Components of working memory and somatic markers in decision making

According to Damasio’s somatic marker hypothesis, affective reactions ordinarily guide and simplify decision making. In an earlier study, we used a modified version of the gambling task developed by Bechara and colleagues so that we could explore the relations among decision making, working memory (WM) load, and formation of somatic markers. This prior work found that an increased WM load produced by secondary tasks interfered with the development of somatic markers and led to poorer gambling task performance. In the present study, we tested whether secondary tasks affect the executive functions of WM, verbal buffering, or both. Our findings indicate that verbal buffering alone does not interfere with gambling task performance or the development of somatic markers. Interference with the executive functions of WM is necessary to disrupt gambling performance and somatic markers.     

Testing Damasio's somatic marker hypothesis with psychopathic individuals: risk takers or risk averse?

Damasio and colleagues (A. R. Damasio, 1994; A. R. Damasio, D. Tranel, & H. Damasio, 1990) have theorized about a possible relationship between somatic markers and the behavior of psychopathic individuals (Ps), but, to date, there are no published data regarding the proposed relationship. The authors assessed 86 Caucasian and 71 African American male offenders using R. D. Hare's (1991) Psychopathy Checklist--Revised and used a modified version of Bechara and colleagues' (A. Bechara, A. R. Damasio, H. Damasio, & S. W. Anderson, 1994; A. Bechara, H. Damasio, D. Tranel, & A. R. Damasio, 1997) gambling task to test the hypothesis that Ps would, consistent with the somatic marker hypothesis, fail to become risk averse. Results indicated that level of anxiety, but not psychopathy, was predictive of response choices. Several limitations and implications of the study are noted.     

Affective biasing of choices in gambling task decision making

The proponents of the somatic marker hypothesis presume that rational decision making is guided by emotional reactions that are developed from prior experience. Supporting evidence for the hypothesis comes almost exclusively from the short-term affective reactions that are learned during the course of a hypothetical decision-making task—the gambling task (GT). We examined GT performance and affective reactions to choices when those choices were biased by words that had preexisting affective value. In one experiment, affectively valued words directly signaled good and bad choices. A congruent relation between affective value of word and choice outcome improved GT performance, whereas an incongruent relation greatly interfered with performance. In another experiment, affectively valued words were maintained as a working memory (WM) load between GT choices. A WM load with affectively positive words somewhat improved GT performance, whereas affectively negative words interfered with performance. Somatic markers—indicated by differential anticipatory skin conductance response (SCR ) amplitude for good and bad choices—appeared at a point in the GT session when choice performance was superior. However, differential SCR developed during the session after good choice performance was already established. These results indicate that preexisting affective biases can influence GT decision making. In addition, the somatic markers that are regular accompaniments of GT decision making appeared to be temporally lagging indicators of choice performance. 2006 Psychonomic Society, Inc.     

Psychopathy, risk taking, and attention: a differentiated test of the somatic marker hypothesis

A. R. Damasio's (1994) somatic marker hypothesis relates psychopathy to deficits in the ventromedial prefrontal cortex. Using the gambling task (A. Bechara, A. R. Damasio, H. Damasio, & S. Anderson, 1994), the authors tested this premise and the role of attention as a moderator. Forty-nine male prison inmates were assessed with the Psychopathy Checklist--Revised (R. D. Hare, 1991), the gambling task, and standardized tests on attention-concentration, and intelligence. Results revealed no general relation between psychopathy and gambling task performance. However, psychopathic inmates with low attention scores gambled worse than did the attentive ones. They also had more previous convictions. In nonpsychopathic individuals, attention had no impact. Different processing strategies for psychopathic and nonpsychopathic individuals are proposed to explain these findings.     

Stronger autonomic response accompanies better learning: A test of Damasio's somatic marker hypothesis

According to Damasio's (1994, 1999) somatic marker hypothesis (SMH), positive and negative events are “marked” by bodily feelings. These markers aid future adaptive learning by producing signals to warn against or affirm behavioural options. An implicit assumption of the SMH is that the stronger the signal is, the stronger the resultant behaviour will be. In this study, we tested 30 healthy women on a gambling task (Bechara, Damasio, Damasio, & Anderson, 1994), while measuring skin conductance responses. For half of the participants, real money was used, and for half, fake money was used. Success on the task was positively correlated with anticipatory autonomic response, with no difference in pattern between real and fake money conditions. The results show clear support for Damasio's SMH, and suggest that it can be used to predict learning performance within a healthy population.     

