courtship behaviour. The analysis of such signals has recently been strongly facilitated by the use of video and audio techniques. It has already been shown that male Zebra Finches (Taeniopygia guttata) show preferences to video images of conspecifics compared with heterospecifics and emit directed song towards live pictures of conspecific females. There is no experiment as yet to show whether Zebra Finches can also recognize intraspecific cues from videos, for example discriminate their mate from an unknown conspecific male or female. Zebra Finches were trained to choose between two live images from two video cameras, which were alternatively displayed on a 100 Hz CRT monitor by hopping on one or the other of two perches within the experimental cage. Our results show that most Zebra Finches are able to solve this task after one day of learning, the preference for one of the video images rising steadily. The birds easily distinguish b...

The role of images of conspecifics as visual cues in the development and behavior of larval anurans

The role of images of conspecifics as visual cues in the development and behavior of larval anurans

The role of images of conspecifics as visual cues in the development and behavior of larval anurans

Tadpoles can alter their behavior, morphology, and life history in response to habitat change. Although chemical signals from conspecifics or predators play an important role in tadpole habitat assessment, little is known about the role of visual cues and the extent to which tadpoles rely on their vision for intraspecific social assessment. The aim of our experiments was to determine whether larval anurans use visual images of other tadpoles as indicators of density and to analyze how, and to what extent, images of conspecifics alone affect tadpole development, growth, and behavior. To assess this, we raised both Rana sylvatica and Bufo americanus tadpoles in aquaria with either quarter- or half-mirrored walls. Both physically increased density and increased density simulated with mirrors decreased tadpole growth and developmental rates, and increased activity in Rana tadpoles. Bufo tadpoles did not significantly alter their growth and development in response to visually increased density. Only true, i.e., physically, increased density had an effect on growth and activity in Bufo tadpoles. Our data show that images of conspecifics are used as visual cues by Rana tadpoles and can induce phenotypically plastic changes in several traits. This response to visual cues is taxon-specific.

The influence of visual stimulation on the behaviour of dogs housed in a rescue shelter

AbstractThis study explored the influence of five types of visual stimulation on the behaviour of 50 dogs housed in a rescue shelter. These conditions were: one control condition (no visual stimulation) and four experimental conditions (blank television screen, and moving televised images of conspecifics, interspecifics [ie unfamiliar animal species] and humans). The dogs were exposed to each condition for 4 h per day for five days, with an intervening period of two days between conditions. The dogs' behaviour was recorded on days 1, 3 and 5 during each condition. Dogs spent relatively little of the total observation time looking at the television monitors (10.8%). They spent significantly more of their time looking at the moving images of conspecifics, interspecifics and humans than at the blank screen, although their interest in all experimental conditions declined over time. Dogs spent more time at the front of their enclosures during all of the experimental conditions than during the control condition. Images of conspecifics were more likely to attract the dogs to the front of their kennels than the blank screen. The conspecific and human conditions of visual stimulation attracted slightly more attention from the dogs than the interspecific condition, although not significantly. All of the experimental conditions encouraged significantly less vocalisation and movement than the control condition. Overall, the findings suggest that the behaviour of kennelled dogs is influenced by visual stimulation in the form of television programmes. Such animals, however, may not benefit from this type of enrichment to the same degree as species with more well-developed visual systems. The addition of other types of enrichment strategy for dogs housed in rescue shelters is advocated.

Pigeons do not perceptually complete partly occluded photos of food: an ecological approach to the “pigeon problem”

Humans routinely complete partly occluded objects to recognize the whole objects. However, a number of studies using geometrical figures and even conspecific images have shown that pigeons fail to do so. In the present study, we tested whether pigeons complete partially occluded objects in a situation simulating a natural feeding context. In Experiment 1, we trained pigeons to peck at any photograph of food and not to peck at any containing a non-food object. At test, we presented both photos of food partly occluded by pigeon's feather and photos simply truncated at the same part. We predicted that if the pigeons perceptually completed the occluded portion, then they would discriminate the photos of occluded food better than the truncated photos. The result was that the pigeons pecked at the truncated photos earlier than the occluded photos. Placing the occluder next to all of the stimuli in Experiment 2 or substituting indented lozenge for the feather in Experiment 3 did not affect the results. Thus, even in a simulated ecologically significant situation, pigeons continued to not show evidence of perceptual completion.

