TITLE:
THE EFFECT OF AGE ON SHORT TERM MEMORY

ABSTRACT:
Age associated declines in cognitive processes are important to the understanding of the human mind. This study investigates the relationship between ageing and short term memory in particular, by first exploring current cognitive and neuroscientific research involving concepts such as short term/working memory, long term memory and ageing, and secondly, by means of a short term memory experiment involving verbal and numerical stimuli, that was administered to two age groups- 20 to 40 year old adults and 50 to 70 year olds. The results of the experiment were then analysed using the ANOVA statistical software programme. The results did not conclusively show age related decline in short term memory performance in all segments of the test. Memory decline with increased age was apparent in the free recall word stimuli, and in the analyses of the number of incorrectly remembered words. The serial recall digit sequence did not show any statistically significant effects. The final section of this study addresses the possible explanations for the results, as well as the limitations of the study.

Contents
1.Introduction 5
2.What is memory? 5
2.1 short term memory 5 2.2 working memory 7
2.3 the relationship between ageing and memory 8
2.4 long term memory 8
3.the relationship between ageing and memory 9
3.1 The biology of memory 10
3.2 ageing and memory 11
4. aim of study 11
5.method 12
5.1 the sampling process:participants 12
5.2 data collection 12
6. analysis of results 14
6.1 primacy and recency effects 19
6.2 chunking 20
7. Discussion 21
7.1limitations 23
8.conclusion 23
9.references 25

1.INTRODUCTION The study of the human mind has long presented a fascinating frontier in the realm of psychological research. Optimal cognitive functioning is a most prized possession, a most valuable human resource, with memory being an integral focus area in cognitive neuroscience research. More specifically, research investigating the association between ageing and cognitive decline is imperative if one considers that a growing population throughout the world is sixty five years and older (Sternberg, 2006)
According to Cohen (2005), as cited in Park and Reuter – Lorenz (2009) a longer life-span and low birth –rates will result in more older adults than children under 15 in developed countries by the 2050. Age related deficiencies in cognitive and mental capabilities is a major concern for these older adults (Sue, Et Al, 2006), and self-observed complaints about the deterioration of memory related abilities are frequent. As such, it is essential that significant ground is covered in age-related cognitive impairments to maximise human mental functioning and potential with increased age, thereby reducing both tangible and intangible cost of cognitive decline to the individual, and society, as well as arenas such as politics & economy.
Indeed, scientific research has lent substance to self observed memory deterioration with age by producing evidence of cognitive & neurophysiologic changes. (Park, Et Al, 2009).

2.WHAT IS MEMORY?

Memory is a vital and integral asset throughout life, primarily, it is through memory that we are able to learn, think and plan. McLeod (2007) describes memory as the psychological function of processing & preserving vast amounts of information such as visual images, acoustic sounds and semantic meanings. According to the Oxford Dictionary of Psychology (2009), memory involves a series of interconnected systems that serve different functions. The basic divisions of these systems are declarative and procedural memory, episodic and semantic memory and long and short term memory.

2.1 SHORT TERM MEMORY
Short term memory refers to a memory system that stores a limited amount of information in conscious awareness for a brief period of time, (McLeod, 2007). Short term memory is integral to cognitive activities such as reading, comprehension & problem solving & language as without it we would be unable to recall the beginning of a sentence by the time we reach the end of it, nor e.g. perform simple mental mathematical calculations (Hedden,et al, 2004). Interestingly because language , reading and problem solving occur sequentially (Hedden,et al, 2004) , information stored in short term memory is stored and retrieved sequentially.( McLeod, 2007) for example, when asked to recall the 3rd digit in a numeric sequence, one would go through the sequence in the order that it was heard in order to retrieve the 3rd digit in a numerical sequence, one would go through the sequence in the order that it was heard to retrieve the 3rd digit.

