Experimental Psychology

Chapter
10
Remembering and forgetting
◦ the faculty by which the mind stores and
remembers information
◦ failure to remember something.
Memory
 The process by which we encode, store, and retrieve information

 Encoding (Putting in): Initial process of recording information in a

form usable to memory.
 Storage (Retaining): Maintenance of material saved in memory.
 Retrieval (Recovering): Material in memory storage has to be
located and brought into awareness to be useful.
 How memory Function?
Three system Approach to Memory (Atkinson & Shiffrin)

 There are different memory storage systems or stages through which

information must travel if it is to be remembered.
 There are three separate memory stores each system has a different function.
Memories entre the various systems in a specific order.
Sensory Memory
Sensory memory (brief impressions of sensory stimuli)
 The first storehouse of the information the world presents to us. The initial,
momentary storage of information, lasting only for an instant.
 Information consists of representation of raw sensory stimuli.
 A momentary flash of lightning and the sting of a pinprick are stimulation of
exceedingly brief duration, but they may nonetheless provide important
information that can require a response.
Iconic memory reflects information from the visual system.
Echoic memory stores auditory information coming from the ears.
 Sensory memory can store information for only a very short time (last for
few seconds only). If information does not pass into short-term memory, it is
lost.
 Iconic memory seems to last less than a second, and echoic memory typically
fades within two or three seconds.
 Despite the brief duration of sensory memory, its precision is high.
 Sensory memory can store an almost exact replica of each stimulus to which
it is exposed.
Existence of Sensory Memory
Psychologist George Sperling (1960)
 Series of clever and now-classic studies
 Briefly exposed people to a series of 9 letters arranged in the
following pattern:
F T Y
K D N
Y W B
 When exposed to this pattern of letters for just one twentieth of a
second, most people could recall only four or five of the letters
accurately.
 They knew that they had seen more, the memory of those letters had
faded by the time they reported the first few letters.
 Information had initially been accurately stored in sensory memory.
But during the time it took to verbalize the first four or five letters, the
memory of the other letters faded.
 Existence of Sensory Memory
George Sperling (1960) an experiment
 A high, medium, or low tone sound was presented just after a person had been exposed to the
full pattern of letters.
 People were told to report the letters in the highest line if a high tone was sounded, the middle
line if the medium tone occurred, or the lowest line at the sound of the low tone.
 Tone occurred after the exposure, they did not know which row to recall, so people had to rely
on their memories to report the correct row.
Results - people had been storing the complete pattern in memory. They accurately recalled the
letters in the line that had been indicated by the tone regardless of whether it was the top,
middle, or bottom line.
 All the lines they had seen, had been stored in sensory memory.
 Despite its rapid loss, the information in sensory memory was an accurate representation of
what people had seen.
 Capacity of sensory memory was about 9items (even with larger array of letters).
Existence of Sensory Memory
 Gradually lengthening the time between the
presentation of the visual pattern and the tone
leads to the decline in ability to recall a particular
row of pattern when the tone was sounded.
Sensory memory operates as a kind of snapshot that
stores information— of a visual, auditory, or
other sensory nature—for a brief moment in time.
Each snapshot, immediately after being taken, is
destroyed and replaced with a new one. Unless
the information in the snapshot is transferred to
some other type of memory, it is lost.
 Short Term Memory
Short-term memory (link between rapidly changing sensory memory and long
standing long term memory)
 The information we attend to goes from sensory memory to short term memory
where we focus on meaning of information.
 The specific process by which sensory memories are transformed into short-term
memories is not clear.
 Some theorists suggest that the information is first translated into graphical
representations or images, and others hypothesize that the transfer occurs when the
sensory stimuli are changed to words.
 Unlike sensory memory, which holds a relatively full and detailed, short-lived
representation of the world, short-term memory has incomplete representational
capabilities.
 Here the maximum length of retention is relatively short (holds information for 15
to 25 seconds when nothing is done; unless it is transferred to long-term memory).
 Short Term Memory
George Miller’s “Magical Number Seven”(1956)
Capacity: Information that can be held in short-term memory has been identified as
seven items, or “chunks,” of information, with variations up to plus or minus two
chunks
Chunk
A meaningful unit of information that can be stored in short-term memory.
 A chunk can be individual letters or numbers, permitting us to hold a seven-digit
phone number (such as 226-4610) in short-term memory.
 But a chunk also may consist of larger categories, such as words or other
meaningful units.
 Chunks can vary in size from single letters or numbers to categories that are far
more complicated.
For example, consider the following list of 21 letters:
PB S FO X C N NAB C C B S MTVN B C
 List exceeds seven chunks, it is difficult to recall the letters after one exposure. But
suppose they were presented as follows:
PBS FOX CNN ABC CBS MTV NBC
Transfer of Material from Short to Long
Term Memory
Rehearsal
 The repetition of information that has entered short-term memory.
Rehearsal accomplishes two things
1. As long as the information is repeated, it is maintained in short-term
memory.
2. Rehearsal allows us to transfer the information into long-term memory.

