Journal of Comparative Psychology

The ephemeral reward task involves providing subjects with a choice between two distinctive stimuli, A and B, each containing an identical reward. If A is chosen, the reward associated with A is obtained and the trial is over. If B is chosen, the reward associated with B is obtained but A remains, and the reward associated with A can be obtained as well. Thus, the reward-maximizing solution is to choose B first. Although cleaner fish (wrasse) and parrots easily acquire the optimal response by choosing B, paradoxically, several nonhuman primate species, as well as rats and pigeons, do not...

Neophilia is a measure of individuals' attraction to novelty and is thought to provide important fitness benefits related to the acquisition of information and the ability to solve novel problems. Although neophilia is thought to vary across individuals and species, few studies have made direct comparisons to assess the factors that predict this variation. Here we operationalized neophilia as the probability of interacting with novel objects and compared the response to familiar and novel objects in 53 captive individuals belonging to seven different primate species: chimpanzees (Pan troglodytes ), bonobos ( Pan paniscus ), Sumatran orangutans ( Pongo abelii ), gorillas ( Gorilla gorilla ), long-tailed macaques ( Macaca fascicularis ), tufted capuchin monkeys ( Sapajus apella ), and Geoffroy's spider monkeys ( Ateles geoffroyi )...

The ability to quickly perceive and interpret threatening facial expressions from others is critical for successfully maintaining group cohesion in social nonhuman primate species. Rapid detection of threatening or negative stimuli in the environment compared to neutral stimuli, referred to as an attentional bias toward threat, is adaptive in that faster threat detection can lead to greater survival outcomes. However, the evolutionary roots of attentional bias formation toward social threat are not well understood...

Meter induction is a key process for rhythm perception. However, while some nonhuman animals readily detect temporal regularities and perceive beats in auditory sequences, there is no consistent evidence that they extract metrical structures. In the present experiment, we familiarized rats (Rattus norvegicus ) to auditory rhythmic sequences that evoked a duple or a triple meter. We then tested their recognition of these familiar sequences when pitted against novel sequences that evoked no meter (isotonic), evoked a different meter (either duple or triple), or were nonmetrical (nonisochronous)...

Based on the invention and development of photography and movie in the 19th century, schools of contemporary art, such as Futurism, have emerged that express the dynamism of motion in painting. Painting techniques such as multiple stroboscopic images, motion blur, and motion lines are culturally based, but the biological basis of their perception has also been intensively investigated recently. Then what are the evolutionary origins of such pictorial representations of motion? Do nonhuman animals also have sensitivity to such representations? To address this question, we examined the effects of motion blur and motion lines on the judgments of global motion directions in chimpanzees...

Animals navigate complex environments that present both hazards and essential resources. The prioritization of perceptual information that is relevant to their next actions, such as accessing or avoiding different resources, poses a potential challenge to animals, one that can impact survival. While animals' attentional biases toward negatively valanced and threatening stimuli have been explored, parallel biases toward differently valued resources remain understudied. Here, we assessed whether three primate species (chimpanzees [ Pan troglodytes ], gorillas [ Gorilla gorilla gorilla ], and Japanese macaques [ Macaca fuscata ]) prioritized their attention to positively valued resources-preferred foods compared to unpreferred foods...

Delay of gratification and inhibitory control are generally considered measures of self-control. In humans, individual differences in measures of self-control are associated with a host of behavioral, neurological, cognitive, and health-related outcomes. Self-control is not unique to humans and has been demonstrated in a variety of nonhuman species using a variety of paradigms. In this study, the effect of sex and age on delay of gratification performance, as measured by the hybrid delay task, was tested in a sample of 88 chimpanzees...

Dogs are able to cooperate in reciprocal exchange with humans but little is known about the extent of these abilities (Range & Virányi, 2015). In the Still Face paradigm, infants reply to a sudden nonreciprocal facial expression with gaze aversion and an increase in re-engagement and distress behaviors (E. Tronick et al., 1978). We directly adapted this method; the dog's owner talked to the dog, then abruptly switched to a still, neutral face, maintaining eye contact. In Study 1 ( N = 20), we found that dogs showed a significant decrease in the amount of looking at the owner in the Still Face phase, paralleling the results found in gaze aversion in infants, and they performed fewer pawing and vocalizations toward the person in the Still Face phase...

Animals can use asocial (e.g., environmental cues) or social (e.g., conspecific behavior) information when making decisions. We investigated decisions made by zebra finches when asocial and social sources conveyed agreeing or conflicting information, and assessed the influence of initial bias on decision making. Finches completed an initial preference test ranking preference for three colors of nest-building material. Birds in the agree group ( n = 14) then observed demonstrators build nests using nonpreferred color material (social information) that matched the environment color (asocial information)...

Engaging executive functions provides an individual with the means to engage in cognitive control by adjusting to the environment and processing information in a way that leads to optimal outcomes. There are some claims that explicit training on certain executive functioning abilities provides benefits beyond the training tasks, but other studies indicate that this may not be true or may be limited based on age and other factors. This same mixed pattern has been reported with nonhuman species, where training or even experience in one specific area, like inhibition, sometimes leads to positive transfer in new but similar tasks that presumably also require executive functions...

