Memory

Memory

1. The four different Experimental Types

   • Lab Experiment in a lab experiment, an independent variable (the cause) is manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled.
   • Natural Experiment observational study in which an event or a situation that allows for the random or seemingly random assignment of study subjects to different groups is exploited to answer a particular question.
   • Quasi Experiment are employed when the researcher is interested in independent variables that cannot be randomly assigned. Usually this happens when the independent variable in question is something that is an innate characteristic of the participants involved.
   • Field Experiment are done in the everyday, real life environment of the participants. The experimenter still manipulates the independent variable, but in a real life setting, so they cannot really control extraneous variables. An example is Holfing's hospital study on obedience.

2. The working Memory model Baddeley and Hitch in 1974 developed the Working Memory Model (WMM), which focuses specifically on the workings of short-term memory (STM).

3. Case Studies that are essential for memory

   • Bahrick et al. in 1975 investigated what they called very long term memory. Nearly 400 participants aged 17 – 74 were tested. There were various tests including: A free recall test, where participants tried to remember names of people in a graduate class. A photo recognition test, consisting of 50 pictures. A name recognition test for ex school friends.
     • Results of the study showed that participants who were tested within 15 years of graduation were about 90% accurate in identifying names and faces. After 48 years they were accurate 80% for verbal and 70% visual. Free recall was worse. After 15 years it was 60% and after 48 years it was 30% accurate.
   • Peterson and Peterson A lab experiment was conducted in which 24 participants who were psychology students had to recall trigrams . The trigrams were presented one at a time and had to be recalled after intervals of 3, 6, 9, 12, 15 or 18 seconds. To prevent rehearsal participants were asked to count backwards in threes or fours from a specified random number until they saw a red light appear. This is known as the brown peterson technique.
     • After 3 seconds 80% of the trigrams were recalled correctly. After 6 seconds this fell to 50%. After 18 seconds less than 10% of the trigrams were recalled correctly.
   • Glanzer and Cunitz

4. The multi Store Model The multistore model of memory also known as the modal model was proposed by Atkinson and Shiffrin (1968) and is a structural model. They proposed that memory consisted of three stores, a sensory register, short-term memory (STM) and long-term memory (LTM).

5. Key knowledge

   • Encoding is the way information is changed so that it can be stored in the memory. There are three main ways in which information can be encoded. Visual, Acoustic and Semantic
   • Short Term Memory Duration: 0-18 seconds Capacity: 7 +/- 2 items Encoding: mainly acoustic
   • Duration refers to the period of time information can last in the memory stores.
   • Capacity concerns how much information can be stored.
   • Sensory Register • Duration: ¼ to ½ second Capacity: all sensory experience very large capacity Encoding: sense specific
   • Long Term Memory • Duration: Unlimited • Capacity: Unlimited • Encoding: Mainly semantic