Risk-sensitive Decision-making Research Articles

Auditory risk recognition is socially transmitted across territory borders in wild birds

Prey species commonly assess predation risk based on acoustic signals, such as predator vocalizations or heterospecific alarm calls. The resulting risk-sensitive decision-making affects not only the behavior and life-history of individual prey, but also has far-reaching ecological consequences for population, community, and ecosystem dynamics. Although auditory risk recognition is ubiquitous in animals, it remains unclear how individuals gain the ability to recognize specific sounds as cues of a threat. Here, it has been shown that free-living birds (Wood Warblers Phylloscopus sibilatrix) can learn to recognize unfamiliar, complex sounds (samples of punk rock songs) as cues of a threat from conspecifics holding adjacent territories during the spring breeding season. In a playback experiment, Wood Warblers initially ignored the unfamiliar sounds, but after repeatedly hearing that these sounds trigger alarm calling reaction of neighbors, most individuals showed an anti-predator response to them. Moreover, once learned soon after nestlings hatching, the anti-predator response of parents toward previously unfamiliar sounds was then retained over the entire nestlings rearing period. These results demonstrate that social learning via the association of unfamiliar sounds with known alarm signals enables the spread of anti-predator behavior across territory borders and provides a mechanism explaining the widespread abilities of animals to assess predation risk based on acoustic cues.

Risk-Sensitive Decision-Making and Self-Harm in Youth Bipolar Disorder.

Risk-Sensitive Decision-Making and Self-Harm in Youth Bipolar Disorder.

Homicide, Inequality, and Climate: Untangling the Relationships.

Researchers debate the causal connections between homicide, inequality, and temperature. This study examines these relationships globally based on country-level data. A new measure of inequality is introduced that provides a more granular measure of inequality patterns than commonly used metrics. The approach allows estimation of risk sensitive decision-making that helps to explain how class impacts violence under different climate conditions. The results indicate that homicide rates are higher when poorer segments of populations are disproportionately influenced by temperature, middle class segments are influenced by inequality, and the wealthy are influenced by middle and impoverished class dynamics.

Flexible modulation of risk attitude during decision-making under quota

Risk attitude is often regarded as an intrinsic parameter in the individual personality. However, ethological studies reported state-dependent strategy optimization irrespective of individual preference. To synthesize the two contrasting literatures, we developed a novel gambling task that dynamically manipulated the quota severity (required outcome to clear the task) in a course of choice trials and conducted a task-fMRI study in human participants. The participants showed their individual risk preference when they had no quota constraint (‘individual-preference mode’), while they adopted state-dependent optimal strategy when they needed to achieve a quota (‘strategy-optimization mode’). fMRI analyses illustrated that the interplay among prefrontal areas and salience-network areas reflected the quota severity and the utilization of the optimal strategy, shedding light on the neural substrates of the quota-dependent risk attitude. Our results demonstrated the complex nature of risk-sensitive decision-making and may provide a new perspective for the understanding of problematic risky behaviors in human.

Temperature influences host instar selection in an aphid parasitoid: support for the relative fitness rule

The relative fitness rule states that parasitoid females should adopt risk-prone reproductive behaviours when expecting low reproductive success. Temperature influences the reproductive success of insects by affecting their basal metabolic rate during development, their egg load at emergence, and their life expectancy as adults. Using an aphid–parasitoid model system, we investigated the influence of developmental and adult temperature on the risk-sensitive decision-making of females. We considered the use of a low-quality host nymphal instar by the aphid parasitoid Aphidius ervi to be a risk-prone behaviour. Immature females were reared at 12, 20 or 28 °C and had access to the four nymphal instars of the potato aphid Macrosiphum euphorbiae for oviposition at one of these temperatures. Host selection behaviour was continuously recorded during exploitation of an aphid patch. We observed that warm-developed females and parasitoids foraging at high temperature attacked low-quality hosts more frequently than females from other treatments. These results support the hypothesis that a decrease in expected parasitoid reproductive success resulted in risk-prone behaviours. To our knowledge, this is the first experimental evidence suggesting that temperature influences host stage selection and risk-sensitive making decision in parasitoids, and the present study is the first to support the relative fitness rule. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, ●●, ●●–●●.

Effects of psychosocial stress on psychophysiological activity during risky decision-making in male adolescents

Adolescence is characterized by increases in both perceived stress and risk-taking, although the effects of stress on risk-sensitive decision-making have received little attention in adolescent groups. We report psychophysiological data from the healthy control group of a larger project examining neuroendocrine and neuropsychological function in boys with conduct disorder. The present analysis focussed on healthy male adolescents (n=66) performing a decision-making task that involved selection between two wheel-of-fortune gambles. The task was completed in a neutral state, and again following a psychosocial stress induction that robustly increased salivary cortisol levels and baseline autonomic arousal. Task-related changes in electrodermal activity (EDA) and heart rate (HR) were monitored during the receipt of win and loss outcomes. On gamble choice, stress attenuated the difference in risk taking between the losses-only and wins-only trials (the ‘reflection effect’) and reduced risk-taking on one further gamble type (i.e. a stress×gamble type interaction). In the neutral condition, EDA and HR deceleration responses were significantly greater for losses compared to wins. This physiological differentiation of losses and wins was reduced under stress, with a significant attenuation of the HR deceleration response. In addition, higher trait impulsivity scores predicted reduced EDA differentiation of the outcomes, and reduced EDA stress reactivity. As a limitation, the order of neutral and stress sessions was not counter-balanced. Reduced psychophysiological discrimination between positive and negative outcomes may contribute to the effects of stress on risky decision-making in adolescents.