A mixed-effects expectancy-valence model for the Iowa gambling task

The Iowa gambling task (IGT; Bechara, Damasio, Damasio, & Anderson, 1994) was developed to simulate real-life decision making under uncertainty. The task has been widely used to examine possible neurocognitive deficits in normal and clinical populations. Busemeyer and Stout (2002) proposed the expectancy-valence (EV) model to explicitly account for individual participants’ repeated choices in the IGT. Parameters of the EV model presumably measure different psychological processes that underlie performance on the task, and their values may be used to differentiate individuals across different populations. In the present article, the EV model is extended to include both fixed effects and subject-specific random effects. The mixed-effects EV model fits the nested structure of observations in the IGT naturally and provides a unified procedure for parameter estimation and comparisons among groups of populations. We illustrate the utility of the mixed-effects approach with an analysis of gender differences using a real data set. A simulation study was conducted to verify the advantages of this approach.     

Evaluating the Iowa Gambling Task as a direct assessment of impulsivity with low-income children

This study examined performance on the Iowa Gambling Task (IGT; Bechara, Damasio, Damasio, & Anderson, 1994) as a measure of low-income school-aged children’s affective decision-making and considered its utility as a direct indicator of impulsivity. One hundred and ninety-three 8–11 year olds performed a computerized version of the Iowa Gambling Task, a validated measure of decision-making. Multi-level modeling was used to examine children’s performance over the course of the task, with age, gender, and teachers’ ratings of child impulsivity (BIS-11; Patton, Stanford, & Barratt, 1995) used to predict children’s Iowa Gambling performance. Higher impulsivity scores predicted a decrease in slope of Iowa Gambling performance, indicating students rated higher on impulsivity chose more disadvantageously across the task blocks. Results support evidence of the validity of the Iowa Gambling Task as a measure of impulsivity in low-income minority children.     

Somatic Markers and Response Reversal: Is There Orbitofrontal Cortex Dysfunction in Boys with Psychopathic Tendencies?

This study investigated the performance of boys with psychopathic tendencies and comparison boys, aged 9 to 17 years, on two tasks believed to be sensitive to amygdala and orbitofrontal cortex functioning. Fifty-one boys were divided into two groups according to the Psychopathy Screening Device (PSD, P. J. Frick & R. D. Hare, in press) and presented with two tasks. The tasks were the gambling task (A. Bechara, A. R. Damasio, H. Damasio, & S. W. Anderson, 1994) and the Intradimensional/Extradimensional (ID/ED) shift task (R. Dias, T. W. Robbins, & A. C. Roberts, 1996). The boys with psychopathic tendencies showed impaired performance on the gambling task. However, there were no group differences on the ID/ED task either for response reversal or extradimensional set shifting. The implications of these results for models of psychopathy are discussed.     

Cognitive modeling analysis of decision-making processes in cocaine abusers

This article examines the theoretical basis of decision-making deficits exhibited by cocaine abusers in a laboratory decision-making task first described by Bechara, Damasio, Damasio, and Anderson (1994). A total of 12 male cocaine abusers and 14 comparison subjects performed the task, and the cocaine group performed significantly worse than the comparison group. A cognitive modeling analysis (Busemeyer & Stout, 2002) was used to estimate three parameters that measure importance of the cognitive, motivational, and response processes for determining the observed performance deficit. The results of this analysis indicated, for the first time, that motivational and choice consistency factors, but not learning/ memory were mainly responsible for the decision-making deficit of the cocaine abusers in this task.     

A contribution of cognitive decision models to clinical assessment: decomposing performance on the Bechara gambling task

The Bechara simulated gambling task is a popular method of examining decision-making deficits exhibited by people with brain damage, psychopathology, antisocial personality, or drug abuse problems. However, performance on this task is confounded by complex interdependencies between cognitive, motivational, and response processes, making it difficult to sort out and identify the specific processes responsible for the observed behavioral deficits. The authors compare 3 competing cognitive decision models of the Bechara task in terms of their ability to explain the performance deficits observed in Huntington's disease patients as compared with healthy populations and people with Parkinson's disease. The parameters of the best fitting model are used to decompose the observed performance deficit of the Huntington patients into cognitive, motivational, and response sources.     

Secondary psychopathy,but not primary psychopathy,is associated with risky decision-making in noninstitutionalized young adults

Although risky decision-making has been posited to contribute to the maladaptive behavior of individuals with psychopathic tendencies, the performance of psychopathic groups on a common task of risky decision-making, the Iowa Gambling Task (IGT; Bechara, Damasio, Damasio, & Anderson, 1994), has been equivocal. Different aspects of psychopathy (personality traits, antisocial deviance) and/or moderating variables may help to explain these inconsistent findings. In a sample of college students (N = 129, age 18–27), we examined the relationship between primary and secondary psychopathic features and IGT performance. A measure of impulsivity was included to investigate its potential as a moderator. In a joint model including main effects and interactions between primary psychopathy, secondary psychopathy and impulsivity, only secondary psychopathy was significantly related to risky IGT performance, and this effect was not moderated by the other variables. This finding supports the growing literature suggesting that secondary psychopathy is a better predictor of decision-making problems than the primary psychopathic personality traits of lack of empathy and remorselessness.     

