Images Of Snakes Research Articles

Increased attention to snake images in cynomolgus monkeys: an eye-tracking study.

Previous studies have revealed faster detection of snake images in humans and non-human primates (NHPs), suggesting automatic detection of evolutionary fear-relevant stimuli. Furthermore, human studies have indicated that general fear-relevance rather than evolutionary relevance is more effective at capturing attention. However, the issue remains unclarified in NHPs. Thus, in the present study, we explored the attentional features of laboratory-reared monkeys to evolutionary and general fear-relevant stimuli (e.g., images of snakes, capturing gloves). Eye-tracking technology was utilized to assess attentional features as it can provide more accurate latency and variables of viewing duration and frequency compared with visual search task (VST) and response latency adopted in previous studies. In addition, those with autism spectrum disorder (ASD) show abnormal attention to threatening stimuli, including snake images. Rett syndrome (RTT) is considered a subcategory of ASD due to the display of autistic features. However, the attentional features of RTT patients or animal models to such stimuli remain unclear. Therefore, we also investigated the issue in MECP2 gene-edited RTT monkeys. The influence of different cognitive loads on attention was further explored by presenting one, two, or four images to increase stimulus complexity. The eye-tracking results revealed no significant differences between RTT and control monkeys, who all presented increased viewing (duration and frequency) of snake images but not of aversive stimuli compared with control images, thus suggesting attentional preference for evolutionary rather than general fear-relevant visual stimuli. Moreover, the preference was only revealed in visual tasks composed of two or four images, suggesting its cognitive-load dependency.

"Prepared" fear or socio-cultural learning? Fear conditioned to guns, snakes, and spiders is eliminated by instructed extinction in a within-participant differential fear conditioning paradigm.

Across three experiments, we investigated whether electrodermal responses conditioned to ontogenetic fear-relevant (pointed guns) and phylogenetic fear-relevant stimuli (snakes and spiders) would resist instructed extinction in a within-participant differential fear conditioning paradigm. Instructed extinction involves informing participants before extinction that the unconditional stimulus (US) will no longer be presented. This manipulation has been shown to abolish fear conditioned to fear-irrelevant conditional stimuli, but is said to leave fear conditioned to images of snakes and spiders intact. The latter finding, however, has only been demonstrated when fear-relevance is manipulated between-groups. It is also not known whether instructed extinction affects fear conditioned to ontogenetic fear-relevant stimuli, such as pointed guns. In Experiment 1, we demonstrated that fear conditioned to images of pointed guns does not resist instructed extinction. In Experiment 2, we detected some evidence to suggest that fear conditioned to images of snakes and spiders survives instructed extinction but this evidence was not conclusive. In Experiment 3, we directly compared the effects of instructed extinction on fear conditioned to snakes and spiders and to guns and provide strong evidence that fear conditioned to both classes of stimuli is reduced after instructed extinction with no differences between ontogenetic and phylogenetic stimuli. The current results suggest that when fear relevance is manipulated within-participants fear conditioned to both phylogenetic and ontogenetic, fear-relevant stimuli responds to instructed extinction providing evidence in favor of a socio-cultural explanation for "preparedness" effects.

Enhanced cognitive processing by viewing snakes in children with autism spectrum disorder. A preliminary study

BackgroundPrioritization of the processing of threatening stimuli induces deleterious effects on task performance. However, emotion evoked by viewing images of snakes exerts a facilitating effect upon making judgments of their color in neurotypical adults and schoolchildren. We attempted to confirm this in school and preschool children with and without Autism Spectrum Disorder (ASD).MethodsForty French children participated and corresponded to two age groups: a group of schoolchildren and a group of preschool children, each group including 10 children with typical development and 10 children with ASD. Each participant was exposed to 120 trials composed of 20 photographs of snakes and 20 photographs of flowers, each of which appeared 3 times (in red, green and blue). Participants were asked to indicate the color of each image as quickly as possible via key-press. A three-way analysis of variance test for reaction time (RT) considering image type (IMAGE), participant group (PARTICIPANT), and age (AGE) as main effects and its interaction terms was performed for each subject.ResultsWhen the reaction time required to respond to presented stimuli was measured, schoolchildren tended to respond faster when stimuli were snake images than when stimuli were flower images whether the children had or did not have ASD. For the 5-to-6-year-old preschool participants, the difference between reaction time for the color-naming of snake images and flower images was ambiguous overall.ConclusionsThere were possible odd color-specific effects in children with ASD when images were presented to the children in green. Implications of the findings are argued with respect to active avoidance or attraction as one of the behavioral characteristics commonly noted in children with ASD.

