You thought you were done learning about moral development? Not quite yet! Let’s examine one more aspect of the study to help you see what it’s like for experimenters to tweak and refine their research questions.

Across the first two experiments, infants appear to prefer puppets (and, by extension, maybe people, as well) that are helpful over those that are not helpful.  Experiment 2 complicated our story a bit, but it still appears that prosocial behavior is attractive to infants and antisocial behavior is unattractive. But another experiment, again using the bouncing ball show, suggests that infants as young as 8-months of age may have some other motives that are less altruistic than the first two experiments indicate.

EXPERIMENT 3: Do infants judge others based on their preferences?

In a study by Hamlin, Mahanjan, Liberman, and Wynn from 2013, 9-month-old infants watched the bouncing ball show, but with a new twist.

At the beginning of the experiment—Phase 1—the infants were given a choice between graham crackers and green beans. The experimenters determined which food the infant preferred.

Then, in Phase 2, the infants watched a puppet make the same choice. For half of the infants, the puppet chose the same food that they preferred, saying “Mmmm, yum! I like ___(graham crackers or green beans)!” and saying “Eww, yuck! I don’t like _____ (graham crackers or green beans!”  This was called the SIMILAR condition, because the puppet was similar to the child in its food preference. For the other half of the infants, the puppet chose the other food, choosing graham crackers if the infant preferred green beans and preferring green beans if the infant liked graham crackers. This was the DISSIMILAR condition.

Why did experimenters do this? They wanted to know if young children form in-groups and out-groups by perceiving some people as being like them and other people as being unlike them. The experimenters noted in their research introduction that we (adults) are influenced by our perception that others are similar to us or not like us. We tend to project positive qualities—being trustworthy, intelligent, kind—on people we perceive as similar to ourselves, and people we see as unlike us are seen as having negative qualities—being relatively untrustworthy, unintelligent, and unkind.^[1]

Of course, there is a big difference between claiming that adults use similarity to make judgments about others and saying that infants less than a year of age do the same thing. However, the researchers note that some recent research has suggested that infants less than a year old are more likely to develop peer friendships with other infants who “share their own food, clothing or toy preferences” compared to those who don’t.

So, back to the experiment. In Phase 3, the infants either saw a similar puppet (one that chose the food the baby preferred) or a dissimilar puppet (one that chose the food the baby did not prefer) bouncing the ball. As in the other experiments, the ball got away from the bouncer and rolled to the back of the stage. In one instance, the giver puppet returned the ball and, in the other instance, the other puppet ran away with the ball. Finally, in Phase 4, the 9-month-old baby was shown the giver and taker puppet and the experimenters recorded which of the two puppets the baby preferred (reached out to touch). This video shows the dog in the light blue shirt giving the ball back to the red bunny that preferred graham crackers.

Here is a summary of the four phases in Experiment 3:

• Phase 1: The infant chooses graham crackers or green beans.
• Phase 2: The bouncer puppets chooses graham crackers or green beans.
  • Similar condition: The bouncer chooses the same food that the infant chose.
  • Dissimilar condition: The bouncer chooses the food that the infant did not choose.
• Phase 3: This is the same bouncing ball experiment that you have been reading about.
  • Remember that each child sees both the Giver and Taker version of the puppet shows.
• Phase 4: This is the same choice—Giver or Taker—that was the final phase in the other two experiments

Now make predictions for the results. Here is a matrix picture of the design of the experiment:INSTRUCTIONS: Adjust bars A and C to make your predictions. Bar A represents the “nice” puppet who gave the ball to the bouncer puppet that liked the same food as the child, while bar B represents the “mean” puppet who took the ball away from the bouncer puppet who liked the same food as the child. Bar C represents the “nice” puppet who gave the ball back to the puppet who did not like the same food as the child, and bar D represents the puppet who took the ball away from the puppet who did not like the same food.As before, move the bars on the left to indicate the percentage of infants preferring the giver puppet in the similar condition (purple bars) and in the dissimilar condition (green bars). The bars on the right will adjust to make the total in each of the similarity conditions equal 100%.After you have recorded your predictions, click the “Show Answer” link to see the results from the experiment.

Show Answer

Here are the results from Experiment 3:

These results are similar to those for the 8-month-olds in the previous experiment. But remember that, in this experiment, the variable that distinguishes the two bouncer puppets was a food choice, not the prosocial or antisocial behavior in Experiment 2. If we take the results from Experiments 2 and 3 together, the results here suggest that the similar puppet is being treated as if it is nice or good. Puppets that treat this similar puppet in a nice way are preferred. Conversely, the dissimilar puppets are treated as if they have done something negative and puppets that treat these dissimilar puppets badly are preferred.

The experimenters also tested an older group of babies that were 14-months-old. The results for these older babies were consistent with the 9-month-old and, if anything, the effects were stronger. Their results showed that all infants preferred when the giver puppet was nice to the puppet that was similar to them and all infants preferred when puppets were mean to the puppet that was dissimilar to them.

Conclusions

This exercise started with a reminder that Lawrence Kohlberg found that children went through a long developmental process in their moral reasoning. Based on children’s reasoning aloud about moral dilemmas, Kohlberg concluded that children younger than about 8 or 9 years of age make moral decisions based on avoiding punishment and receiving praise. Neither his research nor that of most others in the 1970s and 1980s suggested that young children would use multiple sources of information and judgments about the meaning of behaviors in their thinking about what sorts of behaviors are better or worse.

If Dr. Hamlin and her colleagues are right, then infants are much more sophisticated and complex in their thinking about the world than these earlier researchers thought. In Dr. Hamlin’s view, infants like good things to happen to good puppets and people, and bad things to happen to bad puppets and people.

The research we have been reviewing is just part of an impressive set of research on infant thinking. The ideas that the researchers have developed are intriguing and they are consistent with the modern view of the infant as an active, creative thinker. At the same time, remember that science doesn’t rest on an early set of explanations based on a small set of complicated experiments. Science pushed beyond what we currently know and believe. This starts with curiosity on your part. Are the experimenters correct in interpreting reaching behavior as showing a preference or is something else going on? Do infants really prefer prosocial behaviors to antisocial behaviors, or is there some other explanation for their preferences? How else could we test moral judgments of infants without using puppet shows? The next generation of creative scientists will push beyond what we know now, with new research methods and new ideas about the mind.