Optimistic Judgment Research Articles

A News Media Representation on Disability and Information Accessibility in China from the Perspective of Critical Discourse Analysis

Based on critical discourse analysis, this paper takes thirty news articles related to disability and information accessibility from three Chinese news media as its research object to explore themes that describe how Chinese news media reflects and constitutes its understanding of disability and information accessibility. By doing this, it intends to reveal the themes of those articles and identify potential prejudices, illusions, and stereotypes that may influence the disability. This paper aims to address the following two questions: 1) What content exists in mainstream Chinese news media concerning disability and information accessibility? 2) What themes do these discourses present regarding disability and information accessibility? The results show that 1) The content of thirty news articles includes introductions, evaluations and advice of apps related to information accessibility, activities promoting information accessibility, audiovisual works with information accessibility, and official policies regarding information accessibility; 2) Five key themes are found in these discourses, which are discourses of problem-solving, criticism, awareness as advocacy, self-congratulations or overly optimistic judgments and a tendency of elderly-oriented over disability. Through the analysis of these themes, this paper concludes with implications to advance the development of information accessibility for disability.

How pictogram arrangements impact consumer optimism and judgments

ABSTRACT Frequency pictograms are one of the most common graphical representations of quantitative information used in communication. The paper shows that individuals react differently to objectively equivalent information when represented in a sorted pictogram versus an unsorted pictogram. We show that individuals form more optimistic judgments when presented with numerical information in a sorted pictogram than in an unsorted pictogram. Using the backdrop of attribute framing across six studies, we demonstrate the aforementioned phenomenon and find evidence of an optimism bias-based underlying mechanism. This paper demonstrates the impact of the perceptual features of pictograms that communicate frequency information in different contexts on consumers’ self-related judgments. Additionally, the paper contributes to the field of attribute framing by demonstrating its effects using a graphical representation of numerical information.

Power flow modeling considering detailed constraints of the DFIGs and collector networks based on 3-layer BFS and convergence improvement

Difficulty of power flow modeling with the doubly-fed induction generators (DFIGs) lies in: (1) Due to small capacity and large number of the DFIGs, a wind farm (WF) has many variables. The impedance level and the resistance/reactance ratio are different from those of the main system. Unified solution to the main system and the WF is impractical. The existing solutions with a few aggregated DFIGs simplify or ignore detailed constraints of the DFIGs and the collector networks (CNs). (2) The rotor voltage of the DFIG is small. The traditional flat voltage start is not suitable. Furthermore, convergence of the DFIG is related to the slip which changes with the wind speed. (3) For the DFIG at the synchronous mode with zero slip, the equivalent circuit of the DFIG with the rotor resistance and the rotor voltage divided by the slip is not valid. To solve these difficulties, a 3-layer backward/forward sweep (BFS) algorithm is newly proposed. The originalities are, (1) To facilitate power flow modeling and improve its convergence, the total system is classified into 3 layers, i.e. the DFIG, the WF with the DFIGs and the CNs, and the total system with the WFs and the main system. Each DFIG, each CN, and the main system are solved iteratively. The DFIGs and the CN are solved alternatively, interfaced by the voltages/powers at the stators. The WF and the main system are solved alternatively, interfaced by the voltages/powers at the point of common coupling. (2) To improve the convergence of the DFIG, the flat start is modified. The initial value of the rotor voltage is decided by the slip. (3) The DFIG at the synchronous speed is newly solved as a synchronous generator (SG) with the dc excitation, but the unknowns and the solution procedure are different from those of the SG. Solution to the DFIG at the synchronous mode is more accurate than the existing solution to the DFIG, since the latter ignores the power supply to the exciter. Numerical results verify the convergence improvement to the DFIG. Power flow results to IEEE RTS system with 79 DFIGs are given to show the detailed solution of each DFIG. Comparison with the existing models shows that ignoring the CNs overestimates active power of the WFs and yields optimistic judgment to var balance and voltage magnitudes of the main system. Equivalence to wind speeds will under- or overestimate the active power of the WFs.