Preference for mirror images and video image in Java sparrows ( Padda oryzivora)

Java sparrows were exposed to a mirror and a frosted mirror, a mirror and a live bird, a mirror and a live bird with frosted screen, a closed circuit TV monitor and a TV program or the closed circuit monitor and an upside down monitor. The birds showed strong preference for the self-image on the mirror, the live bird and the self-image on the monitor. They preferred almost equally to the mirror and the frosted live bird. These results suggest that the Java sparrows saw the self-image on the mirror as conspecific image.

Lateralization of response to social stimuli in fishes: A comparison between different methods and species

We measured the time spent in monocular viewing during inspection of their own mirror images in females of three species of fish ( Xenotoca eiseni, Gambusia holbrooki and Xenopoecilus sarasinorum) using a rectangular tank in which animals could observe their own reflections in two mirrors positioned along the major walls, and in females of five species of fish ( X. eiseni, G. holbrooki, X. sarasinorum, Danio rerio and Gnatonemus petersii) using a quasi-circular tank in which fish could rotate clockwise or anticlockwise and observe their own reflections in a mirror positioned along the outer wall. Results revealed a consistent left-eye preference during initial sustained fixation in all species irrespective of the apparatus. However, in the quasi-circular tank, fish showed more variability of response. The asymmetry was apparent during the first 5 min of observation and tended to fade thereafter, probably as a result of habituation. These findings add to current evidence for a quite invariant pattern in the direction of lateralization in similar tasks in a variety of vertebrate species, with a preferential involvement of structures located to the right side of the brain in response to the viewing of images of conspecifics.

Domestic chicks' runway responses to video images of conspecifics.

Because chickens are highly social animals, live conspecifics are often used to provide an incentive or goal in studies of gait, sociality or fear that require the bird to traverse a runway. However, the variable behaviour of the stimulus birds can influence the approach/avoidance responses of the test birds and thereby confound the results. Because chickens modify their behaviour readily and appropriately to a variety of video images, including social stimuli, we asked if video playback might represent easily controllable and standardized alternatives to live birds. Female ISA Brown chicks were housed in groups of eight and then exposed to a blank illuminated television for 10min per day from 2 to 7 days of age. At 8 or 9 days of age they were placed individually in the start box of a 1.6m long runway and we recorded their responses to a monitor displaying selected video images that was situated in the goal box at the opposite end of the runway. In Experiment 1 chicks approached a monitor playing the video image and soundtrack of feeding chicks significantly sooner than one of a goal box with the food dish and background noise. In Experiment 2, chicks were exposed to the same video of feeding conspecifics with or without the associated sounds or to a video of the goal box with or without the chick soundtrack. Both the videos of other chicks elicited faster approach than did those of the goal box and the sound and silent versions were equally attractive. Adding the soundtrack of feeding chicks to the goal-box video failed to increase its attractiveness. The present results suggest that chicks are attracted towards televised images of other chicks. They also indicate that the visual and auditory components of the video stimuli did not exert additive effects and that approach reflected attraction to the visual image. Collectively, our findings suggest that video playback of selected social stimuli, such as feeding conspecifics, could be a valuable tool in tests requiring voluntary locomotion along a predetermined path.

Depth cues, behavioural context, and natural illumination: some potential limitations of video playback techniques

By expanding on issues raised by D’Eath (1998), I address in this article three aspects of vision that are difficult to reproduce in the video- and computer-generated images used in experiments, in which images of conspecifics or of predators are replayed to animals. The lack of depth cues derived from binocular stereopsis, from accommodation, and from motion parallax may be one of the reasons why animals do not respond to video displays in the same way as they do to real conspecifics or to predators. Part of the problem is the difficulty of reproducing the closed-loop nature of natural vision in video playback experiments. Every movement an animal makes has consequences for the pattern of stimulation on its retina and this ”optic flow” in turn carries information about both the animal’s own movement and about the three-dimensional structure of the environment. A further critical issue is the behavioural context that often determines what animals attend to but that may be difficult to induce or reproduce in an experimental setting. I illustrate this point by describing some visual behaviours in fiddler crabs, in which social and spatial context define which part of the visual field a crab attends to and which visual information is used to guide behaviour. I finally mention some aspects of natural illumination that may influence how animals perceive an object or a scene: shadows, specular reflections, and polarisation reflections.

