Aspects of your environment can hurt or help your brain
Matching patterns of sales data for lottery games in one American county for a year against daily temperature has revealed that sales for scratch tickets (many options to select) fell by nearly $600 with every 1° Fahrenheit increase in temperature. On the other hand, sales for lotto tickets, which require fewer decisions, were not affected.
A comparison of traditional African villagers and those who have moved to town indicates that urban living improves working memory capacity even as it makes us more vulnerable to distraction.
Another study looking into the urban-nature effect issue takes a different tack than those I’ve previously reported on, that look at the attention-refreshing benefits of natural environments.
In this study, a rural African people living in a traditional village were compared with those who had moved to town. Participants in the first experiment included 35 adult traditional Himba, 38 adolescent traditional Himba (mean age 12), 56 adult urbanized Himba, and 37 adolescent urbanized Himba. All traditional Himba had had little contact with the Western world and only spoke their native language; all adult urbanized Himba had grown up in traditional villages and only moved to town later in life (average length of time in town was 6 years); all adolescent urbanized Himba had grown up in town the town and usually attended school regularly.
The first experiments assessed the ability to ignore peripheral distracting arrows while focusing on the right or left direction of a central arrow.
There was a significant effect of urbanization, with attention being more focused (less distracted) among the traditional Himba. Traditional Himba were also slower than urbanized Himba — but note that there was substantial overlap in response times between the two groups. There was no significant effect of age (that is, adolescents were faster than adults in their responses, but the effect of the distracters was the same across age groups), or a significant interaction between age and urbanization.
The really noteworthy part of this, was that the urbanization effect on task performance was the same for the adults who had moved to town only a few years earlier as for the adolescents who had grown up and been educated in the town. In other words, this does not appear to be an educational effect.
The second experiment looked at whether traditional Himba would perform more like urbanized Himba if there were other demands on working memory. This was done by requiring them to remember three numbers (the number words in participants’ language are around twice as long as the same numbers in English, hence their digit span is shorter).
While traditional Himba were again more focused than the urbanized in the no-load condition, when there was this extra load on working memory, there was no significant difference between the two groups. Indeed, attention was de-focused in the traditional Himba under high load to the same degree as it was for urbanized Himba under no-load conditions. Note that increasing the cognitive load made no difference for the urbanized group.
There was also a significant (though not dramatic) difference between the traditional and urbanized Himba in terms of performance on the working memory task, with traditional Himba remembering an average of 2.46/3 digits and urbanized Himba 2.64.
Experiment 3 tested the two groups on a working memory task, a standard digit span test (although, of course, in their native language). Random sequences of 2-5 digits were read out, with the participant being required to say them aloud immediately after. Once again, the urbanized Himba performed better than the traditional Himba (4.32 vs 3.05).
In other words, the problem does not seem to be that urbanization depletes working memory, rather, that urbanization encourages disengagement (i.e., we have the capacity, we just don’t use it).
In the fourth experiment, this idea was tested more directly. Rather than the arrows used in the earlier experiments, black and white faces were used, with participants required to determine the color of the central face. Additionally, inverted faces were sometimes used (faces are stimuli we pay a lot of attention to, but inverting them reduces their ‘faceness’, thus making them less interesting).
An additional group of Londoners was also included in this experiment.
While urbanized Himba and Londoners were, again, more de-focused than traditional Himba when the faces were inverted, for the ‘normal’ faces, all three groups were equally focused.
Note that the traditional Himba were not affected by the changes in the faces, being equally focused regardless of the stimulus. It was the urbanized groups that became more alert when the stimuli became more interesting.
Because it may have been a race-discrimination mechanism coming into play, the final experiment returned to the direction judgment, with faces either facing left or right. This time the usual results occurred – the urbanized groups were more de-focused than the traditional group.
In other words, just having faces was not enough; it was indeed the racial discrimination that engaged the urbanized participants (note that both these urban groups come from societies where racial judgments are very salient – multicultural London, and post-apartheid Namibia).
All of this indicates that the attention difficulties that appear so common nowadays are less because our complex environments are ‘sapping’ our attentional capacities, and more because we are in a different attentional ‘mode’. It makes sense that in environments that contain so many more competing stimuli, we should employ a different pattern of engagement, keeping a wider, more spread, awareness on the environment, and only truly focusing when something triggers our interest.
 Linnell, K. J., Caparos S., de Fockert J. W., & Davidoff J.
(2013). Urbanization Decreases Attentional Engagement.
Journal of experimental psychology. Human perception and performance.
A small study finds memory and processing speed tend to be significantly worse in warmer weather for those suffering from multiple sclerosis.
