Escape Decisions Research Articles

Escape behavior lateralization of pointed‐belly frog (Leptodactylus podicipinus) (Anura, Leptodactylidae) in the southern Pantanal

AbstractFunctional lateralization in directional preference for predator evasion was examined in 45 Pointed‐belly frogs (Leptodactylus podicipinus). T‐maze trials revealed a preference for rightward escape, though individual bias was minimal, at only 33%, to evade predictability. Sex and size didn't influence escape decisions, aligning with predator avoidance strategies.Abstract in Portuguese is available with online material.

Functional sophistication in human escape

Animals including humans must cope with immediate threat and make rapid decisions to survive. Without much leeway for cognitive or motor errors, this poses a formidable computational problem. Utilizing fully immersive virtual reality with 13 natural threats, we examined escape decisions in N= 59 humans. We show that escape goals are dynamically updated according to environmental changes. The decision whether and when to escape depends on time-to-impact, threat identity and predicted trajectory, and stable personal characteristics. Its implementation appears to integrate secondary goals such as behavioral affordances. Perturbance experiments show that the underlying decision algorithm exhibits planning properties and can integrate novel actions. In contrast, rapid information-seeking and foraging-suppression are only partly devaluation-sensitive. Instead of being instinctive or hardwired stimulus-response patterns, human escape decisions integrate multiple variables in a flexible computational architecture. Taken together, we provide steps toward a computational model of how the human brain rapidly solves survival challenges.

Impact of tourism on the vigilance behavior of the Cyprus rock agama (Laudakia cypriaca).

Escape behavior is a common antipredator strategy among wild animals. Here, we investigated the effect of four factors on the vigilance behavior of the endemic Cyprus rock agama (Laudakia cypriaca). Flight initiation distance (FID, the minimum distance to which an observer can approach a lizard before it flees) was measured in relation to the type of location (tourist vs. nontourist area), the observer's starting distance, air temperature, and substrate temperature. We collected data for 39 agamas in tourist areas and 34 of these lizards in nontourist areas. As a whole, the mean starting distance was 10.5 m and the FID was 3.6 m. The average substrate temperature was 34.0°C and the average air temperature 29.6°C. Only the type of area affected the agamas' escape decisions with FID being 1.8 m shorter in tourist areas than in nontourist areas (2.7 m vs. 4.5 m). This is probably due to the habituation of lizards to the presence of humans in the former areas. This study shows that tourism strongly affects the behavior of lizards, which may have consequences for the functioning of the population. Tourists can increase the safety of lizards by creating a human shield to deter predators. Once the tourist season is over, lizards may become more vulnerable to predators.

Leash Status of Approaching Dogs Mediates Escape Modality but Not Flight-Initiation Distance in a Common Urban Bird

Controversy exists around owned dogs’ impacts in public open spaces, with concerns about dogs’ impact on wildlife, including birds. Leashing dogs in public open spaces offers a tractable way of reducing dogs’ deleterious impacts on birds. Although dogs in public spaces are often unleashed, some dogs roam freely, whilst other unleashed dogs remain close to their owners. It is currently unknown whether birds can perceive and incorporate subtle differences in the leash status of approaching, but non-roaming, dogs into their escape decisions. We compare escape responses of a common urban bird, the magpie-lark Grallina cyanoleuca, in parks in Melbourne, Australia, to standardized approaches by a walker and a dog, which was either leashed or not leashed (but with the dog at the same distance from the walker). Flight-initiation distances, the distance between the lark and dog when escape commenced, did not vary between treatments. However, the unleashed dog evoked more intense responses (mostly flying away) than the leashed dog (mostly walking away). Thus, this species appears to perceive unleashed dogs as especially threatening, independent of their roaming behavior. Our findings suggest that leashing may be an effective way to reduce dog disturbance to wildlife, even for non-roaming dogs.