 Transfer of material from short to long term memory depends upon the type of
rehearsal.
 Repetitive/Maintenance Rehearsal
 Simple rehearsal of numbers or words like phone numbers by just repeating
them over and over, while looking for some number, will make them current
in short-term memory but it will not necessarily be placed in long-term
memory.
 As soon as we stop punching in the phone numbers, the number is likely to be
replaced by other information and will be completely forgotten.
 Transfer of Material from Short to
Long Term Memory
Elaborative rehearsal
 By this method information is more likely to be transferred into long term memory
 Elaborative rehearsal occurs when the information is organized and associated in
some fashion with information already in the long-term memory.
 The organization might include expanding the information to make it fit into a logical
framework, linking it to another memory, turning it into an image, or transforming it in
some other way.
For example, a list of vegetables to be purchased at a store could be woven together in
memory as items being used to prepare an elaborate salad, could be linked to the items
bought on an earlier shopping trip, or could be thought of in terms of the image of a
farm with rows of each item.
 By using organizational strategies such as these—called mnemonics —we can vastly
improve our retention of information.
Mnemonics (pronounced “neh MON ix”) are formal techniques for organizing information
in a way that makes it more likely to be remembered.
For example
when we learn the rhyme “Thirty days hath September, April, June, and November . .,”
Arithmetic: A Rat In The House May Eat The Ice Cream
Working Memory
 STM is also referred to as working memory and defined as a set of temporary
memory stores that actively manipulate and rehearse information.
 WM is not an independent way station into which memories arrive, either to
fade or to be passed on to long-term memory, it is an active relay station.
 WM is like an information-processing system that manages both new
material gathered from sensory memory and older material that has
been pulled from long-term storage.
 WM help to keep information in an active state briefly so that we can do
something with the information.
Examples
When we’re doing a multistep arithmetic problem in our heads, storing the
result of one calculation while getting ready to move to the next stage.
figure a 20% tip in a restaurant by first calculating 10% of the total bill and
then doubling it
 Working memory contain a central executive processor that is involved in reasoning and
decision making.
 Central executive processor coordinates three distinct storage-and-rehearsal systems: the
visual store, the verbal store, and the episodic buffer.
Working Memory
 Working memory aids in the recall of information, it uses a significant
amount of cognitive resources during its operation.
 Stress can reduce the effectiveness of working memory by reducing its
capacity.
 This can make individual less aware of surrounding, e.g using cell phone
while driving. If a phone conversation requires thinking, it will burden
working memory and leave drivers less aware of their surroundings (Sifrit,
2006; Strayer & Drews, 2007).
Long Term Memory
Long-term memory ( a permanent store house of memories)
 Stores information on a relatively permanent basis, although it may be difficult
to retrieve.
 Storehouse of almost unlimited capacity
 Like hard drive, information in long-term memory is filed and coded so that it
can be retrieved when needed.
For example, people with certain kinds of brain damage have no lasting recall of
new information received after the damage occurred, although people and
events stored in memory before the injury remain intact (Milner, 1966).

Why is it so?
Information that was encoded and stored before the injury can be recalled and
because short-term memory after the injury appears to be operational— new
material can be recalled for a very brief period—so that can be concluded that
there are two distinct types of memory: one for short-term and one for long-
term storage.
 Short and Long Term Memory is
Separate
Laboratory Experiments
 In one set of studies, people were asked to recall a relatively small amount of
information (such as a set of three letters).
 Then, to prevent practice of the initial information, participants were required to
recite some extraneous material aloud, such as counting backward by threes (Brown,
1958; Peterson & Peterson, 1959).
 By varying the amount of time between the presentation of the initial material and the
need for its recall, investigators found that recall was quite good when the interval
was very short but declined rapidly thereafter.