Research Progress and Improvement Ideas of Anti-Epidemic Resilience in China's Urban Communities.

In the post-epidemic era, China's urban communities are at the forefront of implementing the whole chain of accurate epidemic prevention and control. However, the uncertainty of COVID-19, the loopholes in community management and people's overly optimistic judgment of the epidemic have led to the frequent rebound of the epidemic and serious consequences. Existing studies have not yet formed a panoramic framework of community anti-epidemic work under the concept of resilience. Therefore, this article first summarizes the current research progress of resilient communities from three perspectives, including ideas and perspectives, theories and frameworks and methods and means, and summarizes the gap of the current research. Then, an innovative idea on the epidemic resilience of urban communities in China is put forward: (1) the evolution mechanism of community anti-epidemic resilience is described through the change law of dynamic networks; (2) the anti-epidemic resilience of urban communities is evaluated or predicted through the measurement criteria; (3) a simulation platform based on Multi-Agent and dynamic Bayesian networks simulates the interactive relationship between "epidemic disturbance-cost constraint--epidemic resilience"; (4) the anti-epidemic strategies are output intelligently to provide community managers with decision-making opinions on community epidemic prevention and control.

Classifying Examples is More Effective for Learning Relational Categories Than Reading or Generating Examples

Successful teaching requires that student teachers acquire a conceptual understanding of teaching practices. A promising way to promote such a conceptual understanding is to provide student teachers with examples. We conducted a 3 (between-subjects factor example format: reading, generation, classification) x 4 (within-subjects factor type of knowledge: facts, concepts, principles, procedures) experiment with N = 83 student teachers to examine how different formats of learning with examples influence the acquisition of relational categories in the context of lesson planning. Classifying provided examples was more effective for conceptual learning than reading provided examples or generating new examples. At the same time, reading provided examples or generating new examples made no difference in conceptual learning. However, generating new examples resulted in overly optimistic judgments of conceptual learning whereas reading provided examples or classifying provided examples led to rather accurate judgments of conceptual learning. Regardless of example format, more complex categories were more difficult to learn than less complex categories. The findings indicate that classifying provided examples is an effective form of conceptual learning. Generating examples, however, might be detrimental to learning in early phases of concept acquisition. In addition, learning with examples should be adapted to the complexity of the covered categories.

Judgement bias of group housed gestating sows predicted by behavioral traits, but not physical measures of welfare.

Judgement bias testing has emerged as a potential tool for assessing affective states in animals. Researchers infer an animal's affective state based on an animal's response to an ambiguous stimulus that is intermediate to both the rewarded and punished conditioned stimuli. Animals can be classified as "optimistic" or having a positive affective state if the animal displays behaviors that suggest an increased expectation of reward in the face of ambiguous stimuli. Alternatively, animals can be classified "pessimistic" or having a negative affective state if the animal displays behaviors that suggest an increased expectation of punishment in the face of ambiguous stimuli. Recent reports in multiple species question what factors influence performance in judgement bias testing, and which may allow for erroneous conclusions regarding individual affective state. In order to better understand this concern, 25 female swine were subjected to behavioral assessments at critical rearing stages to determine response variability. These same individuals were then assessed for physical measures of welfare and judgement bias using the "go/no-go" task as breeding adults. Sows which were more aggressive approached the ambiguous, but not the positive, stimulus significantly faster than others. Both optimistic and pessimistic biases were observed despite all sows living in enriched housing, and, sows with more positive physical welfare measures (fewer skin lesions and healthy body condition) did not exhibit more optimistic judgement biases. Our data demonstrate that behavior traits, such as aggressiveness, can affect a sow's performance in a judgement bias test, while measures of physical health did not. We suggest that individual differences in behavior (e.g., bold-aggressive behavioral syndrome, or, proactive coping style) generate different emotional responses and can contribute to the animal's overall affective state more so than physical ailment. Our findings highlight the complexity of how different factors impact an animal's overall affective state and support the need for complementary measures in future JBT studies, including personality assessment.