Opposing effects of vigilance and foraging on escape behaviour in hooded crows

Abstract Escape represents an important component of animals’ antipredator behaviour entailing both benefits and costs dependent on a moment an animal flees upon predator’s approach. In this study, I examined how the level of vigilance and foraging activity affected escape decision in the urban hooded crow Corvus cornix, predicting that alert distance (AD) and flight initiation distance (FID) should be positively affected by the level of vigilance and negatively affected by foraging activity, whereas buffer distance (BD) should be negatively affected by the level of vigilance and positively affected by foraging activity. Using LMMs it was shown that percent of time crows allocated to vigilance was positively correlated with AD and FID, whereas foraging activity of crows had negative impact on AD and FID. In addition, both AD and FID were positively related to starting distance (SD), while AD was also positively influenced by tree coverage. BD was positively affected by foraging activity and AD. This study demonstrated that more vigilant birds detected predators earlier, which is in accordance with the major function of vigilance. Also, it was shown that foraging crows delayed their escape, once the predator has been detected, as benefits of delayed flight, such as feeding on a profitable food item or within a profitable patch, may outweigh costs, which is consistent with the optimal escape theory.

How does damselfish risk assessment vary with increased predator and shoal size?

Predation is an important factor that influences the behavior of prey species. When approached by a predator, individuals must make escape decisions that may be sensitive to the level of perceived risk. Both predator size and prey group size influence vulnerability and may influence this assessment. If fish perceive larger predators as a greater threat, differences in predator size should reflect differences in their antipredator response. Group size may also influence antipredator response in congregated fish. We investigated the flight initiation distance (FID) of differently sized groups of dusky damselfish (Stegastes nigricans) to measure their antipredator response to varying sizes of artificial stimuli. We found no effect of shoal size on FID, indicating that damselfish risk assessment is not influenced by group size. However, we did find that stimulus size interacted with starting distance (SD) to affect FID, with damselfish distinguishing between stimulus sizes at shorter SD but not at longer SD. Adjustment of FID in response to varying stimuli indicates that damselfish risk assessment is plastic, and consequently, antipredator responses may be adaptable in changing ocean ecosystems. Because damselfish are herbivores that feed on algae in coral reefs, understanding factors affecting their assessment of risk is important to understanding the overall ecosystem structure. These behavioral responses could be significant in the context of anthropogenic activities, mainly overfishing, which shifts community composition by disproportionately removing larger top predators.

Fear in urban landscapes: conspecific flock size drives escape decisions in tropical birds.

Human-induced disturbances affect animal behaviours such as anti-predatory responses. Animals in urban environments tend to exhibit a reduced escape response, measured as a shorter flight initiation distance (FID), compared to their rural counterparts. While FID has been evaluated in animals dwelling in contrasting habitats (e.g. urban versus rural), little is known about how this response varies within urban environments, especially in tropical cities. Here, we studied the FID of 15 resident bird species in Bogota, Colombia, at 22 sites grouped into four categories (natural sites, metropolitan parks, zonal parks and residential areas) that differed in landscape features and evaluated which factors affected the escape responses of birds. We showed that birds foraging in larger flocks are more tolerant when being approached but they do not seem to be influenced by other factors such as heterospecific flock size, noise levels, pedestrian density, predator density, natural cover or body length. Also, birds inhabiting residential areas and parks showed a shorter FID compared to birds in natural areas suggesting that they are more tolerant of human-related disturbances compared to their conspecifics that live in natural areas within the city. Our study shows important differences in bird anti-predatory responses within the city and suggests that social strategies (i.e. flocking patterns) may be a mechanism for adapting to human-induced disturbances in urban tropical environments.

Fiddler crabs are unique in timing their escape responses based on speed-dependent visual cues

Predation risk imposes strong selection pressures on visual systems to quickly and accurately identify the position and movement of potential predators.1,2 Many invertebrates and other small animals, however, have limited capacity for distance perception due to their low spatial resolution and closely situated eyes.3,4 Consequently, they often rely on simplified decision criteria, essentially heuristics or "rules of thumb", to make decisions. The visual cues animals use to make escape decisions are surprisingly consistent, especially among arthropods, with the timing of escape commonly triggered by size-dependent visual cues such as angular size or angular size increment.5,6,7,8,9,10 Angular size, however, confuses predator size and distance and provides no information about the speed of the attack. Here, we show that fiddler crabs (Gelasimus dampieri) are unique among the arthropods studied to date as they timed their escape response based on the speed of an object's angular expansion. The crabs responded reliably by running away from visual stimuli that expanded at approximately 1.7 degrees/s, irrespective of stimulus size, speed, or its initial distance from the crabs. Though the threshold expansion speed was consistent across different stimulus conditions, we found that the escape timing was modulated by the elevation at which the stimulus approached, suggesting that other risk factors can bias the expansion speed threshold. The results suggest that the visual escape cues used by arthropods are less conserved than previously thought and that lifestyle and environment are significant drivers determining the escape cues used by different species.

