Extreme indoor heat also reduces cognition in young people

The summer is just coming to an end, and with it a period of heat wave. The elderly and babies in particular suffer from high temperatures and can be exhausted more quickly. Previous studies have measured the impact of heat mainly in such vulnerable groups, in laboratories where the heat could be controlled. But does extreme heat also affect cognitive ability in young people? 

Air conditioning on/off
In this new study, the researchers followed 44 young adults who lived in student rooms. Out of this group, 24 students lived in relatively new apartments (built around 1990) which came with AC. The remaining 20 students lived in buildings over 60 years old and did not have air conditioning included. The researchers installed a device in all the rooms to measure temperature, CO2 levels, humidity and sound. To measure the impact on cognition in a natural setting, the researchers waited until a heat wave approached Boston. The effects were measured over a 12-day period: five days with comparably normal summer temperatures for this area and five days during a heat wave. Finally, the measurements took place 2 more days once the weather cooled down. 

Naming colors
Meanwhile, study participants were asked to perform several tests on their cell phones on 12 consecutive days: the Stroop test and simple math tests. In the Stroop test, participants are shown words such as red or green, while the word may or may not have the corresponding color. The task is to name the color depicted as quickly as possible. In general, we are much slower to name the color of the word when it does not correspond to the content of the word.

The results showed that students in buildings without air conditioning performed worse on both tests than students who had air conditioning. Students with air conditioning were not only faster, but also more accurate in their answers. What was particularly surprising was that the greatest negative impact was seen during the two days when it cooled down outside. On these days, temperatures outside returned to normal, but living room temperatures were still on the high side.

So if you fail that test during a heat wave or do worse at your job in a room without air conditioning: refer to this study and demand a good air conditioner!

This study was  published in the journal PLoS Medicine

Author: Stefan Jongen (edited and translated by Sophie Ruppert)
Originally published on Brainmatters: June 18th, 2018



Do babies consciously perceive faces?

A newborn baby often sees many faces pass by above their crib. Although the visual system is not fully developed at birth, babies develop a preference for the mother's face within a few weeks. However, the extent to which babies are aware of the stimuli around them remains to be determined. Because babies cannot share their experiences with us, it is difficult to answer this question. Nevertheless, by making use of EEG it is still possible to try to figure out what babies perceive.

To distinguish conscious perceptions from unconscious perceptions, so-called masked stimuli are often used. For example, an image of a face is shown for several hundred milliseconds, immediately followed by another image. The latter image acts as a "mask" of the previously shown picture. In research it may be an image of a distorted figure of the same size and shape as a face, which is not recognizable as such. By varying the timing and duration of the mask stimulus, a subject will sometimes consciously perceive the image of the face and sometimes not. While performing such a task, the brain activity can be captured with the help of an EEG. In adults, it has been shown that peaks in EEG brain activity can only be measured when a person indicates that they have consciously perceived the stimulus. 

The above research design has now also been applied to infants aged 5, 12 and 15 months. In all age groups the same EEG characteristic of conscious perception was measured, as has also been found in adults. In the youngest infants, however, this response was very weak and delayed. In the older infants, the response was stronger and also occurred earlier. It therefore seems that the brain mechanisms responsible for conscious perceptions are present early in development. However, these processes still need to develop further, as shown by the slow response in the younger infants. This may be because myelination is still in full swing or because certain connections between brain regions have yet to form. Myelination is a process during brain maturation in which a layer of fatty material forms around the part of a neuron which transports signals to another neuron. This helps our brain to send information faster to other brain parts. 

Nevertheless, the authors of this study emphasize that the results say nothing about the subjective experience of the babies. We can only speculate because verbal communication of babies is needed for that. It is therefore going too far to say that babies have memories, feelings or associations when seeing a face. 

This research was published in Science on April 19, 2013.

Author: Bart Aben (translated and edited by Sophie Ruppert)

Originally published on Brainmatters: May 8th, 2013 

A first encounter with the brain

Here at brainmatters.nl, we love the brain and we hope to get you just as excited about this mysterious organ inside our heads. If you don't know much about the brain, this is a good place to start. Let's start at the beginning: How did the brain originate?

As with anything that develops, the growth of the brain begins with the most important parts. Namely, the parts that make sure we stay alive. As a fetus grows into a baby in 9 months, so does the brain. The brain initially develops from a neuronal tube, which after a few weeks grows into three different parts at its end. These are very conveniently called the hindbrain, midbrain and forebrain. The rest of that tube later becomes the spine, while the hind, mid and forebrain continue to develop.

After all, what does a baby need to stay alive? A heartbeat and breathing. That's not a mere luxury. The areas that control these functions develop first. That development happens as follows: The hindbrain develops in the myelencephalon (or medulla) and the metencephalon, which in turn develops in the cerebellum and the pons. Together, the pons, medulla and midbrain form the brainstem. And it is precisely this brainstem that regulates the heartbeat and breathing of the future baby. 