The danger of interpreting detection differences between image categories: A brief comment on "Mind the snake: Fear detection relies on low spatial frequencies" (Gomes, Soares, Silva, & Silva, 2018).

Using breaking continuous flash suppression (b-CFS; a perceptual suppression technique), Gomes, Soares, Silva, and Silva (2018) showed that human observers have an advantage in detecting images of snakes (constituting an evolutionarily old threat) over birds. In their study, images of snakes and birds were filtered to contain either coarse-scale or fine-grained information. The preferential detection of snakes relied on coarse-scale (rather than fine-grained) information, which was taken as support for the existence of an evolutionarily old subcortical pathway dedicated to snake detection. Here, we raise the concern that images of snakes and birds inherently differ in their visual characteristics, which can strongly affect detection times in b-CFS. Images of snakes, for instance, have a larger perimeter-to-surface ratio than images of birds. Importantly, these visual characteristics are not snake specific, as they are shared with many nonthreatening object categories. To illustrate this point, we compared detection times between images of bicycles and cars-nonthreatening image categories that differ in visual characteristics but for which detection is unlikely to capitalize on an evolutionarily old dedicated subcortical pathway. Observers exhibited an advantage for detecting bicycles over cars. Mirroring the snake-bird differences reported in Gomes et al., this advantage was driven by the coarse-scale (rather than fine-grained) information in the images. Hence, differences in visual characteristics between two nonthreatening, semantically matched stimulus categories suffice to produce the exact same pattern of findings as observed with snakes versus birds. We conclude that spatial frequency-specific detection differences in b-CFS cannot be unequivocally attributed to differences in processing pathways. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Edge Detection and Contour Based Ear Recognition Scheme

In recent days, with the advancements in computer vision technology pattern recognition for biometric data has been the focus of many researchers. The human ear can be used to assist in the recognition of an individual. In this article, a new scheme for ear recognition is presented, based on edge features such as the helix shape and contours between the edge pixels. First, an ear image is detected from the acquired image using a snake model-based image segmentation technique, and then histogram equalization is applied to form an enhanced ear image. After that, an Infinite Symmetric Exponential Filter (ISEF) edge is applied to the image, the contouring of edges is calculated, and then the contour values of pixels are extracted as ear features. Finally, the ear matching is performed between query ear features and enrolled ear features. Based on the matching score, the decision about individual authentication is performed. The experimental results showed that this proposed scheme performs better than existing schemes in the literature.

Visual features and perceptual context modulate attention towards evolutionarily relevant threatening stimuli: Electrophysiological evidence.

The snake detection hypothesis claims that predatory pressure from snakes has shaped the primate visual system, but we still know very little about how the brain processes evolutionarily important visual cues, and which factors are crucial for quick detection of snakes. We investigated how visual features modulate the electrophysiological markers of early attentional processes. In Experiment 1, we compared snake, rope, gun, and bird images to isolate the effects due to curvilinearity of the stimuli. The results showed that both snake and rope images elicited enhanced P1 and N1 event-related potential components as well as early posterior negativity (EPN). In Experiment 2, we studied whether nonthreatening curvilinear images (i.e., ropes) still elicit the enhanced electrophysiological responses when snake images are not presented as stimuli, and therefore the context does not provoke top-down attention to curvilinear shapes. Rope images still evoked an enhanced EPN, suggesting that curvilinear shapes are preferably captured by attentional processes. However, this effect was smaller than in Experiment 1, in which snake images were present. Thus, our results hint to the possibility that the perceptual context may interact with processing of shape information, drawing attention to curvilinear shapes when the presence of snakes is expectable. Furthermore, we observed that spatial frequency of the visual stimuli modulated especially the early electrophysiological responses, and decreased the differences between stimulus categories in EPN without completely eliminating them. The findings suggest that low-level and high-level mechanisms interact to give an attentional priority to potentially threatening stimuli. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Preferential attentional engagement drives attentional bias to snakes in Japanese macaques (Macaca fuscata) and humans (Homo sapiens)

In humans, attentional biases have been shown to negative (dangerous animals, physical threat) and positive (high caloric food, alcohol) stimuli. However, it is not clear whether these attentional biases reflect on stimulus driven, bottom up, or goal driven, top down, attentional processes. Here we show that, like humans, Japanese macaques show an attentional bias to snakes in a dot probe task (Experiment 1). Moreover, this attentional bias reflects on bottom up driven, preferential engagement of attention by snake images (Experiment 2a), a finding that was replicated in a study that used the same methodology in humans (Experiment 2b). These results are consistent with the notion that attentional bias to snakes reflects on an evolutionarily old, stimulus driven threat detection mechanism which is found in both species.

