Neal Hinvest

The effects of real versus hypothetical reward on delay and probability discounting

Delay discounting and probability discounting tasks providing hypothetical rewards have commonly been used to measure levels of impulsivity and risk taking. Results have been inconsistent as to whether real, compared with hypothetical, rewards influence choice behaviour in delay discounting tasks. This experiment examined choice behaviour in 38 healthy individuals using delay and probability discounting tasks involving both real and hypothetical rewards (£0.10/£0.20), real delays, and probabilistic outcomes. It was hypothesized that choice behaviour when receiving real rewards would be less impulsive and less risky than when receiving hypothetical rewards. The tasks were designed so that a mathematical model (the multiplicative hyperbolic model of choice) could be applied to assess effects on discounting parameters. The provision of real rewards was associated with significantly decreased impulsive, but not risky, choice although the size of effect was small and was influenced by the order of presentation. Repeated presentation of both tasks increased quantity discounting but not delay or probability discounting parameters. These results indicate that the nature of the reward provided, and repetition effects, need to be taken into account when designing discounting studies.

Risk-taking behavior in a gambling task associated with variations in the tryptophan hydroxylase 2 gene: relevance to psychiatric disorders

Decision making, choosing the best option from the possible outcomes, is impaired in many psychiatric conditions including affective disorders. We tested the hypothesis that variations in serotonergic genes (TPH2, TPH1, SLC6A4, HTR1A), which influence serotonin availability, affect choice behavior in a probabilistic gambling task. A population cohort (N=1035) completed a paper-and-pencil gambling task, filled out personality and symptom questionnaires and gave consent for the use of their DNA in a genetic association study. A subgroup of subjects (N=69) also completed a computer version of the task. The gambling task was designed to estimate an individuals tendency to take a risk when choosing between a smaller but more certain ‘win’ and a larger, less probable one. We genotyped seven haplotype tagging SNPs in the TPH2 gene, and previously reported functional polymorphisms from the other genes (rs1800532, 5HTTLPR, and rs6295). Carriers of the more prevalent TPH2 haplotype, which was previously associated with less active enzyme variant, showed reduced risk taking on both tasks compared with subjects not carrying the common haplotype. The effect of TPH2 haplotypes on risk-taking was independent of current depression and anxiety symptoms, neuroticism and impulsiveness scores. We did not find an association between functional polymorphisms in the TPH1, SLC6A4, HTR1A genes and risk-taking behavior. In conclusion, our study demonstrates the role of the TPH2 gene and the serotonin system in risk taking and suggests that TPH2 gene may contribute to the expression of psychiatric phenotypes through altered decision making.

Neural correlates of choice behavior related to impulsivity and venturesomeness.

Impulsivity has been associated with several psychiatric disorders including drug addiction and gambling. Impulsive subjects typically have a preference for short-term over long-term rewards and make risky choices. This study used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of self-rated impulsivity and venturesomeness during tasks involving delayed and risky choice. A broader sampling approach was taken by recruiting participants with behaviors that have been linked to impulsivity (gambling N=15, and recreational drug use N=10) and those without these behaviors (N=9). Selection between delayed or probabilistic rewards was associated with activation in fronto-parietal regions in line with previous research. When selecting between delayed rewards, activity within the pregenual anterior cingulate cortex and ventrolateral prefrontal cortex correlated positively with impulsivity scores while activity within the orbitofrontal cortex, subgenual anterior cingulate cortex and caudate correlated positively with venturesomeness scores. Selection between probabilistic rewards revealed no correlation between scores and regional activations. The results from this study provide targets for future research investigating the neural substrates of impulsivity. They also provide targets for the further investigation into the pathophysiology of addiction and impulse-control disorders.

Emotional and Cognitive Processing Deficits in People with Parkinson's Disease and Apathy

Background: Apathy is a common non-motor syndrome of Parkinson’s disease (PD), understood as a quantitative reduction in goal-directed behaviour consisting of cognitive and emotional dimensions. Methods: Participants with PD (n=61) were assessed in different medication states on tasks of executive function and emotional processing. Performance was compared to that of a healthy control group (HC, n=19). The PD group was further divided into those with and without clinically significant apathy and compared using the same measures in an exploratory manner. Results: Compared to the HC group, the PD participants performed significantly worse on tests of executive function, the Iowa Gambling Task, and recognition of happiness on the Facial Emotional Recognition Task. Compared to PD participants without apathy, those with PD and apathy were found to have selective impairments on tasks of attention and the recognition of disgust, fear and happiness. No ef fects of dopamine were seen. Conclusion: The presence of apathy in PD is associated with selective cognitive and emotional processing deficits, which do not appear to be dopamine dependent.

Autistic characteristics in adults with epilepsy

INTRODUCTION The reported prevalence of autism spectrum disorders in people with epilepsy ranges from 15% to 47%. Despite the high comorbidity, there has been a lack of systematic studies of autistic characteristics in epilepsy. Little is known about the relationship of epilepsy to the core characteristics of autism. The aim of this research was to measure autistic traits and characteristics in adults with epilepsy who do not have a diagnosis of any autism disorder. METHOD We investigated autistic characteristics in adults with epilepsy and those without epilepsy employing the Autism Spectrum Quotient (group with epilepsy, n = 40; control group, n = 38) and systemizing and empathizing abilities employing the Intuitive Physics test and the Adult Eyes Task-Revised (group with epilepsy, n = 19; control group, n = 23). RESULTS Significantly more autistic behavioral traits, as measured by the AQ, were related to having epilepsy, but intact systemizing and empathizing abilities in these adults suggest that, in adults with epilepsy, autism-like symptoms may be present in the absence of wider cognitive profiles characteristic of autism. CONCLUSION Increased autistic characteristics found in adults with epilepsy without an ASD diagnosis suggest that epilepsy syndromes may incorporate behavioral aspects of autism in the absence of some of its core cognitive features.

