Exploratory: The A-not-B Error

[orbacht]

Here's tomorrows exploratory, sorry I couldn't get it up earlier but I emailed it out. See you in the morning!

[derek]

Here's Tessa's exploratory on the A-not-B error. Enjoy!

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Tessa Orbach
9/14/08
Exploratory

I thought the Ahmed & Ruffman study was incredibly well thought out and detailed. As the paper went on all of my concerns were addressed. They set about trying to determine why the A not B error happens and did so by testing whether infants are capable of expressing understanding that the object is located in a different place another way than reaching and then proved that this was not a novelty preference. All the way through I was convinced by the results that showed that infants looking longer at the impossible than possible events in all delay conditions. I think this alternate method of testing whether infants understand object permanence is very clever. The fact that infants remembered where the object was located after a delay of 15 seconds in the non-search condition contradicts the argument that infants fail on the A not B task due to poor memory.

One of my main concerns was that the infant did not physically look for the object in the first two experiments. Infants could somehow organize their memory differently if they acted on the object and if they simply observed the object. Experiment 3 addressed this issue, allowing the infant to retrieve the object from A. Allowing the infant to search for the object had no effect on looking times in the non-search part of the task, which shows that infants are not somehow categorizing the information differently when observing and physically interacting with the object.

It is particularly interesting that performance on the non-search task does not improve with age but performance on the search task does. Could this be an argument for motor control getting in the way of success on the search task? It could also be that infants are unable to inhibit a habitual response of looking under A even though they understand that the object is now under B. Could this have something to do with the development of executive functioning? It would be interesting to see if there is a change in performance on the search task around the time that executive functioning develops.

This paper reminded me of the discussion we had on the first day of class about different ways to measure infant’s attention and understanding. The fact that results were so strikingly different in the search and non-search task really goes to show that the way an experimenter chooses to test a hypothesis can make a huge difference! This paper flies in the face of a lot of the Piaget readings we have been doing for this class. Piaget believed that infants of this age did not have a fully developed concept of object permanence but this data shows that they do have some understanding of where the object was located and where it should appear. The Scholl article supported this idea, showing that training can help infants’ performance. According to these results infants who saw the ball swinging without an occluder were more accurate and faster at anticipating the balls reappearance on the other side of the occluder when it was present. This gives strong support to a “nurture” over “nature” hypothesis, as experience seems to help the infant. The effect faded with time so there must be some cognitive threshold that the infant has to pass in order to gain permanent understanding. Infants were able to learn something about object permanence at 4-6 months old, which supports the notion that it is something inherent in the testing process that is causing infants to consistently fail on the search task.

If infants can be rapidly trained to have a greater understanding of object permanence they would perform better on the search task after a familiarization period. A potential follow up study would be to familiarize infants with the search task and allow them to practice. This may help their success rate. If that doesn’t work, seeing if training leads to a spike in the effect of the non-search task or helps even younger children succeed at the non-search task would also support the idea that infants are capable to understanding where the object should be even if they cannot stop themselves searching for it at its previous location.