Environmental complexity positively impacts affective states of broiler chickens

Affective state can bias an animal’s judgement. Animals in positive affective states can interpret ambiguous cues more positively (“optimistically”) than animals in negative affective states. Thus, judgement bias tests can determine an animal’s affective state through their responses to ambiguous cues. We tested the effects of environmental complexity and stocking density on affective states of broiler chickens through a multimodal judgement bias test. Broilers were trained to approach reinforced locations signaled by one color and not to approach unreinforced locations signaled by a different color. Trained birds were tested for latencies to approach three ambiguous cues of intermediate color and location. Broilers discriminated between cues, with shorter latencies to approach ambiguous cues closest to the reinforced cue than cues closest to the unreinforced cue, validating the use of the test in this context. Broilers housed in high-complexity pens approached ambiguous cues faster than birds in low-complexity pens–an optimistic judgement bias, suggesting the former were in a more positive affective state. Broilers from high-density pens tended to approach all cues faster than birds from low-density pens, possibly because resource competition in their home pen increased food motivation. Overall, our study suggests that environmental complexity improves broilers’ affective states, implying animal welfare benefits of environmental enrichment.

Educational experiment in the structure of blended learning technologies

In the article, based on the material of physics, the significance of an educational experiment in teaching natural sciences is actualized. The data of the analysis of the evolution of an educational experiment in teaching a school course in physics are presented. A decrease in the share of demonstration and laboratory experiments in educational programs has been noted. The conclusion is made about reducing the requirements for teachers to put an educational experiment at the forefront of all teaching of the subject. The data of the conducted micro-research among future physics teachers revealed their unwillingness to build the teaching of the subject on an experimental basis. The reason for the low level of experimental training of students is the formal approach on the part of teachers and regulatory bodies to the setting of demonstration and laboratory experiments. Optimistic judgments were expressed regarding the demonstration experiments, which, without prejudice to the level of teaching physics, can be replaced by corresponding video recordings. The article presents three options for solving the problem of setting up a laboratory experiment in the implementation of distance and blended physics teaching technologies at school and university. The first option involves conducting experiments on simple home-made equipment. According to the second and third options, in the remote learning mode for conducting educational research, students receive instructions and video recordings of the experiments, as well as materials for processing the measurement results. In the second version, experiments are carried out using software and hardware systems. In the third version, traditional measuring instruments are used. The article provides information on access to experimental materials prepared by the authors of the ongoing pedagogical research.

An extended method for evaluating assumptions deviations in quantitative risk assessment and its application to external flooding risk assessment of a nuclear power plant

In quantitative risk assessment, assumptions are typically made, based on best judgement, conservative, or (sometimes) optimistic judgments. Best judgment and optimistic assumptions may result in failing to meet the quantitative safety objectives, whereas conservative assumptions may increase the margins which the objectives are met with but result in cost-ineffective design or operation. In the present paper, we develop an extended framework for the analysis of the criticality of assumptions in risk assessment by evaluating the risk that deviations from the assumptions lead to a reduction of the safety margins. The framework aims to support risk-informed decision making by identifying important assumptions and integrating the assessment of their criticality into the quantitative risk assessment (QRA). The framework is, finally applied within the quantitative risk assessment of a Nuclear Power Plant (NPP) exposed to external flooding. Compared to previous works on the subject, we consider also conservative assumptions and introduce decision flow diagrams to support the classification of the criticality of the assumptions. The framework provides a more comprehensive and transparent evaluation of the assumptions deviation risk through the decision flow diagrams that facilitate the standardization of the evaluation of the assumption deviation effects on the risk assessment.

