The Better Things Get, the Worse They May Seem

“Too much of a good thing” and “it’s all relative” now take on new meaning. A new research report of seven studies suggests an explanation for the paradox that humans misjudge the extent of a changing situation. This report, published in the June 29^th issue of the premier journal, Science, demonstrated that people often respond to diminished prevalence of a stimulus by expanding their perception of its prevalence. For example, when looking at a matrix panel of blue and purple dots, if the experimenter reduces the percentage of blue dots, the subjects began to see purple dots as blue. Or when shown panels of threatening faces mixed with neutral faces in which the percentage of angry faces became rarer, they began to see neutral faces as threatening. Or when unethical requests of the subjects were made rarer, subjects began to regard innocuous requests as unethical. In other words, reduced prevalence of a certain stimulus created a bias for finding more of that stimulus than actually existed.

The investigators began with the blue/purple dot test. When they saw the biasing effect of reducing incidence of blue dots, they wondered if this same principle applied to other kinds of stimuli and to more abstract comparisons. The bias showed up also in their test with angry and neutral faces and in the test with unethical and innocuous requests.

Everyday experiences suggested this research. For example, others had reported that when unprovoked attacks and invasions decline, the perception of new instances receive magnified judgement. I might speculate that the empowerment of women by the women’s rights movement has made recent incidents of sexual harassment more notable than would have been the case years ago when it was not so unexpected. Or perhaps the current outrage over illegal immigrant children separated from their parents and attempts to close the border are magnified by the fact that so many have been already reunited and set free in the U.S.

The authors rightly concluded, “These results may have sobering implications. Many organizations and institutions are dedicated to identifying and reducing the prevalence of social problems, from unethical research to unwarranted aggression. But our studies suggest that even well-meaning agents may sometimes fail to recognize the success of their own efforts.”

They add reference citations that show that societies have made “extraordinary” progress in solving a wide range of social problems, but that the majority of people think the world is getting worse. In prosperous countries, like the U.S., social problems usually continue to improve. However, many people in such environments seem to keep finding more and more things to complain about. For example, as the economy improves, it seems increasingly easy to find poverty or wealth gaps. As civil rights improve, it seems easy to find abuses and even to misinterpret neutral events as abuse. Thus, despite all progressive efforts, the problems seem intractable, when in fact they are not. Politics is contaminated by flawed judgment caused by changed prevalence of social problems contaminates our politics.

We tend to cling to old myths when they no longer apply as well as before. This diminishes appreciation of the successes of government policy. In the U.S., the growing hostility of citizens toward their country may actually be the result of the improvements in the country. Compounding the problem is the common feeling that it is not politically correct to consider that this kind of bias might exist. Even when a person knows of this bias, sometimes it is of political benefit to keep contentious issues alive.

Help kiddos get ready for school. 

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Source:

Levari, David E. et al. (2018). Prevalence-induced concept change in human judgment. Science. 360(6396), 1462-1467.

Three Ways to Slow Brain Aging

Moderate physical exercise, dietary restriction, and enriched environment stimulation are all known to be good for the brain in general and memory in particular. However, few studies have directly compared these three factors all in the same study, as has been done in the lab of Alois Strasser in the University of Veterinary Medicine in Austria. Moreover, Strasser examined also a brain chemical that is likely to cause some of the brain improvement, the so-called brain-derived neurotrophic factor (BNDF), which sustains neuron life and promotes growth of neuronal processes and synapse formation.


As brain ages, the levels of BNDF typically decline. Several studies have demonstrated that BNDF is important for memory function. Research prior to that of Strasser’s lab showed that exercise “up-regulates” BNDF; that is, exercise stimulates its production. And there had been some indication that environmental enrichment (stimulation, social interactions, etc.) had a similar effect. Therefore, Strasser and colleagues examined the tissue concentrations of BDNF in the cerebral cortex of old rats.

Rats were divided randomly into six groups, living from 5 months up to 23 months. In each age group, rats were divided into those that were given free access to running wheels (RW), forced running on treadmills, food restriction, and sedentary controls with no food restriction. Rats were either either housed individually or in groups of 4 to provide social enrichment. At the end of experiments, BDNF concentrations were determined.

Researchers found higher BNDF concentrations in the 5-month-old animals than in the 23-month-old-animals, suggesting that decline in BNDF accompanies old age and probably accounts for some of the mental decline. Within the older group of rats, sedentary rats that were housed in groups had significantly higher BNDF concentration compared to the old individually caged groups. Their BNDF concentrations were even higher than those of the young baseline group. The results suggest that housing and social interactions have more influence on BDNF concentrations in the cerebral cortex of aging rats than do physical exercise and food restriction.
There was some benefit of the exercise, but only from forced running on the treadmill, not voluntary activity. However, other studies had established that even voluntary exercise by old animals increased BNDF in other parts of brain, including the area so crucial to memory formation, the hippocampus.

The lack of beneficial effect of caloric restriction in sedentary rats to weight levels matching those of the voluntary exercise group was somewhat unexpected. Prior studies in other labs had shown that such restriction does promote synaptic plasticity and even birth of new neurons. Thus, there are no doubt multiple influences that can be beneficial to brain that are not mediated by BNDF. So, to the extent that these results can be extrapolated to aging humans, it would seem like a good idea to:

1. Exercise regularly and vigorously (assuming you don’t have heart trouble or other conditions that would prevent it)
2. Lose weight
3. Get out of the house and socialize.

Source:

Strasser, A. et al. 2006. The impact of environment in comparison with moderate physical exercise and dietary restriction on BNDF in the cerebral parietotemporal cortex of aged Sprague-Dawley rats. Gerontology. 52: 377-381.