Behavioural and neural responses of crabs show evidence for selective attention in predator avoidance

Selective attention, the ability to focus on a specific stimulus and suppress distractions, plays a fundamental role for animals in many contexts, such as mating, feeding, and predation. Within natural environments, animals are often confronted with multiple stimuli of potential importance. Such a situation significantly complicates the decision-making process and imposes conflicting information on neural systems. In the context of predation, selectively attending to one of multiple threats is one possible solution. However, how animals make such escape decisions is rarely studied. A previous field study on the fiddler crab, Gelasimus dampieri, provided evidence of selective attention in the context of escape decisions. To identify the underlying mechanisms that guide their escape decisions, we measured the crabs’ behavioural and neural responses to either a single, or two simultaneously approaching looming stimuli. The two stimuli were either identical or differed in contrast to represent different levels of threat certainty. Although our behavioural data provides some evidence that crabs perceive signals from both stimuli, we show that both the crabs and their looming-sensitive neurons almost exclusively respond to only one of two simultaneous threats. The crabs’ body orientation played an important role in their decision about which stimulus to run away from. When faced with two stimuli of differing contrasts, both neurons and crabs were much more likely to respond to the stimulus with the higher contrast. Our data provides evidence that the crabs’ looming-sensitive neurons play an important part in the mechanism that drives their selective attention in the context of predation. Our results support previous suggestions that the crabs’ escape direction is calculated downstream of their looming-sensitive neurons by means of a population vector of the looming sensitive neuronal ensemble.

Simulation and Analysis of Coal Mine Safety Escape Routes Based on a Multi-agent Model

In order to discuss the influencing factors of mine escape decision when underground disaster occurs, this paper uses the multi-agent modeling theory to construct the coal mine safety accident escape model. The real escape scenarios of different chamber positions and multiple exits are simulated. Dijkstra algorithm was used for site selection and the shortest escape path is searched by combining breadth-first algorithm and adjacency matrix. The simulation results show that the multi-agent simulation modeling method has great advantages in simulating the evolution of complex systems.

Empirical studies of escape behavior find mixed support for the race for life model.

Escape theory has been exceptionally successful in conceptualizing and accurately predicting effects of numerous factors that affect predation risk and explaining variation in flight initiation distance (FID; predator–prey distance when escape begins). Less explored is the relative orientation of an approaching predator, prey, and its eventual refuge. The relationship between an approaching threat and its refuge can be expressed as an angle we call the “interpath angle” or “Φ,” which describes the angle between the paths of predator and prey to the prey’s refuge and thus expresses the degree to which prey must run toward an approaching predator. In general, we might expect that prey would escape at greater distances if they must flee toward a predator to reach its burrow. The “race for life” model makes formal predictions about how Φ should affect FID. We evaluated the model by studying escape decisions in yellow-bellied marmots Marmota flaviventer, a species which flees to burrows. We found support for some of the model’s predictions, yet the relationship between Φ and FID was less clear. Marmots may not assess Φ in a continuous fashion; but we found that binning angle into 4 45° bins explained a similar amount of variation as models that analyzed angle continuously. Future studies of Φ, especially those that focus on how different species perceive relative orientation, will likely enhance our understanding of its importance in flight decisions.

A Neural Basis for Categorizing Sensory Stimuli to Enhance Decision Accuracy

Sensory stimuli with graded intensities often lead to yes-or-no decisions on whether to respond to the stimuli. How this graded-to-binary conversion is implemented in the central nervous system (CNS) remains poorly understood. Here, we show that graded encodings of noxious stimuli are categorized in a decision-associated CNS region in Drosophila larvae, and then decoded by a group of peptidergic neurons for executing binary escape decisions. GABAergic inhibition gates weak nociceptive encodings from being decoded, whereas escalated amplification through the recruitment of second-order neurons boosts nociceptive encodings at intermediate intensities. These two modulations increase the detection accuracy by reducing responses to negligible stimuli whereas enhancing responses to intense stimuli. Our findings thus unravel a circuit mechanism that underlies accurate detection of harmful stimuli.

