Predictions about reward outcomes in rhesus monkeys.

Human infants and nonhuman animals respond to surprising events by looking longer at unexpected than expected situations. These looking responses provide core cognitive evidence that nonverbal minds make predictions about possible outcomes and detect when these predictions fail to match reality. We propose that this phenomenon has crucial parallels with the processes of reward prediction error, indexing the difference between expected and actual reward outcomes. Most work on reward prediction errors to date involves neurobiological techniques that cannot be implemented in many relevant populations, so we developed a novel behavioral task to assess monkeys' predictions about reward outcomes using looking time responses. In Study 1, we tested how semi-free-ranging monkeys (n = 210) responded to positive error (more rewards than expected), negative error (less rewards than expected), and a number control. We found that monkeys looked longer at a given reward when it was unexpectedly large or small, compared to when the same quantity was expected. In Study 2, we compared responses in the positive error condition in monkeys ranging from infancy to old age (n = 363), to assess lifespan changes in sensitivity to reward predictions. We found that adolescent monkeys showed heightened responses to unexpected rewards, similar to patterns seen in humans, but showed no changes during aging. These results suggest that monkeys' looking responses can be used to track their predictions about rewards, and that monkeys share some developmental signatures of reward sensitivity with humans, providing a new approach to access cognitive processes underlying reward-based decision making. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The influence of interactions with pet dogs on psychological distress.

Many people, including nearly half of American households, own a pet dog. Previous work has found that therapy dog interactions reduce distress, but little work to date has empirically established the mood-enhancing effects of interaction with one's own pet dog. In this study, dog owners (N = 73; 86.3% female, 13.7% male; age 25-77 years) underwent a stress-inducing task followed by random assignment to either (a) interacting with their dog (n = 24), (b) an expectancy control (n = 25; "stress-reducing" coloring books), or (c) a waiting control (n = 24). We compared the effects of each condition on affect and state anxiety. Participants assigned to the dog interaction showed greater increases in positive affect, as well as greater reductions in anxiety compared to both expectancy and waiting controls (ds > 0.72, ps < .018). No significant reductions in negative affect were detected. Second, we found that self-reported experiences with animals, attitudes toward animals, or bondedness with their dog did not differentially predict the condition's impact on the owner's mood. Finally, we coded participants' degree of engagement (e.g., time spent playing) with the dog and found that higher engagement predicted reduced negative affect. Overall, interacting with one's own pet dog reduced owners' distress. Such interactions, which occur commonly in daily life, may have the potential to alleviate distress at a large scale. Precisely how this works and for whom it is especially well suited remain intriguing open questions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Impact of the Dog-Human Bond on Canine Social Evaluation: Attachment Predicts Preference toward Prosocial Actors.

Scholars have argued that social evaluation, the capacity to evaluate different potential social partners, is an important capacity not just for humans but for all cooperative species. Recent work has explored whether domesticated dogs share a human-like ability to evaluate others based on prosocial and antisocial actions toward third parties. To date, this work has shown mixed results, suggesting that individual differences may play a role in dogs' capacity to evaluate others. In the present study, we test whether attachment-an individual difference that affects human social evaluation performance-can explain the mixed pattern of social evaluation results observed in dogs. We first tested dogs on a social evaluation task in which an experimenter either helped or refused to help the dog's owner open a container. We then assessed dogs' attachment strength using a subset of the C-BARQ. We found that attachment was a statistically significant predictor of dogs' preference toward the prosocial actor but was not a predictor in antisocial or control conditions. This finding provides early evidence that attachment may drive positivity biases in dogs and that attachment might explain mixed results within canine social evaluation literature.

When Naïve Pedagogy Breaks Down: Adults Rationally Decide How to Teach, but Misrepresent Learners' Beliefs.

