The above descriptive analysis tells us what we have learned about the 16 infants in the study. But can we say more than just what these 16 infants did?
One way to approach the analysis is to suppose for the moment that the researchers’ conjecture is wrong, and 10-month-old infants do not really have any preference for either type of toy. In other words, infants just blindly pick one toy or the other, without any regard for whether it was the helper toy or the hinderer. So for each infant, the probability of choosing the helper toy is .5. Put another way, the infants’ selections are just like flipping a coin: choose the helper if the coin lands heads and the hinderer if it lands tails.
- Thought Question (Think about, briefly discuss with partner, move on) If this is really the case (the infants have no preference between the helper and hinderer), is it possible that 14 out of the 16 infants would have chosen the helper toy just by chance? (In other words, is it possible that in 16 tosses of a fair coin, you might randomly get 14 heads?)
Well, sure, it’s definitely possible that the infants have no real preference and simply pure random chance alone led to 14 of 16 choosing the helper toy.
- Thought Question: But how do we decide whether the data we have observed are convincing evidence that this result didn’t just happen by chance? What do we need to know to be able to determine the chances of observing 14 of 16 infants choosing the helper if they are all flipping a coin? How do we do this?