It’s estimated that 43%-70% of those with multiple sclerosis suffer from some level of cognitive impairment (yes, a very broad range! perhaps the finding of this study offers one clue why). Most commonly, this is seen in slower processing speed, impaired memory, impaired executive function, and poorer visuospatial processing. There are a number of factors that have been implicated in why some people suffer from cognitive impairment and others don’t, such as age of onset and male gender. As with dementia, depression also may be a factor, while cognitive reserve appears protective.
Another factor specific to MS may be temperature. Previous research has shown that people with MS tend to have more symptoms and greater lesion activity when the weather is warmer. More recently, this association has also been found with memory and processing speed.
I mentioned this research very briefly last year, when it was presented at conference. Here are a few more details now the journal article is out.
There were two parts to this study: cross-sectional and longitudinal. In the former, 40 patients with MS and 40 healthy controls were recruited throughout the calendar year, and cognitive performance and outdoor temperature were recorded for the day of testing. A different group of 45 patients with MS were recruited for the longitudinal analysis, in which cognitive status and outdoor temperature were recorded twice, six months apart.
In the cross-sectional analysis, warmer temperature was related to significantly worse cognitive performance in patients with MS, while controls were unaffected by temperature. Similarly, the longitudinal analysis found that an increased outdoor temperature from the first cognitive test to the second was related to a decline in cognitive performance within patients with MS.
 Leavitt, V. M., Sumowski J. F., Chiaravalloti N. D., & DeLuca J.
(2012). Warmer Outdoor Temperature Is Associated with Worse Cognitive Status in Multiple Sclerosis.
Neurology. 78(13), 964 - 968.
New research confirms the correlation between lower neighborhood socioeconomic status and lower cognitive function in older adults, and accounts for most of it through vascular health, lifestyle, and psychosocial factors.
In the last five years, three studies have linked lower neighborhood socioeconomic status to lower cognitive function in older adults. Neighborhood has also been linked to self-rated health, cardiovascular disease, and mortality. Such links between health and neighborhood may come about through exposure to pollutants or other environmental stressors, access to alcohol and cigarettes, barriers to physical activity, reduced social support, and reduced access to good health and social services.
Data from the large Women’s Health Initiative Memory Study has now been analyzed to assess whether the relationship between neighborhood socioeconomic status can be explained by various risk and protective factors for poor cognitive function.
Results confirmed that higher neighborhood socioeconomic status was associated with higher cognitive function, even after individual factors such as age, ethnicity, income, education, and marital status have been taken into account. A good deal of this was explained by vascular factors (coronary heart disease, diabetes, stroke, hypertension), health behaviors (amount of alcohol consumed, smoking, physical activity), and psychosocial factors (depression, social support). Nevertheless, the association was still (barely) significant after these factors were taken account of, suggesting some other factors may also be involved. Potential factors include cognitive activity, diet, and access to health services.
In contradiction of earlier research, the association appeared to be stronger among younger women. Consistent with other research, the association was stronger for non-White women.
Data from 7,479 older women (65-81) was included in the analysis. Cognitive function was assessed by the Modified MMSE (3MSE). Neighborhood socioeconomic status was assessed on the basis of: percentage of adults over 25 with less than a high school education, percentage of male unemployment, percentage of households below the poverty line, percentage of households receiving public assistance, percentage of female-headed households with children, and median household income. Around 87% of participants were White, 7% Black, 3% Hispanic, and 3% other. Some 92% had graduated high school, and around 70% had at least some college.
 Shih, R. A., Ghosh-Dastidar B., Margolis K. L., Slaughter M. E., Jewell A., Bird C. E., et al.
(2011). Neighborhood Socioeconomic Status and Cognitive Function in Women.
Am J Public Health. 101(9), 1721 - 1728.
Lang IA, Llewellyn DJ, Langa KM, Wallace RB, Huppert FA, Melzer D. 2008. Neighborhood deprivation, individual socioeconomic status, and cognitive function in older people: analyses from the English Longitudinal Study of Ageing. J Am Geriatr Soc., 56(2), 191-198.
Sheffield KM, Peek MK. 2009. Neighborhood context and cognitive decline in older Mexican Americans: results from the Hispanic Established Populations for Epidemiologic Studies of the Elderly. Am J Epidemiol., 169(9), 1092-1101.
Wight RG, Aneshensel CS, Miller-Martinez D, et al. 2006. Urban neighborhood context, educational attainment, and cognitive function among older adults. Am J Epidemiol., 163(12), 1071-1078.
A recent study found significant cognitive impairment in MS sufferers who used marijuana for relief. Another study found cognition was better in MS sufferers on cooler days.