HISTORICAL AND LEGAL COURSES IN RUSSIAN LEGAL EDUCATION: TRADITIONS, MODERNIZATION, CONTINUITY

The article considers one of the stable features of the Russian legal education - the presence and development of the historical and legal component in it. The evolution of educational standards for the professional training of lawyers is analyzed from the point of view of the mandatory inclusion of historical and legal courses in pre-revolutionary Russia, in the Soviet decades and on the breaks of eras. The change of names of historical and legal disciplines in the context of the development of legal education and science as a whole is shown. Some problems of teaching subjects of historical and legal content at the present stage, as part of a practice-oriented model of legal education, are identified. In addition, the results of a local study conducted at USLU are presented to determine the attitude of students to the history of the state and law, to reveal their understanding of the role of historical and legal subjects for the chosen future professional activity; among them - optimistic judgments of junior students about the need for knowledge of historical and legal experience. The conclusion is drawn on the fundamental importance of historical and legal courses to ensure state legal and legal educational traditions.

КИТАЙСКИЕ ДИСКУССИИ ОБ ОТНОШЕНИЯХ С США И ТОРГОВОЙ ВОЙНЕ

The article analyzes the debates of Chinese researchers on the relations with the United States at the backstage of the “trade war”. The statements of the Chinese leadership about the continuation of the “period of historical chances” for national development are combined with calls to be prepared for contingencies and to pay extra attention to new trends in international environment that do not correspond with normative theses about irreversible tendencies of multipolarity, economic globalization and impossibility of a large-scale war. “Trade war” has become an incentive for understanding the reasons of deterioration in bilateral relations and searching for new sources of their stability. The most of Chinese foreign policy analysts believe that it is possible to extend the “period of historical chances” even in time of such a deterioration. However, the standard set of recommendations from Chinese experts (deepening of market reforms, participation in the reform of global governance and world order, strengthening national power while expanding cooperation with other countries for the sake of construction of a “new type of international relations”) have not offered a recipe how to prevent further worsening of Chinese-American relations. Broad positive recommendations to develop dialogue and avoid serious conflicts are useless at strategic junctures when the opposite side speaks the language of ultimatums. Chinese mainstream habitually emphasizes that cooperation between Beijing and Washington is beneficial to both countries and for the world, while no one gains from the confrontation. The proposals to the American side to “get rid of the zero-sum game mentality”, “take a more positive look at the development of China”, “constantly expand the space and prospects for bilateral win” were not able to curb constantly rising tensions in bilateral relations. Nevertheless, in a number of academic publications one can find optimistic statements that in the next couple of years, Donald Trump will surely soften the U.S. policy towards China. Realist point of view recognizes the possibility of intensifying rivalry between Beijing and Washington. Chinese researchers are increasingly turning to the analysis of the interaction of the two countries as “competition together with cooperation” or “struggle without destruction” (“dou er bu po”). The intention to establish an atmosphere of “healthy competition” in bilateral relations may not be feasible, since China does not have tools to convince Trump administration to abandon the pursuit of absolute superiority. After the bilateral trade lost its function as a stabilizer of Sino-American relations, experts felt the necessity to find new sources of stability. The main task is not focused on restoring the previous levels of cooperation. It is more important to recognize the differences between the two countries and create new effective mechanisms for conflict management by clearly defining “red lines” and communicating with other party to clarify interests and strategic intentions. In reliance on research publications in Chinese academic journals, the article demonstrates that optimistic judgments about the continual importance and strength of China-U.S. relations gradually gave way to realistic estimates based on the recognition of fundamental changes in this sphere. More notable became the efforts of Chinese researchers in comparative analysis of national strategies and consideration of alternative scenarios for further development of relations with the United States.&nbsp

Environmental complexity buffers against stress-induced negative judgement bias in female chickens

