Coding Capacity and duration

• -Coding is the format or 'type' of information that is stored in each memory store. -Coding is acoustic in STM and semantic in LTM, as demonstrated by Baddeley (1966)-He found that more mistakes are made when recalling information acoustically (similar words straight after learning them), whilst more mistakes are made when recalling semantically (similar words 20 mins after learning them) all in the LTM recall.
• Capacity is the volume of information that can be held in any memory store at any one time. -capacity of STM is 7 + or -2.Capacity of LTM is unlimited -based on Millers idea that things come in groups of 7 for example, the 7 days in the week -he suggested that we are predisposed to remembering this quantity and that such as 'chunking', it can help us recall information better. -Jacobs also demonstrated that the mean letter span is 7.3 and the mean digit span is 9.3
• Duration is the amount of time that information can be stored in each memory store. -duration of STM is 18-30 secs, this was demonstrated by Peterson and Peterson, who found that increasing retension decreased the accuracy of recall of consontant syllables in 24 undergraduates, when counting down from a 3-digit number -duration of LTM is unlimited, shown by Barick et al, who found that photo recognition of graduating classmates of the 396 ppts decreased from 90% to 70% between 15 years and 46 years of graduating.
• Capacity: (Jacobs study 1887)-developed a technique to measure digit span-The researcher gives the pts 4 digits and then asks them to recall them in the correct order out loud-if correctly recalled by the researcher then reads out 5 digits and so on until the pts cannot recall the order correctly.-determines the individual's digit span -he found that the mean span of digits was 9.3 and the mean span of letters was 7.3
• Weakness in coding: One limitation of Baddeley's study was that it used artificial stimuli rather than meaningful material as the words presented in the lists have no personal meaning to pts. This means that it would be inappropriate to generalise findings to different kinds of memory tasks. For example, when processing more meaningful information people may use semantic coding even for STM tasks. Suggests that the findings from this study have limited application.
• Research for Duration: (Bahrick et al 1975)-studies 392 pts from Americans aged between 17 to 74-Pts were tested using their high school yearbooks, in which they had to recall information in various ways-photo-recognitions tests, whereby the test consisted of 50 photos from the pts year pts year book and the pts had to recall names free recall in which pts had to recall all the names from their graduating class with no photo cues
• Weakness in duration:-Both Peterson and Peterson's studies used artificial stimuli, as the consonant syllables used by Peterson and Peterson had no meaning to the participants. This means that it would be inappropriate to generalise findings to different kinds of memory tasks.
• Research for Duration: (Bahrick et al 1975)-studies 392 pts from Americans aged between 17 to 74-Pts were tested using their high school yearbooks, in which they had to recall information in various ways-photo-recognitions tests, whereby the test consisted of 50 photos from the pts year pts year book and the pts had to recall names free recall in which pts had to recall all the names from their graduating class with no photo cues
• Strength of Bahrick's study: higher external validity -real-life meaningful memories were studied. This is a strength as it means findings can be generalised to a more meaningful memory tasks. However, confounding variables are not controlled, such as many of the pts had looked at the yearbooks over the years and so had rehearsed this information over the years.