P335 Cognitive Psychology, Prof. Kruschke

Exam 2 Questions from Students (with answers)

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From previous classes, but still relevant...
Questions regarding:
The Loftus experiment showing influence of interventing questions on eye-witness memory.
The leaves of the knowledge organization diagram; e.g., depth of processing
Amnesia; and, method of loci
Questions regarding:
Too much! How can I learn it all?
Brown/Peterson experiment (duration of STM).
Decay vs. interference in STM (Waugh & Norman experiment)
Release from proactive inhibition
Expert vs. novice STM (DeGroot et al. experiment)
STM scanning (serial-exhaustive search...)
Depth/Levels of processing?
State dependency?
Mug shots and eye-witness identification.
Confabulated vs. veridical memories.

> Professor Kruschke, Would you please outline the main points of the
> Loftus experiment?  I'm not sure I got everything during lecture.
> Thanks a lot

Here's a very quick outline.

There were three phases of the procedure:
1. Witness the event. This is a sequence of slides.
2. After a certain retention interval (this is one I.V.), answer questions about the event. The questions could contain info that is neutral about the event, inconsistent with it, or consistent (this is a second I.V.).
3. Recognition test: Which of two presented slides actually occurred in the original event? (Recognition accuracy is the D.V.)

The results showed that recognition accuracy after neutral questions dropped off to chance within a short time. After inconsistent questions, performance began worse than chance and got worse, and after consistent questions, performance stayed above chance. These results show that people were remembering the info in the questions, not the details of the original event.

> Hello!  I need some help breaking down experiments.  I understand the
> overall experiment, but breaking it into stimulus, task, procedure,
> IV, DV, results, representation and process, is kind of hard.  I know
> what the IV, DV and results are, but the others confuse me. Are task
> anprocedure the same thing?  Could You give me an example using the
> Craik and Tulving experiment?  Representation and process is confusing
> me too.  I know the stimulus is probably really easy, but i'm not
> quite sure what it is.  Thanks so much for your time!  I really
> appreciate it!

The levels of processing experiment by Craik and Tulving:

What was done:

Stimuli: Words.
One Task: Respond to yes/no questions about a list of words.
Another Task: Recognition test of words.
Procedure: First do the "question" task, then subsequently do the recognition task. A full specification of the procedure (not given in the book or in lecture) would also include details like how many words and how many trials, how long each was displayed, how they were randomized, etc., etc.
I.V.'s: Type of question asked (either structural, phonemic, or semantic), and correct response (yes or no).
D.V.'s: Percent correct in recognition; and, response time. But we're just emphasizing percent correct.

The results:
See Figure 6.2, p.157. Notice how it plots the D.V. as a function of both I.V.'s.


Representation: Mental representation of words exists in several different types of content -- visual/structural, acoustic/phonemic, and semantic. The theory doesn't really specify the formats for these different types of content, except to say that they are at different "depths" or "levels".

Process: Processing progresses through those types of content in successive levels -- first visual/structural, then acoustic/phonemic, and finally semantic. Moreover, within each level, there can be different degrees of elaboration. It is assumed in this theory that deeper processing, and more elaborate processing within any level, leads to better memory.

> HI!  I have two questions for you.  First, I cannot find in my notes
> where I have characteristics of amnesia and implications for
> theoretical divisions of memory. What exactly do you want us to know?
> Second, when talking about the method of loci, is that what you were
> talking abo t withth th the he rabbit in the tree, with the carrot on
> the mailbox? Thank you very much for your time and help.

In lecture we discussed a couple cases of anterograde amnesia, in which people retain memories from their past, but can't learn new (non-procedural) information. These people apparently do have LTM. And they also have STM, because they can participate in conversations and remember things for a few seconds. But what seems to be missing is the transfer of information from STM to LTM. (This is just one theoretical interpretation of the observed behavior, consistent with the distinction between STM and LTM. There might be better theories.) Another possible implication is that procedural memory is different than non-procedural (or declarative) memory, because these people can (slowly) learn new skills, but claim not to recognize these tasks.

The method of loci is discussed in the textbook on pp.188-191. The method of loci is a mnemonic technique, in which items to be remembered are mentally associated with locations in some previously memorized place. It does not have any direct connection with the experiment discussed in class, involving the example of the rabbit in the tree with mailbox stuck in the trunk and the carrot as a flag on the mailbox. In the method of loci, the items are recalled in order by systematically moving from location to location in your remembered image of the place. In the experiment discussed in class, there's no intended order in the recall, and the imagery does not need to involve locations. There is, however, a similar theme: Interactive imagery can be very beneficial for recall, when the imagery can be appropriately used during recall.

>       I'm a student in your P335 class and I'm beginning to
> study for the upcoming exam.  The thing is I'm having great
> difficulty trying to piece together information to fully
> answer your example topics.  I don't really know how to
> tackle them.  When I look at the readings my mind goes
> bonkers because I feel that the readings are fairly difficult
> to understand and very technical.  Should I be focusing on
> the notes more than the book or both.  I need help!!!!
> Thanks.
>  Sincerely, Confused

Keeping your knowledge organized is crucial for understanding and for remembering. The time you spend figuring out how it all fits together will pay off in terms of performance on exams and in terms of your enjoyment of the class!

To help digest the readings, it's crucial always to keep in mind the "big picture" --- why is the author discussing this particular thing in this particular place? What point is it supposed to be illustrating or demonstrating? Be sure you can answer this question; if you can't, then you don't really understand!

