Behavioural Processes最新文献

Spontaneously Hypertensive Rats (SHR) have been extensively studied as an animal model of Attention Deficit Hyperactivity Disorder (ADHD) because they show some of the defining features of that disorder, like some forms of impulsivity and hyperactivity. However, other characteristics of the disorder, like a deficit in motivation, have been scarcely studied in the SHR strain. In the present report, we studied in 45 SHR and 45 Wistar rats as a comparison group, the capacity of attribution of incentive salience to a stimulus predictor of reinforcement, which has become a central concept in the study of motivation. We employed the Pavlovian Conditioned-Approach (PCA) task, in which a lever is presented 8 s before a pellet is delivered. The attribution of incentive salience is indicated by responses to the lever, in contrast to the absence of attribution of incentive salience, which is indicated by entrances to the pellet receptacle. For quantifying the attribution of incentive salience, we employed the PCA index, which integrates three related variables for each type of response, lever presses and entrances to the feeder: 1) the number of responses, 2) the latency to the first response, and 3) the probability that at least one response occurred during the presence of the lever. SHR showed lower levels of PCA, suggesting a deficit in the attribution of incentive salience to the lever. This finding replicates the results reported by previous research that compared SHR’s performance in the PCA task against that of Sprague-Dawley rats.

Understanding how animal collectives and societies form and function is a fundamental goal in animal biology. To date, research examining fish shoaling behavior has focused mostly on the general principles and ecological relevance of the phenomeon, while the ways in which physiological state (e.g., nutrition) affects collective behavior remain overlooked. Here, we investigated the shoaling behavior of common minnows (Phoxinus phoxinus) with three different nutritional states (control treatment: fasting for 24 h, fasting treatment: fasting for 7 days, and digestion treatment: 1 h after satiation feeding) across two ecological contexts (i.e., without and with food). No effects of either nutritional state or context were found on swimming speed, but the acceleration was greater in the digestion group than in the control group, with that in the fasting group being intermediate. Similar to change tendency in group length and group width of shoals, both interindividual distance and nearest neighbor distance were also greater in the fasting group than in the digestion group, suggesting that fasting and digestion may exert opposite driving forces on group cohesion. However, neither nutritional state nor context influenced the group area, group speed, group percent time moving, or group polarization. Both the foraging efficiency and the percentage of food items consumed by the fish shoals were greater in the fasting and control groups than in the digestion group. Our study suggested that one week of hunger and the energetically demanding stage of food digestion tend to have opposite influences on group shape, while the social foraging context does not influence the individual and group behavior of fish.

The phenomenon of extinction-induced resurgence is well established, but there is comparatively little experimental evidence for punishment-induced resurgence. Punishment-induced resurgence can by tested by contingent shocks following the alternative response. The purpose of Experiment 1 was to test whether low-intensity shocks, that do not decrease rate of reinforcement, result in resurgence. Four rats served as subjects. Rats were exposed to three sequential conditions: (a) variable-interval (VI) 30-s food delivery for a lever press (target response); (b) VI 30-s food delivery for a nose poke (alternative response) and extinction of the lever press; (c) VI 30-s reinforcement for a nose poke with superimposed VI 60-s shock delivery. In the final condition, shocks increased gradually from 0.1 to 0.5 mA. Experiment 2 evaluated whether an abrupt introduction of a high-intensity shock would result in resurgence. Three rats served as subjects and were exposed to three sequential conditions: (a) VI 30-s food delivery for a lever press; (b) VI 30-s food delivery for a nose poke and extinction of the lever press; (c) continued VI 30-s reinforcement for a nose poke with superimposed VI 60-s 0.6 mA shock delivery. Resurgence was observed in all subjects, including in situations in which rate of responding, but not rate of reinforcement, decreased. The present study provides additional evidence for punishment-induced resurgence, but future studies are warranted to determine the extent to which punishment can produce resurgence with or without decreases in rates of reinforcement.

The nearest-neighbour distance is an important property of a group, as individuals can obtain environmental information more quickly and easily from nearby individuals. We examined whether distance to the nearest neighbour affected two components of escape behaviour – alert distance (AD) and flight initiation distance (FID) – in an urban population of hooded crows Corvus cornix, while controlling for confounding variables. We did not find evidence that AD and FID were influenced by the nearest neighbour distance. However, both AD and FID were negatively affected by feeding activity of individuals – focal crows alerted later and escaped at shorter distance if they were feeding during our approach. In addition, AD and FID were positively related to starting distance and grass coverage. The lack of evidence for the nearest neighbour effect on escape behaviour of crows may be due to: (1) disturbance by close neighbours that may impede antipredator behaviour of focal birds, (2) variable distribution of familiar, dominant or experienced individuals within a flock, and (3) dynamic change in position of the nearest neighbour during the potential predator approach.

