Experimental Techniques: Memory
Independent Variables in Memory Research
Materials Retention interval Presentation modality Instructions Memory task
Designing Memory Tasks
One of the challenges with developing memory tasks is that they need to be an appropriate difficulty level It is problematic if responses are nearly perfect (ceiling effect) or completely wrong (floor effect) These scale-attenuation effects occur whenever a task is too easy or difficult, causing subjects to use only part of the full response scale When this occurs, it may not be possible to detect any differences between groups
Modern Research on Memory
Our understanding of memory has come a long way since Ebbinghaus' time and the methods we use to investigate memory has advanced accordingly Most importantly, memory is no longer viewed as a unitary construct, but rather, a whole set of related processes
Short-Term/Working Memory Tasks
Short-term/working memory tasks can be divided into four categories Complex span tasks Updating tasks n-back tasks Binding tasks
Short-term memory
holds information briefly from the time when the info is perceived to when it leaves conscious awareness
forgetting curve
immediately+100% 20 min=58% 1 hour=44% 9 hours36% 1 day=33% 2days=28% 6days=26% 31days=21%
Explicit memory is the conscious
intentional recollection of factual information, previous experiences, and concepts
, Implicit memory
is the unconscious use of past experiences and information
Scale-Attenuation Effects
too easy What is your name? What is one plus one? What color is grass? How many legs do dogs have? too difficult How many symphonies did Beethoven write? What was Elvis Presley's middle name? What did you eat for dinner six Thursdays ago? How long is the Panama canal?
Control Variables in Memory Research
t to avoid confounding variables Amount of material Presentation rate Word frequency
n-back Tasks
tasks involve comparing the identity of a stimulus to a previous stimulus in a sequence at a given lag (n) This requires memory for the previously presented stimuli as well as active comparison between stimuli
Complex Span Tasks
"Cspan" tasks measure simultaneous storage and processing in conditions of high interference Using the Brown-Peterson technique, subjects must recall a trigram (CVM) after a distraction period in which they count backwards by threes from a given number CVM 172, 169, 166, 163, 160, 157 "CVM"
Ebbinghaus' Memory
Ebbinghaus studied his memory by learning lists of nonsense syllabus (e.g., GOC, PID, SAR) These stimuli were chosen because they would be free of linguistic or other contextual associations Using this technique, he was able to measure learning, relearning, and forgetting
measure relearning-saving score
Ebbinghaus would study a list that he had previously memorized The difference in the trials to criterion for the original trials and the relearning trials For example, if only 5 trials were necessary to memorize a list that originally required 10 trials, he would have a 50% savings
Dependent Variables in Memory Research
In terms of research, we can divide memory into three broad categories
Tetrahedral Model
Jenkins (1979) proposed that memory research is composed of four dimensions The subjects being tested The materials used for learning and testing The orienting task or instructions given to subjects The type of test used to measure memory
Early Research on Memory
The first experimental investigation of memory was conducted by Hermann Ebbinghaus in the late 1800s Ebbinghaus is best known for his unique approach to measuring memory in which he used himself as his only subject
Memory
The mental processes involved in storing and remembering information
Forgetting curve
To measure forgetting, Ebbinghaus would memorize a list and then measure recall at increasing intervals of time,
Learning-trials of criterion
To measure learning, Ebbinghaus would read through a list of nonsense syllables and then attempt to recall the entire list If he was unable to recall the entire list, he would study it a second time and attempt recall again This continued until he correctly recalled the list The number of attempts necessary to fully memorize the list became a measure of memory
Interactions in Memory Research
Warrington and Weiskrantz (1970) compared the explicit and implicit memories of amnesiacs and control subjects Two independent variables were being manipulated: test type and subject group This factorial design has three possible effects Main effect of test type Main effect of subject group Interaction between test type and subject group
Binding Tasks
measure the ability to create and maintain associations between stimuli Stimuli from different domains are paired together (e.g., letter-color, word-number, location-letter) In testing, one stimulus from the pair is presented and subjects must recall the paired stimulus
Updating Tasks
measure the accuracy of changes in working memory across a series of steps In these tasks, the to-be remembered information is constantly changing and must be kept up-to-date
Explicit Memory Tasks
memory tasks can be divided into two broad categories Recall Serial recall Free recall Paired-associate recall Recognition Yes/no recognition Forced-choice recognition
Implicit Memory Tasks
memory tasks do not require conscious retrieval of information, but are instead influenced by unconscious memories Perceptual memory tests present subjects with ambiguous stimuli (e.g., K I _ _) which are automatically interpreted based on prior information
human memory
sensrory memory, shor term memory, long term memory-explicit(sematic, episodic, autobigraphical), Implicit memory(procedual, priming)