Time-varying decision boundaries: insights from optimality analysis

The most widely used account of decision-making proposes that people choose between alternatives by accumulating evidence in favor of each alternative until this evidence reaches a decision boundary. It is frequently assumed that this decision boundary stays constant during a decision, depending on the evidence collected but not on time. Recent experimental and theoretical work has challenged this assumption, showing that constant decision boundaries are, in some circumstances, sub-optimal. We introduce a theoretical model that facilitates identification of the optimal decision boundaries under a wide range of conditions. Time-varying optimal decision boundaries for our model are a result only of uncertainty over the difficulty of each trial and do not require decision deadlines or costs associated with collecting evidence, as assumed by previous authors. Furthermore, the shape of optimal decision boundaries depends on the difficulties of different decisions. When some trials are very difficult, optimal boundaries decrease with time, but for tasks that only include a mixture of easy and medium difficulty trials, the optimal boundaries increase or stay constant. We also show how this simple model can be extended to more complex decision-making tasks such as when people have unequal priors or when they can choose to opt out of decisions. The theoretical model presented here provides an important framework to understand how, why, and whether decision boundaries should change over time in experiments on decision-making.     

Determinants of credit card debt: Differentiating between revolving credit debt and petty installment loan in China

This research explores the determinants of the probability of having credit debt, as well as the determinants of the severity of credit card debt. Credit card debt includes revolving credit debt and petty installment loan. The severity of credit card debt was measured by the duration of revolving credit debt and the amount of petty installment loans. Analysis of behavioral data from a Chinese commercial bank showed a significant difference between the determinants of the probability of having credit card debt and the determinants of the severity of credit card debt. Specifically, credit limit, gender, length of ownership of a credit card, and the total credit card expenditure were closely related to the likelihood of having revolving credit debt and to the duration of revolving credit debt. However, age, the square of age, credit ranking, and risk ranking were significantly correlated with the likelihood of having revolving credit debt rather than the duration of revolving credit debt. Credit card balance had a special influence on the duration of revolving credit debt. Compared with revolving credit debt, petty installment loan had few significantly related factors. Both age and the square of age could significantly predict both the likelihood of having petty installment loan and amount of petty installment loan. Credit ranking, risk ranking, and gender predicted the likelihood of having petty installment loan but did not correlate with the amount of petty installment loan. The frequency of petty installment use was closely related to the amount of petty installment loan. Copyright © 2014 John Wiley & Sons, Ltd.     

Distinguishing non-spatial from spatial biases in visual selection: neuropsychological evidence

Recently, it has been shown that patients with visual extinction can show enhanced awareness of contralesional stimuli that match the contents of working memory [Soto, D., & Humphreys, G.W. (2006). Proceedings of the National Academy of Sciences, USA, 103, 4789–4792]. Here we investigate whether these effects extend to cases where the working memory cue is verbal rather than visual (Study 1), and we show that non-spatial cues can overcome problems in spatial disengagement in patients, and this can affect the first eye movement made in search (Study 2). We discuss the implications of the data for understanding the relations between the cueing of attention from visual and conceptual information held in working memory and the cueing of spatial attention, and for understanding the relations between non-spatial and spatial biases in selection.     

Computer Gaming: A Newer Pathway to Development of Self Concept

Internet and electronic games have become widely and unrestrictedly used tools and one of the major global phenomenona in the last decade. As the computer games advance they provide the players a sense of self without being one self. A case of 17 year old male student is presented and later discussed with a psychological perspective in an attempt to highlight as to how the increased substitution of cyberspace-based personas and relationships lead to wish fulfillment, role playing and putting restrictions on the real social interaction and thereby enabling in the development of self concept.     

Attributions of behavior in the pediatric mild closed head injury (CHI) population

Forty-one children between the ages of 6 and 11 years with a history of a mild closed head injury and 23 age-, gender-, and IQ-matched typically developing control children participated. All of the children in the CHI sample were referred for a magnetic resonance imaging (MRI) scan at 3 months post-injury and children in the CHI sample were further divided into MRI-Negative (n=31) and MRI-Positive (n=10) conditions according to the MRI results. Parents and teachers completed behavioral checklists at three points, including just prior to the MRI and 6 months post-injury. Prior to the MRI (Time 2), in both samples of children with a CHI, parents reported an increase in externalizing symptoms after the CHI. At 6 months post-injury (Time 3: post-MRI), parents of children in the MRI-Positive group did not report any significant changes in their child's externalizing behaviors when compared with pre-MRI, yet parents of children in the MRI-Negative group reported a further increase in externalizing behaviors. Parent attributions also changed as a function of group membership; whereas no changes were noted in the other two groups, parents of children in the MRI-Negative sample ascribed more controllability at Time 3 when compared with Time 2.