Duration of Short-Term Memory
Information on short term memory is stored for up to 30 seconds(Sternberg,2009), Primarily in acoustic form as even if one reads a list it is mentally repeated in order to remember it however if no active maintenance to retain the information occurs the memory can be lost in a matter of seconds.
Incoming information is psychologically processed in three stages: encoding, storage and retrieval (McLeod, 2007). At the first stage sensory information is received from the environment into the short-term memory system. At this stage the information can be rehearsed, encoded (and then transferred to more permanent storage in long-term memory for later retrieval) or information can leave the memory system by forgetting (Brickman & Stern, 2009).
Rehearsal refers to the process of retaining information in short-term memory by repeating it (McLeod, 2007). As the information is repeated it is re-entered into STM thereby retaining it in short-term store for a further 15-20 seconds.
Research, although tentative suggests that “Decay” occurs when information stored in short term memory is lost due to the absence of rehearsal (Nairne, 2002). The decay of a memory in short-term store also allows unnecessary information to be removed from the memory system and replaced with more relevant information (Nairne, 2002). However according to the standard model the rehearsal/decay of a memory is preceded by the cognitive process of activation, which is a mnemonic property that keeps information accessible, in conscious awareness.
Nairne (2002) also raises questions about the complete validity of this model regarding both rehearsal and decay with a view to reconceptualise short term memory using “Cue-driven immediate retention” as a means of remembering over the short-term as a more concrete explanation.
Short Term memory capacity
Research into the capacity of short term memory has indicated a limited memory span. It was suggested that George Miller (cited in Sternberg, 2006) that short term memory has a span of approximately 7 plus or minus 2 items. However further studies have shown that although this is fairly accurate for word and digit lists, memory spans vary depending on the nature of the population and material to be recalled. For example, for longer words with more syllables fewer words tend to be recalled but recall is higher for more common, familiar words or words from a single category e.g. animals. Moreover free recall experiments have shown greater variation in the number of items recalled, possibly as a result of decay (McLeod, 2007).
Sternberg (2002) discussed the process of chunking of information into smaller groups (“chunks”) that increase STM storage capacities. If for example a 10 digit phone number – 0829353512, for example- is divided into a network code (082) plus 2 chunks of numbers, (935) and (3512), the chances of correct recall of these three chunks, but 10 items, of information is greatly increased (Sternberg, 2006).
2.2 Working Memory

Glisky(2007) defines working memory as a multidimensional cognitive construct of limited capacity. It is responsible for the temporary storage and active manipulation of information currently being maintained in ones conscious awareness (Brickman, et al, 2009).
The integrative model of memory suggested by Baddeley and hitch (cited in Sternberg, 2006) describes working memory as consisting of a central executive responsible for controlling information between the phonological/articulatory loop and the visiospatial sketchpad; the episodic buffer then integrates information from the 2 systems and retrieves other relevant information from long term memory while directing attention to important internal and external stimuli (Glisky, 2007).

2.3 The relationship between short term and working memory

Although the terms short term and working memory are often used interchangeably the 2 terms are not entirely the same. Short term memory simply involves the storage of information for a short duration of time, without any manipulation of the information. For example remembering a few items on a word list requires short term memory processors but repeating the words in alphabetical order requires that the content of STM are maintained while simultaneously being reorganized to complete another task i.e. alphabetizing the words, a task accomplished using working memory(Glisky, 2007).
2.4 Long term Memory

Long term memory is a distinct type of memory with a storage duration lasting from minutes to a lifetime. Long term memory is integral to adequate daily functioning. The storage capacity of this system is unknown but it is thought to be infinite (Sternberg, 2006).
Although long and short term memory operates as 2 distinct systems there is interaction between them. According to Atkinsons and Shriffins modal model of informationtransfer sensory stores perceive informationfrom the environment which is then transferred to STM where it is rehearsed coded or decayed. If encoded it enters permanent storage in LTM (Brickman et al, 2009).