Sneakers take a predation risk to gain sneaking opportunities

The act of mating increases predation risk by hindering an animal's ability to detect and escape from predators efficiently. Here, a novel issue of how alternative reproductive tactics differently influence these abilities was examined in the triplefin blenny, Enneapterygius etheostoma. A slow predator approach was presented to males with different mating tactics (territorial and sneaking) and mating states (mating and nonmating), totalling four combinations. Predator–male distance when males became wary was independent of tactics. The distance was shorter for mating males than nonmating males, but only when males faced away from the stimulus. Thus, mating state diminished the capacity for detecting danger similarly for both tactics. Predator–male distance when males initiated the escape was well predicted by mating state in sneakers, with shorter distances for mating individuals; however, the same was not obvious in territorial males. Consequently, sneakers escaped later than territorial males during mating, but both males escaped at a similar distance from the predator when in a nonmating state. Instead, mating territorial males returned to the spawning sites earlier than nonmating males. Overall, sneakers made bold escape decisions, whereas territorial males became risk prone when returning to the spawning sites. In conclusion, sneaking males pay a predation cost when mating.

Childhood Trauma and Escape Decision Dynamics

Childhood Trauma and Escape Decision Dynamics

Intraspecific variation in tree lizard escape behaviour in relation to habitat and temperature

Abstract Optimal escape theory has proven useful for understanding the dynamics of antipredator behaviour in animals; however, approaches are often limited to single-population studies. We studied how the escape behaviour of tree lizards (Urosaurus ornatus) varied across a disturbance gradient. We also considered how sex, body temperature, and perch temperature affected their escape decisions. Both sexes exhibited similar response patterns; however, lizards in the most-disturbed habitat, as well as cooler (body or perch temperature) lizards, initiated escape earlier (but did not flee further) than other animals. Increased wariness as indicated by earlier escape suggests that frequently-disturbed, more-open localities may be stressful habitats for species like U. ornatus. In addition, because cooler temperatures limit locomotor performance capacity, escape decisions should also depend on a species’ thermal ecology. Overall, we stress the importance of multi-population approaches for capturing the variety of ways species adaptively respond to the threat of predation across habitat gradients.

Deciphering interactions between white-tailed deer and approaching vehicles

Deer-vehicle collisions are a major transportation hazard, but factors affecting deer escape decision-making in response to vehicle approach remain poorly characterized. We made opportunistic observations of deer response to vehicle approach during daylight hours on a restricted-access facility in Ohio, USA (vehicle speeds were ≤64 km/h). We hypothesized that animal proximity to the road, group size, vehicle approach, and ambient conditions would affect perceived risk by white-tailed deer (Odocoileus virginianus) to vehicle approach, as measured by flight-initiation distance (FID). We constructed a priori models for FID, as well as road-crossing behavior. Deer responses were variable and did not demonstrate spatial or temporal margins of safety. Road-crossing behavior was slightly and positively influenced by group size during winter. Deer showed greater FIDs and likelihood of crossing when approached in the road; directionality of approach likely increased the perceived risk. These findings are consistent with antipredator theory relative to predator approach direction.

Social information affects Canada goose alert and escape responses to vehicle approach: implications for animal-vehicle collisions.

BackgroundAnimal–vehicle collisions represent substantial sources of mortality for a variety of taxa and can pose hazards to property and human health. But there is comparatively little information available on escape responses by free-ranging animals to vehicle approach versus predators/humans.MethodsWe examined responses (alert distance and flight-initiation distance) of focal Canada geese (Branta canadensis maxima) to vehicle approach (15.6 m·s−1) in a semi-natural setting and given full opportunity to escape. We manipulated the direction of the vehicle approach (direct versus tangential) and availability of social information about the vehicle approach (companion group visually exposed or not to the vehicle).ResultsWe found that both categorical factors interacted to affect alert and escape behaviors. Focal geese used mostly personal information to become alert to the vehicle under high risk scenarios (direct approach), but they combined personal and social information to become alert in low risk scenarios (tangential approach). Additionally, when social information was not available from the companion group, focal birds escaped at greater distances under direct compared to tangential approaches. However, when the companion group could see the vehicle approaching, focal birds escaped at similar distances irrespective of vehicle direction. Finally, geese showed a greater tendency to take flight when the vehicle approached directly, as opposed to a side step or walking away from the vehicle.ConclusionsWe suggest that the perception of risk to vehicle approach (likely versus unlikely collision) is weighted by the availability of social information in the group; a phenomenon not described before in the context of animal–vehicle interactions. Notably, when social information is available, the effects of heightened risk associated with a direct approach might be reduced, leading to the animal delaying the escape, which could ultimately increase the chances of a collision. Also, information on a priori escape distances required for surviving a vehicle approach (based on species behavior and vehicle approach speeds) can inform planning, such as location of designated cover or safe areas. Future studies should assess how information from vehicle approach flows within a flock, including aspects of vehicle speed and size, metrics that affect escape decision-making.

