An Evolutionary Perspective on Goal Seeking and Escalation of Commitment

Maximizing the probability of bypassing an aspiration level, and taking increasing risks to recover previous losses are well-documented behavioral tendencies. They are compatible with individual utility functions that are S-shaped, as suggested in Prospect Theory (Kahneman and Tversky 1979). We explore evolutionary foundations for such preferences. Idiosyncratic innovative activity, while individually risky, enhances the fitness of society because it provides hedging against aggregate disasters that might occur if everybody had pursued the same course of action. In order that individuals choose the socially optimal dosage of innovative activity, the individuals’ preferences should make them strive to improve upon the on-going convention, even if it implies taking gambles that reduce their expected achievements. We show how, in a formal model, the preferences that will be selected for in the course of evolution lead to maximizing the probability of bypassing an aspiration level. Furthermore, when comparing choices with the same probability of achieving this goal, preference is indeed established by maximizing the expected utility of an S-shaped utility function, exhibiting risk loving below the aspiration level and risk aversion beyond it

The role of children in the spread of COVID-19: Using household data from Bnei Brak, Israel, to estimate the relative susceptibility and infectivity of children.

One of the significant unanswered questions about COVID-19 epidemiology relates to the role of children in transmission. This study uses data on infections within households in order to estimate the susceptibility and infectivity of children compared to those of adults. The data were collected from households in the city of Bnei Brak, Israel, in which all household members were tested for COVID-19 using PCR (637 households, average household size of 5.3). In addition, serological tests were performed on a subset of the individuals in the study. Inspection of the PCR data shows that children are less likely to be tested positive compared to adults (25% of children positive over all households, 44% of adults positive over all households, excluding index cases), and the chance of being positive increases with age. Analysis of joint PCR/serological data shows that there is under-detection of infections in the PCR testing, which is more substantial in children. However, the differences in detection rates are not sufficient to account for the differences in PCR positive rates in the two age groups. To estimate relative transmission parameters, we employ a discrete stochastic model of the spread of infection within a household, allowing for susceptibility and infectivity parameters to differ among children and adults. The model is fitted to the household data using a simulated maximum likelihood approach. To adjust parameter estimates for under-detection of infections in the PCR results, we employ a multiple imputation procedure using estimates of under-detection in children and adults, based on the available serological data. We estimate that the susceptibility of children (under 20 years old) is 43% (95% CI: [31%, 55%]) of the susceptibility of adults. The infectivity of children was estimated to be 63% (95% CI: [37%, 88%]) relative to that of adults