A study involving 50 people with MS (aged 18-65), of whom half used marijuana for pain relief, has found that marijuana users performed significantly worse on tests of attention, speed of thinking, executive function and visual perception of spatial relationships between objects. Those who used marijuana were also twice as likely as non-users to be classified as globally cognitively impaired.
The two groups were matched for age, gender, level of education, IQ before diagnosis, level of disability and duration of time with MS. On average, the duration of marijuana use was 26 years, and 72% reported smoking marijuana on a daily basis while 24% reported weekly use and one person reported bi-weekly use. There were no differences between the groups on measures of depression and anxiety.
And on a less-expected note, a study involving 40 people with multiple sclerosis and 40 people without MS has found those with MS scored 70% better on cognitive tests during cooler days compared to warmer days of the year. There was no link between test scores and temperature for those without MS.
 Honarmand, K., Tierney M. C., O'Connor P., & Feinstein A.
(2011). Effects of cannabis on cognitive function in patients with multiple sclerosis.
Neurology. 76(13), 1153 - 1160.
The findings of the temperature study were presented at the American Academy of Neurology's 63rd Annual Meeting in Honolulu April 9 to April 16, 2011.
A large study of very young twins confirms evidence that environment affects cognitive ability far more for those from poor homes, compared to those from better-off homes.
A study involving 750 sets of twins assessed at about 10 months and 2 years, found that at 10 months, there was no difference in how the children from different socioeconomic backgrounds performed on tests of early cognitive ability. However, by 2 years, children from high socioeconomic background scored significantly higher than those from low socioeconomic backgrounds. Among the 2-year-olds from poorer families, there was little difference between fraternal and identical twins, suggesting that genes were not the reason for the similarity in cognitive ability. However, among 2-year-olds from wealthier families, identical twins showed greater similarities in their cognitive performance than fraternal twins — genes accounted for about half of the variation in cognitive changes.
The findings are consistent with other recent research suggesting that individual differences in cognitive ability among children raised in socioeconomically advantaged homes are primarily due to genes, whereas environmental factors are more influential for children from disadvantaged homes.
 Tucker-Drob, E. M., Rhemtulla M., Harden P. K., Turkheimer E., & Fask D.
(2011). Emergence of a Gene × Socioeconomic Status Interaction on Infant Mental Ability Between 10 Months and 2 Years.
Psychological Science. 22(1), 125 - 133.
Adding to research suggesting type of background noise affects whether it impairs learning or not, a new study indicates white noise has different effects depending on whether the students have attention problems.
Five years ago I reported on a finding that primary school children exposed to loud aircraft noise showed impaired reading comprehension (see below). Now a small Norwegian study has found that playing white noise helped secondary school children with attention problems, but significantly impaired those who were normally attentive.
The adolescents were asked to remember as many items as possible from a list read out either in the presence or absence of white noise (78dB). The results were consistent with a computational model based on the concepts of stochastic resonance and dopamine related internal noise, postulating that a moderate amount of external noise would benefit individuals in hypodopaminergic states (such as those with ADHD). The results need to be verified with a larger group, but they do suggest a new approach to helping those with attention problems.
The previous study referred to involved 2844 children aged 9-10. The children were selected from primary schools located near three major airports — Schiphol in the Netherlands, Barajas in Spain, and Heathrow in the UK. Reading age in children exposed to high levels of aircraft noise was delayed by up to 2 months in the UK and by up to 1 month in the Netherlands for each 5 decibel change in noise exposure. On the other hand, road traffic noise did not have an effect on reading and indeed was unexpectedly found to improve recall memory. An earlier German study found children attending schools near the old Munich airport improved their reading scores and cognitive memory performance when the airport shut down, while children going to school near the new airport experienced a decrease in testing scores.
 Soderlund, G., Sikstrom S., Loftesnes J., & Sonuga-Barke E.
(2010). The effects of background white noise on memory performance in inattentive school children.
Behavioral and Brain Functions. 6(1), 55 - 55.
 van Kamp, I., Berry B. F., Stansfeld S. A., Berglund B., Clark C., Lopez-Barrio I., et al.
(2005). Aircraft and road traffic noise and children's cognition and health: a cross-national study.
Lancet. 365(9475), 1942 - 1949.
http://www.eurekalert.org/pub_releases/2010-09/bc-at092710.php Full text available at http://www.behavioralandbrainfunctions.com/content/6/1/55 Previous study: http://www.eurekalert.org/pub_releases/2005-06/l-eta060105.php
Dr McPherson's practical, research-based books are instantly available as digital downloads from the Mempowered store (all formats), Kindle Store, Kobo Store, and iTunes. They are also available in paperback.