“Outline and evaluate research into the duration, capacity, and encoding of information in short-term memory.”
Peterson and Peterson conducted a study of the duration of short-term memory. The experimenter said a consonant syllable to the participant, followed by a three-digit number, for example: IDM 302. The consonant syllable had to not have a meaning, for example: not BBC. Immediately after hearing this, the participant had to count backwards from this number in 3’s or 4’s until told to stop. There was a time interval of either 3,6,9,12,15 or 18 seconds. The participant then had to recall the consonant syllable they were told. The findings were that participants remembered 90% when there was a 3 second interval and 2% when there was an 18 second interval. This study concluded that short term memory lasts approximately 20 seconds at the most and therefore not very long.
One study has challenged this evidence. ...view middle of the document...
In this article, he reviewed psychological research and concluded that the span of immediate memory is 7, people can cope reasonably well with counting 7 dots flashed onto a screen by not many more than this. He concluded that it’s the same if you’re asked to recall musical notes, digits, letters and even words. Miller also found that people can recall 5 words as well as they can recall 5 letters. This is because we chunk things together and can remember more.
One study has challenged this evidence. Cowan’s study reviewed a variety of studies on the capacity of short-term memory and concluded that it’s likely to be limited to about 4 chunks. This study shows that short-term memory may not be extensive as was first thought. Some researchers have also looked at the capacity of short-term memory for visual information and also found that 4 items was about the limit.
Baddeley conducted a study of the encoding of information in short-term memory. He tested the effects of acoustic and semantic similarity of short-term (and long-term) recall. After giving participants a hearing test, Baddeley presented them with four word list. Each list contained words that were acoustically similar or dissimilar and words that were semantically similar or dissimilar. For short-term memory, after each set of 5 words, participants were asked to recall the words they had just heard in the correct order (immediate serial recall). He found that participants had difficulty remembering acoustically similar words in short-term memory, but semantically similar words posed little problems. It was therefore concluded that the dominant form of encoding in short-term memory is acoustic.
One study has challenged this evidence. Brandimote et al found that participants used visual encoding in short-term memory if they were given a visual recall task and prevented from doing any verbal rehearsal in the retention interval before performing a visual recall task. This study shows that if verbal rehearsal is prevented, participants use visual codes for encoding, showing that short-term memory may sometimes use other codes.