From early in childhood, humans exhibit sophisticated intuitions about how to share knowledge efficiently in simple controlled studies. Yet, untrained adults often fail to teach effectively in real-world situations. Here, we explored what causes adults to struggle in informal pedagogical exchanges. In Experiment 1, we first showed evidence of this effect, finding that adult participants failed to communicate their knowledge to naïve learners in a simple teaching task, despite reporting high confidence that they taught effectively. Using a computational model of rational teaching, we found that adults assigned to our teaching condition provided highly informative examples but failed to teach effectively because their examples were tailored to learners who were only considering a small set of possible explanations. In Experiment 2, we then found experimental evidence for this possibility, showing that knowledgeable participants systematically misunderstand the beliefs of naïve participants. Specifically, knowledgeable participants assumed naïve agents would primarily consider hypotheses close to the correct one. Finally, in Experiment 3, we aligned learners' beliefs to knowledgeable agents' expectations and showed learners the same examples selected by participants assigned to teach in Experiment 1. We found that these same examples were significantly more informative once learners' hypothesis spaces were constrained to match teachers' expectations. Our findings show that, in informal settings, adult pedagogical failures result from an inaccurate representation of what naïve learners believe is plausible and not an inability to select informative data in a rational way.

Evaluation of a credit-bearing online administered happiness course on undergraduates' mental well-being during the COVID-19 pandemic.

Psychoeducational courses focused on positive psychology interventions have been shown to benefit student well-being. However, since the onset of the COVID-19 pandemic and accompanying social restrictions, many educators have had to deliver their courses online. Given that online teaching presents a very different university experience for students, do psychoeducational courses provide similar well-being benefits in an online format? In this pre-registered study (https://osf.io/3f89m), we demonstrate that despite the challenges of remote learning, first year university students (N = 166) taking an online "Science of Happiness" course during the first term experienced positive benefits to mental well-being in comparison to a wait-list control group (N = 198) registered to take the course in the second term. Specifically, university students currently taking the course maintained their mental well-being over the semester relative to the wait-list control who showed a significant decline in well-being and increase in anxiety during the same period. Our findings suggest that the online-administered "Science of Happiness" course delivered during the COVID-19 pandemic was associated with a protective effect on mental well-being. We also observed that engagement with the course was high, though there was no evidence that this factor mediated the positive effects we observed. However, we did find evidence that prior interest in increasing well-being influenced the effects of the course; participants with lower well-being interest showed less of a benefit. Our results suggest that online psychoeducational courses might provide a relatively cheap, flexible, and efficient means of providing support as part of an integrated approach to student mental well-being.

How do communicative cues shape the way that dogs (Canis familiaris) encode objects?

Our human capacity to efficiently learn from other individuals is unparalleled in any nonhuman species. Some scholars argue that our propensity to learn socially is supported by an early-emerging expectation that communicative cues will convey generic information (Csibra & Gergely, 2011). In the current 2 studies, we examine whether this expectation about generic information is unique to humans by testing a species that readily attends to human cues-dogs. Specifically, we adapted a violation of expectation paradigm previously used with human infants to examine whether communicative cues lead dogs to selectively encode generic, kind-relevant information about objects (e.g., shape). Prior work has demonstrated that human infants are more likely to notice unexpected changes in kind-relevant information in communicative contexts (i.e., when an agent points to the object; Yoon et al., 2008). In contrast, across 2 studies (N = 136), dogs were no more likely to notice kind-relevant changes in communicative contexts than noncommunicative contexts. These findings suggest that although dogs attend to human communicative cues, such cues do not shape the way that dogs encode objects. More broadly, this finding lends support to the claim that our early-emerging generic expectation crucially supports our human capacity to efficiently learn from one another. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Cleaner fish are sensitive to what their partners can and cannot see.

Much of human experience is informed by our ability to attribute mental states to others, a capacity known as theory of mind. While evidence for theory of mind in animals to date has largely been restricted to primates and other large-brained species, the use of ecologically-valid competitive contexts hints that ecological pressures for strategic deception may give rise to components of theory of mind abilities in distantly-related taxonomic groups. In line with this hypothesis, we show that cleaner wrasse (Labroides dimidiatus) exhibit theory of mind capacities akin to those observed in primates in the context of their cooperative cleaning mutualism. These results suggest that ecological pressures for strategic deception can drive human-like cognitive abilities even in very distantly related species.

Dogs (Canis familiaris) prioritize independent exploration over looking back.

