Mikel M. Delgado

The Evolution of Self-Control

Significance Although scientists have identified surprising cognitive flexibility in animals and potentially unique features of human psychology, we know less about the selective forces that favor cognitive evolution, or the proximate biological mechanisms underlying this process. We tested 36 species in two problem-solving tasks measuring self-control and evaluated the leading hypotheses regarding how and why cognition evolves. Across species, differences in absolute (not relative) brain volume best predicted performance on these tasks. Within primates, dietary breadth also predicted cognitive performance, whereas social group size did not. These results suggest that increases in absolute brain size provided the biological foundation for evolutionary increases in self-control, and implicate species differences in feeding ecology as a potential selective pressure favoring these skills. Cognition presents evolutionary research with one of its greatest challenges. Cognitive evolution has been explained at the proximate level by shifts in absolute and relative brain volume and at the ultimate level by differences in social and dietary complexity. However, no study has integrated the experimental and phylogenetic approach at the scale required to rigorously test these explanations. Instead, previous research has largely relied on various measures of brain size as proxies for cognitive abilities. We experimentally evaluated these major evolutionary explanations by quantitatively comparing the cognitive performance of 567 individuals representing 36 species on two problem-solving tasks measuring self-control. Phylogenetic analysis revealed that absolute brain volume best predicted performance across species and accounted for considerably more variance than brain volume controlling for body mass. This result corroborates recent advances in evolutionary neurobiology and illustrates the cognitive consequences of cortical reorganization through increases in brain volume. Within primates, dietary breadth but not social group size was a strong predictor of species differences in self-control. Our results implicate robust evolutionary relationships between dietary breadth, absolute brain volume, and self-control. These findings provide a significant first step toward quantifying the primate cognitive phenome and explaining the process of cognitive evolution.

Human perceptions of coat color as an indicator of domestic cat personality

ABSTRACT Associations between mammalian coat color and behavior have been investigated in a number of species, most notably the study of silver foxes by the Institute of Cytology and Genetics at the Russian Academy of Sciences. However, the few studies conducted regarding a potential relation between coat color and domestic cat personality have shown mixed results, even though many people believe that differently colored cats have distinct personalities. Understanding how humans might perceive personality in relation to coat color may have important ramifications regarding whether cats are relinquished to shelters or adopted from them. In order to assess human perceptions of differently colored cats, we conducted an anonymous, online survey, using a 7-point Likert scale and 10 terms describing personality traits that were chosen based on previous studies of animal personality. This survey examined how people assigned these given terms (active, aloof, bold, calm, friendly, intolerant, shy, stubborn, tolerant, and trainable) to five different colors of cats (orange, tricolored, white, black, and bi-colored). There were significant differences in how participants in this study chose to assign personality terms to differently colored cats. For example, participants (n = 189) were more likely to attribute the trait “friendliness” to orange cats, “intolerance” to tri-colored cats, and “aloofness” to white and tri-colored cats. No significant differences were found for “stubbornness” in any colors of cats. White cats were seen as less bold and active and more shy and calm than other colors of cats. While survey respondents stated that they placed more importance on personality than color when selecting a companion cat, there is some evidence that they believe the two qualities are linked. We anticipate our findings will be relevant to further study in domestic cat personality and to those who work in animal rescue, particularly in how shelters promote differently colored cats and educate potential adopters.

Are emotionally attached companion animal caregivers conscientious and neurotic? Factors that affect the human-companion animal relationship.

Few studies have examined how personality traits may be related to the amounts and types of attachments humans have toward companion animals (pets). In this study, 1,098 companion animal guardians (owners) completed a survey that included the Big Five Inventory, the Lexington Attachment to Pets Scale, and the Pet Attachment Questionnaire. Each participant chose whether he or she identified as a Cat Person, Dog Person, Both, or Neither. Results indicated that neuroticism, conscientiousness, choosing a dog as a favorite pet, and identifying as a Cat Person, Dog Person, or Both predicted affection for a pet. Conscientiousness, extraversion, and openness decreased avoidant attachment to pets, and neuroticism increased anxious attachment to pets. Both dogs and cats could benefit from pet owners who are conscientious, and there may be some benefits of neuroticism in pet owners. The findings of this study will advance understanding of the human–animal bond. As this understanding increases, measurements of human attachment and personality may be useful for the development of tools that could assist shelter employees and veterinarians in counseling people about pet ownership.

