26

Feb

2016

Carolyn Rovee’s Revolution: Understanding the Cognitive Abilities of Infants

Written by: Arnold Glass

 
Baby Dylan. Photo: peasap via Creative Commons.
 

Anyone who has taken care of a newborn can understand treating them at little more than a digestive system.

Most newborns are either placid babies or colicky babies. Placid babies eat and sleep. Colicky babies eat, spit up, and cry.

Given the limited number of actions a newborn can perform, move their eyes, move their heads, and kick their legs, it is easy to imagine that their cognitive abilities are equally limited. Infants do not sit up until 6 months of age and walk until about a year old. Furthermore, 50 years ago it was believed that language learning did not begin until a year after birth as well.

Jean Piaget

A lifetime of careful observation of infant behavior had led the great Swiss psychologist, Jean Piaget to develop an influential theory of cognitive development that began with a pre-cognitive sensorimotor stage in infancy. The course of cognitive development was consistent with the increase in the myelination of the brain over the first year of life. It was presumed that only at the end of the first year of life, when myelination was well advanced, did cognitive processing begin. The mass of data supporting Piaget’s theory made it seem to many researchers to be beyond doubt.

I still remember a fellow graduate student, who studied the development of visual perception at the beginning of life, mocking the clinical psychologist Lee Salk for suggesting that an infant could recognize her mother’s face at a younger age than was then demonstrated by the existing data. He began his talk by saying, “today I am going to explain why it was Jonas Salk and not his brother Lee Salk who won the Nobel prize.”

Robert Fantz

There was some evidence of early cognitive processing. In 1958, Robert Fantz discovered that when given a choice, an infant would look longer at a pattern than a uniform visual display. In 1964, he found that after previous exposure to one pattern, an infant would spend more time looking at a novel pattern. The preferential looking pattern became and remains to this day a major method for investigating infant cognition.

However, Fantz studied short-term effects and explained his findings within the non-cognitive framework of habituation, so they did not necessarily provide a challenge to the sensorimotor theory of early cognition.

Carolyn Rovee

It was in this context that in 1969 Carolyn Rovee was trying to write her thesis in the area of developmental psychology.

A new mother, she had to share her effort between the papers in front of her and her infant son in the crib beside her. However, her son wanted all of her attention. In a burst of inspiration, she fastened one end of her belt around his ankle and the other end to the hook holding the mobile above his head, so when he squirmed, the mobile moved. The movement immediately caught his attention and he began to kick to move the mobile and laugh happily at the result of his action. This left Carolyn free to work on her thesis.

However, what happened the next day was even more remarkable. As soon as her son was placed in the crib with the mobile he began to kick to try to move it. This action demonstrated long-term for the effect of a voluntary action, a level of cognition that that was not part of the sensorimotor stage.

The ability to move a mobile provided Rovee with a methodology for studying long-term learning and retention. She exploited it in a series of brilliant, labor-intensive experiments testing specific hypotheses about the long-term recognition of a mobile an infant had learned to move derived from milestones in the development of memory in other mammals.

She found that even at the beginning of life, there was never a time when infants merely responded to simple features like color or shape or encoded simple objects independent of their context. Rather, from the beginning of life the basic unit of human memory was the episode, including an infant’s action, the action’s target, the target’s context, and the effect of the action on a target. Consequently, when an infant found that she could move a mobile through kicking, all aspects of the experience were encoded and used to discriminatively kick in the future.

The next day, if the mobile was slightly altered, the crib liner was changed, the room of the test, or even its smell were changed, the infant would recognize it as a new situation and not immediately begin to kick.

However, despite the context-specificity of early memory, the infant could already learn to generalize. I the infant was given the opportunity to move different mobiles through kicking then the infant would subsequently kick to move a third one as well. Furthermore, Rovee established that even at the beginning of life, if the dynamic properties of human memory were respected, something experienced once could be remembered forever.

When the same training mobile was presented on different days, what was most important was not the number of days of training but the spacing between them. If training was distributed over longer and longer intervals, the corresponding robustness of the memory increased. Moreover, the infant did not have to repeatedly move the mobile to remember that it could do so. It was only necessary to briefly present it for a few seconds as a reminder. Also, even before an infant was physically able to mimic an action she observed she was capable of remembering the episode and mimicking the action when she was older.

In short, in terms of the neural processes involved in encoding and retention, at birth human memory is already quite mature. It does not have to develop much at all. All that was necessary to demonstrate this was a task that an infant could perform to demonstrate what she was capable of learning and remembering.

Rovee’s legacy

In the long-term, Rovee’s results were influential.

Today there is considerable research on early infant learning and memory and no one doubts that even language learning begins early in life. She did receive some acclaim in her lifetime. However, that was only after many years when her findings were misrepresented as conditioning, not learning, and derogatory comments from other researchers were frequently repeated to her. Eventually, the results of other researchers began to make Rovee’s results seem more plausible. Also, the invention of video cassette technology was decisive because Rovee could dispel misconceptions about her task by videoing her infants kicking to move a mobile and showing the tape to colleagues.

However, in the end the level of acclaim never equaled the magnitude of her influence, which was rarely openly acknowledged. A few years before her death, at a moment of intense discovery, the National Science Foundation, which had previously been supportive, stopped funding her research. Though she is widely cited today, undoubtedly she was be obliterated from the next generation of textbooks as her seminal studies are replaced by more recent studies elaborating their findings.

In the field of psychology, if an investigator who has been wrong for years suddenly publishes the truth, their previous effort is not held against them.

However, if an investigator who has thought to be wrong for years is suddenly proved to be correct, that person is hated by her cohort of researches forever.

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About the Author: Arnold Glass

Arnold Glass is author of Cognition: A Neuroscience Approach (2016). He is a Professor in the Department of Psychology at Rutgers University....

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