“You must remember this, a kiss is still a kiss, and a sigh is still a sigh. The fundamental things of life remain the same as time goes by.”

I was reminded of these lyrics as I reviewed a new book entitled, Human Development from Early Childhood to Early Adulthood: Findings from a Twenty Year longitudinal Study.(Schneider 2009). Longitudinal studies are the gold standard in research because they follow the same individuals over many years, as opposed to comparing children of different ages at the same time. Such research is very difficult and quite costly and that is why such studies are the exception. The aim of such studies, and that is what brought to mind the theme of Casablanca, is to answer the question:

What are the fundamental things of life that remain the same across the life cycle?

The study was conducted in Germany during the 1980’s and 1990’s and explored age changes in a number of psychological domains from intelligence and personality, to moral motivation and reading and writing. Given the length of the study it is admirable that most of the investigators stayed with the project from beginning to end. Many of the results, such as the stability of the IQ and personal self-confidence over time, simply replicated what earlier studies had found about traits that remain the same. Other results were new. For example the investigators with personal self-confidence remained fairly constant from childhood to young adulthood. Moral motivation, on the other hand was quite variable over time. Indeed some of the subjects in the study seemed to regress in moral motivation, as they grew older.

Of particular interest was the study’s attempt to determine the predictability of scientific reasoning, reading, spelling and math from measures taken in preschool and kindergarten. The results showed that early childhood achievement was a better predictor of later school performance in all domains including reading, math and science, than was the IQ. Another interesting conclusion from these findings is that the stability of academic performance appeared to be independent of schooling. Subjects came from both urban and suburban neighborhoods and schools, yet their level of achievement remained constant over time despite the variability of their school experience.

Of course there were many age related changes as well, particularly in levels of thinking. But overall the many stabilities displayed from early childhood to young adulthood, suggest that, many human traits do indeed remain the same as time goes by.

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Schneider, W. B., Merry, Ed. (2009). Human Development from Early Childhood to Early Adulthood. New York, Psychology Press.