Cognitive processes are often biased by emotions. In humans, affective disorders are accompanied by pessimistic judgement, while optimistic judgement is linked to emotional stability. Similar to humans, animals tend to interpret ambiguous stimuli negatively after experiencing stressful events, although the long-lasting impact on judgement bias has rarely been investigated. We measure judgement bias in female chicks (Gallus gallus domesticus) after exposure to cold stress, and before and after exposure to additional unpredictable stressors. Additionally, we explore if brain monoamines can explain differences in judgement bias. Chicks exposed to cold stress did not differ in judgement bias compared to controls, but showed sensitivity to additional stressors by having higher motivation for social reinstatement. Environmental complexity reduced stress-induced negative judgement bias, by maintaining an optimistic bias in individuals housed in complex conditions even after stress exposure. Moreover, judgement bias was related to dopamine turnover rate in mesencephalon, with higher activity in individuals that had a more optimistic response. These results demonstrate that environmental complexity can buffer against negative effects of additive stress and that dopamine relates to judgement bias in chicks. These results reveal that both internal and external factors can mediate emotionally biased judgement in animals, thus showing similarities to findings in humans.

Improved dynamic power flow model with DFIGs participating in frequency regulation

Summary The primary frequency regulation of the DFIGs is newly introduced to dynamic power flow to analyze the post-disturbance power flow and system frequency. Based on the overspeed/pitch angle control, the equivalent inertia of the DFIGs is quantified by their inherent inertia and the adjustable range of the rotor speed, which together with the inertia of the SGs determines the system frequency. With simultaneous solution to the constraints of the DFIGs and power system, the captured power by the wind turbine, the rotor speed, and the slip of the DFIGs are adjusted in dynamic power flow, thus to quantify power loss and active output of the DFIGs, and avoid optimistic judgment to the frequency regulation capability of the DFIGs. With increasing wind power, the wind turbine generators are expected to participate in the frequency regulation to save the burden of synchronous generators (SGs). The primary frequency regulation of doubly fed induction generator (DFIG) using the dynamic power flow is proposed. The equivalent inertia of the DFIG is decided by the inherent inertia and the rotor speed. Its captured power and rotor speed respond to the change of the system frequency. The constraints of the DFIG and power system are solved simultaneously to quantify the active loss of the DFIG. Then, the power flow is solved alternatively with the dynamic equation describing system frequency. The numerical results validate the feasibility of the proposed model and quantify the frequency-support capability of the DFIG. The proposed model helps to balance the utilization of wind power with the stability of system frequency, while reducing the reserve requirement to the SGs.

Mindsets Affect Risk Perception and Risk-Taking Behavior

Abstract. In two experiments, we investigated the downstream consequences of activating deliberative versus implemental mindsets on risk perception (Experiment 1) and risk-taking behavior (Experiment 2). We hypothesized that participants in an implemental versus deliberative mindset arrive at more optimistic judgments about their own risks of experiencing negative life events, compared to other peoples’ risks. The results of Experiment 1 confirm this hypothesis and reveal perceived controllability as an important moderator. Experiment 2 further augments these findings by demonstrating that participants in a deliberative mindset show less risk-taking behavior than participants in an implemental mindset using a behavioral risk task. Implications for research on mindset theory of action phases and mindset-dependent effects on risk perception and risk-taking behavior are discussed.

