The blank slate, tabula rasa as the Greek termed it, is one of the worst ideas in science. For a long time scientists avoided asserting that anything about human behavior was innate. If they did, someone would point to a quirky tribe from Papua New Guinea to argue that all behavior comes via experience. This attitude has changed in the last couple of decades. Books ranging from Steven Pinker’s The Blank Slate to David Shenk’s The Genius in All of Us, give us a much more accurate picture of the nature-nurture debate. Now scientists know that the human brain is like a book: the first draft is written at birth and the rest is filled in during life. As NYU psychologist Gary Marcus explains, “Nature provides a first draft, which experience then revises… ‘Built-in’ does not mean unmalleable; it means ‘organized in advance of experience.’”
Understanding human behavior in these terms is vital for moral psychologists. For thousands of years philosophers debated if humans are inherently good or evil. But we now know that this is a false choice. As Marcus explains, everyone possess a moral sense from birth that permits altruism, fairness and justice; the interaction between genes and environment influences how these qualities are drawn out.
Some of the most important work in moral development comes from Paul Bloom, Karen Wynn and Kiley Hamlin. In one of their experiments they used a three-dimensional display and puppets to act out helping/hindering situations for six and ten-month-old infants. For example, a yellow square would help a circle up a hill; a red triangle would push it down. After the puppet show Bloom, Wynn and Kiley placed the helper and hinderer on a tray and brought them to the children. They found that they overwhelmingly preferred the helpful puppet to the hindering one. In an NYTimes article, Bloom concludes that, “babies possess certain moral foundations — the capacity and willingness to judge the actions of others, some sense of justice, gut responses to altruism and nastiness. Regardless of how smart we are, if we didn’t start with this basic apparatus, we would be nothing more than amoral agents, ruthlessly driven to pursue our self-interest.”
This brings me to a brand new study by psychologists Stephanie Sloane, Renée Baillargeon and David Premack published in Psychological Science. There were two experiments and babies watched live scenarios in each. In the first, 19-month-olds watched two giraffe puppets dance as an experimenter cheerfully presented the long-necked puppets with two toys. Here was the ripple: the experimenter gave one toy to each giraffe or both to one of them. Sloane et al then timed how long the babies gazed at the scene until they lost interest. (Longer looking times indicated that the babies thought something was wrong). They found that three-quarters of the infants looked longer when one giraffe got both toys.
In the second experiment, two women played with a pile of small toys when an experimented said, “Wow! Look at all these toys. It’s time to clean them up!” In one scenario both women got a reward even though one put all the toys away while the other kept playing. In the other scenario both women got a reward and both put the toys away. Similar to the results of the first experiment, the researchers found that 21-month-old infants gazed longer when the worker and the slacker were rewarded equally.
Here’s Sloane on the implications of the research:
We think children are born with a skeleton of general expectations about fairness and these principles and concepts get shaped in different ways depending on the culture and the environment they’re brought up in… helping children behave more morally may not be as hard as it would be if they didn’t have that skeleton of expectations.
Sloane’s study and remarks complement other research. A study published last November by Kiley Hamlin (along with Karen Wynn) demonstrated that babies preferred puppets that mistreated bad characters from scenarios similar to the ones created by Paul Bloom et al. Hamlin concluded that babies, “prefer it when people who commit or condone antisocial acts are mistreated.” Moreover, last October a study by Marco Schmidt and Jessica Summerville found that, “the infants [expecting] an equal and fair distribution of food… were surprised to see one person given more crackers or milk than the other.”
This small but significant body of research is giving us a better understanding of morality from the developmental point of view. It also reminds us that behavior is not simply nature versus nurture; it is about the interaction of genes and their environments. A better understanding of where our moral sense comes from and how it develops will hopefully help us draw out what Abraham Lincoln called our Better Angels.