Of Marshmallows, Brain Plasticity and Attachment (part I)

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The Marshmallow Test. You know the one. That’s where researchers place marshmallows (or other treats) in front of kids around age six or seven and then give the following direction: “You can eat one marshmallow any time after I leave the room if you wish, however, if you wait until I come back then you can have two marshmallows.” On average kids are made to wait about twenty minutes before the researcher returns. And of course the children are observed using a one-way glass partition.

The Marshmallow Test is designed to assess for the psychological dimension known as “the ability to delay gratification.” Delaying gratification is one of the Executive Function skills. I have written extensively about EF skills here at the BLT blog and I invite the reader to search for those posts. Researchers conduct longitudinal studies by tracking a group over a long time horizon, say, from childhood to adulthood. Yes, researchers have conducted longitudinal studies with kids who have taken the Marshmallow Test. Here’s where the Marshmallow Test story gets very interesting.

According to these longitudinal studies, kids who are able to delay gratification (e.g., are able to wait for the researcher to return in order to double the size of their reward) go on to have more successful lives. High delayers (as researchers call them) typically go on to secure for themselves such things as higher levels of education, higher levels of retirement funds, and higher levels of relationship satisfaction as compared to low delayers (e.g., those kids who eat the marshmallow soon after the researcher leaves). Researchers have gone so far as to show that each additional minute of delay during the Marshmallow Test (from zero up to twenty minutes) translates to additional increases in such things as aptitude test scores (i.e., the SAT), cognitive function levels, and ratings on sociability scales as measured during the teen years. In sum, the Marshmallow Test is a robust predictor of future life success.

If the above wasn’t enough for you, turns out that there is a close relation between the Marshmallow Test and the Strange Situation Assessment. The Strange Situation (which I have blogged about before) is used by researchers to assess for attachment patterns and functioning in toddlers. Toddlers who are assessed as being securely attached at one-and-a-half to two years of age typically go on to be high delayers as measured by the Marshmallow Test. Yeow! As one researcher puts it (who will be identified momentarily), “The self-control strategies that children develop are shaped by their attachment experiences with caretakers from the start of life.” This goes along with the information I presented in my last post: securely attached kids typically go on to develop the ability to appropriately regulate emotion. As I mentioned in my last post, there’s a connection between attachment and affect regulation. It would appear that there is a connection (possibly a continuum) that holds attachment, affect regulation, and delaying gratification.

How do I know all of this? Well, I just finished reading Walter Mischel’s 2014 book entitled The Marshmallow Test—Mastering Self-Control. The above quote is from Mischel’s book. Mischel developed the Marshmallow Test starting back in the 1960s. His book is the story of the Marshmallow Test over the last 50 plus years. Personally I found the story of the Marshmallow Test to be most fascinating. In the past colleagues have mentioned the attachment – delaying gratification connection to me, but it remained so much attachment myth if you will. Mischel’s book presents the hard evidence supporting this connection. Eureka!

In future posts I’ll try to highlight the attachment – delaying gratification connection by using Mischel’s book as a backdrop. However, for the rest of this post (and into the next) I’d like to jump to the end of Mischel’s book where Mischel presents a very definite “either you do, or you don’t” proposition. This proposition concerns what researchers call “brain plasticity.” Brain plasticity (as imagined by researchers) describes the brain’s ability to functionally change and even add new synaptic connections in response to new experiences such as therapy, cognitive exercises, and even certain religious practices (i.e., meditation and mindfulness practices). At the end of his book Mischel asks the reader whether he or she believes in brain plasticity or not. Mischel puts it this way:

A silent revolution in the conception of human nature has been slowly building momentum over the past two decades, as scientists reveal the plasticity of the human brain. … The importance of executive function (EF) for how lives play out, and specifically for our ability to overcome [the] stimulus control [of the hot impulsive middle emotional brain] with [the] self-control [of the cool restrained upper reflective brain], is undisputed. [P]ublic policy implications … depend on whether or not we think that EF skills and the potential for self-control are essentially prewired and fixed. If they are, there is little that interventions can do. But if they are malleable, the public policy implications are profound and call for educational efforts to target the enhancement of these skills as early in life as possible.

Whether you receive Mischel’s message favorably will depend in large part on whether you believe in the brain plasticity conceptual revolution that Mischel alludes to above. Suffice it to say that Bowlbian attachment theory has moved in the direction of supporting and drawing energy from the brain plasticity conceptual revolution. I have tried to understand this conceptual revolution the best I can. Two articles have helped me to make sense of this conceptual revolution:

1) Limits on Plasticity (2003) by Michael S. C. Thomas (J. of Cognition and Development, 4(1) 95–121)

2) The Plastic Brain: Neoliberalism and the Neuronal Self (2010) by Victoria Pitts-Taylor (Health, 14 (6) 635–652)

Thomas’ article is a review of four books on the subject of brain plasticity:

1) Handbook of Developmental Cognitive Neuroscience (2001)

2) Developmental Neuropsychology (2001)

3) Developmental Disorders of the Frontostriatal System: Neuropsychological, Neuropsychiatric, and Evolutionary Perspectives (2001)

4) Neural Plasticity: The Effects of Environment on the Development of the Cerebral Cortex (2002)

I know Thomas’ review article is a bit dated, but it’s hard to find such critical reviews of the topic of brain plasticity. If someone has a more recent review, please send it my way. For now, I’ll stick with Thomas’ review. In the next part I’ll pull some key points from the above two articles. My hope is that the reader will be a bit more informed when it comes to the topic of brain plasticity. Simply, if you do not subscribe to the brain plasticity conceptual revolution, then Mischel’s book is probably not for you.

One last point before I end. As with all conceptual revolutions, there’s a political side. This was true of Freud and his use of the hydraulic conceptual revolution that surrounded him during the turn of the last century. And it’s true of the “chemical imbalance” conceptual model that frames much of mental disease today. I recently read that the chemical imbalance conceptual model is losing ground to a new emerging conceptual model: mental disease as a “neuronal structure defect.” Apparently the psychiatric community wishes to distance itself from the chemical imbalance model because so many abuses were perpetrated in its name (such as feeding kids as young as three-years-old potent psychotropics). For more on this topic see Gary Greenberg’s 2013 book entitled The Book of Woe: The DSM and the Unmaking of Psychiatry. Let us not forget that not too long ago frontal lobotomy procedures were used to “treat” neuronal structure defects. Conceptual revolutions bring with them the potential for increased understanding of complex systems. They also bring with them the potential for increased levels of abuse done in their name.

Oh yeah … would you have eaten the marshmallow or would you have delayed? Red pill or blue?