3. The relationship between aging and memory

The human being undergoes a process of biological aging from the moment of conception. de Oliviera, kissaki, Nascimento, Ordinez and Lima-Silva (2011) explain that the development and the increased neuroplasticity of the central nervous system occurs at a rapid rate until the point of maturation, after which there is a decline in physiological processors as a result of which age related cognitive changes occur. Thus there is a decline in cognitive functioning as a result of the normal process of aging.
Age related memory impairment is a form of this cognitive decline, with the primary symptom being a dimunition in memory associated abilities (Dictionary of psychology 2009).
Research that the aging process impacts on cognition and memory even in the absence of pathology, albeit at a juncture that has not yet been verified, and at a different rate for different individuals(de Oliviera et al, 2011).

3.1 The biology of memory and aging
Cognitive neuroscience has made great advancements in identifying specific brain regions dedicated to memory, with the development of brain imaging technology such as positron emission topography(PET), and functional magnetic resonance imaging (FMRI). Research has also involved comparisons between normally ages brains and pathological brains as well as patience with cognitive deficits due to brain injuries.
Some brain structures such as the prefrontal cortex striatum, entorhinal cortex show age related volumetric decline causing the loss of white matter integrity. In the prefrontal cortex and striatum, the decrease of dopamine receptors and neurotransmitters such as acetylcholine result in disruptions of memory function mechanisms (Hedden, et al 2004).
These changes have implications for memory due to the interconnectedness of the structures and specifically their execution of executive cognitive processors. This PFC and associated structure deterioration with age has a direct impact on working memory which requires the individual to divide the attention while reorganizing/ manipulating information in conscious awareness-an ability that decreases with age(Glisky, 2007). Brickman, et al (2009) suggests that deficiencies in working memory as a result of age mediate age related deficiencies in other memory and cognitive functions e.g. episodic memory.

However all neural brain structures do not deteriorate at the same rate and pattern. Structures such as the amygdala, hippocampus and medial temporal lobes, the cerebellum, neocortex and neostriatum, show volumetric changes with age. These brain regions have been found to be important in integrating sensory perceptions, emotional memory formation (amygdala) and motor co-ordination (cerebellum). As such, implicit and declarative memory, emotional and semantic memory show relative stability through the normal ageing process (Hedden et al, 2004)

3.2 Ageing and short term memory

Current research into the impact of aging and short term memory is relatively well-preserved through the adult lifespan with deficits experienced very late in life (Hedden et al, 2004).
Pharmacological and neurological studies show that the transient nature of short term memory and the fact that this memory system does not entail new protein synthesis nor does it require any anatomical changes to be maintained, short term memory is relatively unaffected by aging (de Oliviera et al, 2011). Short term memory does not involve complex changes in neural substrates of the neural pathways to keep information in conscious awareness for a brief period. De Oliviera et al (2011) discussed the importance of the hippocampus, entorhinal cortex and posterior parietal cortex-which in normal aging show small volumetric changes with age-that mobilize glutamergic receptors modulate cholinergic, dopaminergic and noradrenergic and GABAergic receptors necessary for the formation of short term memory.
4. Aim of the study

The aim of this research report is thus to contribute to existing psychological studies on age – related cognitive decline, with a focus on the following pertinent question: Does age have an effect on short – term memory performance?
The objectives of this study are to A) exploring the current state of human memory research, with regards to biological, neuroscientfic & cognitive aspects of memory. B) to define the relevant constructs such as short term memory and ageing , C) to clarify the differences between working memory & short term memory and D) to determine whether older adults score lower on short – term memory test than younger adults. The empirical information for this report was acquired by means of a simple memory test administrated to two age groups – 20 to 40 year old and 50- 70 year olds, to determine whether differences were evident in the scores between the younger and older groups, as current research suggests. The results of this study are then discussed in detail, as are the limitations of the study. The results were then analysed using