Why is it so?
 After 15 seconds had gone, recall around 10% of the material initially presented.
 The distraction of counting backward prevented almost all the initial material from
reaching long-term memory.
 Initial recall was good because it was coming from short-term memory, but those
memories were lost at a rapid rate.
 All that could be recalled was the small amount of material that had made its way
into long-term storage despite the distraction of counting backward.
Short and Long Term Memory is
Separate
Serial Position Effect
The ability to recall information in a list
depends on where in the list an item
appears (Bonanni et al., 2007; Tan &
Ward, 2008; Tydgat & Grainger, 2009).
Primacy effect - In which items presented
early in a list are remembered better.
Recency effect - In which items presented
late in a list are remembered best
 Explicit and Implicit Memory
Explicit Memory
Intentional or conscious recollection of information, e.g remembering a name or date
we have learned or encountered previously.
Implicit Memory
Memories of which people are not consciously aware but that can affect subsequent
performance and behavior.
e.g
Jumping out of the path of an automobile coming toward us as we walk down the side
of a road.
A feeling of vague dislike for an acquaintance, without knowing why we have that
feeling, may be a reflection of implicit memories.
 Components or Modules of LTM

Declarative Memory Procedural Memory

Factual information: names, faces, (non-declarative memory)
dates, and facts, such as “a bike has Skills and habits, such as riding a
Semantic Memory
two wheels.” bike.
General knowledge and facts
Information about things Information about how to do things
about the world, as well as
the rules of logic that are
used to deduce other facts.
Such as telephone dialing
codes of different areas,
Memoree as incorrect
spelling of memory

Episodic Memory
Events that occur in a
particular time, place, or
context, personal knowledge
Such as recall of learning to
ride a bike, first ever
adventure of life.
Semantic Networks
 Mental representations of clusters of interconnected information.
 Key organizational tool that allows us to recall detailed information
from LTM, is the associations that we build between different
pieces of information.
 Activating one memory triggers the activation of related memories
in a process known as spreading activation
For example, seeing a fire engine may activate our recollections of
other kinds of emergency vehicles, such as an ambulance, which in
turn may activate recall of the related concept of a vehicle. And
thinking of a vehicle may lead us to think about a bus that we’ve
seen in the past
Recalling Long Term Memories
Tip-of-the-tongue phenomenon
The inability to recall information that one realizes one knows—a result of the
difficulty of retrieving information from long-term memory.
Recall
Memory task in which specific information must be retrieved. Such as that
needed to answer a fill-in-the-blank question or to write an essay on a test.
It consists of a series of processes: a search through memory, retrieval of
potentially relevant information, and then a decision regarding whether the
information you have found is accurate. Otherwise search continues.
Recognition
Memory task in which individuals are presented with a stimulus and asked
whether they have been exposed to it in the past or to identify it from a list of
alternatives. Recognition is much easier than recall.
Retrieval cue
A stimulus that allows us to recall more easily, information that is in long-term
memory. It may be a word, an emotion, or a sound; whatever the specific
cue, a memory will suddenly come to mind when the retrieval cue is present.
 Levels of Processing
 The theory of memory that emphasizes the degree to which new material is mentally
analyzed.
 The amount of information processing that occurs when material is initially encountered is
central in determining how much of the information is ultimately remembered.
 The greater the intensity of its initial processing, the more likely we are to remember it.
 At shallow levels, information is processed merely in terms of its physical and sensory
aspects (appearance, size, shape of information). For example, we may pay attention only to
the shapes that make up the letters in the word dog .
 At an intermediate level of processing, the shapes are translated into meaningful units, in this
case, individual letters a viewed. Those letters are considered in the context of words, and
specific phonetic sounds may be attached to the letters. So we focus on sound combinations
that words have.
 At the deepest level of processing, information is analyzed in terms of its meaning. We may
see it in a wider context and draw associations between the meaning of the information and
broader networks of knowledge. For example, we may think of dogs not merely as animals
with four legs and a tail, but also in terms of their relationship to cats and other mammals. We
may form an image of our own dog, thereby relating the concept to our own lives.
Flashbulb Memories
 Memories centered on a specific, important, or surprising event that are
so vivid it is as if they represented a snapshot of the event.
 Flashbulb memories do not contain every detail of an original scene.
 The details recalled in flashbulb memories are often inaccurate.
 Memories that are exceptional are more easily retrieved (although not
necessarily accurately) than are those relating to events that are
commonplace.
 The more distinctive a stimulus is, and the more personal relevance the
event has, the more likely we are to recall it later.
 Even with a distinctive stimulus, however, we may not remember
where the information came from.
Source Amnesia occurs when an individual has a memory for some
material but cannot recall where he or she encountered it. For example,
source amnesia can explain situations in which you meet someone you
know but can’t remember where you’d met that person initially.
Forgetting: When Memory fails
 German psychologist Hermann Ebbinghaus –first studied forgetting
 Using himself as the only participant in his study, memorized lists of three-
letter nonsense syllables—meaningless sets of two consonants with a
vowel in between, such as FIW and BOZ
 By measuring how easy it was to relearn a given list of words after varying
periods of time had passed since the initial learning, he found that
forgetting occurred systematically
Why we Forgot?
 May not have paid attention to the material in the first place—a
failure of encoding, e.g draw coin of five
 Non-use of information i.e Decay. If the information in memory
is not used or rehearsed, it will, eventually be forgotten. Memory
fades due to the mere passage of time. Information is therefore
less available for later retrieval as time passes and memory, as
well as memory strength, wears away. When we learn something
new, a neurochemical “memory trace” is created.
 Interference -The phenomenon by which information in memory
disrupts the recall of other information.
 Cue-dependent forgetting- when there are insufficient retrieval
cues to reawaken information that is in memory. For example,
you may not be able to remember where you lost a set of keys
until you mentally walk through your day, thinking of each place
you visited.
Interference
Proactive interference
Interference in which information learned earlier disrupts the recall
of newer material, e.g learning different languages, native
language and some other languages. Think in native language
first.
Retroactive interference
Interference in which there is difficulty in the recall of information
learned earlier because of later exposure to different material e.g.
if you learn list A and then list B and now are unable to recall
what was there in list A.