The knowledge organization diagram from the syllabus is intended to help you keep the big picture. Whenever you read about an experiment in the book, or hear about one in lecture, you should be able to fill in all the leaves of the knowledge organization tree. Sometimes an experment is discussed in terms of its results only, without a theory thoroughly described. In these cases, you should at least be aware that if a theory were proposed, it would have to specify representation and process.

> could you please review the brown/peterson experiment
> ... i only have the peterson/peterson experiment in my
> notes.

They are the same thing. At about the same time as Peterson and Peterson did their classic experiment on STM in the United States, a researcher named Brown did a comparable experiment in the United Kingdom. So the method is often called the "Brown/Peterson paradigm."

(Don't confuse this "Brown" with the "Brown et al. (1977)" experiment regarding eye-witness identification after seeing mug shots.)

> I have a question regarding the Brown/Peterson paradigm
> for measuring the duration of STM.  I understand that the
> explanation for the results found is decay and/or
> interference.  But I am unclear on how the boat and
> refrigerator metaphor you discussed in class is divided
> into representation and process.

The boat and refrigerator metaphors were intended to clarify the distinction between decay and interference.

The boat metaphor: In this metaphor, an item to remember is a boat in a busy harbor. Remembering an item is like being able to see the boat from the pier. You might lose sight of the boat two different ways: The boat might sink (decay), or it might be occluded by other boats (interference). So the representation is the boat, the process is either sinking (decay) or occlusion by other boats (interference).

The refrigerator metaphor: An item to remember is a tub of leftovers in the frig. Remembering an item is being able to see it when you open the frig door. You might lose sight of the item two different ways: It might spoil and be unrecognizable (decay), or it might be occluded by other leftovers that get placed in front of it (interference). So the representation is the tub of leftovers, the process is spoilage (decay) or occlusion by other leftovers (interference).

The two metaphors motivate the Waugh & Norman experiment as well. You can think about how decay and interference might be independently manipulated in the two metaphorical situations, and how that corresponds to what Waugh and Norman did.

> could you briefly describe the implication of the
> proactive interference on stm/ltm distinction?  thank
> you for your time.

Proactive inhibition (PI) and release from PI are discussed at length in your textbook on pages 84-86.

An implication for the STM/LTM distinction is that STM cannot be purely acoustic, because PI and release from PI show that STM is affected by semantic information. This type of argument is mentioned on p.151 of your textbook (middle of the page), although it doesn't mention PI specifically.

> I also have a question regarding the DeGroot
> experiment on STM of Chess positions by experts or
> novices.  The explanation I understand for this
> experiment is that experts depended on their abilitys
> to code pieces in familar groups or "chunk"
> information.  Is there another part of the explantion
> that I am a missing, and how is this divided into
> representation and process?
> Thank you so much for you time.

You should also be sure to understand how DeGroot et al. ruled out other possible explanations. How did the experiment rule out the possibility that the experts really were not remembering the board but were in fact just guessing the position? How did the experiment rule out the possibility that experts just had good memory for any configuration of chess pieces, not just for "chunk-able" configurations?

I did not interpret these results in terms of representation and process, but if I had, the representation would have emphasized meaningful configurations, or "chunks," and the process would have emphasized how such chunks are learned and recognized.

> I am wonering if the flow/logic diagram you displayed
> re: serial self terminating/serial self exhaustive is
> to be part of the study session this p.m.?  I don't
> remember the layout precisely, but I do know the
> process involved.  Is the logic schematic itself
> deadly important, and if so, how can we get a copy?

It is not crucial to memorize the flow chart exactly. You should know the logic of the various scanning models, though. In fact, you should be able to re-create the basics of the flowcharts on your own if you really understand the processes - but you won't be required to do that on the exam.

> With regards to the level of processing approach and
> the depth of processing what are the differences, I
> am a bit confused. Is one better than the other? Or
> is the depth of processing used to help explain
> levels of processing?  Thanks

Depth of processing and levels of processing refer to the same thing. They are entirely synonymous. When something is processed more deeply, it is being processed at a deeper level. The notion is that there are different levels of processing, at different "depths". Sorry for any confusion.

>  what is state dependency?  Thank you!

This is merely encoding specificity when the context is internal. That is, recall of information is better when your internal state (e.g., mood, sobriety) matches the internal state you had when you initially learned the information.

> what is the main point of Brown's experiment?

You mean the Brown et al. (1977) experiment on pp.134-6 of the text? (Not to be confused with the Brown experiment on duration of STM.)

The main point of the results was that, after seeing mug shots, not only did correct identification of suspects increase (from 51% to 65%), but so did incorrect accusations of innocent people (from 8% to 20%)! In fact, when measured by d', the ability to distinguish between "guilty" and "innocent" actually got worse after seeing the mug shots, although the textbook never explicitly connects the preceding discussion of d' with this aspect of the experiment.

> i am having trouble finding info on confabulated and
> veridical memories.  i was wondering if you would mind
> telling me where this info is in thebook. thanks.

> I understand what a confabulated suppressed memory
> is, but I am unclear on what a veridical suppressed
> memory is.  Can you explain?  Thanks again,

It's not in the textbook (although there is some related material we'll encounter in later chapters). It was only discussed in class. The main point is that it's surprisingly easy to implant false (confabulated) memories which feel and look real (veridical). This does not imply that all memories are false, only that it is surprisingly possible for them to be false.

A veridical suppressed memory would be a genuine memory that has been repressed (and then recovered). It is controversial whether such memories really occur. Some researchers argue that emotionally charged events are the ones remembered best, e.g., post-traumatic stress disorder is a result of remembering trauma too well. Other researchers argue that memories of tramautic events really can be suppressed, especially when experienced in childhood, and there are various theories regarding the mechanisms of suppression and memory recovery.