5) METHOD

In order for this research project to address the question whether or ageing impacts negatively on short term memory recall, two kinds of information collected. Firstly theoretical information addressed in the previous section, and secondly, empirical information. The empirical information was gathered by means of a short term memory – recall test, described as follows:
5.1) THE SAMPLING PROCESS: PARTICIPANTS
The units of analysis in this study are younger and older adults while the unit of observation is each individual adult. A non – probability convenience sample process was employed, based on availability & accessibility of participants. A total of thirty subjects (N=30) were recruited to participate in this study. Inclusion criteria were: a) Ages between 20 – 40 years (N=15) and ages between 50 – 70 (N=15), constituting the two age groups required for the study. b) Good command of spoken and written English to negate any interference due to language differences. c) No evident mental or physical pathology e.g. depression/stroke, that could affect performance on the memory test. d) Of the 30 subjects, 5 from the age group 20 – 40 years were professionals, 3 from the 50 – 70 year age group were recently retired, and the remaining 22 subjects were business people.
5.2) DATA COLLECTION PROCEDURE
A simple short term memory test was administered to each of the 30 subjects individually in a quiet location, at a time suitable to each individual participant. The research project was first explained to the individual, after which the purpose and objectives of this study were further explained. It was the indicated to the participant, what he/she could expect from the memory test i.e., a list of words and a series of digits which will then need to be recalled. At this point participants were also informed that the experiment would take approximately ten minutes to complete. It was reiterated to each individual that their participation in this research experiment was voluntary and that he/she may choose not to participate, and he/she may withdraw from the experiment at any time. The participant were also assured that a case number is allotted to each subject , and that only the gender of the subject is indicated on the data sheet , thereby ensuring a degree of anonymity off the experiment. Once the participant indicated that he/she understood the information explained to him/her, and that he/she was willing to participate in the research project, the memory experiment was then administrated. 5.3) THE APPARATUS Each participant was given a pencil and a paper to write on indicating there specific case number and gender. The memory experiment consisted of 2 types of stimuli – a list of words for the first part, and, then a series of digits. The list of words consisted of 20 common nouns from 5 categories with 4 words from each category i.e.
1) conveyances, e.g., caravan, taxi
2) fruit, e.g., grape, pear
3) furniture, e.g., desk, chair
4) animals, e.g., lion, cat
5) emotions
The participants were instructed to listen carefully to the list of words being read out aloud, as well as possible, and then write down all the words that they could remember on the sheet of paper when instructed to do so, in any order, as this was a free – recall experiment. Each word on the list was read clearly, with a 2 second wait between each word. After reading the last word on the list, there was a 10 second wait before the participants were instructed to start writing. No time limit was set for the completion of the recall.
For each subject the number of words correctly recalled was ticked off on the data sheet. False recollection of words that did not appear on the list of stimuli were also noted
The second part of the memory experiment consisted of a series of digits. The subjects were again requested to remember as many of the digits as possible, in the correct order, as this was a serial recall segment of the experiment. The first sequence of 3 digits was read slowly to each participant, then after a 5 second wait, the subject was asked to recall the digits sequence. If the recall was correct, the next digit sequence was read out. With every correct recall one more digit was added to the next sequence. This process continued until the subject made an error. The number of correctly recalled digits was then recorded on the data entry sheet for that particular subject , as advised in Tutorial letter 103 for HMPYC81 (2013)

4) ANALYSIS OF RESULTS
As discussion in a previous section of this research study addresses the question, “Does age affect short term memory performance?” A research hypothesis was postulated as follows:
H0: There is no relationship between increased age and poorer short-term memory performance
H1: There is a relationship between increased age and poorer short term memory performance.