Proactive interference progresses in time—the past interferes with

the present—whereas retroactive interference reverts in time,
working backward as the present interferes with the past.
Memory Dysfunctions
Alzheimer’s disease
An illness characterized in part by severe memory problems.
 In the beginning, simple forgetfulness of things such as appointments
and birthdays.
 Disease progresses, memory loss becomes more profound, and even the
simplest tasks—such as using a telephone—are forgotten.
 Ultimately, victims may lose their ability to speak or comprehend
language, and physical deterioration sets in, leading to death.
The causes of Alzheimer’s disease
 Not fully understood.
 An inherited susceptibility to a defect in the production of the protein
beta amyloid, which is necessary for the maintenance of nerve cell
connections.
 When the synthesis of beta amyloid goes awry, large clumps of cells
form, triggering inflammation and the deterioration of nerve cells in the
brain
Memory Dysfunctions
Amnesia
Memory loss that occurs without other mental difficulties.
 Retrograde Amnesia

Amnesia in which memory is lost for occurrences prior to a certain

event. Hollywood films involves a victim who receives a blow to the
head and is unable to remember anything from his or her past. Quite rare
form.
 Anterograde Amnesia

Amnesia in which memory is lost for events that follow an injury.

Information cannot be transferred from short-term to long-term memory,
resulting in the inability to remember anything other than what was in
long-term storage before the accident.

Korsakoff’s Syndrome
A disease that affects long-term alcoholics, leaving some abilities intact but
including hallucinations and a tendency to repeat the same story.
Introducing the variables
Dependent variables
 Usually involves issues and conditions related to recall or
recognition.
◦ In serial recall, people are required to recall information in the
serial order in which it was presented
◦ in free recall, the order of recall is irrelevant.
◦ In paired-associate recall, people are presented with pairs of
items, such as igloosaloon; at recall, they are given one member
of the pair (igloo, referred to as the stimulus) and are asked to
produce the other member (saloon, the response).
 Recognition tests are also used
◦ Forced choice or yes/no formats used
Independent variables
Many types of variables are manipulated in
experiments on human memory
◦ nature of the material presented for memory
 It can be letters, digits, nonsense syllables, words,
phrases, sentences, paragraphs, or long passages of
prose
◦ the characteristics of each of these types of
material can also be varied.
Control Variables
Memory experiments are typically quite well
controlled.
Important variables that are usually held
constant across conditions are the amount of
material presented and the rate of presentation,
though these can be interesting variables in their
own right.
The modality of presentation is another factor
that must not vary, unless it is a variable of
major interest. If some characteristic of the
material is being varied, then it is necessary to
hold constant other factors.
Case study-Ebbinghaus Experiments
The experimental investigation of human
memory was begun by a German
psychologist, Hermann Ebbinghaus
He believed that experimental psychology
could be developed to study the higher
mental processes and not just sensory
processes. His main achievement was
demonstrating how empirical research
could answer interesting questions about
memory.
 He developed the non sense syllable experiments
 Tested the theory on himself

◦ Developed the savings score:

