Author Archives: Morgan Leigh McNair

Nearly every morning for the past four weeks, I go to Le Pain Quotidien on Rue de Charonne at 9:05, sit at the long wooden table, order “deux oeufs BIO à la coque et un café crème avec lait de soja” (two organic soft-boiled eggs and a soy latte), and enjoy a nice breakfast before my first class begins at 10. After Dr. Shreckengost’s morning class, I take a leisurely walk from the Accent Center to Le Bar à Soupes, also on Rue de Charonne, wait outside the restaurant until the owner opens the door at 12:00pm, and order one of the six soups of the day “à emporter” (take away).

Le Pain Quotidien and La Bar à Soupes in relation to the Accent Center

Both the waitress at the Le Pain Quotidien and the owner of Le Bar à Soupes identify me as a regular customer. I no longer need to order when I go to breakfast because the waitress knows I order the same thing every morning. The soup bar owner even gave me a Soup Stamp Card to fill up and receive a free soup after 10 purchases! Many friends on my study abroad trip have quickly surmised from my daily routines that I am a “creature of habit,” so I began to wonder how we form habits.

My filled-out Soup Card!

Do I keep going back because of the comforting food and friendly faces or is there another underlying, physiological reason? What differentiates a habit from a choice?

First, let’s start with the definition of habit. From a scientific perspective, habits are “a form of goal-directed [automatic] behavior” (Aarts and Dijksterhuis, 2000). Goals can activate habitual actions. Take an example of biking to school every day: once someone develops this habit, the activation of the goal, going to class, may automatically elicit a habitual response, biking.

Now that we understand what habits are, let’s examine how habits may actually form in our brains!

In a study conducted by Wang et al. (2011), researchers investigated the mechanisms underlying learning and forming habits. Prior research revealed the importance of the neurotransmitter known as dopamine (DA) in habit learning. In both human and rodent models, an impaired ability to form habits correlated to degeneration of dopaminergic neurons. Wang et al. (2011) examined the importance of DA even further by looking at the impact of specific receptors on DA neurons. The researchers bred mice that lacked N-methyl-D-aspartate receptors (NMDARs) on their DA neurons (NR1 mice). NMDARs are glutamate (a type of neurotransmitter) receptors found in nerve cells that play a crucial role in synaptic plasticity—the ability of neuronal synapses to change shape or function in response to activity – and memory function. Wang et al. then hypothesized that the NR1 mice, lacking NMDARs on their DA neurons, will have impaired habit learning as compared to normal, wild type (WT), control mice.

First, researchers tested if WT mice differed from NR1 mice in various abilities other than habit learning, such as fine motor movements, balance, general endurance, anxiety levels, and object recognition. The WT and NR1 mice did not differ in their abilities, proving NR1 mice to be suitable models for testing differences in habit learning. To test the impact of the NMDAR deletion on DA neurons cellular processes, the researchers recorded both WT and NR1 mice DA neuron activity in response to the dopamine receptor agonist apomorphine through electrodes inserted into the ventral tegmental area, an area of the brain that serves as the origin of dopaminergic cell bodies. The researchers discovered reduced activity in the NR1 mice, indicating the NR1 mice DA neurons did not exhibit as much activity in the presence of dopamine or dopamine agonists as compared to WT controls. Additionally, the NR1, as compared to WT, DA neurons showed decreased responses during paradigms testing reward-predicting cues over three days, showing that the NR1 mice exhibited greatly lowered bursting responses, known as DA neuron blunting, and that NMDARs play a crucial role in dopaminergic cell activation.

Figure 8 – Wang et al.
The researchers designed these Water-Filled Zigzag Maze-Based Habit Tasks to more obtain more direct measurements of habit learning by eliminating the competition factor between “spatial” and “habit” memory systems the NR1 deletion may have skewed. You can see a significant difference habitual learning ability between NR1 mice (blue) and WT mice (green).