Discriminative responsiveness by lambs to visual images of conspecifics

A series of experiments was conducted to assess whether lambs are discriminatively responsive to visual images of conspecifics. Lambs (3–4-week-old) consistently responded with more interest and less avoidance when exposed to a life-like image of an unfamiliar lamb, a ewe or the silhouette of a ewe, than to a meaningless mosaic of the same conspecific stimulus. In each instance, lambs preferentially sniffed the head region of the conspecific image. Slides of a ewe and a dog likewise elicited differential responses by lambs, but there were no clear differences in their attraction to, or avoidance of these two categories of stimuli. In contrast, adult ewes responded more negatively to the dog image than to the ewe slide. Overall, lambs appeared to respond to conspecific images as social stimuli, however, social discrimination by visual cues alone may improve with age and experience.

Recognition of moving video images of conspecifics by pigeons: Effects of individuals, static and dynamic motion cues, and movement

Two groups of pigeons were trained with a go/no-go procedure to discriminate video images of conspecifics based on the individuals or else on their actions. Both groups showed rapid acquisition, and the discrimination transferred to new scenes in Experiment 1 and to static scenes in Experiment 2. In Experiment 3, experimentally naive pigeons were trained to discriminate video images of particular birds showing different actions. Transfer to novel scenes, including a new bird and a new motion, revealed the dominance of motion as a cue to discriminate video images. In Experiment 4, the pigeons trained to discriminate video scenes of 2 pigeons showing a variety of activities successfully recognized these stimuli regardless of whether the video was played forward or backward, and transferred the discrimination to still scenes. The findings suggest that pigeons’ discrimination of video images is primarily based on information that is invariant across static and dynamic conditions.

Recognition of Moving Video Images of Conspecifics by Pigeons

Recognition of Moving Video Images of Conspecifics by Pigeons

Laying hens do not discriminate between video images of conspecifics

In a study of social recognition in domestic hens, Gallus gallus domesticus, the suitability of video images as social stimuli was investigated. With live birds behind clear Perspex as stimuli, hens took longer to begin feeding near unfamiliar conspecifics than flockmates, and also discriminated between dominant and subordinate flockmates. When life-size colour video sequences of the same birds were substituted, however, there was no discrimination on the basis of either familiarity or rank, although hens took longer to begin feeding near to videos showing hens with a threat-like posture than hens with normal posture. In a second video experiment, hens again failed to discriminate flockmates from unfamiliar birds. Behavioural observations showed that in early trials, subjects appeared to attend to the stimulus and occasionally moved in synchrony with the video bird or pecked at its head. In later trials these responses were never seen, and hens approached the screen more readily. Despite these behavioural changes, discrimination of flockmates from unfamiliar birds was not found at any stage. Various possible reasons for this failure to discriminate between familiar and unfamiliar conspecifics on video are discussed, and the findings contrasted with other published work in which videos were shown to be adequate substitutes for social stimuli in fowl ( Gallussp.).

Influence of a conspecific image of own vs. different breed on fear reactions of ewes

We observed the influence of slide images of conspecifics on fear reactions of 12 Romanov and 12 Ile-de-France ewes. Each ewe was individually tested twice in isolation: once in the presence of the projected image of an unfamiliar ewe of its own breed, and once when exposed to an image of a ewe of a different breed. Ewes' responses to a slide of an individual of their own breed differed consistently from their responses to a slide of the other breed (i.e., they displayed lower fear reactions to their own breed). There was also a significant main effect for breed of subject, which reflects breed differences in activity level and/or fearfulness. Differential responses to two-dimensional images of unfamiliar animals of own versus other breed suggest that the ewes recognized the characteristics of their breed. Moreover, the manner in which ewes responded to the slide projections indicates that those images were perceived as social stimuli.

Age differences in the ability of chimpanzees to distinguish mirror-images of self from video images of others.