Aquatic prey have impressive abilities to extract information from a variety of chemical cues. For example, they can use the alarm cues released by wounded individuals during a predator attack to learn about predation risk, and they can also distinguish kin from non-kin individuals during interactions. However, it remains unclear whether animals can combine this information on predation risk with kin recognition of the particular individuals under threat. To examine how the relatedness of the individuals in alarm cue affects behaviour we used the self-fertilizing hermaphroditic mangrove rivulus (Kryptolebias marmoratus), in which lineages produce genetically identical offspring through selfing. We explored this in two populations that differ in their level of outcrossing. We measured activity before and after exposure to alarm cue made from individuals (either adults or embryos) from their own lineage or an unrelated lineage from the same population. Fish responded weakly to embryo alarm cues, but tended to reduce their activity more when the alarm cues were from an unrelated lineage compared to alarm cues from their own lineage, particularly in fish from the outcrossing population. In contrast, there was no effect of cue relatedness on the response to adult alarm cues but there was a strong population effect. Specifically, individuals from the outcrossing population tended to react more strongly to alarm cues compared to individuals from the predominantly selfing population. We discuss the potential roles of the major histocompatibility complex in cue detection, differences between adult vs embryo alarm cues in terms of concentration and information, and underlying differences among populations and genetic lineages in their production and detection of chemical cues. Whether this kin recognition offers adaptive benefits or is simply a consequence of being able to detect relatedness in living individuals would be an exciting area for future research.

Ventilation is critical to animal life—it ensures that individuals move air/water across their respiratory surface, and thus it sustains gas exchange with the environment. Many species have evolved highly specialized (if not unusual) ventilatory mechanisms, including the use of behavior to facilitate different aspects of breathing. However, these behavioral traits are often only described anecdotally, and the ecological conditions that elicit them are typically unclear. We study one such “ventilation behavior” in Lake Titicaca frogs (Telmatobius culeus). These frogs inhabit high-altitude (i.e., low oxygen) lakes in the Andean Mountains of South America, and they have become textbook examples of cutaneous gas exchange, which is essentially breathing that occurs across the skin. Accordingly, this species has evolved large, baggy skin-folds that dangle from the body to increase the surface area for ventilation. We show that individuals exposed to acute hypoxic conditions that mirror what free-living individuals likely encounter quickly (within minutes) decrease their activity levels, and thus become very still. If oxygen levels continue to decline, the frogs soon begin to perform push-up behaviors that presumably break the low-oxygen boundary layer around skin-folds to increase the conductance of the water/skin gas exchange pathway. Altogether, we suspect that individuals rapidly adjust aspects of their behavior in response to seemingly sudden changes to the oxygen environment as a mechanism to fine tune cutaneous respiration.

In the biological sciences, sexual behaviours in non-human animals are traditionally investigated in the context of reproduction and direct fitness benefits. While the evolutionary functions of non-conceptive sexual behaviours (‘socio-sexual behaviours’) remain less well explored, these interactions and displays have been suggested to be important for shaping and maintaining social relationships. Here, we report an observation of a captive female carrion crow, Corvus corone corone, mounting her co-housed male partner. We highlight the importance of more systematic research, reporting, and discussions of rarely observed behaviours in social evolution research, including considerations for behaviours that transcend binary or heteronormative frameworks, for a more comprehensive understanding of non-conceptive socio-sexual behaviours.

Urban parks are essential for community revitalization; for example, they are places to walk dogs and interact with other dog keepers. This study focused on an urban park with a dog-friendly area to be used by both dog keepers and other users as an alternative to off-leash dog parks that completely separate them and clarified aspects of park use through behavioral observation. The behaviors of 7122 visitors in 14 areas in the park and 294 pairs of dogs and their keepers in the dog-friendly area were observed. The results showed that the visitors’ age groups and use behaviors differed by area. The dog-friendly area was in constant demand among dog keepers as a place where they could stay and interact with others and as a destination or relay point when walking their dogs. Visitors used the park in accordance with rules and morals, and the park was well managed. As it can be comfortably used by everyone (with or without dogs), this park can serve as a model for the development and maintenance of community-based multifunctional parks in urban areas.

Delay discounting refers to the decrease in subjective value of a reward as the delay until its receipt increases. In the present study we assessed the effects of the sequence of delay blocks (increasing or decreasing) on discounting and the data systematicity using a titrating procedure with human participants. All participants completed the delay discounting task in both an increasing and decreasing sequence of delays. Delays ranged from one day to ten years. We found steeper discounting when the delays were presented in an increasing sequence compared with when they were presented in a decreasing sequence. We also found steeper discounting when participants completed the increasing sequence condition first. Our results agree with other findings reported in the literature and suggest that delay discounting may be affected by prior and subsequent experience.

This study evaluated the effect of delay and magnitude of reinforcement in Pavlovian contingencies, extending the understanding of the phenomenon of autoshaped impulsivity as described in Alcalá's thesis (2017) and Burgos and García-Leal (2015). The effects of adding a trace interval were analyzed on the maintained responses of impulsive choice, seen as the preference of a small and immediate reinforcer over a larger and delayed one, and the role of the contextual unit, as well as the inhibitory units according to the Diffuse Discrepancy Model. In the Simulation, the model with inhibitory units was used, trained in two signals with different delays and reinforcement magnitudes, and subsequently presented concurrently in choice tasks without reinforcement nor learning, using an ABA within-subject design. In general, the DD model successfully simulated the phenomenon of autoshaped impulsivity, consistent with studies from Alcalá's thesis (2017), Burgos and García-Leal (2015), and Picker and Poling (1982). It also predicted the elimination of this effect (autoshaped impulsivity) after introducing a trace interval. The observed results and their implications are discussed, as well as possible future studies with animals and humans.