Zhu-Yuan Liang

Neural mechanism of intertemporal choice: From discounting future gains to future losses

Intertemporal choice, the tradeoff among outcomes occurring at different points in time, involves not only benefit options but also those associated with cost. Previous neuroimaging studies have primarily focused on discounting future gains; thus the neural mechanism underlying discounting future losses remains unidentified. Using event-related functional magnetic resonance imaging, we comprehensively investigated the neural mechanism of temporal discounting using two decision-making tasks with a symmetric pattern of gains and losses. Our results revealed that the lateral prefrontal and posterior parietal areas were activated in discounting both future gains and future losses, but their activations were stronger when discounting losses. Moreover, we found that the insula, thalamus and dorsal striatum were more activated during intertemporal choices involving losses, suggesting that the enhanced sensitivity to losses may be driven by negative emotions. In addition, whereas the posterior cingulate cortex and medial prefrontal cortex were activated when the choices included immediate options, extra regions including the anterior cingulate cortex, insula and superior frontal gyrus were preferentially activated when the choices involved immediate losses. Taken together, our findings suggest that a fronto-parietal network supports the common discounting process, and more importantly, discounting future losses and gains occurs asymmetrically in the brain. We speculate that this may provide a neural basis for the phenomenon that future losses are discounted less steeply than future gains.

Anticipated Regret, Risk Perception, or Both: Which is Most Likely Responsible for Our Intention to Gamble?

The current study investigated whether risk aversion or regret aversion could be related to a lower intention to gamble, and whether the type of gambling was a moderator of this relationship. The study took place in Macau, often called “the Las Vegas of East Asia.” A total of 373 Macau residents completed a questionnaire survey dealing with thirteen types of gambling. The results showed that risk perception and anticipated regret had a significant negative effect on the intention to gamble. This negative effect was domain-specific, varying with the type of gambling. Our findings indicated that neither risk aversion nor regret aversion can uniquely explain an individual’s risk-taking tendency consistently. Instead, which factor plays a greater role in lowering the intention to gamble—regret aversion, risk aversion, or both—is itself dependent on the type of gambling involved. The finding that not all gambles are created equal could be useful in gambling prevention and advertising appeal by providing a basis for understanding the role that cognitive and emotional factors play in different types of gambling.

Disrutpted resting-state functional architecture of the brain after 45-day simulated microgravity.

Long-term spaceflight induces both physiological and psychological changes in astronauts. To understand the neural mechanisms underlying these physiological and psychological changes, it is critical to investigate the effects of microgravity on the functional architecture of the brain. In this study, we used resting-state functional MRI (rs-fMRI) to study whether the functional architecture of the brain is altered after 45 days of −6° head-down tilt (HDT) bed rest, which is a reliable model for the simulation of microgravity. Sixteen healthy male volunteers underwent rs-fMRI scans before and after 45 days of −6° HDT bed rest. Specifically, we used a commonly employed graph-based measure of network organization, i.e., degree centrality (DC), to perform a full-brain exploration of the regions that were influenced by simulated microgravity. We subsequently examined the functional connectivities of these regions using a seed-based resting-state functional connectivity (RSFC) analysis. We found decreased DC in two regions, the left anterior insula (aINS) and the anterior part of the middle cingulate cortex (MCC; also called the dorsal anterior cingulate cortex in many studies), in the male volunteers after 45 days of −6° HDT bed rest. Furthermore, seed-based RSFC analyses revealed that a functional network anchored in the aINS and MCC was particularly influenced by simulated microgravity. These results provide evidence that simulated microgravity alters the resting-state functional architecture of the brains of males and suggest that the processing of salience information, which is primarily subserved by the aINS–MCC functional network, is particularly influenced by spaceflight. The current findings provide a new perspective for understanding the relationships between microgravity, cognitive function, autonomic neural function, and central neural activity.

Belief in Luck or in Skill: Which Locks People into Gambling?

According to the social axioms framework, people’s beliefs about how the world functions (i.e., internal or external locus of control) are related to their social behaviors. Previous researchers have attempted to relate locus of control to gambling behavior, but the results have not been clear-cut. The present study speculated that the effects of perceived control (i.e., belief in luck and belief in skill) on gambling behavior are domain-specific and vary with the type of gambling. A total of 306 adult Macau residents ranging in age from 18 to 65 with casino gambling experience were recruited by going door to door. Empirical data on gambling frequency and perceived control relating to 13 types of gambling were collected. Our results demonstrated that the effects of belief in luck or skill on gambling behavior varied across different gambling categories. Specifically, for football lottery, Chinese lottery, and baccarat, it was not belief in skill but rather belief in luck that was a positive significant predictor of gambling frequency. Only for slot machines and stud poker did belief in skill significantly predict gambling frequency. For the remaining eight gambling categories, neither belief in luck nor belief in skill could predict gambling frequency. Our findings indicate that neither internal nor external locus of control can consistently explain people’s gambling behaviors. Instead, which factor plays a greater role in a person’s gambling behavior is dependent on the gambling type. Therefore, the finding that not all gambles are created equal might be a promising avenue for further research and treatment approaches.