It has been suggested that over the course of domestication, dogs developed the propensity to "look back" or gaze at humans when they encounter a challenging task. Unfortunately, little work to date has addressed the question of why dogs look back. To explore this issue, we conducted 3 experiments in which dogs had the option of doing something other than looking back at their owner when encountering an unsolvable task. In Experiments 1 and 2, dogs could look back or attempt an alternative puzzle. In both experiments, dogs attempted the alternative puzzle prior to looking back. In Experiment 3, when dogs encountered the unsolvable task, they could look back or attempt to solve the same puzzle using an alternate approach. As in Experiments 1 and 2, dogs attempted the alternate approach prior to looking back. Although some scholars have suggested that dogs may look back because they are overly reliant on humans, our findings suggest that dogs may instead prioritize independent exploration over looking back. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Benefits of a psychoeducational happiness course on university student mental well-being both before and during a COVID-19 lockdown.

We tested whether a psychoeducational course improved well-being in three cohorts. Study 1 found significantly higher mental well-being in first year undergraduates who took the course compared to a waiting-list control. Study 2 revealed that students taking the course when COVID-19 restrictions began did not experience increases in mental well-being but had significantly higher well-being than a third matched group. In Study 3, an online course increased mental well-being in University students and staff during a COVID-19 lockdown. These findings support the claim that psychoeducational courses are beneficial in both live and online formats and in times of collective uncertainty.

Teaching well-being at scale: An intervention study.

Courses that teach evidence-based interventions to enhance well-being are a public health tool that could be used to improve mental health in the population. We compared the well-being of six cohorts of adult students before and after they completed one of two massive open online courses: The Science of Well-Being (N = 581; 441; 1,228) and a control course, Introduction to Psychology (N = 677; 480; 1,480). Baseline well-being levels were equivalent across all six samples. Students in both courses increased in their well-being from baseline to follow-up in all three samples (p < .001); however, at follow-up, students in The Science of Well-Being course had higher subjective well-being than the control course (sample 1: r = .18, d = .37, p < .001; sample 2: r = .21, d = .43, p < .001; sample 3: r = .19, d = .38, p < .001). Overall, across three samples, we found that students who completed either of these online psychology courses increased in their well-being--but that students in The Science of Well-Being course showed greater improvement. These findings suggest that large free online courses that teach evidence-based approaches to well-being could positively impact mental health at large scales.

Disentangling perceptual awareness from nonconscious processing in rhesus monkeys (Macaca mulatta).

Scholars have long debated whether animals, which display impressive intelligent behaviors, are consciously aware or not. Yet, because many complex human behaviors and high-level functions can be performed without conscious awareness, it was long considered impossible to untangle whether animals are aware or just conditionally or nonconsciously behaving. Here, we developed an empirical approach to address this question. We harnessed a well-established cross-over double dissociation between nonconscious and conscious processing, in which people perform in completely opposite ways when they are aware of stimuli versus when they are not. To date, no one has explored if similar performance dissociations exist in a nonhuman species. In a series of seven experiments, we first established these signatures in humans using both known and newly developed nonverbal double-dissociation tasks and then identified similar signatures in rhesus monkeys (Macaca mulatta). These results provide robust evidence for two distinct modes of processing in nonhuman primates. This empirical approach makes it feasible to disentangle conscious visual awareness from nonconscious processing in nonhuman species; hence, it can be used to strip away ambiguity when exploring the processes governing intelligent behavior across the animal kingdom. Taken together, these results strongly support the existence of both nonconscious processing as well as functional human-like visual awareness in nonhuman animals.

How do non-human primates represent others' awareness of where objects are hidden?

Although non-human primates (NHPs) generally appear to predict how knowledgeable agents use knowledge to guide their behavior, the cognitive mechanisms that enable this remain poorly understood. We assessed the conditions under which NHPs' representations of an agent's awareness break down. Free-ranging rhesus macaques (Macaca mulatta) watched as an agent observed a target object being hidden in one of two boxes. While the agent could no longer see the boxes, the box containing the object flipped open and the object either changed in size/shape (Experiment 1) or color (Experiment 2). Monkeys looked longer when the agent searched for the object incorrectly rather than correctly following the color change (a non-geometric manipulation), but not the size/shape change (a geometric manipulation). Even though the agent maintained knowledge of the object's location in both cases, monkeys no longer expected the agent to search correctly after it had been geometrically (but not non-geometrically) manipulated. Experiment 3 confirmed that monkeys were sensitive to the color manipulation used in Experiment 2, making it unlikely that a failure to perceive the color manipulation accounted for our findings. Our results show that NHPs do not always expect that knowledgeable agents will act on their knowledge to obtain their goals, consistent with heuristic-based accounts of how NHPs represent others' mental states. These findings also suggest that geometric changes that occur outside the agent's perceptual access may disrupt attribution of awareness more so than non-geometric changes.