Well, now that the brain is up to the most essential tasks, it can continue to develop. Now it's the forebrain's turn. This develops into the telencephalon and diencephalon. The diencephalon turns into the thalamus, the structure that is particularly important for communication between brain parts and the hypothalamus, the structure that controls needs such as hunger, thirst, fight or flight and fatigue and sleep, among others. The telencephalon also develops from the forebrain. From this later develops the limbic system, responsible for emotions, and the basal ganglia, responsible for regulating movement. So now, very simply put, we have a fetus that is alive (has a heartbeat and breathing), has needs (sleep, hunger, thirst, etc.), and can respond to them (with emotions or movement). 

Now there is a large part of the brain that we have not yet discussed, namely the cortex. The cortex is what most people know as the brain, that squiggly structure on the outside of the brain. It also originated in the telencephalon and is divided into four parts called lobes: The frontal lobe, temporal lobe, parietal lobe and occipital lobe. Each part has specific functions associated with it, but it is important to note that most of the actions people perform involve multiple parts. The occipital lobe is used primarily for seeing, the temporal lobe for hearing, and the parietal lobe for sensing and spatial awareness. These parts ensure that our future human can perceive things around them.

The only thing missing is a kind of control system that ensures that we do not act like unguided projectiles reacting to every need (for example, that we do not go peeing in the street, or eat the entire birthday cake at a party). That's what we have the frontal lobe for. This is the most complex lobe and you could say that it distinguishes us from monkeys. This is because this lobe is involved in driving goal-directed behaviour including self-control, speech and memory. At birth, however, this lobe is not yet fully developed (this can also be seen in the behaviour of babies and children). The frontal lobe continues to develop until sometime in adolescence. Only then is the brain fully developed, which is exactly why you can only drive a car and drink alcohol when you are older.

This was a brief introduction to the brain, but there is much more to learn. So did you find this article interesting? And would you like to learn more about the different parts of the brain and the ways research is done? Then read our Brain Basics articles. 

Author: Loes Beckers
Pauline van Gils

Reference: Breedlove, S. M., and Watson, N. v (2013). Biological psychology: An introduction to behavioral, cognitive, and clinical neuroscience, 7th ed. Sunderland,  MA,  US: Sinauer Associates.

Love on the brain

When talking about new impressions, a topic that cannot be left undiscussed is love. What happens in our brain when we see a potential partner for the first time?

Head, shoulders, knees and toes, knees and toes.
Let me set the scene: You’re walking on the street, suddenly you see someone who catches your attention… What are we actually looking at, and what indication can this give? A study investigating eye-movements reveals that we are more likely to look at someone’s head and chest when we are assessing whether they could be a potential partner or not. More eye-movement in those areas indicates a greater interest in the person as a partner. On the other hand, we look more at someone’s legs and feet when we are thinking about whether someone could become a good friend. In this case, more eye-movement in the feet and leg areas indicates a greater interest in forming friendship with this person. So, the next time you see someone staring at your legs and feet for a long time, you know to recognize this sign and make a friend! Jokes aside, it's all about a small change in ratio of where we gaze, but I think it’s rather interesting to know about this distinction.

Do first impressions matter for the long-term potential of relationships?
We’re now at the next stage, a fresh love has just started. But how do we know whether it will last? Perhaps we can gain insight from brain activity… A study investigated fMRI brain activation at early-stage love and after 40 months. And what do you know, there was a difference in initial brain activation between those who were still together after 40 months and those who weren’t. While the data from this study is just a first indicator, it appears that an increase in activity in the frontal lobe (involved in reward functions among other things) serves as a predictor for how strong a relationship is and whether it will last. Thus, when the forebrain of your newfound partner shows reduced activity, perhaps it’s better to jump ship!

How does our brain compute whether we are interested in someone as a potential partner or not?
So, from the previous parts we learned about the role of eye-movements in first impressions and that brain activity of the forebrain can be indicative of the potential of a new relationship. But what happens in our brain when we see someone, where do we compute whether we like them or not? According to the neural common currency hypothesis, the brain areas related to making choices are the same, irrespective of the kind of choice. Thus, when we are making choices about whether to date someone, or whether to buy a new phone, the same neural network plays a role. fMRI data supports this hypothesis, and points to the ventromedial prefrontal cortex and the orbitofrontal cortex as key areas for weighing almost any reward values.

Author: Kobus Lampe

Don't judge a book by its cover

Whenever you meet someone new, you immediately (believe to) have a general sense of what the person is like. This is the first impression we get from someone. Studies show that first impressions are made in just 100 milliseconds. That is literally in the blink of an eye. But do these first impressions actually matter?

We base our first impression (often unknowingly) on a wide range of characteristics, such as tone of voice, how someone dresses, and body odor. During a first impression, we categorize this individual as a certain type of person. Is this person nice? Or dangerous? And especially “is this person like me?”. Our brain likes to categorize things.This makes a complicated and chaotic world a bit more organized. Initially this is done by the amygdala, a small almond shaped structure in the brain that is responsible for attaching emotions to the things we perceive. The posterior cingulate cortex also plays a role in the first impression. This brain area is involved in many different functions (the exact function is still unclear, but it seems to be involved in memory and associations). First impressions are very useful. They allow us to make fast decisions. However, many nuances do get lost during this categorisation, and sometimes lead to incorrect judgments. These initial categorisations made by the brain are also known as “biases”.  