A Jug from Sarata

The results of the visual study of well-known and repeatedly published jag from grave no. 13 of the barrow no. 10 near Sarata village in Odesa Region are shown in the paper. The barrow was excavated by professor of the Kyiv St. Volodymyr University F.I. Knauer in 1888—1890. According to the publication of the first results of study, the localization and composition of the barrow group is specified. In the paper the burial no. 13 and the vessel which was placed behind the scull are described. The study of the decoration of Sarata jug de visu in the National Museum of History of Ukraine allows to conclude that the volutes typical for the Basarabi Culture were ending not only with curls as was previously considered but with two heads of snakes (fig. 4, 3). The volute with the snake head was filled with white paste on the right side, and with pink paste on the left. The enlargement of images suggests that the heads appeared later. They were marked by deep notches, not by a small-notched stamp by which the ornament of the vessel was spouted. The white paste filling the head of snake is more dense on the right side. These observations somewhat change the opinion on the image on Sarata vessel. Probably the images were made in different time. So, the initial decoration was engraved during the manufacture of the vessel among Culture of Basarabi. The image of the snake heads was added later. Perhaps it was done while preparing the vessel for a funerary ritual — after all the snake image had a chthonic meaning in many cultures. There was made a conclusion that the jug was decorated not with geometrical but with subject ornament. The aviability of realistic depicted heads of snakes allows recall the Scythian animal style. No one can exclude that the Sarata burial had been made just in the Early Scythian time using the vessel preserved as a relic for a long time. If such observations will receive additional arguments the burial no. 13 of the barrow no. 10 near Sarata could be included in the small group of Early Scythian burials of the Steppe zone.

THE IMAGE OF SNAKE IN ELAM AND JIROFT SITES IN SOUTHWEST AND SOUTHEAST OF IRAN AND ITS COMPARISON WITH ZOROASTRIANISM

Snake, the renowned slither, is a creature that has appeared in various shapes in myths across numerous cultures and nations. This creature comprises a great number of designs in Iran, as well. It seems that the image of the snake contains a special meaning, which has been used as a symbol and shares ties to people’s beliefs and the religion. Thus, the researcher’s attention has been turned to how the image of the snake has been used in the remaining artifacts from Elam and its neighboring regions, such as Jiroft, and its general differences to the Zoroatrian culture. In this paper, taking on a comparative descriptive approach, the repetition of the image of this creature in different designs is examined, a separate division is presented for each region (Elamite and Jiroft) and the mythological meanings and concepts related to each design are explained. In the end, the image of the snake in Zoroastrianism is briefly explained. The snake's image in Elam reveals more than anything, its connection with God, water, fertility, and the other world. In Jiroft, the image of interwoven snakes, coiled snakes, and even snakes fighting other animals are seen. Afterwards, with the influence of the Zoroastrian culture in Iran, this creature finds a new and completely different role to the point where it is introduced as a devilish creature.

An Improved Technique for Obtaining Accurate and Precise Morphometric Data on Snakes.

Morphometric measurements are basic but essential data in morphological and ecological research. It is thus beneficial to develop a safe, convenient, multipurpose device/technique to determine body length and physical characteristics of living snakes with high accuracy/precision and low stress, and to enable the probing of snakes and collection of tissue samples. To meet these requirements, we developed an improved technique, which we named the Confining-Box Method (CBM). On measuring the body lengths of a total of 72 live snakes, we found significant differences in the accuracy and precision of measurements among the squeeze-box method, the anesthesia method, and the CBM, as well as between vertebral line and the mid-ventral line measurements. Body lengths, as measured along the vertebral line and corrected for perspective errors, using the CBM, did not differ significantly from the standard lengths measured by hand using anesthesia. The squeeze-box method produced substantial negative bias and/or less precision in ventral measurements, especially for large snakes (> 1.2 m in snout-vent length). The differences between measurers were much smaller than among the different techniques. Compared to the anesthesia technique, CBM is a fast and simple method that is also safer for snakes. Unlike the traditional squeeze-box technique, CBM can record both dorsal and ventral body images of snakes simultaneously and enable researchers to measure accurate and/or precise total length (from dorsal images), tail length (from ventral images), and snout-vent length using images from a single photography session. CBM could therefore become a standard to improve measurement consistency, allowing improved data comparison in future studies.

Prepared stimuli enhance aversive learning without weakening the impact of verbal instructions.