The Journal of Comparative Psychology (JCP) is the flagship APA journal dedicated to understanding psychological processes from a comparative perspective. Traditionally, "comparative" has meant comparison across species. However, "comparative" means more than just assessing as many species as possible or relating species to each other. I also think of the importance of a "comparative psychology" perspective in two other ways that should be reflected in the journal's publications. I would like to outline a few important points about how I view the mission of JCP, and how my term as chief editor will address some of the major issues that exist for the journal and for the field of comparative psychology more broadly...

Many animals, including humans, must make decisions when outcomes involve risk and/or ambiguity. To explore the evolutionary roots of decision making when outcomes are unknown, we modified the Balloon Analogue Risk Task (BART) for use with tufted capuchin monkeys ( Sapajus [Cebus] apella ), creating the Primate Analogue Risk Task (PART). Using both the BART and the PART, we first compared human performance across the two tasks using analogous parameters. Humans' performance on the two tasks was positively correlated...

Exploratory behaviors describe the actions performed by an animal to obtain information on an object, environment, or individual by using its different senses. Exploration is described in some marine mammals, but not yet in manatees. Our study investigated behavioral and acoustic responses of two groups of Antillean manatees ( N = 12 and N = 4) housed in zoological parks toward various stimuli involving three sensory modalities: visual, tactile, and auditory. Simultaneous audio and video recordings were collected during three periods of time (i...

Black-capped chickadees ( Poecile atricapillus ) and other species that feed at bird feeders balance the benefit of easy foraging with the added risk of predation. Individual birds respond differently to risky situations, and these differences have been attributed to the birds' personalities, which researchers commonly assess with an "open-field" behavioral assay. However, these behavioral assays in birds have not been compared to behavior in the wild in the context of foraging in the presence of a predator (i...

The traveling salesman problem (TSP) is an optimization problem in which the goal is to find the shortest possible route that passes through each of a set of points in space. The TSP is of interest not only in the fields of mathematics, computer science, and engineering, but also in cognitive and behavioral research to study problem-solving and spatial navigation. Humans are able to complete even complex TSPs with a high degree of efficiency, and distance minimization in TSP analogs has been observed in a variety of nonhuman species as well...

Prikrylová et al. (see record 2023-79461-001) contribute a paper to this issue in which they tested two-dimensional individual recognition of familiar subjects in African gray parrots. They not only tested familiar individual recognition per se but also the effect of manipulating individual and combined features in the head and the body of their stimuli. Notably, instead of using discrimination tasks, which have previously been applied in bird studies (e.g., Hauser & Huber-Eicher, 2004; Nakamura et al...

A growing body of research demonstrates that humans can accurately perceive the emotional states of animals solely by listening to their calls, highlighting shared evolutionary ancestry. Yet, the cognitive and perceptual mechanisms underlying heterospecific emotion perception have remained open to investigation. One hypothesis is that humans rely on simple acoustic heuristics to make such judgments, for example, perceiving higher-pitched calls as reflecting heightened emotional arousal (the "pitch rule"). This could lead to accurate judgments of emotion since in most mammals, as in humans, vocal fundamental frequency (the acoustic determinant of the pitch percept) does objectively correlate with emotional arousal...

When making decisions, humans often strive to uphold objective, absolute standards, such as about what is small versus large, blue versus purple, or unfair versus fair, suggesting that our judgments should not be swayed by extraneous factors such as the sequence or frequency of events to be judged. Yet in previous research, when some items (e.g., threatening faces) became less frequent, humans responded by expanding their concept (of "threatening") to include more ambiguous stimuli. We assessed the origins of this perceptual frequency bias by testing 25 capuchins, seven rhesus monkeys, and 102 humans on a computer task in which they had to classify one circle at a time (pulled from a continuum of 50 circle sizes) as either small or large...

Goodyear and Kamil (2004) assessed the ability of Clark's nutcrackers to find buried food based on a cross-shaped array of landmarks at different distances from the goal. Their findings suggested that proximal landmarks overshadowed learning about distal landmarks, and this was attenuated when assessing the effect of distal landmarks on learning about proximal landmarks. In this study, we aimed to replicate their findings in human spatial navigation by using a virtual environment. Three groups of participants were trained in an open environment featuring orientation cues, and they had to find a hidden goal with reference to four landmarks that were arranged in the shape of a cross and placed at different distances from the goal...

A defining feature of most primates is a hand with five fingers. Spider monkeys are an exception because they have four fingers and no thumb. Despite the prevalence of reach-to-grasp research in primates, it is not known how the lack of a thumb affects reaching and grasping in spider monkeys. Drawing on patterns that have been well described in human adults, human infants, and other nonhuman primates, this study characterized prehension in Colombian spider monkeys ( Ateles fusciceps rufiventris ). Monkeys reached for two differently sized food objects and reaches were digitized offline for two-dimensional kinematic analysis...