Macaque species with varying social tolerance show no differences in understanding what other agents perceive.

A growing body of work demonstrates that a species' socioecology can impact its cognitive abilities. Indeed, even closely related species with different socioecological pressures often show different patterns of cognitive performance on the same task. Here, we explore whether major differences in social tolerance in two closely related macaque species can impact a core sociocognitive ability, the capacity to recognize what others see. Specifically, we compared the performance of Barbary macaques (Macaca sylvanus, n = 80) and rhesus macaques (Macaca mulatta, n = 62) on a standard test of visual perspective understanding. In contrast to the difference in performance, one might expect from these species' divergent socioecologies that our results show similar performance across Barbary and rhesus macaques, with both species forming expectations about how another agent will act based on that agent's visual perspective. These results suggest that differences in socioecology may not play as big of a role in the evolution of some theory of mind capacities as they do in other decision-making or foraging contexts.

Training differences predict dogs' (Canis lupus familiaris) preferences for prosocial others.

Humans evaluate other agents' behavior on a variety of different dimensions, including morally, from a very early age. For example, human infants as young as 6-months old prefer prosocial over antisocial others and demonstrate negative evaluations of antisocial others in a variety of paradigms (Hamlin et al. in Nature 450(7169):557, 2007; Dev Sci 13(6):923-929, 2010; Proc Natl Acad Sci 108(50):19931-19936, 2011). While these tendencies are well documented in the human species, less is known about whether similar preference emerge in non-human animals. Here, we explore this question by testing prosocial preferences in one non-human species: the domestic dog (Canis lupus familiaris). Given the ubiquity of dog-human social interactions, it is possible that dogs display human-like social evaluation tendencies. Unfortunately, prior research examining social evaluation in dogs has produced mixed results. To assess whether differences in methodology or training differences account for these contrasting results, we tested two samples of dogs with different training histories on an identical social evaluation task. Trained agility dogs approached a prosocial actor significantly more often than an antisocial actor, while untrained pet dogs showed no preference for either actor. These differences across dogs with different training histories suggest that while dogs may demonstrate preferences for prosocial others in some contexts, their social evaluation abilities are less flexible and less robust compared to those of humans.

Metacognition in canids: A comparison of dogs (Canis familiaris) and dingoes (Canis dingo).

Metacognition refers to the ability to monitor one's own mental states. In the current study, we investigate whether domesticated dogs (Canis familiaris) and nondomesticated dingoes (Canis dingo) demonstrate metacognition by seeking information to remedy their own ignorance. In 2 studies, we used a naturalistic information-seeking paradigm in which subjects observed a human experimenter hiding a food reward behind an apparatus. Subjects could seek information by looking through a central window-like section of the apparatus to see where the reward was hidden. In Study 1, we tested whether dogs and dingoes were willing to seek information when interacting with the apparatus, finding that both species readily sought information when it was available to them. Study 2 provided a direct test of whether dogs and dingoes would seek information to rectify their own ignorance. We found evidence that both dogs and dingoes sought out information and were more likely do so when they did not already know where the treat was hidden. These results provide additional evidence suggesting that domesticated dogs seek information in the face of ignorance, as well as the first evidence of similar behavior in a nondomesticated canid. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Do Non-Human Primates Really Represent Others' Beliefs?

Over two decades of research have produced compelling evidence that non-human primates understand some psychological states in other individuals but are unable to represent others' beliefs. Recently, three studies employing anticipatory looking (AL) paradigms reported that non-human primates do show hints of implicitly understanding the beliefs of others. However, measures of AL have been increasingly scrutinized in the human literature owing to extensive replication problems. We argue that new reports of belief representation in non-human primates using AL should be interpreted cautiously because of methodological and theoretical challenges paralleling trends in the human literature. We explore how future work can address these challenges, and conclude by identifying new evolutionary questions raised by the prospect that non-human primates implicitly represent others' beliefs without an explicit belief representation system that guides fitness-relevant behavior.