Fear-relevant stimuli such as snakes and spiders are thought to capture attention due to evolutionary significance. Classical conditioning experiments indicate that these stimuli accelerate learning, while instructed extinction experiments suggest they may be less responsive to instructions. We manipulated stimulus type during instructed aversive reversal learning and used quantitative modeling to simultaneously test both hypotheses. Skin conductance reversed immediately upon instruction in both groups. However, fear-relevant stimuli enhanced dynamic learning, as measured by higher learning rates in participants conditioned with images of snakes and spiders. Results are consistent with findings that dissociable neural pathways underlie feedback-driven and instructed aversive learning.

MICROCOMPUTED TOMOGRAPHIC, MORPHOMETRIC, AND HISTOPATHOLOGIC ASSESSMENT OF CONGENITAL BONE MALFORMATIONS IN TWO NEOTROPICAL VIPERIDS.

Congenital malformations have been reported in all classes of vertebrates and may be a determinant of life span and survival. In reptiles, the incidence of congenital malformations can be associated with genetic and environmental causes, including pollution. The characterization of pathological processes involved in the development of congenital malformations of bone in snakes is rare in the literature, but is of great relevance in the field of reptile conservation and environmental health. We describe congenital bone lesions in 50 newborn jararaca (Bothrops jararaca) and 26 South American rattlesnakes (Crotalus durissus terrificus) born from wild-caught pregnant females in Southeastern Brazil. Lesions were evaluated by morphometric quantitative analysis, x-ray microtomography, and histopathologic descriptive analysis. Morphometric analysis showed that jararaca presented more severe axial lesions (kyphosis, scoliosis, and kyphoscoliosis) than rattlesnakes. Female rattlesnakes presented more severe axial lesions than did males. In rattlesnakes, spinal deformities were more frequently diagnosed in the caudal segment of the body. We present x-ray microtomographic assessments and images of malformed snakes (n=9) and characterized novel malformations, such as the agenesis of frontal, parietal, and supraoccipital bones in a jararaca specimen. Histopathologic findings included vertebral body fusion, myositis, coagulation necrosis, and disorganization of periaxial muscle fibers. The new methods and results presented in this study will be useful and informative for future research in pathology, teratology, embryology, and ecotoxicology in snakes.

Negative emotion evoked by viewing snakes has a motivating effect on cognitive processing in human children with or without intellectual disability.

BackgroundIt is well known that prioritization of the processing of threatening stimuli generally induces deleterious effects on task performance. However, a study recently reported that emotion (possibly fear) evoked by viewing images of snakes exerts a facilitating effect upon making judgments of the images’ color in neurotypical adults and schoolchildren. Here, the author has attempted to confirm the relevance of this notion in children with and without intellectual disability.MethodsThe author here compared the reaction time required to name the colors of snake and flower images between children with Down syndrome (DS) and mental age matched, typically‐developing (TD) children.ResultsSnake images were responded to faster than flower images in both the groups, while the children with DS tended to respond more slowly overall.ConclusionsAs in TD children, negative emotion can have a motivating effect on cognitive processing in children with DS. Some implications of the findings are pointed out with respect to the lower‐level task persistence as a characteristic motivational orientation in children with DS.

Traditional use and perception of snakes by the Nahuas from Cuetzalan del Progreso, Puebla, Mexico

BackgroundIndigenous cultures are the result of their adaptation to the natural surroundings, in such a way that, amongst their main features is a set of knowledge, technologies and strategies for the appropriation of nature. In Cuetzalan del Progreso, Puebla, Mexico snakes represent 71.1% of the total local herpetofauna; and in addition to this, different groups of Nahuas have shown to have information of their use of various snake species in many ways. This study was conducted to investigate the traditional uses of snakes in this cultural group.MethodsFormal and informal interviews were conducted with the inhabitants of the communities. During these interviews, 30 images of the different species of snakes present in the area were presented to the subjects, so that they would recognize them and reveal information about the knowledge they possess on them. A usage analysis was applied to each species considering the following categories: food purposes, medicinal, artisanal and magical-religious. Likewise, the frequency, the diversity and the value of use was estimated for these snakes.ResultsA total of 51 interviews were carried out. The individuals recognized 18 out of 30 images of snakes that were presented. The total of usage categories was five; we found that the magic-religious use was the most mentioned by 32 personas. Boa imperator and Antropoides nummifer were the species with the highest value of use. More than half of the interviewees mentioned killing snakes because they’re poisonous and aggressive. In the magic-religious aspect the “Danza de los Negritos” is highlighted; this is a local festival, brought by Africans, and alludes to snakes.ConclusionsThis study revealed that snakes are still very important for the culture in Cuetzalan del Progreso, finding that the magical-religious and the medicinal use stand out. On the other hand, the fear and misperception on the toxicity of snakes might represent a potential threat for their conservation. Therefore, it is necessary to carry out a long-term monitoring of the ethno-zoological activities, and develop a sustainable management plan compatible with the cultural characteristics of the natives of the region.