Female and male pigs’ performance in a spatial holeboard and judgment bias task

Studies of the cognitive abilities of pigs are increasing in number, due to their relevance for the fields of animal welfare and biomedical research. While both female and male pigs have been used in cognitive tasks, possible sex differences in performance have not yet received extensive attention. This is of interest, as sexual dimorphism in cognitive abilities has been documented for a variety of species. The aim of this study was to assess the effects of sex on pigs’ performance in two cognitive tasks. Spatial learning and memory of ten female and ten male pigs was compared in a spatial holeboard task. Working and reference memory, as well as measures of motivation and exploration were assessed. Both females and males acquired the task and no differences were found between sexes for any measures of spatial memory. However, female pigs performed more successfully during reversal trials (shorter latency to first reward, higher number of rewards found), indicating greater response flexibility. This difference between sexes was transient, with males eventually reaching the same level of performance as the females. Judgment bias, a cognitive measure of affective state, was subsequently assessed using an active choice judgment bias task. Pigs were trained to respond differently to a negative and a positive stimulus, signaling either a small or a large reward. During judgment bias testing, pigs were presented with ambiguous cues and their trained ‘positive’ and ‘negative’ responses were recorded as optimistic or pessimistic choices, respectively. Both females and males displayed a slightly optimistic judgment bias. Optimistic choosing decreased with repeated testing for both groups. It is likely the pigs learned about the unrewarded outcome of ambiguous cues, rendering them no longer ambiguous. Further improvement of the judgment bias task as a cognitive measure of affective state is deemed necessary. Overall, our results indicate that sex is not a confounding factor when measuring baseline performance of pigs in the spatial holeboard or judgment bias task. Sex effects were only found when subjecting the pigs to a reversal task, warranting further study of sex differences in response flexibility. Such a difference would have implications for pig welfare, as it suggests that males are slower to cope with changes in their environment.

Influence of Domain Knowledge on Monitoring Performance Across the Life Span

Two studies were conducted to investigate effects of domain knowledge on metacognitive monitoring across the life span in materials of different complexity. Participants from 4 age groups (3rd-grade children, adolescents, younger and older adults) were compared using an expert–novice paradigm. In Study 1, soccer experts’ and novices’ ease-of-learning judgments (EOLs), judgments of learning (JOLs), and confidence judgments (CJs) were contrasted when memorizing soccer-related word pairs. In Study 2, monitoring judgments (i.e., a rating of global comprehension, JOLs, and CJs) were collected in regards to a soccer-related narrative. The results of both approaches showed that experts’ better memory performance obtained in both studies was not always accompanied by advantages in monitoring performance. In Study 1, experts of all ages outperformed novices in monitoring accuracy. In Study 2, no benefits of expertise on monitoring were found; in children, novices even surpassed experts in monitoring quality. In both studies, the most consistent influence of previous domain knowledge on monitoring performance concerned more optimistic judgments of experts compared with novices, regardless of stimuli and recall format. In sum, our results document a twofold effect of expertise on monitoring. Although domain-specific knowledge enhances monitoring performance in some situations, more optimistic estimates, presumably due to the application of a familiarity heuristic, typically reduce experts’ monitoring accuracy.

Making Decisions under Ambiguity: Judgment Bias Tasks for Assessing Emotional State in Animals.

Judgment bias tasks (JBTs) are considered as a family of promising tools in the assessment of emotional states of animals. JBTs provide a cognitive measure of optimism and/or pessimism by recording behavioral responses to ambiguous stimuli. For instance, a negative emotional state is expected to produce a negative or pessimistic judgment of an ambiguous stimulus, whereas a positive emotional state produces a positive or optimistic judgment of the same ambiguous stimulus. Measuring an animal’s emotional state or mood is relevant in both animal welfare research and biomedical research. This is reflected in the increasing use of JBTs in both research areas. We discuss the different implementations of JBTs with animals, with a focus on their potential as an accurate measure of emotional state. JBTs have been successfully applied to a very broad range of species, using many different types of testing equipment and experimental protocols. However, further validation of this test is deemed necessary. For example, the often extensive training period required for successful judgment bias testing remains a possible factor confounding results. Also, the issue of ambiguous stimuli losing their ambiguity with repeated testing requires additional attention. Possible improvements are suggested to further develop the JBTs in both animal welfare and biomedical research.