Learning about the Ellsberg Paradox reduces, but does not abolish, ambiguity aversion.

Ambiguity aversion-the tendency to avoid options whose outcome probabilities are unknown-is a ubiquitous phenomenon. While in some cases ambiguity aversion is an adaptive strategy, in many situations it leads to suboptimal decisions, as illustrated by the famous Ellsberg Paradox. Behavioral interventions for reducing ambiguity aversion should therefore be of substantial practical value. Here we test a simple intervention, aimed at reducing ambiguity aversion in an experimental design, where aversion to ambiguity leads to reduced earnings. Participants made a series of choices between a reference lottery with a 50% chance of winning $5, and another lottery, which offered more money, but whose outcome probability was either lower than 50% (risky lottery) or not fully known (ambiguous lottery). Similar to previous studies, participants exhibited both risk and ambiguity aversion in their choices. They then went through one of three interventions. Two groups of participants learned about the Ellsberg Paradox and their own suboptimal choices, either by actively calculating the objective winning probability of the ambiguous lotteries, or by observing these calculations. A control group learned about base-rate neglect, which was irrelevant to the task. Following the intervention, participants again made a series of choices under risk and ambiguity. Participants who learned about the Ellsberg Paradox were more tolerant of ambiguity, yet ambiguity aversion was not completely abolished. At the same time, these participants also exhibited reduced aversion to risk, suggesting inappropriate generalization of learning to an irrelevant decision domain. Our results highlight the challenge for behavioral interventions: generating a strong, yet specific, behavioral change.

Do young rhesus macaques know what others see?: A comparative developmental perspective.

Humans undergo robust ontogenetic shifts in the theory of mind capabilities. Are these developmental changes unique to human development or are they shared with other closely related non-human species? To explore this issue, we tested the development of the theory of mind capacities in a population of 236 infant and juvenile rhesus macaques (Macaca mulatta). Using a looking-time method, we examined what developing monkeys know about others' perceptions. Specifically, we tested whether younger monkeys predict that a person will reach for an object where she last saw it. Overall, we found a significant interaction between a monkey's age and performance on this task (p = .014). Juvenile monkeys (between two and 5 years of age) show a nonsignificant trend towards human infant-like patterns of performance, looking longer during the unexpected condition as compared to the expected condition, though this difference is nonsignificant (p = .09). However, contrary to findings in human infants, infant rhesus macaques show a different trend. Infant monkeys on average look slightly longer on average during the expected condition than the unexpected condition, though this pattern was not significant (p = .06). Our developmental results in monkeys provide some hints about the development of the theory of mind capacities in non-humans. First, young rhesus macaques appear to show some interest in the perception of other agents. Second, young rhesus seems able to make predictions based on the visual perspective of another agent, though the developmental pattern of this ability is not as clear nor as robust as in humans. As such, though an understanding of others' perceptions is early-emerging in human infants, it may require more experience interacting with other social agents in our non-human relatives.

The Influence of Interactions with Dogs on Affect, Anxiety, and Arousal in Children.

Interactions with animals represent a promising way to reduce the burden of childhood mental illness on a large scale. However, the specific effects of child-animal interactions are not yet well-established. This study provides a carefully controlled demonstration that unstructured interactions with dogs can improve clinically relevant symptoms in children. Seventy-eight children (55.1% female, 44.9% male) ages 10 to 13 (M = 12.01, SD = 1.13) completed the Trier Social Stress Test for Children, followed by (a) interaction with a dog, (b) a tactile-stimulation control condition, or (c) a waiting control condition. The Positive and Negative Affect Schedule for Children, Short Form and the State/Trait Anxiety Inventory for Children were completed at baseline and posttest, and salivary cortisol was assessed at 5 time points. Adjusting for baseline scores, participants in the experimental condition showed higher scores on the Positive Affect scale than participants in both control conditions and lower scores on the State/Trait Anxiety Inventory for Children than participants in the waiting control condition at posttest. Negative affect was not assessed reliably, and we detected no effect of the interactions on salivary cortisol, as measured by area under the curve with respect to ground. Brief, unstructured interactions with dogs boosted children's positive emotions and reduced anxiety. Additional research is needed to further clarify which features of the interactions produce these benefits and the extent to which interactions with animals offer benefits that exceed the effects of other common coping strategies, activities, and interventions.