To evaluate Heyes's (1994) claim that chimpanzees are incapable of using mirrored information to obtain otherwise unavailable information about the self, we exposed two different age groups of chimpanzees (3-year-olds and 7- to 10-year-olds) to mirrors and video images of conspecifics. Their reactions to these stimuli were videotaped and were later scored for behavioral indices of self-recognition by a trained observer who was blind to the purpose and conditions of the study. Some types of behavior (contingent facial and body movements) were clearly influenced by the type of stimulus that the chimpanzees were viewing but not by age; however, other behaviors (self-exploration) were affected by age in conjunction with the type of stimulus the animals were viewing. The results suggest that, unlike self-exploratory behavior, contingent facial and body movements may not, by themselves, be reliable indicators of self-recognition.

Images of conspecifics as categories to be discriminated by pigeons and chickens: Slides, video tapes, stuffed birds and live birds

Four experiments investigated the discrimination of images of conspecifics by pigeons; in Experiment 1, chickens were also used as subjects, and images of allospecifics were also used as discriminative stimuli. In Experiment 1, chickens were successfully trained to discriminate slides of pigeons, pictures of one bird being positive stimuli and pictures of another bird being negative; and pigeons were similarly trained to discriminate slides of chickens. However, an attempt to train pigeons to discriminate slides of pigeons only succeeded with one bird out of six. Pigeons were slower to learn chicken slides, and chickens were slower to learn pigeon slides, than chickens were to learn chicken slides in a previous experiment. In Experiment 2, a dishabituation technique was used to demonstrate that pigeons readily discriminate individual live pigeons. In Experiment 3, an attempt was made to test habituation to life-size moving video images of pigeons, but these images did not elicit any natural social responses from the subject pigeons. In Experiment 4 pigeons were trained in a discrimination in which the objects to be discriminated were two different stuffed pigeons. No pigeon learned this discrimination. The experiments give some evidence that chickens are better at discriminating images of individuals than pigeons. No single feature seems to be sufficient for pigeons to discriminate between conspecifics, but the combination of features that is required remains unknown.

Social stimuli influencing feeding behaviour of Burmese fowl: video analysis

Abstract. After adolescent Burmese red junglefowl, Gallus gallus spadecius, were exposed to videotapes of conspecifics feeding from visually distinctive food dishes, the viewers exhibited enhanced preferences for food dishes of the type that they had observed conspecifics exploit. Both auditory and visual stimuli associated with feeding fowl played a role in producing these socially enhanced feeding-site preferences, and videotapes of fowl actually feeding from a food dish were more effective in enhancing preference for that type of food dish than were videotapes of fowl either active or immobile near a food dish. Thus, juvenile junglefowl not only responded to video images of conspecifics and generalized from video images of objects to the objects themselves, they also responded differentially to video images of general activity near a food dish and feeding behaviour directed towards a food dish. Whether exposure to a videotape sufficed to influence feeding behaviour during testing depended on: (1) the duration of the subjects' exposure to videotapes, (2) the duration of the delay between videotape viewing and preference testing and (3) the criteria used to detect social influence on feeding behaviour.

Video image recognition by the jumping spider, Maevia inclemens (Araneae: Salticidae)

Jumping spiders of the family Salticidae have well developed eyes, which mediate their highly stereotyped predatory and commnicative behaviour. Experimental studies presented here provide behavioural evidence that salticids are capable of perceiving televised (video) images. Juvenile and sexually mature individuals of the dimorphic jumping spider, Maevia inclemens (Walckenaer), were tested in V-maze choice test and behavioural chambers where they were allowed to view images of videotaped prey and spiders presented on Sony Watchman micro-television unuits. Results from this study suggest that jumping spiders interpret video images as real, because: (1) spiders did not discriminate between live prey and its simulateously presented video image; and (2) they behave appropriately when presented with televised images of prey insects (e.g. stalk and attack televised prey), conspecifics (e.g. courtship and sexual receptivity behaviour directed toward televised conspecifics) and heterospecific jumping spider species (e.g. retreat from predator stimulus). These observations support a previous estimate, of low critical flicker fusion frequency values in this group, and enable the development of a powerful new method for the study of animal behaviour.

The effects on schedule-induced attack of covarying meal size and spacing

Pigeons were exposed to fixed-time food schedules of 30, 120, and 480 sec with two reinforcer magnitudes at each. Attack behavior against a rear-projected conspecific image was assessesd at each interfood/reinforcer magnitude combination. For seven of eight subjects, attack rate was related to interfood interval by an inverted-U or bitonic function. The larger reinforcer magnitude typically induced more attack than the smaller.