Researchers Revisit Famous Stanford Marshmallow Test With Added Factor of Reliability

Posted on October 14, 2012

Mashmallow Test University of Rochester


Scientists from the University of Rochester have revisited the famous Stanford marshmallow experiment from the 1960s that tested how long a child would hold out before consuming a yummy fluffy white marshmallow. This time a reliability factor was added. Would kids wait patiently to eat a marshmallow if they knew the test instructors were not very reliable? The answer is no, which was expected, but it was surprising how quickly the kids lost patience with test administrators that they deemed to be unreliable. Why continue to wait if it is unlikely the unreliable adult will ever return with more marshmallows? The researchers say the new study demonstrates that being able to delay gratification is influenced as much by the environment as by innate ability.

The researchers assigned 28 three- to five-year-olds to two contrasting environments: unreliable and reliable.

In the unreliable condition, children were given a container of used crayons and told that if they could wait, the researcher would return shortly with a bigger and better set of new art supplies for their project. After two and a half minutes, the researcher returned with no new art supplies and this explanation: "I'm sorry, but I made a mistake. We don't have any other art supplies after all. But why don't you use these instead?"

The researcher then helped to open the same crayon container with the used crayons. Next a quarter-inch sticker was placed on the table and the child was told that if he or she could wait, the researcher would return with a large selection of better stickers to use. After the same wait period, the researcher returned empty handed.

The reliable group experienced the same set up, except the researcher returned with all the promised materials, including a rotating tray full of art supplies the first time and a set of large, die-cut stickers the second time.

The marshmallow task followed with a child being told you can have "one marshmallow right now. Or - if you can wait for me to get more marshmallows from the other room - you can have two marshmallows to eat instead." The art supplies were removed and a large single marshmallow was placed in a dish four inches from the edge of the table directly in front of the child.

The researchers and the parent of the child then watched through a hidden video camera until fifteen minutes had passed or the child tasted the marshmallow. All kids were given 3 extra marshmallows at the end of the experiment, regardless of whether or not they had waited the full fifteen minutes.

Children who experienced unreliable interactions with an experimenter waited for a mean time of just three minutes and two seconds on the marshmallow task, while kids who experienced reliable interactions held out for 12 minutes and two seconds. Only one of the 14 children in the unreliable group waited the full 15 minutes, compared to nine children in the reliable condition.

Holly Palmeri, coauthor and coordinator of the Rochester Baby Lab, said some of the strategies the children had for waiting were "quite entertaining." She says, "Kids danced in their seats, sang, and took pretend naps. Several took a bite from the bottom of the marshmallow then placed it back in the desert cup so it looked untouched. A few then nibbled off the top, forgetting they could then longer hide the evidence since both ends were eaten."

Celeste Kidd, a doctoral candidate in brain and cognitive sciences at the University of Rochester and lead author on the study said, "We had one little boy who grabbed the marshmallow immediately and we thought he was going to eat it." Instead the boy sat on the marshmallow. "Instead of covering his eyes, he covered the marshmallow."

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The research was published here in the journal Cognition.

Photo: J. Adam Fenster / University of Rochester