Breaking Snake Camouflage: Humans Detect Snakes More Accurately than Other Animals under Less Discernible Visual Conditions.

Humans and non-human primates are extremely sensitive to snakes as exemplified by their ability to detect pictures of snakes more quickly than those of other animals. These findings are consistent with the Snake Detection Theory, which hypothesizes that as predators, snakes were a major source of evolutionary selection that favored expansion of the visual system of primates for rapid snake detection. Many snakes use camouflage to conceal themselves from both prey and their own predators, making it very challenging to detect them. If snakes have acted as a selective pressure on primate visual systems, they should be more easily detected than other animals under difficult visual conditions. Here we tested whether humans discerned images of snakes more accurately than those of non-threatening animals (e.g., birds, cats, or fish) under conditions of less perceptual information by presenting a series of degraded images with the Random Image Structure Evolution technique (interpolation of random noise). We find that participants recognize mosaic images of snakes, which were regarded as functionally equivalent to camouflage, more accurately than those of other animals under dissolved conditions. The present study supports the Snake Detection Theory by showing that humans have a visual system that accurately recognizes snakes under less discernible visual conditions.

Who is afraid of the invisible snake? Subjective visual awareness modulates posterior brain activity for evolutionarily threatening stimuli

Snakes were probably one of the earliest predators of primates, and snake images produce specific behavioral and electrophysiological reactions in humans. Pictures of snakes evoke enhanced activity over the occipital cortex, indexed by the “early posterior negativity” (EPN), as compared with pictures of other dangerous or non-dangerous animals. The present study investigated the possibility that the response to snake images is independent from visual awareness. The observers watched images of threatening and non-threatening animals presented in random order during rapid serial visual presentation. Four different masking conditions were used to manipulate awareness of the images. Electrophysiological results showed that the EPN was larger for snake images than for the other images employed in the unmasked condition. However, the difference disappeared when awareness of the stimuli decreased. Behavioral results on the effects of awareness did not show any advantage for snake images.

Addendum: Seeking Hawthorne’s Niagara

Addendum: Seeking Hawthorne’s Niagara

Snakes elicit earlier, and monkey faces, later, gamma oscillations in macaque pulvinar neurons.

Gamma oscillations (30–80 Hz) have been suggested to be involved in feedforward visual information processing, and might play an important role in detecting snakes as predators of primates. In the present study, we analyzed gamma oscillations of pulvinar neurons in the monkeys during a delayed non-matching to sample task, in which monkeys were required to discriminate 4 categories of visual stimuli (snakes, monkey faces, monkey hands and simple geometrical patterns). Gamma oscillations of pulvinar neuronal activity were analyzed in three phases around the stimulus onset (Pre-stimulus: 500 ms before stimulus onset; Early: 0–200 ms after stimulus onset; and Late: 300–500 ms after stimulus onset). The results showed significant increases in mean strength of gamma oscillations in the Early phase for snakes and the Late phase for monkey faces, but no significant differences in ratios and frequencies of gamma oscillations among the 3 phases. The different periods of stronger gamma oscillations provide neurophysiological evidence that is consistent with other studies indicating that primates can detect snakes very rapidly and also cue in to faces for information. Our results are suggestive of different roles of gamma oscillations in the pulvinar: feedforward processing for images of snakes and cortico-pulvinar-cortical integration for images of faces.

Rapid Categorization of Snakes in the Infant’s Occipital Cortex: Evidence from Fast Periodic Visual Stimulation

Rapid Categorization of Snakes in the Infant’s Occipital Cortex: Evidence from Fast Periodic Visual Stimulation

Possible Engraved Canebrake Rattlesnake Motifs on Sherds from the Etoile Site (41NA11) in the Angelina River Basin in East Texas

Engraved canebrake rattlesnake motifs on bottles has been found in ceramic assemblages in at least 18 Middle (ca. A.D. 1200–1400) and Late Caddo (ca. A.D. 1400–1680) period sites in the Big and Little Cypress Creek, mid–Sabine, Red River, and Angelina River basins in East Texas. The motif consists of “representational images of snakes with entwined or interlocking tails."