To investigate habit learning deficits in NR1 mice, the researchers tested both NR1 and WT mice in a lever-pressing operant-conditioning task. This task, pressing a lever to obtain food, can transform goal directed responses into habitual responses through extensive training. Over time, mice typically become desensitized to outcome devaluation, the decrease in reward value. Wang et al. (2011) discovered that the NR1 mice showed a significant difference in lever presses from Non-Devalued to Devalued outcomes, suggesting that the NR1 mice failed to develop the lever pressing habit, and their actions remained goal directed. The researchers continued to test habit learning through various maze-like paradigms and discovered that the NR1 mice showed habitual learning, but not spatial memory, impairments as compared to WT controls.

Wang et al. (2011) studied the importance of DA neuron NMDARs in habit learning and formation both on a behavioral and a cellular level, providing various methodological analyses for their findings. Their control experiments testing the differences in behavior for NR1 and WT mice provided clear evidence that the researchers could use the NR1 mice to only test behavioral differences in habit learning. Additionally, the researchers discovered an interesting phenomenon exhibited in some DA neurons – decreased and then rapidly increased responses to negative experiences – suggesting the importance of NMDARs extend beyond habit formation of reward stimuli and may apply to habitual learning through the reward of escaping negative stimuli (Wang et al., 2011).

The findings of this study not only provide the scientific community with better understanding of the crucial role NMDARs play in habit formation but also lay the groundwork for future researchers to better understand the underlying mechanisms of habit disorders, such as Obsessive-Compulsive Spectrum Disorders. Who knows, maybe even executives at Starbucks rely, in part, on the science behind how and why people form habits to boost their sales and marketing efforts.

Getting lunch at Le Bar à Soupes – yum!!!

For me, my taste buds thanks my DA neurons NMDARs for their role in my behavior to seek yummy foods at the same places every day. Based on the information in Wang et al.’s study and the Aarts and Dijksterhuis (2000) definition, I am not sure if my daily trips to Le Pain Quotidien and Le Bar à Soupes have fully transitioned to a “habit” as, without the delicious food and friendly faces, I would likely seek other rewards. While habits are the result of reflexive and automatic behavior (Dolan and Dayan, 2013), I still make the reflective decision to seek the reward my reliable breakfasts and lunches provide me. I find comfort in routine, especially amid a busy schedule in an unfamiliar country. While many people use the colloquial phrase “creature of habit,” I think of myself as more of a creature of conscious goal-directed behavior… who likes consistency in my rewards 🙂

References:

Aarts H, Dijksterhuis A (2000) Habits as knowledge structures: automaticity in goal-directed behavior. Journal of Personality and Social Psychology 78(1): 53-63

Wang LP, Li F, Wang D, Xie K, Wang D, Shen X, Tsien JZ (2011) NMDA Receptors in Dopaminergic Neurons Are Crucial for Habit Learning. Neuron 72(6): 1055-1066.

Dolan RJ and Dayan P (2013) Goals and Habits in the Brain. Neuron 80(2): 312-25.

“Parlez-vous anglais?” I find myself saying this phrase in almost every interaction I have with a French speaker–ordering food, asking for directions, shopping. The answer I dread occasionally follows, “Non…” The first thought that comes to mind is “I should have kept up with French in elementary school.” Then I resort to my next resource: my hands. Hand gestures not only help me communicate but help me understand what the other person is saying. Over my past two weeks in France, much of my French vocabulary stems from these gestural experiences.

This resource came in “handy” (pun intended!) when I found out, after returning home from a group project meeting at 1am, that my room key deactivated. I went to the security guard in my dorm and said, “Bonsoir, Parlez-vous anglais?” His reply: “Non…” I proceeded to try to tell him through hand gestures and pantomime that my card does not work. He responded back to me in rapid French. Surely, the puzzled look on my face cued him to speak slower and provide some supplemental help: gestures. I understood and still remember nearly all the words he said after that cue.

Cité Universitaire – Where I live!

Why did I understand and can now remember the words the security guard said? In a study done by Mayer et al. (2015), researchers found that self-performed gestures enhance learning a foreign language. The study supports the cognitive neuroscience theory known as multisensory learning, a concept that “attributes the benefits of enrichment to recruitment of brain areas specialized in processing the enrichment” (Mayer et al., 2015).