Impulsive decision-making: learning to gamble wisely?

A decade ago, Bechara et al. [Bechara, A., Damasio, A. R., Damasio, H., & Anderson, S. W. (1994). Insensitivity to future consequences following damage to human prefrontal cortex. Cognition, 50, 7-15] published a paper in Cognition, introducing a Gambling Task which was designed to mimic everyday decision-making. Since then, the task has been computerized, its decision-making components have been scrutinized, and it has been employed in various patient groups, such as pathological gamblers, substance abusers, and so forth. Time and again it has been shown that while normal controls perform well on the task, it is the various target populations under scrutiny who exhibit poor performance. Yet, as we show in this paper, a total of 46% of normal individuals exhibited poor performance on the task, indicating a lack of learning. We argue that while so much importance has been placed on contrasting patients with controls, perhaps the real emphasis should lie in distinguishing among different individual profiles of performance on the task, irrespective of clinical classification. Our basic recommendation is to look at the individual data, pool when you can, and only then to contrast groups.     

Bayesian parameter estimation in the Expectancy Valence model of the Iowa gambling task

The purpose of the popular Iowa gambling task is to study decision making deficits in clinical populations by mimicking real-life decision making in an experimental context. Busemeyer and Stout [Busemeyer, J. R., & Stout, J. C. (2002). A contribution of cognitive decision models to clinical assessment: Decomposing performance on the Bechara gambling task. Psychological Assessment, 14, 253-262] proposed an “Expectancy Valence” reinforcement learning model that estimates three latent components which are assumed to jointly determine choice behavior in the Iowa gambling task: weighing of wins versus losses, memory for past payoffs, and response consistency. In this article we explore the statistical properties of the Expectancy Valence model. We first demonstrate the difficulty of applying the model on the level of a single participant, we then propose and implement a Bayesian hierarchical estimation procedure to coherently combine information from different participants, and we finally apply the Bayesian estimation procedure to data from an experiment designed to provide a test of specific influence.     

Adapted to explore: Reinforcement learning in Autistic Spectrum Conditions

Recent studies have recorded a tendency of individuals with Autism Spectrum Conditions (ASC) to continually change their choices in repeated choice tasks. In the current study we examine if this finding implies that ASC individuals have a cognitive style that facilitates exploration and discovery. Six decision tasks were administered to adolescents with ASC and matched controls. Significant differences in shifting between choice options appeared in the Iowa Gambling task (Bechara, Damasio, Damasio, & Anderson, 1994). A formal cognitive modeling analysis demonstrated that for about half of the ASC participants the adaptation process did not conform to the standard reinforcement learning model. These individuals were only coarsely affected by choice-outcomes, and were more influenced by the exploratory value of choices, being attracted to previously un-explored alternatives. An examination of the five simpler decision tasks where the advantageous option was easier to determine showed no evidence of this pattern, suggesting that the shifting choice pattern is not an uncontrollable tendency independent of task outcomes. These findings suggest that ASC individuals have a unique adaptive learning style, which may be beneficial is some learning environment but maladaptive in others, particularly in social contexts.     

风险取向类型与爱荷华赌博任务成绩的影响

神经科学领域的研究者们设计了测量情感决策的经典爱荷华赌博任务并提出了体细胞标记假说来解释其研究结果,但迄今为止这一假说还没有得到一致认可。许多研究提出了可能影响爱荷华赌博任务成绩的其他因素。本研究试图在前人研究的基础上采用实验法探讨风险取向类型这一人格因素是否影响正常个体的爱荷华赌博任务成绩。实验结果显示,不同风险取向类型的个体在爱荷华赌博任务中的成绩和表现截然不同。典型风险趋向型个体在爱荷华赌博任务中的表现类似于某些神经系统患者,倾向于更多地选择不利纸牌,其任务成绩显著差于典型风险回避型个体。这一研究结果表明：风险取向类型是影响正常个体爱荷华赌博任务成绩的重要因素之一。     

Is short‐term memory involved in decision making? Evidence from a short‐term memory patient

It is reasonable to suggest that working memory (WM; Baddeley & Hitch, 1974 ) is involved in decision making, as decision making is dependent on the ability to remember and update past choices and outcomes. However, contradictory results have been reported in the literature concerning the role of two of its components, namely the central executive and the phonological loop. In order to investigate the role of these components in the decision‐making process, we tested a patient with intact central executive but impaired phonological loop on a laboratory decision‐making task involving hypothetical gambles (gambling task, GT). When tested in a no‐load condition (simple keypress task), her performance was not significantly different from that of matched controls. We also verified whether her performance would be affected differently by memory‐load when compared with control subjects. The memory task (holding a string of letters in memory) loaded WM without incurring number‐number interference. When the memory‐load was imposed during the GT, both the patient and the controls showed a decline in performance, but the strategy they adopted differed. Possible explanations are discussed. In conclusion, our results suggest that the phonological loop is not directly involved in decision making.     