Anandamide mediates cognitive judgement bias in rats

In the present study, we investigated the effects of acute pharmacological manipulation of the endocannabinoid (EC) system on the valence of cognitive judgement bias of rats in the ambiguous-cue interpretation (ACI) paradigm. To accomplish this goal, after initial behavioural training, different groups of rats received single, systemic injections of the irreversible anandamide (AEA) hydrolysis inhibitor URB597, the cannabinoid receptor type 1 (CB1) inverse agonist AM251, the cannabinoid receptor type 2 (CB2) inverse agonist AM630, the combination of URB597 and AM251, and a combination of URB597 and AM630 and were subsequently tested with the ACI paradigm. We report that URB597 at a dose of 1 mg/kg significantly biased animals towards positive interpretation of the ambiguous cue and that this effect was abolished by pre-treatment with AM251 (1 mg/kg) or AM630 (1 mg/kg). The CB1 and CB2 inverse agonists administered alone (1 mg/kg) had no statistically significant effects on the interpretation of the ambiguous cue by rats. Our findings suggest involvement of the endocannabinoid system in the mediation of optimistic judgement bias.

Acute administration of lithium, but not valproate, modulates cognitive judgment bias in rats.

Rationale and objectivesBoth valproic acid (VPA) and lithium (LI) are well-established treatments for therapy of intense and sustained mood shifts, which are characteristics of affective disorders, such as bipolar disorder (BP). As mood and cognitive judgment bias have been found to be strongly interrelated, the present study investigated, in an animal model, whether acute treatment with VPA or LI could affect cognitive judgment bias.MethodsTo accomplish this goal, two groups of rats received single injections of either VPA or LI after initial behavioral training and were subsequently tested with the ambiguous-cue interpretation (ACI) test. Both drugs were administered in three doses using the fully randomized Latin square design.ResultsVPA (100, 200, and 400 mg/kg) had no significant effect on the interpretation of the ambiguous cue. LI at the lowest dose (10 mg/kg) had no effect; at an intermediate dose (50 mg/kg), it significantly biased animals towards positive interpretation of the ambiguous cue, and at the highest dose (100 mg/kg), it impaired the ability of animals to complete the test.ConclusionTo our knowledge, this is the first study demonstrating lithium’s effects on increased optimistic judgment bias. Future studies may focus on the ability of putative pharmacotherapies to modify the cognitive judgment bias dimension of patients at risk for bipolar disorder or depression.

Generating positive affective states in sheep: The influence of food rewards and opioid administration

This study investigated the involvement of the opioid system in modulating the affective state after the consumption of palatable and unpalatable rewards, using judgement bias as an indicator of the affective state. We hypothesised that consuming a palatable food reward would generate a more optimistic bias compared to receiving unpalatable wood chips. We hypothesised that morphine administration would further enhance the optimistic judgement bias after consumption of a food reward while reducing a pessimistic bias after receiving wood chips. Naloxone administration was expected to prevent the formation of an optimistic bias after consumption of a food reward, and was expected to have little effect after receiving the wood chips. The judgement bias arena consisted of a positive and a negative location cue, associated with conspecifics and a dog, respectively, as well as three non-reinforced ambiguous location cues between the positive and negative locations. Thirty sheep were successfully trained to approach the conspecifics and avoid the dog. Following training, sheep were randomly assigned to one of three treatments; morphine (1mg/kg), naloxone (2mg/kg) and control. Within each treatment, half the ewes received a small food reward and the other half wood chips before exposure to each of the five locations. Judgement bias was assessed by recording the latency to approach the five locations. Animals receiving the food reward approached the locations faster than animals receiving the wood chips (0.83±0.04 and 1.00±0.04 log-transformed latencies (s), respectively, P<0.01). The latency was also near-significantly affected by a treatment×reward type interaction (P=0.05), mostly due to the morphine treated ewes approaching the locations faster after receiving the food reward (log-transformed latencies (s): 0.82±0.07 for control sheep after consuming food, 0.71±0.07 for morphine treated sheep after food, 0.96±0.07 for naloxone treated sheep after food, 0.94±0.07 for control sheep after wood chips, 1.07±0.07 for morphine sheep after wood chips and 1.00±0.07 for naloxone sheep after wood chips). These results show that consumption of a food reward induced an optimistic judgement bias and suggest that morphine administration further enhanced this optimistic judgement bias. However, animal numbers and statistical power were low in this experiment and further research is necessary to confirm whether the opioid system is involved in the formation of judgement biases.