Christian Agrillo

The male sexual overperception bias describes the male tendency to sometimes misinterpret friendliness in women as sexual interest. Sexual overperception is a risk factor for sexual coercion and therefore deserves special attention in research, especially since differences in this bias across age groups may lead to differences in coercion risk across the lifespan. Previous research has mainly worked with undergraduate students as participants. Considering that other behavioral biases were found to change across the lifespan, this tendency in research was hypothesized to prejudice the results. We reviewed the literature in this field, revealing a mean participant age of 22.9 years across studies on the topic of sexual overperception, which points to the presence of a potential research bias as a function of participants’ age. As far as we are aware, no research efforts attempting to replicate previous findings in samples aged 40 + have been made. The implications of these findings are discussed as well as the possibility of sexual overperception bias as a universal phenomenon. We call for future investigation with older age groups as well as across different cultural contexts to form a broader picture in this field.

Fishes are among the oldest and most diverse groups of vertebrates, encompassing a vast array of species that differ in morphology, ecology, and behavior. While such diversity can pose challenges to comparative cognition research, it can also offer valuable insights into how different ecological and evolutionary pressures shape cognitive abilities. As the earliest diverging extant vertebrates, and the simplest neural architecture, fishes also provide a critical window into the origins and evolution of vertebrate intelligence. However, despite their potential, we have only just begun to scratch the surface of what fish cognition can reveal, in part due to practical limitations that have constrained cross-species comparisons, including the use of small, single-species samples and a lack of standardized testing procedures. To address these challenges, we introduce ManyFishes , the first big team science collaboration dedicated to comparative cognition and behavior in fishes. Here, we discuss the benefits, potential, challenges and solutions, and impact of this large-scale collaborative effort. Like other big team science initiatives, ManyFishes relies on the ability to establish an infrastructure that facilitates communication and coordination among collaborators from diverse backgrounds, while promoting openness, transparency, and reproducibility in fish cognition research. With this paper, we aim to raise awareness of the ManyFishes initiative and invite researchers to join, contribute to, and benefit from this large-scale collaborative effort in future projects.

When animals explore a novel environment, they often aggregate in groups rather than staying isolated to reduce the risks of predation. This effect is known as ‘safety in numbers’ and has been widely reported in terrestrial and aquatic species. Jellyfish are often found to be clustered in the same areas in seas and oceans. Here, we asked whether one reason for such behavior might be the tendency to actively join other conspecifics when encountering novel environments. We observed moon jellyfish ( Aurelia spp.) in a free-choice test measuring the proportion of time spent near conspecifics when they are inserted into an unfamiliar environment. We found evidence that jellyfish detect the presence of other conspecifics and use this information to actively direct their behavior in a given direction. Contrary to what was expected by the ‘safety in numbers’ effect, moon jellyfish have significantly distanced themselves from their social companions throughout the whole observation period. This result suggests that, although moon jellyfish are commonly observed in large aggregates in nature due to various environmental factors, they may exhibit limited social behavior in unfamiliar environments.

Assuming that cognitive complexity follows a single, centralized trajectory overlooks key gaps: (1) the scarcity of cognitive studies on non-centralized species; (2) the potential of alternative neural architectures to support complex behavior; and (3) the influence of ecological niche pressures. Here we present evidence of curiosity-like behavior in a jellyfish, challenging the assumed link between centralized brains and complex cognition.

Understanding inter-species differences in behavioral lateralization and exploration patterns is crucial for advancing the study of animal behavior. In this study, we standardized the experimental procedure to minimize methodological variability and examined the behavioral responses of eight fish species (Girardinus falcatus, Poecilia reticulata, Paracheidon axelrodi, Kriptoterus bichirris, Hyphessobrycon megalopterus, Danio rerio, Corydoras aeneus, and Xenopoecilius sarasinorum) in a novel, circular environment. We focused on boldness-related measures (latency to explore and freezing time) and motor activity (circular vs. linear swimming). Significant inter-species differences were observed in the boldness measures. Fish also showed a preference for circular swimming over linear swimming. However, no lateralization bias (clockwise vs. counterclockwise) was detected in any species. These findings may establish a baseline for future research on the spontaneous behaviors of eight teleost species and offer valuable insights for the design of future behavioral studies focusing on these species.