How the human brain most effectively learns foreign languages still puzzles many researchers. Typical in-classroom settings use verbal learning techniques to teach new languages; however, Mayer et al. (2015) investigated the benefits of enriched learning methods, such as pictures and gestures, as compared to learning methods without enrichment, verbal learning. While they found learning with self-performed gestures more effective than learning with pictures, both enriched approaches benefitted the learner more than the utilization of strictly verbal learning.

Mayer et al. (2015) conducted the research by having two experimental groups. In the first experiment, 22 German adults, split into groups of seven or eight to simulate a classroom learning environment, learned foreign language words under three conditions. The participants first learned words by watching a large projection screen where a person performed gestures symbolic to the word’s meaning and then repeated the gesture. The second condition utilized the photo enrichment approach, where participants looked at a picture projected on a large screen and then, as the picture was presented a second time, traced a line on the picture with their finger in the air. The third condition acted as a control condition, where participants learned words with no enrichment.

My experience with the security guard somewhat mimicked the gestural enrichment condition of Experiment 1. As the security guard said to me, “Je” (pointing to himself), “donne” (pantomiming giving me something), “vous” (pointing to me), “un clé” (holding up the new key card), “fin” (crossing his hands), “après une jour” (distinguishing with his finger today versus tomorrow). As he made these gestures, I tried to follow him to make sure I understood what he was saying. Surely enough, I did. Even better, almost a week later, I remember the meaning of those words!

In the study, Mayer et al. (2015) confirmed the benefits of enriched learning through functional magnetic resonance imaging (fMRI) of the brain. After a week of learning foreign language words under the three conditions, the researchers collected brain images measuring blood-oxygenation-level-dependent (BOLD) responses, a method of fMRI to observe activity in the brain or other organs, while they presented the participants with auditory foreign words and asked them to select the correct translation on a response screen.

For translated words learned with gesture enrichment, the fMRI images show brain activity in the biological motion superior temporal sulcus (bmSTS), an area sensitive to perception of others, and motor areas of the brain. For translated words learned with picture enhancement, the fMRI images show brain activity in the lateral occipital complex (LOC), an area of visual-object sensitivity.

A) LOC (Lateral occipital complex) BOLD responses
B) bmSTS (biological motion superior temporal sulcus) BOLD responses
C) Correlation of gesture and picture enrichment benefit
Figure S2 – Mayer et al. (2015)

In further analysis of the fMRI images, Mayer et al. (2015) found significant correlations between gesture and picture enrichment with distinct brain activity in sensory and motor areas as compared to neuronal activation for words learned without enrichment. The data show that using the gesture enrichment benefited the learner more than the picture enrichment; however, both enrichments benefited the learner more than no enrichment.

Mayer et al. conducted a second experiment where another 22 German adults learned foreign language words under the three enrichment conditions, but participants did not imitate the gesture or trace the picture, thus excluding a motor component. Photo enrichment benefitted the learner more than gesture, in this case; however, looking at the study as a whole, gesture enrichment enhanced learning the most.

Experiment 1 and 2 results demonstrating the benefits of enriched learning approaches to foreign words
Figure S3 – Mayer et al. (2015)

Each finding of the study supported the hypothesis that implementing enriched learning methods, as compared to learning methods without enrichment, would increase correct translation of foreign language words. The study also continuously supported the multisensory learning theory in that distinct brain activity occurred in sensory and motor areas of the brain when translating foreign words that participants learned with enriched learning approaches. Not only can language teachers use the findings of this study to enhance their students’ learning but also future researchers can apply the data to better understanding learning disorders, such as dyslexia or processing issues. While overall a compelling article, I believe Mayer et al. (2015) should have tested whether being monolingual, bilingual, or polylingual prior to the study had any confounding effects on acquisition of foreign words.

My enriched learning experience with the very patient and kind security guard probably influenced why I can remember the meanings of those French words. By watching him gesture almost every word and by copying these gestures, politely of course, to internalize them, I employed both visual and kinesthetic associations to the French words, and thus, enriched my learning of these words. Hopefully I experience more enriched learning of French words… without getting locked out of my room!

Resources:

Mayer KM, Yildiz IB, Macedonia M, Kriegstein K (2015) Visual and Motor Cortices Differentially Support the Translation of Foreign Language Words. Current Biology 25(4): 530–535