Slow escape decisions are swayed by trait anxiety.

Theoretical models distinguish between neural responses elicited by distal threats and those evoked by more immediate threats1-3. Specifically, slower 'cognitive' fear responses towards distal threats involve a network of brain regions including the ventral hippocampus (vHPC) and medial prefrontal cortex (mPFC), while immediate 'reactive' fear responses rely on regions such as the periaqueductal grey4,5. However, it is unclear how anxiety and its neural substrates relate to these distinct defensive survival circuits. We tested whether individual differences in trait anxiety would impact escape behaviour and neural responses to slow and fast attacking predators: conditions designed to evoke cognitive and reactive fear, respectively. Behaviourally, we found that trait anxiety was not related to escape decisions for fast threats, but individuals with higher trait anxiety escaped earlier during slow threats. Functional magnetic resonance imaging showed that when subjects faced slow threats, trait anxiety positively correlated with activity in the vHPC, mPFC, amygdala and insula. Furthermore, the strength of functional coupling between two components of the cognitive circuit-the vHPC and mPFC-was correlated with the degree of trait anxiety. This suggests that anxiety predominantly affects cognitive fear circuits that are involved in volitional strategic escape.

Suicidal thoughts and behaviors are associated with an increased decision-making bias for active responses to escape aversive states.

Suicide is a leading cause of death worldwide. Despite decades of clinical and theoretical accounts that suggest that suicidal thoughts and behaviors are efforts to escape painful emotions, little prior research has examined decision making involved in escaping aversive states. We compared the performance of 85 suicidal participants to 44 nonsuicidal psychiatric patients on a novel reinforcement learning task with choices to make either active (i.e., "go") or passive responses (i.e., "no-go") to either escape or avoid an aversive stimulus. We used a computational cognitive model to isolate decision-making biases. We hypothesized that suicidal participants would exhibit a relatively elevated bias for making active responses to escape an aversive state and would show worse performance when escape required a passive response (i.e., "doing nothing" to escape). Our hypotheses were supported: The computational model revealed that suicidal participants exhibited a higher bias for an active response to escape compared with nonsuicidal psychiatric controls, suggesting that this finding was not just the result of the presence of psychopathology. The bias parameter also accounted for unique variance in predicting group status among several constructs previously related to suicidal thoughts and behaviors. This study provides a new method for testing escape decision making and does so using a computational cognitive model, allowing us to precisely index processes underlying suicidal and related behaviors. Future research examining escape decision making from a computational perspective could help link neural processes or environmental stressors to suicidal thoughts or behaviors. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Heterogeneity of decision strategy in collective escape of human crowds: On identifying the optimum composition

IntroductionWe raise the question of whether an escaping crowd can benefit from a mixture (or heterogeneity) of direction-choice-making strategies, and if so, how would an optimal composition of strategies be like. MethodsWe perform extensive computer simulation analyses and examine crowds of evacuees composed of two different behavioural classes in terms of their direction-choice strategies. We examine three possible strategies: (I) follow the majority (II) follow the minority without the possibility of decision update and (III) follow the minority with the possibility of decision update. FindingsResults showed that the types of escape decision strategy and their composition in the crowd vastly impacted on the efficiency of the evacuation process. The numerical analyses showed the followings: (1) The highest degree of optimality was achieved from a homogenous crowd of minority followers with the possibility of decision update. (2) The magnitude of the detriment resulted from greater concentrations of the follow-the-majority strategy in the crowd was much larger than the benefit of having more of the follow-the-minority strategy. (3) The marginal benefit of increasing the concentration of the follow-the-minority strategy largely diminished once this strategy became dominant in the crowd. A substantial portion of this benefit was realised at about 50% concentration level. (4) The system's efficiency was more sensitive to the behavioural strategy when there was only a one-off chance of direction-choice making. ApplicationsThese findings have implications for evacuation management. They offer quantitative evidence on how training or modifying individuals’ decision-making behaviour can potentially facilitate evacuation processes. They provide insight into ideal (or optimum) forms of behaviour.