Several studies have reported an association between music training and enhanced visuo-spatial abilities—for example, musicians have been found to pay greater attention to local details of the visual scene. However, no studies have directly tested whether long-term music training impacts the global-to-local precedence commonly described in literature. We address this issue by comparing the performance of professional musicians and non-musicians in the traditional Navon test, in which it is required to identify large letters (global task) or the small letters composing the larger ones (local task). Our results did not support the idea of musicians having a different global-to-local precedence over non-musicians. However, musicians proved to be faster, without losing accuracy, than non-musicians in both global and local tasks. A control test showed that the two groups did not differ in motor response speed. In agreement with other studies describing an association between music expertise and enhanced cognitive abilities, our results point toward the idea that long-term music training may facilitate the performance in visuo-spatial tasks and, in particular, those tasks that require simultaneous processing of global and local information and inhibiting the irrelevant ones.

The zebrafish model is rapidly advancing numerous areas of basic and translational research, including toxicology, drug discovery, molecular genetics, genomic research, developmental biology, and the study of human diseases (reviewed in

Most studies on the cognitive abilities of fish have focused on model organisms adopted in behavioural neuroscience. To date, little attention has been devoted to characiformes fish and we record a lack of cognitive investigation on the piranha. In this study, we conducted a preliminary set of experiments to assess whether red-bellied piranhas (Pygocentrus nattereri) can solve an automated operant conditioning task, specifically, a reversal learning task. In Experiment 1, the fish were required to discriminate between red and green, while in Experiment 2, they had to discriminate between white and yellow. In either case, we found no evidence of learning capacities with our protocol after extensive training exceeding one thousand trials overall. In Experiment 3, we simplified the learning task by using achromatic stimuli (black and white discrimination) and always presenting the reinforced stimulus on the same side of the tank (a combination of response learning and place learning). Subjects did learn how to discriminate between the colours, although no subject was able to reach the criterion in the subsequent reversal learning task, suggesting that piranhas may be limited in their cognitive flexibility. However, our training procedure may have been inefficient in addressing this issue. We outline some potential limitations of the current methodology to help to establish a more effective approach for investigating operant conditioning in this species.

Summary: Despite some similarities in numerical abilities among vertebrates, animals seem to differ with respect to the perceptual factors underlying numerical estimation. This is particularly evident in the case of numerosity illusions, a type of illusory phenomena elicited by the spatial arrangement of the elements that compose it. We investigated whether an insect experiences the most famous numerosity illusion, the Solitaire Illusion. Bumblebees ( Bombus terrestris audax ) presented with two mixed arrays containing magenta and yellow dots were trained to select the array containing the larger number of a target colour (either magenta or yellow). In the test phases, bumblebees were presented with sets of stimuli differing in the numerical ratio, including the illusory arrays: in one array, magenta dots were centrally located (yellow dots in the perimeter), whereas in the other one, magenta dots were located in the perimeter (yellow dots in the centre). Bees discriminated up to a ratio of 0.78 (14 vs. 18). Video analyses showed that bumblebees sequentially scanned the stimuli before making a choice. Bumblebees required longer scanning time for patterns with smaller numbers of reinforced colour dots, suggesting that bumblebees spent longer time on searching for more information or finding a reinforced arrangement of spatial dots before making an accurate decision. In the presence of the “illusion arrangement”, bees behaved in a manner consistent with misperception of numerosity, overestimating the number of centrally located dots. The spatial configuration of the stimuli influenced how the patterns were assessed: bees examined the clustered reinforced colour dots longer. Flying paths analysis suggested that bumblebees followed the paths formed by similar colour dots rather than counting each dot to make a numerical discrimination. These results challenge the notion that visual illusions can be inferred simply from evaluating choices of different visual patterns and reinforce the idea that multiple strategies can potentially be used to achieve seemingly similar cognitive outcomes. Detailed analyses of decision-making processes are essential to deduce the cognitive strategies underpinning discrimination tasks, whether they are numerical or other visual tasks.