EVALUATION OF THE MODAL MODEL OF MEMORY Lecturer: Dr. Benjamin - - PowerPoint PPT Presentation

College of Education School of Continuing and Distance Education

2014/2015 – 2016/2017

EVALUATION OF THE MODAL MODEL OF MEMORY Lecturer: Dr. Benjamin Amponsah, Dept. of Psychology, UG, Legon Contact Information: bamponsah@ug.edu.gh

Session Overview

• The session will critically examine the rationale for

the existence and importance of the sensory register. We would also examine the functional distinction between the short-term and the long-term memories.

Slide 2

Session Objectives

• Evaluate the existence and Importance of the

Sensory Register

• Decide on the propriety of the distinction between

STM and LTM

• Evidence from Neuropsychology on the distinction

between STM and LTM

Slide 3

Session Outline

The key topics to be covered in the session are as follows:

• Topic One: Rationale and Importance of the Sensory Register
• Topic Two: Distinction between STM and LTM
• Topic Three: The Issue of Coding
• Topic Four: Capacity Differences between STM and LTM
• Topic Five: Mechanisms of forgetting and Neurological

Correlates of STM

Slide 4

Reading List

• Ashcraft, M. H. (2006). Cognition (4th edn.), London: Pearson

Education Int.

• Galotti, K. M. (2004). Cognitive Psychology: In and out of the

laboratory (3rd Edn.). Belmont, CA: Wadsworth.

• Hunt, R. R. & Ellis, H. C. (1999). Fundamentals of Cognitive

Psychology (6th edn.), New York: McGraw-Hill.

• Willingham, D, B. (2001). Cognition: The thinking animal. NJ:

Prentice-Hall.

Slide 5

RATIONALE AND IMPORTANCE OF THE SENSORY REGISTER

Topic One

Slide 6

Sensory Register

• Since the Sensory register is precategorical and we are not

aware of its existence, the following are plausible :-

• Cuing a subject to report a particular kind of stimulus (e.g.,

letters or numbers) was ineffective, because the material in the sensory register had not yet been transferred into the STM, where the material is coded.

• Sperling’s procedure is highly artificial. Human beings do

not use tachistoscope in viewing at such high speeds

• According to Haber (1983), why would our cognitive system

depend on a component in whose use we are not skilful and which has no utility value anyway?

Slide 7

Sensory Register

• Obviously, having that component will have no

practical value to humans since we are in the first place not aware of it.

• The evidence suggests that the boundaries

around the sensory register, its limits may be much blurred than was once thought.

Slide 8

DISTINCTION BETWEEN STM AND LTM

Topic Two

Slide 9

Coding in STM and LTM

• The distinction between separate storages beyond the

sensory register is based on several lines of evidence.

• On the issue of coding:

– STM is acoustically coded, whereas – LTM is semantically coded. – Shulman (1972) showed in a classic experiment that people do have information (which is meaning based) in STM thereby arguing against the traditional view.

Slide 10

Coding in STM and LTM

• VISUAL CODES

Some experimenters also suggest that visual codes are also stored in the short-term storage. – For example, in a Mental Rotation Test subjects have to rotate an image and decide within 30 seconds as to whether it is normal or a mirror image. – Subjects are able to decide this, which shows clearly that STM processes information about imagery.

Slide 11

Coding in STM and LTM

Slide 12

Coding in STM and LTM

• VISUAL CODES AND LTM

– Long-term memory can also be coded in less rigid

• ways. There is evidence that shows that LTM

processes visual codes as against the only semantic codes.

• LTM AND ACOUSTIC CODES

– The LTM is also able to store Acoustic or phonetic codes as it is clear from our ability to remember a range of sound patterns.

Slide 13

Coding in STM and LTM

• We also have very large stock of memory

codes for smell. For example, the smell of rotten eggs, perfume, pheromones and hot cakes are but a few examples of smells we can remember.

• Clearly, we may have different codes but none

exclusively characterises either the STM or the LTM.

Slide 14

CAPACITY DIFFERENCES IN STM AND LTM

Topic Three

Slide 15

Capacity Differences between STM and LTM

• One of the foundations of the STM and LTM is that
• f capacity.
• STM has smaller capacity (7±²) whereas LTM has

infinite capacity.

• Is this distinction valid?
• If we look at the phenomenon of chunking and the

relative ease with which chunking is done by most people, it argues against the idea of necessary differences in the capacities of STM and LTM.

Slide 16

Capacity Differences between STM and LTM

• Many people also use mnemonic devices (e.g.,

method of loci – strategies to facilitate retention and later retrieval of information) to code their information and that enables them to increase the capacity of the STM.

Slide 17

Controlled Processes

• Some useful controlled processes:

– Coding – process by which external stimulation is transformed into a representation for purposes

• f memory.

– Chunking – the formation of individual units of information into larger units. Used as a means of overcoming short-term memory limitations. – Mnemonics – Strategies or devices to facilitate retention and later retrieval of information.

Slide 18

Controlled Processes

– Attention – is described as a spotlight that focuses your awareness on a subset of what is going on in your head or in your environment.

Slide 19

MECHANISMS OF FORGETTING /NEUROLOGICAL CORRELATES

Topic Four

Slide 20

Mechanisms of forgetting and Neurological Correlates of STM

• Mechanism of Forgetting (Decay or Interference)

– We have noticed that decay occurs in the STM whereas interference occurs in the LTM. – Unfortunately, this distinction has come under scrutiny. – In a series of controlled experiments Keppel and Underwood (1962) subjected their subjects to practice on two trials and in a replication study, subjects performed the task without practice.

Slide 21

Mechanisms of forgetting and Neurological Correlates

• f STM

– They concluded that at least some interference seems to be involved in forgetting from STM. – Again Keppel and Underwood have shown that there was some interference in the Brown-Peterson’s experiment. – Remember, there was Rehearsal Prevention Task (RPT) as part of the experimental procedure. – The RPT itself constitutes interference.

Slide 22

Neurological Correlates of STM/LTM

• Neurological Correlates of Short-term

Memory

• Do STM and LTM occupy different locations in

the brain?

• Interestingly, the answer to the question is both

yes and no.

Slide 23

Neurological Correlates of STM/LTM

• Experiments with monkeys using Spatial Delayed-response Task

(Goldman-Rakic, 1987) indicate that neurons in the frontal lobes act like “pointers” to LTM representations stored in more posterior areas of the brain.

• Studies using PET (Positron Emission Tomography) has also revealed

that the patterns of activation seen in monkeys can also be found in human subjects performing similar tasks.

• Based on this research, information “in” STM is really just

information stored in LTM that is under active consideration by conscious processes.

• Slide 24

Neurological Correlates of STM/LTM

• Currently, the neural finding suggests that instead of acting as

a place for the temporary storage of information, STM is better thought of as a set of processes that works with information stored in LTM.

Slide 25

Sample Questions

• Describe the argument for separate systems of short- and

long-term memories.

• Why have so many theorists become increasingly sceptical of

the structural distinction between short- and long-term memory?

• What does the emerging field of cognitive neuroscience say

about short-term memory?

Slide 26

References

• Haber, R. N. (1983). The impending demise of the icon: A

critique of the concept of iconic storage in visual information processing. The Behavioral and Brain Science, 6, 1-54.

• Keppel, G., & Underwood, B. J. (1962). Proactive inhibition in

short-term retention of single items. Journal of verbal learning and verbal behaviour, 1, 153-161

• Shulman, H. G. (1972). Semantic confusion errors in

short-term memory. Journal of Verbal learning and verbal behaviour, 11, 221-227.

Slide 27