The subjects constituting the 2 age groups of the research sample were analysed regarding gender and occupational levels to ascertain whether both males and females were fairly represented, & that the subjects were relatively well-educated middle class individuals i.e. with a tertiary education, or running/employed in businesses which demonstrate a degree of cognitive effort. Figure 1 and 2 summarizes the above background data, showing that for the age group 20-40, 53% of the subjects were male and 47% were female and for the 50-70 year age group, males were slightly more represented (60%), while females constituted 40% of the sample.
Figure 3 shows the occupational backgrounds of all (N=30), with the greatest percentage (73%) being business owners & employees, 17% being young professionals, and 10% formally business people/ professionals who are now retired.

Figure1: Bar chart for gender group 20-40

Figures 4 and 5 are tables showing the scores of the memory test for each subject for the 2 age groups. Colum 2 indicates the scores for the free recall word segment, column 3 indicates the number of words incorrectly recalled i.e. false recollections of words that did not appear on the stimulus list, and column 3 shows the number of digits incorrectly recalled. The mean for each column and subsequently the standard deviation was then calculated. These scores were then computed in to the one directional ANOVA statistical software program, for analysis of variance of the results, for the 3 separate segments of the memory experiment. This method of analysis is the most suitable as it allows us to compare the produced results most suitable to comparing the memory test scores of the two independent age groups. A fairly low level of significance (α=0.01) was prescribed to avoid type 1 error due to the multiple variants testing.
Figure 4: Table of Results: Group 1(Age group 20-40 years) | Case no. | No. Of words correctly recalled | No. Of false recollections | No. Of digits correctly recalled | | 1 | 12 | 1 | 7 | | 2 | 11 | 0 | 7 | | 3 | 12 | 3 | 7 | | 4 | 10 | 3 | 6 | | 5 | 9 | 2 | 7 | | 6 | 11 | 0 | 8 | | 7 | 8 | 1 | 6 | | 8 | 11 | 0 | 9 | | 9 | 8 | 1 | 6 | | 10 | 9 | 0 | 7 | | 11 | 7 | 0 | 6 | | 12 | 12 | 1 | 7 | | 13 | 11 | 1 | 7 | | 14 | 8 | 0 | 6 | | 15 | 13 | 1 | 7 | Mean µ | | 10.13 | 0.93 | 6.8 |

Figure 4: Table of Results: Group 2(Age group 50-70 years)

| Case no. | No. Of words correctly recalled | No. Of false recollections | No. Of digits correctly recalled | | 1 | 12 | 1 | 7 | | 2 | 11 | 0 | 7 | | 3 | 12 | 3 | 7 | | 4 | 10 | 3 | 6 | | 5 | 9 | 2 | 7 | | 6 | 11 | 0 | 8 | | 7 | 8 | 1 | 6 | | 8 | 11 | 0 | 9 | | 9 | 8 | 1 | 6 | | 10 | 9 | 0 | 7 | | 11 | 7 | 0 | 6 | | 12 | 12 | 1 | 7 | | 13 | 11 | 1 | 7 | | 14 | 8 | 0 | 6 | | 15 | 13 | 1 | 7 | Mean µ | | 10.13 | 0.93 | 6.8 |

The following table shows the descriptive statistics for the 3 segments of the memory test scores for the 2 groups.

| Group | N | Free Recall: words | False recollections | Serial Recall digits | Statistical Hypothesis | | | H0:µ1=µ2H1:µ1>µ2 | H0:µ1=µ2H1:µ1µ2 | H0:µ1=µ2H1:µ1>µ2 | | | | Mean | Std.dev | Mean | Std.dev | Mean | Std.dev | | 1(20-40 year old) | 15 | 10.13 | 1.85 | 0.93 | 1.03 | 6.8 | 0.79 | | 2(50-70 year old) | 15 | 8.06 | 1.65 | 2.13 | 1.3 | 6.7 | 0.96 | p-value | | | 0.003 | 0.009 | 0.758 |

The results reveal that group 1 (ages 20-40) performed better on the free–recall word test, with an average of 10,13 words remembered (50.65% correctly recalled).This group also had fewer false recollections than the older age group.
Group 2 scored an average of 40.5% for correctly recalled words. However, for the serial recall of numerical data, the difference between the 2 means seemed negligible, with group 1 scoring only slightly higher (6,8-6,7=0.1)
Consequently, significant effects have been found for the word recall stimuli (p value of 0.003 α=0, 01) as well as the incorrectly recalled words (0.009 α=0, 01), while no significant effects are apparent for the numerical recall (p=0.758 > α=0.01).