An example of a bias is the beautiful-is-good bias, meaning that we tend to assume that beautiful people are also good people. This can be explained by the halo-effect. The halo-effect entails that the brain incorrectly thinks that if someone has one positive trait (in this case, beauty), this person is also likely to have other good traits (like intelligence, competency, or kindness).

A study published in 2021 in the Journal of Nonverbal Behavior investigated this beautiful-is-good bias in an experiment. Participants were shown attractive and unattractive faces on a computer screen. Then they were asked how likely these individuals are to possess a character trait. For example bravery, intelligence, or kindness. It turned out that people are more likely to assign positive traits to attractive faces compared to unattractive faces. On top of that, participants thought that the people with attractive faces had a higher morality than those with less attractive faces.

So, do first impressions matter? Yes, they do. Our brain draws many conclusions from how someone looks, although they are sometimes unjustified. However, we still treat people accordingly. For example, studies show that attractive people are more likely to be hired or promoted, less likely to be found guilty or receive less severe punishment in court, and are more likely to be elected as political candidates. We even tend to give more attention and care to attractive children compared to less attractive children.

This is unjustified. You can’t know about someone’s intelligence or kindness based on the symmetry of their face. To prevent injustice, we would have to actively counteract the beautiful-is-good bias. To do so, the most important thing is to be aware of your brain making this thinking error (Congratulations! Since you’ve read this article, that has already been achieved). So, the next time you meet someone new, hopefully, you will ask yourself “Do I base my impression on facts? Or am I falling prey to a bias?” 

Author: Pauline van Gils

The life of a highly sensitive person

how new impression can drain your energy

Last year I moved far away from home to study in Maastricht. I had to start from scratch; adapting to a new city, a new study, meeting lots of new people and receiving in person education again. After the first week, I felt overwhelmed by all these new impressions, and my social as well as my physical battery was running low. While enjoying the last rays of sunshine on the terrace, I talked about this with my peers who were all feeling like this. One of them dropped the term ‘HSP’, which means ‘Highly Sensitive Person’. The question is whether all people experience this feeling of overstimulation in the same way as we did, or whether these kinds of feelings are more prevalent for some. However, It turns out that actually 15 to 20 percent of the people are thought of as a Highly Sensitive Person. 

Over the past couple of years, more knowledge has been gained about this subset of the population who are high in a personality trait known as sensory-processing sensitivity (SPS). According to a theory by an American psychologist named Elaine Aron, you may score highly in SPS if you become physically and emotionally overstimulated more easily compared to others, react stronger to somebody else’s emotions or feelings, and experience higher feelings of empathy for the people that surround you. 

Actually this sensory-processing sensitivity can be traced back in the brain! FMRI studies where participants watched happy and sad photographs showed that people who scored higher on the Highly Sensitive Person scale showed more activation in the brain regions that are usually involved in awareness, processing of sensory information, empathy and action planning. These increases in activity were even stronger when the happy or sad photograph involved their romantic partner instead of a stranger. 

This was confirmed in a more recent study published in 2021 where results showed that this over responsiveness of HSP can actually also be seen during rest. In this study, participants were shown first happy as well as sad photographs of either strangers or their romantic partner just as in the previous study. However, the second part of this study allowed the participants to ‘just relax’. Interestingly, memory processing, specifically memory of experiences that happen to you (also called episodic memory), is heightened during rest in HSP. This enhanced memory processing, reflected in a stronger connection between two brain areas (hippocampus and precuneus), can ultimately improve awareness of and responsiveness to feelings and emotions of others. 

But how is it possible that people who are highly sensitive show higher brain activity compared to people who are not highly sensitive? Well, we know that each person is ‘programmed’ in a different way and therefore has their own unique personality. This uniqueness in personality is partly determined by the genetic code you are born with (just like the fact that you inherit the eye color from your father and mother), as well as the influences of your environment (how you were raised as a child or the friends you choose in high school). This nature and nurture determination also plays a role in sensory processing sensitivity. Especially genes related to our dopamine system (an important messenger in our brain mostly responsible for movement and feelings of pleasure and reward) seem to play a role in this increase in brain activity of people scoring high on sensory processing sensitivity. However, I hate to break this news to you, but one specific gene involved in causing high sensitivity has not been found yet.

This brings me back to the beginning of this story, where the focus is mostly on the downsides of being a highly sensitive person such as easily getting overstimulated and drained of energy. On the other hand, there is also an upside of being a HSP. They tend to have better parenting abilities, the ability to form deeper relationships with friends and family, and higher creativity. So, if you are in the same boat and feel like everything is too much at the beginning of this academic year, firstly, know that you are not the only one, and secondly, take it easy and realize that this feeling also brings a lot of qualities and good friendships to the table!

Author: Joyce Burger
Pauline van Gils