Two recent articles in TiGS by Gerald Crabtree float the notion that we, as a species, are gradually declining in average intellect because we are accumulating mutations that deleteriously affect brain development or function. The observations that prompted this view seem to be: (i) intellectual disability can be caused by mutations in any one of a very large number of genes; and (ii) de novo mutations arise at a low but steady rate in every new egg or sperm. He further proposes that (iii) genes involved in brain development or function are especially vulnerable to the effects of such mutations. Considered in isolation, these could reasonably lead to the conclusion that mutations reducing intelligence must be constantly accumulating in the human gene pool. Thankfully, these factors do not act in isolation. If we, as a species, were simply constantly accumulating new mutations, then one would predict the gradual degradation of every aspect of fitness over time, not just intelligence. Indeed, life could simply not be sustained over evolutionary time in the face of such genetic entropy. Fortunately (for the species, although not for all individual members), natural selection is an attentive minder. […] Whether causally or as a correlated indicator, intelligence is strongly associated with evolutionary fitness, even in current societies. The threat posed by new mutations to the intellect of the species is therefore kept in check by the constant vigilance of selection. Thus, despite ready counter-examples from nightly newscasts, there is no scientific reason to think that we humans are on an inevitable genetic trajectory towards idiocy. [Cell]
Member-to-group comparisons are prevalent in everyday life. A person might consider whether one politician would make a better president than other candidates, whether one home is more suitable than other prospective homes on the market, whether one food item is healthier than others, or whether one vacation spot is more desirable than others. In turn, the outcomes of such comparisons have important consequences for a person’s choices, decisions, moods, thoughts, and, ultimately, welfare. Indeed, rational models of choice are predicated on the idea that human beings can maximize their utility by identifying the best and worst options in a choice set. However, recent work by Klar and his colleagues suggests that people are far from unbiased in their comparisons. Individual members of positively valenced groups (e.g., healthy foods, good politicians) are rated better and individual members of negatively valenced groups (e.g., unhealthy foods, bad politicians) are rated worse than the group average, in defiance of simple mathematical rules stating that the average of the individual members must equal the group average. In one of the first studies demonstrating these nonselective inferiority and superiority biases, Giladi and Klar had shoppers evaluate randomly selected pleasant-smelling or unpleasant-smelling soaps and found that any given pleasant soap was rated better than the rest of the group, and any given unpleasant soap was rated worse than the rest of the group. These effects have since been observed with other object categories, including desirable and undesirable acquaintances, restaurants, social groups, pieces of furniture, hotels, and songs, and thus appear to be highly robust and reliable. In explaining these nonselective biases, Giladi and Klar proposed that when one member of a positive or negative group is compared with others (e.g., how does good restaurant A compare with other good restaurants B and C?), that member is evaluated against a standard that is one part local (restaurants B and C) and one part general (all other restaurants, including bad ones). Thus, although the member that is being evaluated should be compared only with the normatively appropriate local standard, it is actually compared with a hybrid standard that includes both the local and the general standard. Consequently, almost any member of a positive group will be rated better than others (because the general standard is more negative than the local standard), and almost any member of a negative group will be rated worse than others (because the general standard is more positive than the local standard). In this article, I propose an additional reason (beyond the confusion of local and general standards) why almost any group member is rated more extremely than others in its group. [APS/SAGE]
Making small easy changes to our eating habits on a consistent basis – 25 days or more per month – can lead to sustainable weight loss, according to research. The challenge is to figure out which changes work for specific individuals and how to stick with changes long enough to make them second nature. [EurekAlert]
Closed systems, or three-party systems, such as Discover and American Express typically issue cards to consumers and acquire merchants to accept the card. They set fees to both sides, which largely consist of an annual fee, an interest rate (for credit cards) and a rewards program for consumers, and a fee for merchants (termed the merchant discount in the industry). A closed card platform can choose any structure of prices that it so desires between cardholders and merchants. In particular, if low cardholder fees and high merchant fees are what generate the most card transactions or profit, then the closed card system is free to set this structure of prices. In contrast, many of the largest systems separate the clearing-house services from the task of obtaining consumers and merchants. This is true for Visa and MasterCard, as well as for debit networks such as NYCE and Pulse. Thus, the direct customers of these systems are banks. The systems are open in the sense that any bank or equivalent financial institution can join. In these systems, banks join and then seek to issue cards to consumers and acquire merchants to accept cards. When a consumer makes a purchase from a merchant, the payment is authorized and routed from the issuing bank through the payment system (i.e., Visa or NYCE) to the merchant’s account with the acquiring bank; subject to liability rules governing fraud, payments are generally guaranteed to the merchant, and the issuer is responsible for collecting funds from the consumer. Since many banks are typically associated with each system, there can be substantial competition among banks to offer access to the system. The competition takes place over the terms mentioned above, fees and rewards, and other features such as consumer protection and customer service. Open systems are often referred to as four-party systems, referring to the merchant, the consumer and the two banks, although the network owner is really a fifth party. Typically, the owner of the open system collects a fee, often called the switch fee for the service. These are fairly small and, to date, have been largely uncontroversial. In addition to the switch fee, open systems set an interchange fee. The interchange fee is an amount that the merchant’s bank pays to the consumer’s bank as part of a typical purchase transaction. [The Economics of Payment Cards/SSRN]
To stretch out their supply of penicillin, a member of Florey’s lab would visit the hospital each morning to collect Alexander’s urine. He would carry it back by bicycle to the lab, where the scientists extracted the penicillin that Alexander’s body hadn’t absorbed. Alexander’s doctors then injected the recycled antibotic into Alexander’s arm. […] The microbiome keeps us healthy. It breaks down some of our food into digestible molecules, it detoxifies poisons, it serves as a shield on our skin and internal linings to keep out pathogens, and it nurtures our immune systems, instructing them in the proper balance between vigilance and tolerance. It’s a dependence we’ve been evolving for 700 million years, ever since our early animal ancestors evolved bodies that bacteria could colonize. [National Geographic]
Instagram Retreats Back to Old Policies. But are those older policies really better for users?
Following months of congressional pressure, the TSA has agreed to contract with the National Academy of Sciences to study the health effects of the agency’s X-ray body scanners.
Hudson Yards, a series of buildings to be built over the rail yards on Manhattan’s West Side, will add a new neighborhood with the population of downtown Detroit to the Big Apple. How do you create a city within a city?
Written like a linguistics textbook, the fourteen-page Web site ran to almost a hundred and sixty thousand words. It documented the grammar, syntax, and lexicon of a language that Quijada had spent three decades inventing in his spare time. Ithkuil had never been spoken by anyone other than Quijada, and he assumed that it never would be…
One of the more poignant moments in Nietzsche’s long and tormented career was when the catalogue of his many ailments, both mental and physical, started to include encroaching blindness. To remedy that he turned to experimentation with the (very primitive) typewriters of the time – a Malling-Hansen Writing Ball.