Psychology of financial decisions, using large transaction datesets

Behavioral studies show that people tend to use various decision heuristics which discard part of the available information, simplify the decision problem, and find a good enough answer. In addition, people’s decision and behavior may change because they learn from experience. This thesis investigates people’s heuristic decision making and learning from experience in two frequent real-world financial decision contexts—credit card repayments and stock trading. Chapter 1 reviews the literature about decision heuristics and nudges. Literature about learning from experience is also reviewed. Chapter 2 shows that automatic minimum credit card repayment as a default nudge has the adverse effect of reducing repayments by allowing card holders to neglect their monthly bill. Chapter 3 examines whether people learn from the negative feedback provided by credit card fees. We show that cardholders tend to adapt to late payment fees, which are typically due to forgetting a repayment, by setting up an automatic repayment. On the other hand, cash advance and over-limit fees are due to card holders’ liquidity needs rather than their mistakes, and thus, they do not learn from experiencing those fees. Our findings are contrast to those in a previous study in the US suggesting that people learn from all three types of fees. Chapter 4 shows evidence of people’s heuristic processing of numerical information in the context of credit card repayments. We find a strong tendency of card holders repaying at several prominent numbers. We also find people’s preference for round numbers. Conducting an online experiment, Chapter 5 confirms the anchoring effect of numerical information in a credit card bill, as in previous studies, and finds a false consensus bias where people who usually repay only the minimum greatly overestimate the commonness of minimum repayments among others. However, a social nudge phrase in a mock bill fails to correct the false belief, and thus, dose not reduce the likelihood of people repaying only the minimum. Chapter 6 presents a two-stage model of the choice of a stock to sell. Typically investors show a disposition effect, being more likely to sell a stock in gain than loss, other things equal. In our model, investors first decide whether to sell a stock in the domain of gains or losses, and only then, evaluate stocks within the chosen domain. As evidence for the model, our analysis shows that the likelihood of an individual stock being sold is inversely proportional to the number of stocks in the same domain in the portfolio but is not sensitive to the number of stocks in the other domain. Our findings indicate that existing estimation methods of the disposition effect result in substantial biases because those estimations assume that all stocks in a portfolio are simultaneously evaluated across domains of gains and losses. Chapter 7 summarizes the findings and implications of Chapters 2-6. Plans and suggestions for future research are also discussed

Development and characterization of nuclear microsatellite markers in Aphananthe aspera (Thunb.) Planch. (Cannabaceae)

Nuclear microsatellite markers were developed for Aphananthe aspera (Thunb.) Planch. (Cannabaceae), a deciduous canopy tree species distributed in East Asia, to evaluate the genetic diversity and genetic structure of A. aspera populations in remnant forest fragments in urbanized areas of Japan. A total of 94 primer pairs were designed based on genomic sequence data. Of the 25 primer pairs which showed clear microsatellite peaks, 20 pairs showed allelic polymorphisms in 57 individuals collected from two distant populations. The length of PCR products ranged from 120 to 482 bp, and expected heterozygosity for the 20 microsatellite markers ranged from 0.017 to 0.768. These newly developed simple sequence repeat markers will be used in population genetic studies of A. aspera to evaluate genetic diversity and the extent of genetic isolation of the fragmented populations in urban areas

Determination of QCD phase diagram from the imaginary chemical potential region

We test the reliability of the the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model, comparing the model result with the lattice data at nonzero imaginary chemical potential. The PNJL model with the vector-type four-quark and scalar-type eight-quark interactions reproduces the lattice data on the pseudocritical temperatures of the deconfinement and chiral phase transitions. The QCD phase diagram in the real chemical potential region is predicted by the PNJL model. The critical endpoint survives, even if the vector-type four-quark interaction is taken into account.Comment: 8 pages, 12 figure

Chiral phase transition in an extended NJL model with higher-order multi-quark interactions

The chiral phase transition is studied in an extended Nambu--Jona-Lasinio model with eight-quark interactions. Equations for scalar and vector quark densities, derived in the mean field approximation, are nonlinear and mutually coupled. The scalar-type nonlinear term hastens the restoration of chiral symmetry, while the scalar-vector mixing term makes the transition sharper. The scalar-type nonlinear term shifts the critical endpoint toward the values predicted by lattice QCD simulations and the QCD-like theory.Comment: 11pages, 7 figure

The effect of anastrozole on bone mineral density during the first 5 years of adjuvant treatment in postmenopausal women with early breast cancer

PURPOSE: The administration of aromatase inhibitors is associated with bone loss in postmenopausal women. We assessed changes in bone mineral density (BMD) from baseline to 60 months of treatment in patients receiving anastrozole as initial adjuvant therapy. METHODS: Postmenopausal women with hormone receptor-positive breast cancer receiving anastrozole as adjuvant therapy at our center since 2004 were enrolled in this study. BMD was assessed by dual-energy X-ray absorptiometry at baseline and after 6, 12, 24, 36, 48 and 60 months. Oral bisphosphonate (Bis) treatment was initiated when patients were diagnosed with osteoporosis having a T-score of −2.5 or lower. RESULTS: Fifty-five patients were enrolled in the study between 2004 and 2011, and the mean follow-up period was 53.6 months. Thirty-five patients were administered Bis (risedronate in 27 patients, alendronate in 8 patients). After 6 months of hormone therapy, BMD decreased by 0.5% from baseline at the lumbar spine (LS) and BMD decreased by 1.5% at the femoral neck (FN). However, BMD increased by 1.9% at the LS and BMD decreased by 1.5% at the FN for 60 months of treatment. In patients treated with upfront Bis (n = 19), 5.4% BMD increase from baseline was noted at the LS whereas in those without Bis (n = 21) BMD decreased by 4.3% from baseline within 24 months (P < 0.0001). Fractures were observed in 4 patients (7.3%), and 1 patient (1.8%) had a fragility fracture. CONCLUSIONS: Upfront treatment of Bis with anastrozole significantly increased BMD at the LS and an optimal use of Bis would not increase bone fractures. TRIAL REGISTRATION: UMIN000001757

Naïve diversification and narrow framing among individual investors

We provide the first tests to distinguish whether individual investors equally balance their overall portfolios (naive portfolio diversification - NPD) or, in contrast, equally balance the values of same-day purchases of multiple assets (naive buying diversification - NBD). We find NBD in purchases of multiple stocks, and in mixed purchases of individual stocks and funds. In contrast, there is little evidence of NPD. Evidence suggest NBD arises due to stock picking behaviour and neglect of diversification. These findings suggest that behavioral finance theory should incorporate transaction as well as portfolio framing