Researchers at the University of California, San Diego have developed a robotic infant to test a hypothesis that babies can (and regularly do) manipulate their mothers into smiling on command. Turns out that your 4-month-old progeny is a lot craftier than you thought.
The team first observed the interaction between 13 mother-child pairs and analyzed them along four categories: how often just the kid smiled, how often just the mother smiled, how often both smiled and how often neither smiled. This initial study, which assumed that each party was attempting to influence the other, found that mothers most often tried to maximize the time both they and their kids were smiling. Their babies, on the other hand, most often smiled only as a means of getting their mothers to do the same. That is, moms were primarily motivated to make both parties smile while babies were almost exclusively in it just to be smiled at.
Using the statistical analysis from this initial study, the team then programmed this mechanical monstrosity, named Diego-San (what, was "nightmare fuel" already taken?), to smile like biological babies do. They then set Diego loose on 32 undergrad test subjects. According to the team's study, which was recently published in the journal PLOS One, "the duration of participant-only smiling was significantly longer for the controller based on the inferred infant goals than for each of the other 3 control conditions." Which is exactly what real babies are after. In fact, the study concluded that "infants exhibited sophisticated timing behaviors to achieve their goals." In short, these kids are using all of their cunning to effectively trick their parental units into doing exactly what they want: smiling at them.