'Little Baby Thumpins'

You wouldn't think that reading Developmental Psychobiology journals on a Friday night was at all fun, but I love that stuff! What can I say, I am a nerd. I read college level astronomy textbooks when I was in 6th grade. That probably makes me a dork, but I don't care. Knowledge is thrilling. Science is thrilling.

My reading was sparked by a question I had, based on an observation and a hypothesis. See, my developing baby is now kicking. Even Mr. Field Notes can feel it. Most first-timers can't detect the baby's movements this early so I chalk it up to being highly observant. The kicking got me wondering if babies who move and kick a lot grow up to have highly active personalities. Do they grow up to be more extraverted and bold? That's the question I had in mind when I started my mini lit review.

All good literature reviews begin with knowing which key words to search for. I think a lot of students have trouble at this stage, which makes sense. They don't yet have the jargon of the field down enough to know which terms will quickly get them the relevant research. I also think they don't realize that they don't know which terms to search for and don't ask for help early enough so they waste time searching around for stuff like "baby personality development" and maybe adding in something like "movement during pregnancy" when a simple "fetal movement infant temperament" would return the landmark research right away.

In psychology, temperament is the key word. It's like personality — in the sense that it refers to an individual's pattern of behavior and emotional states (level of arousal, motivation, mood) that are apparent and stable over time. But — it's a little different in the sense that temperament typically only refers to what is seen in infants and it's more often thought of as genetically based, if not nearly completely genetically determined.

Temperament varies from individual to individual. Babies may have the same level of motor development and ability level but differ in their mood (calm to irritable), how distractable they are and their ability to adapt to changes. These patterns are believed to be dependent on inherited physiology — concentration of neurotransmitters like dopamine, serotonin and epinephrine as well as density of receptors on the brain's neurons for those neurotransmitters. They form a biological basis for personality development.

I would go so far as to say that all animals have a temperament. Even some paramecium are more active and mobile than others. Behavioral differences are one of the variables that make evolution possible. These difference fall into three broad areas:

• Emotionality: calm vs. irritable, easy vs. difficult to soothe during distress, frequency of crying and tantrums
• Activity: lethargic vs. energetic
• Sociability: reclusive vs. social, prefers to be alone vs. with others

Katy and Yuki, the lovable Newfoundlands that grace these pages now and then, have remarkably different temperaments. Katy is incredibly difficult to soothe if she's upset and is a bit of a loner. Yuki on the other hand, calms down easily and strongly prefers to be with others. These two are very different in temperament in spite of growing up on the same farm, with the same family and having the same biological parents. I suppose Forrest Gump would now say something like: DNA is like a box of chocolates. You never know what you're gonna get!

But, I sure would like to be able to predict whether Baby Field Notes is going to be hell on wheels or a relatively easy baby. I thought perhaps fetal movement would be associated in some way with later temperament.

These are precisely the kind of thoughts that lead scientists into new avenues of research or at least a decent start at a thesis or dissertation topic. My brief review of the literature suggests there's no need for me to embark on a new field of research — it's actually already been done before and the question is answered.** It turns out there is evidence that the roots of temperament begin during the prenatal period and can be observed in fetal movements. Cool beans!

More fetal movement is associated with being easier to calm but also to being more active, and perhaps hyperactive. I can handle that. But, I still don't know whether 'Little Baby Thumpins' kicks any more or less than other developing fetuses. I guess I get what I get! I'm excited either way, but I really would love love love to have an "easy" baby. Mine just seems to kick and squirm an awful lot!

DiPietro et al., Child Development, 67(5):2568-2583, 1996