By Cynthia Graber
(Click here for the original article and podcast)

It’s a confusing world for babies. To make sense of it, they look for intellectual stimulation. But they’re only interested if what they look at is not too hard to comprehend—or boringly easy. Researchers call it the Goldilocks effect, in a study in the journal Public Library of Science One. [Celeste Kidd, Steven T. Piantadosi and Richard N. Aslin, "The Goldilocks Effect: Human Infants Allocate Attention to Visual Sequences That Are Neither Too Simple Nor Too Complex"]

Seventy-two seven- and eight-month-old babies had their eye movements tracked as they watched videos. They sat on their parents’ laps for security—but the grown-ups wore visors and headphones, so they couldn’t see the videos and give subconscious cues.

In the videos, objects appeared behind or in boxes. When a video became too boring—exactly the same thing happened all the time—the babies lost interest and looked away.

But when the videos got too complex—with no pattern or action that could be anticipated—the babies again stopped looking. They needed just enough complexity.

The researchers say the study suggests that babies need some element of surprise to maintain attention. They add this finding is reminiscent of theories about adult learners, who might lose interest if material is too easy or too hard. Like Goldlocks’s porridge, it has to be just right.

Related on HuffPost:

Seven surprising things you may not know about babies:
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  • Their Baby Cuteness Doesn't Predict Adult Attractiveness

    A study published in the journal <em>Infant Behavior & Development</em> revealed that the standard "<a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCQQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch?v%3DXTV8bOv3Jhs&ei=0uLBToKrMuPu0gHkmNH0BA&usg=AFQjCNFtutJJhlTFZJ2fm-cmsDo46XMpzw" target="_hplink">You Must Have Been a Beautiful Baby</a>" has little to do with reality. When 253 college students were asked to rank photos of the same individuals as infants and young adults (without being told who was who), there was <a href="http://bodyodd.nbcnews.com/_news/2011/08/31/7542626-must-have-been-a-beautiful-baby-maybe-not" target="_blank">no relationship between how cute the students found the babies and how attractive they found the grown-ups</a>.

  • They're Good At Sharing

    No, really, it's true. It doesn't matter how many times you've heard the shout "Mine!" -- research shows babies can sense fairness at 15 months. During one study at the <a href="http://www.washington.edu/news/articles/babies-show-sense-of-fairness-altruism-as-early-as-15-months-1" target="_hplink">University of Washington</a>, 47 babies observed videos of an experimenter distributing milk and crackers to two people. When one recipient received more food than the other, the babies paid more attention. That means they had expected a fair distribution. The researchers also found that babies who did notice unfairness were more likely to share their own toys.

  • They Read Minds

    OK, so they're not exactly psychic. But a <a href="http://www.sciencedaily.com/releases/2011/11/111101130204.htm" target="_hplink">recent study</a> from the University of Missouri found that babies just 10 months old are starting to follow the thought processes of others. Yuyan Luo, an associate professor of developmental psychology who conducted the study, tells The Huffington Post, "Babies, like adults, when they see something for the first time -- when something is surprising -- they look for a long time. It shows [they recognize] something is inconsistent." It's called the "violation of expectation," she explained. When babies are surprised by something or notice something unexpected has happened, they tend to gaze at that thing longer. In Luo's research, babies watched actors consistently choose object A (such as a block or a cylinder) over object B. When an actor then switched to object B, the babies stared for about five to six seconds longer, meaning they recognized the change in preference.

  • They're A Little Bit Racist

    Don't judge a book by its cover. Treat all people the same. We're all equals. These are sentiments parents strive to teach their kids from a very young age. And they should. Starting, like, immediately. Researchers at the University of Sheffield in the United Kingdom found that babies at three months <a href="http://www.world-science.net/exclusives/060212_racefrm2.htm" target="_hplink">begin showing a preference for the faces of people of their own race</a>. But not all hope for equality is lost. The same study showed that babies who are exposed to people of all different races are less likely to develop bias at such an early age.

  • The Rhythm Is Gonna Get Them

    Researchers from Brigham Young University found that five-month-old babies can <a href=" http://news.byu.edu/archive08-oct-babymusic.aspx" target="_hplink">identify an upbeat song as being different from a series of sad, slow songs</a>. In other words, they are happy. They know it. They will clap their hands. Or stare longer, as the case may be. The experimenters showed babies an emotionless face while music played. When they played a new sad song, the babies looked away. When the music pepped up, the babies stared for three to four seconds longer.

  • They Can Tell The Good Guy From The Bad Guy

    Babies have a sense of morality at six months old, <a href="http://www.dailymail.co.uk/news/article-1275574/Babies-know-difference-good-evil-months-study-reveals.html" target="_hplink">say Yale researchers</a>. During the Yale study, babies watched a puppet show in which a wooden shape with eyes tried to climb a hill over and over again. Sometimes a second puppet helped him up the hill, and other times a third puppet pushed him down. After watching the act several times, the babies were presented with both puppets. They showed a clear preference for the good characters over the bad ones by reaching to play with the good puppet.

  • They Can Read Lips ... Kind Of

    Dr. Janet Werker of the University of British Columbia, who studies how babies perceive language, found that if a mother spoke two languages while pregnant, her infant could <a href="http://www.livescience.com/13016-bilingual-babies-brain-language-learning.html" target="_hplink">recognize the difference</a> between the two. And they don't even have to be spoken out loud. Werker's research found that infants four to six months old can <a href="http://www.nytimes.com/2011/10/11/health/views/11klass.html" target="_hplink">visually discriminate two languages</a> when watching muted videos of someone speaking both.