6.1) PRIMACY & RECENCY EFFECTS

A further analysis of the memory experiment revealed certain aspects that were evident in the pattern of recall for both age groups, i.e. (100% of the sample) showed a recall of a minimum of 3 and a maximum of 5 of the 1st 5 words at the top of the list. This effect of the order of presentation on memory is called “primacy” which resulted in information presented earlier being remembered better than information presented later on (Macleod, 2009). This matter was discussed after the participants many of whom reported actively rehearsing the words at the beginning of the list as the rest of the list was being read out, resulting in less attention being given to the words in the middle of the list i.e. words 6-15. Another pattern that emerged was that all subjects recalled a minimum or 2 and a maximum of 5 of the last 5 words on the stimulus list i.e. 16-20. This alludes to the recency effect of recall, which results in better recall of the most recent information presented, (McLeod, 2007). Thus primacy & recency effects have resulted in the words in the middle of the list (words 6-15) remembered the least. However although primacy & recency effects were present in all subjects, they were more pronounced in the age group 50-70, with a maximum recall of 2 words from the middle of the list. This group (50-70) also exhibited the higher number of false recollections/of words that did not appear on the stimulus list. False recollection refers to a distorted/fabricated memory of an event or information that did not actually occur (McLeod, 2007). Subjects were confident that the incorrect words did appear on the list, and surprised when informed that the recollections were inaccurate which demonstrated that being sure of the accuracy of the memory does not guarantee that the memory is in fact, correct.

6.2 CHUNKING/CLUSTERING

The last aspect discovered in the analysis of the results was the memory strategy of Chunking/Clustering. Subjects that fared better in both age groups for both the verbal and numerical stimuli (i.e. for more words /digits recalled) organised the words into their respective categories e.g. fruit/animals, and as such, remembered the words better. When instructed to recall the digit sequence, subjects who used this chunking strategy to memorise the numerical string were able to recall more digits than the subjects who tried to remember the digits individually. For example, in the sequence 649251, those subjects who recalled the numbers as 649-241 or 64-92-51 performed better than those that tried to recall the digits individually as 6-4-9-2-5-1.