Risk-sensitive decision-making in patients with posterior parietal and ventromedial prefrontal cortex injury.

Successful choice under risk requires the integration of information about outcome probabilities and values and implicates a brain network including the ventromedial prefrontal cortex (vmPFC) and posterior parietal cortex (pPAR). Damage to the vmPFC is linked to poor decision-making and increased risk-taking. Electrophysiological and neuroimaging data implicate the pPAR in the processing of reward probability during choice, but the causal contribution of this area has not been established. We compared patients with lesions to the pPAR (n = 13), vmPFC (n = 13), and healthy volunteers (n = 22) on the Roulette Betting Task, a measure of risk-sensitive decision-making. Both lesion groups were impaired in adjusting their bets to the probability of winning. This impairment was correlated with the extent of pPAR, but not vmPFC, damage. In addition, the vmPFC group chose higher bets than healthy controls overall, an effect that correlated with lesion volume in the medial orbitofrontal cortex. Both lesion groups earned fewer points than healthy controls. The groups did not differ on 2 tasks assessing probabilistic reasoning outside of a risk-reward context. Our results demonstrate the causal involvement of both the pPAR and vmPFC in risk-sensitive choice and indicate distinguishable roles of these areas in probability processing and risk appetite.

A Kind of Risk-Sensitive Group Decision-Making Based on MDP

One-switch utility function is used to describe how the risk attitude of a decision maker changes with his wealth level. In this paper additive decision rule is used for the aggregation of decision member’s utility which is represented by one-switch utility function. Based on Markov decision processes (MDP) and group utility, a dynamic, multi-stages and risk sensitive group decision model is proposed. The proposed model augments the state of MDP with wealth level, so the policy of the model is defined as an action executed in a state and a wealth level interval. A backward-induction algorithm is given to solve the optimal policy for the model. Numerical examples show that personal risk attitude has a great influence on group decision-making when personal risk attitudes of members are different, while the weights of members play a critical role when personal risk attitudes of members are similar.

Impairment in risk-sensitive decision-making in older suicide attempters with depression.

Suicidal behavior is a potentially lethal complication of late-life depression. In younger adults, suicide has been linked to abnormal decision-making ability. Given that there are substantial age-related decreases in decision-making ability, and that older adults experience environmental stressors that require effective decision-making, we reasoned that impaired decision-making may be particularly relevant to suicidal behavior in the elderly. We thus compared performance on a probabilistic decision-making task that does not involve working memory ("Cambridge Gamble Task") in four groups of older adults: (1) individuals with major depression and a history of suicide attempt (n = 25), (2) individuals with major depression with active suicidal ideation but no suicide attempt (n = 13), (3) individuals with major depression without suicidality (n = 35), and (4) nondepressed control subjects (n = 22). There was a significant effect of group on quality of decision-making, whereby the suicide attempters exhibited poorer ability to choose the likely outcome, compared with the nonsuicidal depressed and nondepressed comparison subjects. There were no group differences in betting behavior. The suicide attempters differed in several aspects of social problem-solving on a self-report scale. Quality of decision-making was negatively correlated with the score on the impulsive/careless problem-solving subscale. These data suggest that older suicide attempters have a deficit in risk-sensitive decision-making, extending observations in younger adults. More specifically, older suicide attempters seem to neglect outcome probability and make poor choices. These impairments may precipitate and perpetuate suicidal crisis in depressed elders. Identification of decision-making impairment in suicidal elders may help with designing effective interventions.

You can’t always get what you want: The motivational effect of need on risk-sensitive decision-making

Risky behavior in humans is typically considered irrational, reckless, and maladaptive. Risk-sensitivity theory, however, suggests that risky behavior may be adaptive in some circumstances: decision-makers should prefer high-risk options in situations of high need, when lower risk options are unlikely to meet those needs. This pattern of decision-making has been well established in the non-human animal literature, but little research has been conducted on humans. We demonstrate in a two-part experimental study that young men and women ( n = 115) behave as predicted by risk-sensitivity theory, shifting from risk-aversion to risk-proneness in situations of high need. This shift occurred whether decisions were made from description or from experience, and was observed controlling for sex and individual differences in general risk-taking propensity. This study is the first ecologically-relevant demonstration of risk-sensitive decision-making in humans.

Implications of risk-sensitive decision-making for the design of economic policies

Implications of risk-sensitive decision-making for the design of economic policies