Autistic characteristics in adults with epilepsy and perceived seizure activity

UNLABELLED The prevalence of autism spectrum disorders in epilepsy is approximately 15%-47%, with previous research by Wakeford and colleagues reporting higher autistic traits in adults with epilepsy. The aim of this study was to investigate autistic characteristics and their relationship to having seizures by employing two behavioral assessments in two samples: adults with epilepsy and controls. METHOD The study employed the Social Responsiveness Scale - Shortened (SRS-S) (patients with epilepsy (n=76), control (n=19)) and the brief Repetitive Behavior Scale - Revised (RBS-R) (patients with epilepsy (n=47), control (n=21)). This study employed a unique method to quantify the extent to which autistic characteristics are related to perceived mild seizure activity. Adults with epilepsy were instructed to rate their usual behavior on each assessment and, at the same time, rate their behavior again when they perceived that they were having mild seizure activity. RESULTS Significantly higher SRS-S scores were related to having a diagnosis of epilepsy and were perceived by adults with epilepsy to increase during mild seizure activity. These scores positively correlated with antiepileptic drug control. No difference was found for RBS-R scores in adults with epilepsy compared with controls. CONCLUSION Together, these results suggest that adults with epilepsy have higher autistic characteristics measured by the social responsiveness scale, while sameness behaviors remain unimpaired. The autistic characteristics measured by the social responsiveness scale were reported by adults with epilepsy to be more severe during their mild seizure activity.

Physiological markers of biased decision-making in problematic Internet users

Background and aims Addiction has been reliably associated with biased emotional reactions to risky choices. Problematic Internet use (PIU) is a relatively new concept and its classification as an addiction is debated. Implicit emotional responses were measured in individuals expressing nonproblematic and problematic Internet behaviors while they made risky/ambiguous decisions to explore whether they showed similar responses to those found in agreed-upon addictions. Methods The design of the study was cross sectional. Participants were adult Internet users (N = 72). All testing took place in the Psychophysics Laboratory at the University of Bath, UK. Participants were given the Iowa Gambling Task (IGT) which provides an index of an individual’s ability to process and learn probabilities of reward and loss. Integration of emotions into current decision-making frameworks is vital for optimal performance on the IGT and thus, skin conductance responses (SCRs) to reward, punishment, and in anticipation of both were measured to assess emotional function. Results Performance on the IGT did not differ between the groups of Internet users. However, problematic Internet users expressed increased sensitivity to punishment as revealed by stronger SCRs to trials with higher punishment magnitude. Discussion and conclusions PIU seems to differ on behavioral and physiological levels with other addictions. However, our data imply that problematic Internet users were more risk-sensitive, which is a suggestion that needs to be incorporated into in any measure and, potentially, any intervention for PIU.

The Conflict Between Economic and Social Preferences: Social Investing, Social Enterprise, Mind-Sets and Nudges

Investing into the financial markets has become increasingly complex in recent years, with a multitude of investment products and motives. With the rapid growth in social investing and social entrepreneurship, scholars recognise that investors and entrepreneurs often consider a wide range of social factors, in addition to financial return, when making their financial decisions. Behavioural economists argue that it is important to understand the complex economic and behavioural/psychological factors affecting social investors’ decision-making. In this paper, we draw upon lessons from behavioural economics (and in particular, social preference theory) in order to develop neuro-economic tests of investors’ social and financial mind-sets. We focus on two main research questions: a) How heterogeneous are (social-) investors, in terms of the unconscious weightings that they place upon financial and social returns? Can investors’ mind-sets be placed upon a continuum from focussing on social returns, through mixed motivations/weightings, through to focussing on financial returns? b). Can investors be nudged along this continuum? We address these two research questions by means of two neuro-experiments. We employ eye-tracking techniques to examine investors’ attention to, and fixation on, social and financial aspects of financial market investment. In addition, we employ nudges in the form of images relating to positive and negative social behaviour. Our experiments demonstrate that a) investors can indeed be placed on the financial-social motivation continuum (and that there is heterogeneity in social-investors’ motives along this scale), and b) investors can be nudged along the scale. Our experiments thus provide policy implications regarding nudges towards social investment. Practically, we suggest the development of a phone application that integrates real-time stock-tracking with nudges in order to inspire socially responsible investing; banks would play a key role in encouraging its download. Nudges can help to overcome the conflict between social and financial returns.

Warning: Trading Can Be Hazardous to Your Wealth! (Just Watch Out for Bears!)

In this paper, we conduct a quantitative, qualitative and neuro-economic experiment investigating the effects of risk-preferences and emotions on investors’ trading strategies and performance. The focus of our experiment is a computerised simulated trading game, where investors decide, on a tick-by-tick basis, how much of their wealth to allocate to risk-free cash and/or risky shares (in each period, they can buy or sell shares, or hold their position). Overall, the trading game represents a bear market. Our results demonstrate that risk-aversion and emotions may be detrimental to trading performance in a bear market, and that an optimal level of each may exist.