7.) Discussion

In this research study, an important and prominent topic in cognition was explored: Does short term memory show age-related declines? The findings, which partially support the hypothesis that increased age is associated with poorer short term memory performance, have been intriguing. Evidence in support of memory decline as a function of age emerged in the results and the analysis of the free recall word test as well as in the analysis for incorrect recollections between the two age groups.
Although current research suggests that short term memory remains relatively unaffected by ageing (Hedden et al, 2002), the results of the memory test in this study suggest otherwise. One tentative explanation for the statistically significant scores in favour of age-related short term memory decline is that the stimulus words did not appear in categorical order i.e. the words from the 5 different categories were dispersed throughout the list. On inspection of the word stimulus test sheets it was apparent that most participants from both age groups used chunking as a memory strategy. However, the older adults remembered less words in each category. I postulate that this may be because that is because the subjects had to reorganise the words into their respective categories, while still paying attention to the rest of the list. This task thus required a division of attention,which, as research by Glisky (2007) suggests, shows greater impairment in older adults due to a decrease in attentional resources.
The results also demonstrated that the number of falsely recalled words increased with an increase in age. An explanation could be that this is a result of acoustic confusion, as many of the incorrectly recalled words were similar in sound to the stimulus words e.g. instead of cat, the subject recalled hat (Sternberg, 2006). However, more research is required to fully explore the false memories/recollections as a function of age.
The analysis of the 3rd segment of the memory experiment- the serial recall results- yielded a different set of findings. As mentioned earlier, in serial recall, the subject is required to remember the digit sequence as it was heard. In this test, the time lag between digits was negligible although the sequences were read slowly. The time lag between the reading of the last digit in the sequence and the instruction to recall was 5 seconds, compared to the final 10 second lag for the word stimuli. As such, the period required for the retention and maintenance of the digit sequence was shorter, and older adults showed no significant differences in scores compared to younger adults. Many members of the older age group mentioned that this segment was the easier of the two stimuli to remember, as the numbers were grouped together as one would do in order to remember a phone number. Hence, chunking strategies were once again implemented. Current research also corroborates the above findings of there being no significant age-related short term memory decline (Brickman, et al, 2009). The better performance of the older adults on part of the memory test may also be explained within the context of the following discussion:
The shrinkage of brain structures, decline of gray and white matter integrity, and dopamine depletion as a result of ageing have been well established (Park, et al, 2008) as was mentioned in the previous sections. However, some adults that exhibit minimal decline in memory and general cognitive function show compensatory activity in the prefrontal cortex (PFC), that offset the effects of age to a degree (Hedden,et al,2004 ).
Park et al (2008) suggests that the Scaffolding Theory of ageing and cognition explains this increased PFC activity that creates more efficient circuitry with age, avoiding inefficient structures that have undergone age-related deterioration. Although scaffolding cab occur throughout life, it becomes more frequent- yet less efficient – at older ages.
Another interesting pattern that emerged from the experiment was that from the 50-70year age group, those that scored higher (9-11 words and 7 or more digits correctly recalled) reported healthier lifestyles, and importantly, continuous activities that require mental effort, such as running businesses, reading books and tackling crossword puzzles. More investigations are thus needed to address the relationship between short term memory and a healthy physical and mental lifestyle.
Lastly, it is likely that the variability in the results of the overall experiment could also be due to the increased reliance by older adults on accumulated knowledge and mental strategies, rather than on new processes, and the adaptations and cognitive alterations that are made to decrease the consequences of age-related cognitive declines in order to mentally cope with deficits, even though an advantage is that older adults are not expected to perform at optimal potential in real-life situations (Salthouse, 2011).
7.1)Limitations of the study

The first issue of concern is the sufficiency of the gathered empirical information due to the small sample size (N=30). A larger sample size would have yielded more reliable and valid results. However, the scope of this study was limited and as such, a nonprobability convenience sample of a manageable size was appropriate.
Ecological validity refers to the extent to which the results of a study can be generalised to other contexts (McLeod, 2007). Low ecological validity may also be a limiting factor in the experiment as it can be argued that the task of remembering a list of words/digits is artificial. But this argument can be refuted when one considers that individuals often memorise telephone numbers for brief periods.
Another issue of concern was that in the administration of the memory test, particularly for the older age group, the “experimenter effect” was noticeable. Older subjects appeared to be nervous, anxious and over-eager to perform well which may have negatively affected test performance.

8.) Conclusion

In conclusion, cognitive ability is, and will continue to be integral to daily life. A general consensus exists regarding the impairment of memory related functioning in older adults and through exploration of key memory concepts, current cognitive and neuroscientific literature, and through the analysis of the short term memory experiment it is clear that memory declines are not uniform in extent, rate or patter. Both neurobiological and individual factors contribute to the variability of the impact of ageing on cognition and memory (Hedden, 2004).
Although this study was unable to conclusively find proof of short term memory decline, due to older adults performing poorly on majority, but not all, of the tests compared to younger adults, this study adds important evidence to the understanding of age related short term memory decline. Many pertinent questions remain, which, when explored, would profoundly improve the quality of functioning, of life, in old age.

9.) References

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