Age-related changes in decision making: comparing informed and noninformed situations

Advantageous decision making progressively develops into early adulthood, most specifically in complex and motivationally salient decision situations in which direct feedback on gains and losses is provided (Figner & Weber, 2011). However, the factors that underlie this developmental improvement in decision making are still not well understood. The current study therefore investigates 2 potential factors, long-term memory and working memory, by assigning a large developmental sample (7-29 years of age) to a condition with either high or low demands on long-term and working memory. The first condition featured an age-adapted version of the Iowa Gambling Task (IGT; Bechara, Damasio, Damasio, & Anderson, 1994; i.e., a noninformed situation), whereas the second condition provided an external store where explicit information on gains, losses, and probabilities per choice option was presented (i.e., an informed situation). Consistent with previous developmental IGT studies, children up to age 12 did not learn to prefer advantageous options in the noninformed condition. In contrast, all age groups learned to prefer the advantageous options in the informed conditions, although a slight developmental increase in advantageous decision making remained. These results indicate that lowering dependence on long-term and working memory improves children's advantageous decision making. The results additionally suggest that other factors, like inhibitory control processes, may play an additional role in the development of advantageous decision making.     

Somatic responses in behavioral inhibition

In the present study, skin conductance responses (SCRs) were measured postdecision and prefeedback in a go/no-go (GNG) task in which participants used response feedback to learn when to respond or not to respond to numeric stimuli. Like somatic markers in gambling tasks and somatic reactions to error monitoring in choice reaction time tasks, SCR patterns distinguished between correct and incorrect trials over time. These somatic reactions were disrupted by a reversal of GNG contingencies, and they were facilitated by pretraining of the stimulus—response mappings. In all cases, however, the somatic reactions appeared to be a product of competent decision making rather than a contributor to performance. Differential somatic responses to good and bad choices appear to be a robust and fairly general phenomenon, but researchers should be cautious in assuming that the somatic responses contribute to performance.     

Older adults as adaptive decision makers: evidence from the Iowa Gambling Task

Older adults process emotional information differently than younger adults and may demonstrate less of a negativity bias on cognitive tasks. The Iowa Gambling Task designed by A. Bechara, H. Damasio, D. Tranel, and A. R. Damasio (1997) has been used to examine the integration of emotion and cognition in a risky-choice decision task and may give insight into differences in the decision-making strategies in younger and older adults. Eighty-eight younger adults (18-34 years) and 67 older adults (65-88 years) completed the Iowa Gambling Task. Using a theoretical decomposition of the task designed by J. R. Busemeyer and J. C. Stout (2002), the authors found that both groups were successful at solving the task but used very different strategies that reflected each group's strength. For younger adults, that strength was learning and memory. For older adults, that strength was an accurate representation of wins and losses (valence).     

爱荷华博弈任务(IGT)与决策的认知神经机制

爱荷华博弈任务(IGT)是一项检查情感性决策机制的常用实验范式。据此, Damasio等人提出了躯体标记假设(SMH)解释情绪影响决策的神经生理机制。近期, 大量研究在IGT究竟是模糊决策还是风险决策、与情绪和认知的关系、与工作记忆和陈述性记忆的关系以及IGT的神经网络与分子遗传机制等方面积累了丰富资料。结果显示, IGT加工的早期由模糊决策主导, 情绪性躯体信号对引导决策选项的偏好可能起关键作用, 后期则倾向是一种风险决策, 认知评价和预期对选项偏向逐渐占优势; IGT与工作记忆的加工成分有相互重叠, 也需陈述性记忆的参与; IGT的加工不仅依赖于杏仁核、腹内侧前额皮层、眶额皮层等组成的情绪脑网络的活动, 还与背外侧前额皮层、海马、腹侧纹状体、岛叶皮层、辅助运动前区、扣带回皮层等许多脑区的活动有关; COMT和5-HTT的基因多态性会调节IGT相关的决策加工。总之, IGT是一项需要多重神经系统协同活动的决策加工任务, 且模糊与风险决策可能具有不同的遗传基础。