◦ Percentage savings is the difference between the number

of trials in original learning (OL) of a list and its
relearning (RL) divided by the number of trials in
original learning (OL), with this ratio multiplied by
100.
◦ For example, if Ebbinghaus took 10 trials to learn a list
of nonsense syllables in order, and then a week later, he
took only 5 trials to relearn the list, this would represent
50 percent savings
Savings method
Generalizability of research
TetrahedralModel of Memory (Jenkins,
1979) guides experiments in memory
The model suggests that any research that
studies memory will be affected by four
factors:
◦ (1) the subjects being tested,
◦ (2) the material used for learning and testing,
◦ (3) the orienting tasks (or the features of the
setting in which subjects are tested), and
◦ (4) the type of test used.
 For example: Craik and Tulving (1975)
 researchers were interested in how the orienting task (the
questions orienting the subjects to process the words in
particular ways) affected retention:
◦ All subjects were college students, the memory test was
recognition, and the materials used were words.
◦ But is that enough for a just cause and effect statement?
What other factors could affect the results
Jenkins’s (1979) framework points out that
any experimental result should be viewed
in the context of other potential variables
that could have been manipulated.
The issue of generality of results can then
be framed as follows:
◦ If the other control variables were manipulated,
would the same results hold?
◦ If the independent variable was operationally
defined in a different way, would the result
replicate?
Tetrahedral Model Of Memory (Jenkins, 1979)
THE NUTS AND BOLTS

Problem:
◦ Is reading better than listening?
Possible Hypothesis:
◦ Subjects who read a long passage of material
will be better able to answer multiple-choice
questions about the material than will subjects
who listen to another person reading the
material.
Page 291
Independent reading
Memory In and Out of the
Laboratory
 Researching in the Laboratory  Researching in the Real World
 Pros:  Pros:
 More experimental control  Validates theory by testing various
 Easier to develop and populations while advancing
rigorously test theories in therapeutic treatments
rapid succession  Highlights important gaps in
 Cons: current understanding and
advances future theory
 Overrepresentation of
development
certain participant
 Cons:
populations (students)
 Reduced generalizability  Less experimental control; more

of findings confounding variables

 Less ecological validity  Harder to isolate causes of

(not like real life) observed phenomena

Neuropsychological Studies of
Memory
 Disease-Related Studies  Lesion Studies
 Involves characterizing the  Involves profiling patients with
deficits and preserved abilities organic brain damage to
in patients suffering from relatively focal regions (like
HM’s hippocampal lesions)
specific diseases (e.g.
 Pros:
Alzheimer’s)
 Helps identify causal links
 Pros:
between brain and behavior
 Provides a direct route to  Cons:
advancing diagnosis and  Such cases are relatively
treatment of diseases rare
 Cons:  Lesions are almost never
 Often difficult to separate entirely confined to a specific
memory impairments from region of interest and/or
other deficits related to the patients’ deficits are not
disease entirely pure
Electroencephalography (EEG)

 Since the early 1900s, researchers have used electrodes

placed on the scalp to record the electrical signals generated
by the brain’s neurons
 The characteristics of the continuous brainwaves can help identify
abnormal brain activity and different stages of sleep and arousal
 By dividing the continuous wave into segments called evoked
response potentials or event-related potentials (ERPs), each
beginning with a particular event, one can characterize the response
elicited by that particular occurrence
 Pros:
 Millisecond temporal resolution
 Relatively low cost to perform and non-invasive
 Cons:
 Inability to precisely locate the brain region generating the
recorded signal
Neuroimaging Techniques
 The use of newly developed technologies that allow researchers to
study the structure and function of the brain by tracking indicators
of brain activity
Scale Attenuation
Scale attenuation in psychological
research refers to situations in which a
measurement scale is too restricted to
measure differences that may exist
between conditions.
◦ Ceiling effect: when performance is nearly
perfect
◦ Floor effect: when performance is nearly
absent altogether
Error to assume that performance in two
conditions is equivalent when it is at the
ceiling or floor of a measurement scale.
 Although subjects in two conditions may score
equivalently on the dependent variable (near either 0
percent or 100 percent), there may be a true difference
between conditions, but the measurement scale of the
variable may be too restricted (too “short”) to show
the real difference.
◦ If the mean recall in a memory experiment
involving 2- and 3-year-old children is 2 % for
each age group, are we justified in concluding that
memory capacity is the same for both groups of
children?
 Thus there can be errors in interpreting interactions
when performance in some conditions is constrained by
ceiling and floor effects.
 One way to avoid this problem in Scarborough’s
experiment would be to ignore the data points at the 0-
second retention interval and ask whether the rate of
forgetting is greater between 3 and 18 seconds for
auditory than for visual presentation.
Current Issues
Neurological bases for memory
Impact and importance of emotion on memory
Use of multiple memory sources
Embodied cognition – how our grounding in the
world influences memory