Food puzzles for cats Feeding for physical and emotional wellbeing

Practical relevance: Many pet cats are kept indoors for a variety of reasons (eg, safety, health, avoidance of wildlife predation) in conditions that are perhaps the least natural to them. Indoor housing has been associated with health issues, such as chronic lower urinary tract signs, and development of problem behaviors, which can cause weakening of the human–animal bond and lead to euthanasia of the cat. Environmental enrichment may mitigate the effects of these problems and one approach is to take advantage of cats’ natural instinct to work for their food. Aim: In this article we aim to equip veterinary professionals with the tools to assist clients in the use of food puzzles for their cats as a way to support feline physical health and emotional wellbeing. We outline different types of food puzzles, and explain how to introduce them to cats and how to troubleshoot challenges with their use. Evidence base: The effect of food puzzles on cats is a relatively new area of study, so as well as reviewing the existing empirical evidence, we provide case studies from our veterinary and behavioral practices showing health and behavioral benefits resulting from their use.

Inaccessibility of reinforcement increases persistence and signaling behavior in the fox squirrel (Sciurus niger).

Under natural conditions, wild animals encounter situations where previously rewarded actions do not lead to reinforcement. In the laboratory, a surprising omission of reinforcement induces behavioral and emotional responses described as frustration. Frustration can lead to aggressive behaviors and to the persistence of noneffective responses, but it may also lead to new behavioral responses to a problem, a potential adaptation. We assessed the responses to inaccessible reinforcement in free-ranging fox squirrels (Sciurus niger). We trained squirrels to open a box to obtain food reinforcement, a piece of walnut. After 9 training trials, squirrels were tested in 1 of 4 conditions: a control condition with the expected reward, an alternative reinforcement (a piece of dried corn), an empty box, or a locked box. We measured the presence of signals suggesting arousal (e.g., tail flags and tail twitches) and found that squirrels performed fewer of these behaviors in the control condition and increased certain behaviors (tail flags, biting box) in the locked box condition, compared to other experimental conditions. When faced with nonreinforcement, that is, frustration, squirrels increased the number of interactions with the apparatus and spent more time interacting with the apparatus. This study of frustration responses in a free-ranging animal extends the conclusions of captive studies to the field and demonstrates that fox squirrels show short-term negatively valenced responses to the inaccessibility, omission, and change of reinforcement. (PsycINFO Database Record

Development and Psychometric Evaluation of the Cat Care and Needs Scale (CCANS)

ABSTRACT The objective of this study was to develop a brief scale, primarily intended for research applications, that measures how well people report meeting the welfare needs of their pet cats. The practice of keeping cats as a companion animal has increased, and despite their popularity, many cats suffer from poor welfare and behavioral problems. The failure to meet their welfare needs and provide for natural behaviors impacts their quality of life and may affect cats’ retention in adoptive homes. We present three studies in which we developed, piloted, and psychometrically evaluated the Cat Care and Needs Scale (CCANS) by surveying cat guardians, examining their selfreported care-taking habits and interactions in regards to a pet cat. The final study (n = 1,591) resulted in a 15-item scale which shows high reliability, with application of item response theory indicating that individual items were all suitable for inclusion. Diverse evidence, including a factor analysis, parallel analysis, and confirmatory factor analysis, supports that the scale is unidimensional. The CCANS is scalable and allows for correlational comparisons with other scales which measure any variable of interest in research exploring human–companion animal relationships or cat welfare. We propose that the CCANS scale is a step forward in measuring how well pet owners understand and meet their cats’ behavioral, welfare, and basic care needs.

Caching for where and what: evidence for a mnemonic strategy in a scatter-hoarder

Scatter-hoarding animals face the task of maximizing retrieval of their scattered food caches while minimizing loss to pilferers. This demand should select for mnemonics, such as chunking, i.e. a hierarchical cognitive representation that is known to improve recall. Spatial chunking, where caches with the same type of content are related to each other in physical location and memory, would be one such mechanism. Here we tested the hypothesis that scatter-hoarding eastern fox squirrels (Sciurus niger) are organizing their caches in spatial patterns consistent with a chunking strategy. We presented 45 individual wild fox squirrels with a series of 16 nuts of four different species, either in runs of four of the same species or 16 nuts offered in a pseudorandom order. Squirrels either collected each nut from a different location or collected all nuts from a single location; we then mapped their subsequent cache distributions using GPS. The chunking hypothesis predicted that squirrels would spatially organize caches by nut species, regardless of presentation order. Our results instead demonstrated that squirrels spatially chunked their caches by nut species but only when caching food that was foraged from a single location. This first demonstration of spatial chunking in a scatter hoarder underscores the cognitive demand of scatter hoarding.

Data Caching for Where and What.xlsx

Excel file of data used in analyses. Data is a measure of how much squirrels overlapped caches by nut type under different experimental conditions.