Are Risky Choices Actually Guided by a Compensatory Process? New Insights from fMRI

The dominant theories about risky decision-making assume that decision conflicts are solved by a compensatory process involving a trade-off of probability against payoff, but it is unclear whether these theories actually represent the events that occur when people make a risky decision. By contrasting a preferential choice with a judgment-based choice that required a compensatory process, we explored the mechanisms underlying risky decision-making. First, using parametric analyses, we identified the dorsomedial prefrontal cortex (dMPFC) as the specific region in charge of task-related conflict in risky decision-making tasks. We also showed that the dMPFC was activated less when judgment-based choices were being made, implying that the conflict experienced during a judgment-based choice was not as strong as the conflict that was experienced during the preferential choice. Our results provide neural evidence that preferential choice cannot be characterized solely as a compensatory process. Thus, questions were raised about whether existing compensatory theories could adequately describe individual risky decisions.

Toward a mental arithmetic process in risky choices

Mainstream theories about decision-making under risk suggest that risky decisions are made by choosing the option that offers the highest mathematical expectation. The present event-related potentials (ERPs) study investigated the neurocognitive mechanisms underlying risky choice by contrasting a preferential choice task with an expected value choice task. The ERP data revealed that (1) the computational difficulty, which would be expected to influence a compensatory process, affected the slow wave only when participants were forced to choose the option with the highest expectation; and that (2) the difference in the minimum outcome dimension between two options, which would be expected to be influential in a heuristic process, affected the P300 and slow wave when participants were asked to choose the preferred option. Our findings provide neural evidence that preferential choice is not based on an expectation computation and thus raised the question of whether expectation theories can provide an adequate description of individual risky decisions.

Effect of 45-day simulated microgravity on the evaluation of orally reported emergencies

Accurate evaluation of emergencies is a critical concern in long-duration space flights. Accordingly, we studied the effect of 45 days of − 6° head-down bed rest – a model that simulates the conditions in microgravity environments – on the evaluation of orally reported emergencies. Sixteen male participants listened to corresponding emergency scenarios and assessed the severity of these situations eight times before, during and after bed rest. The results revealed a ‘ recency effect’: compared with emergency descriptions in the order of serious to mild, those framed in the reverse order were judged to be more serious. However, the severity ratings did not vary with time spent in the simulated microgravity environment. These findings are similar to those observed in a regular environment on Earth, indicating that the design principles of information presentation for situations on Earth may also be extended to designs intended for outer space. Practitioner Summary: A recency effect was found in the evaluation of orally reported emergencies under simulated microgravity conditions. The design principles of information presentation for situations on Earth may also be extended to designs intended for outer space.

Gain-loss asymmetry in neural correlates of temporal discounting: An approach-avoidance motivation perspective

Gain-loss asymmetry in temporal discounting (i.e., when individuals discount gains more than losses) has been implicated in numerous problematic and addictive behaviors, resulting in enormous personal and societal costs. On the basis of findings from a previous study, we speculated that approach-avoidance motivation would modulate gain-loss asymmetry. To test this speculation, we examined the effects of motivation on gain-loss asymmetry by analyzing functional connectivity. We found that approach and avoidance motivation were negatively associated with functional connectivity between the medial orbitofrontal cortex (MOFC) and the dorsolateral prefrontal cortex and functional connectivity between the MOFC and the posterior parietal cortex (PPC) in the gain domain. Only avoidance motivation was found to be positively associated with functional connectivity between the medial prefrontal cortex (MPFC) and the posterior cingulate cortex (PCC) as well as between the MPFC and the insula in the loss domain. Our findings suggest that the relationships of approach-avoidance motivation and neural correlates yielded an asymmetrical pattern between the gain and loss domains in temporal discounting. Thus, we provide new insight into understanding gain-loss asymmetry in temporal discounting.

Not all gamblers are created equal: gambling preferences depend on individual personality traits

Previous studies have presented evidence revealing that the dispositional personalities of consumers, or the traits associated with their gambling behaviors and risk preferences, differ across various gambling types. Those studies leave open the question of whether and how personality differences affect domain-specific gambling preferences. Using latent class analysis (LCA), we explored the latent classes of risk preference for different gambling types and the effects of personality traits on these classes. A total of 732 Macau residents completed a questionnaire assessing 13 gambling types and personality traits. Preferences for gambling shown by the participants varied between three latent classes of games: chance gambling, entertainment gambling, and technical gambling. Moreover, not all personality traits consistently predicted preferences for these gambling classes. For instance, aggression-hostility positively predicted a general preference for both chance gambling and technical gambling, but impulsive sensation-seeking positively predicted only a preference for chance gambling. However, neuroticism-anxiety traits showed no such predictive effect for any of the three gambling classes. This study suggests that personality patterns emerge for overall and specific gambling types and underscores the value of LCA to help resolve the longstanding debate over whether gambling is domain specific.

New Paradigms for the Old Question: Challenging the Expectation Rule Held by Risky Decision-Making Theories

In risky decision making, whether decision makers follow an expectation rule as hypothesised by mainstream theories is a compelling question. To tackle this question and enrich our knowledge of the underlying mechanism of risky decision making, we developed a series of new experimental paradigms that directly examined the computation processes to systematically investigate the process of risky decision making and explore the boundary condition of expectation rule over the course of a decade. In this article, we introduce these methods and review behavioural, eye-tracking, event-related potential, and functional magnetic resonance imaging studies that employed these methods. Results of these studies consistently showed that decision makers in the single-application condition did not perform the weighting and summing process assumed by the expectation rule. Moreover, decision makers were inclined to adopt a non-compensatory strategy, such as a heuristic one, in risky decision making. Furthermore, results indicated that the expectation rule was only applicable for conditions that involved decisions applied to numerous events (multiple applications) or to people (everyone). The findings indicated that using an index based on expected value to prescribe human risk preferences appears to be an artificial or false index of risk preference, and emphasised a new methodological direction for risky decision-making research.