VOL: 102, ISSUE: 09, PAGE NO: 26
Sherrill Snelgrove, MPhil, PGCE, BSc, RGN, is lecturer in nursing and psychology, School of Health Science, University of Wales, SwanseaMemory has been defined as 'the retention of experience or learning' (Cassells, 1991). We cannot live fully without memory. We need memory to process and retain information, knowledge and skills, and recall past emotional experiences and situations. Memory may be studied in two ways: analysing the psychological processes of memory or investigating how and where memories are stored in the brain. Both are important to fields of study but this article explores the processes of memory.
Memory has been defined as 'the retention of experience or learning' (Cassells, 1991). We cannot live fully without memory. We need memory to process and retain information, knowledge and skills, and recall past emotional experiences and situations. Memory may be studied in two ways: analysing the psychological processes of memory or investigating how and where memories are stored in the brain. Both are important to fields of study but this article explores the processes of memory.
Types of memory
There are different types of memory that depend on different learning mechanisms and have different functions (Young and Concar, 1992). For instance, you might be telling a colleague about the day you taught a patient how to self-administer insulin. This would involve your semantic memory (knowledge about language and what you know about diabetes, insulin and so on) and your episodic memory (memory about the day itself and associated feelings and events).
Semantic and episodic memories are collectively known as declarative memory or explicit memory and require conscious recollection of the experience. The actual skill involved in the patient intervention involves non-declarative memory or implicit memory and is the kind of memory that enables us to perform familiar tasks, often without much thought or even consciousness. This memory for skills is also known as procedural memory. The conversation itself would involve working memory that enables understanding and the construction of sentences.
Memory and attention are intimately linked. Many failures of memory are due to lack of attention. We will only take notice of some of the information that comes our way. For example, during a consultation, the patient's attention to what is being said may be distracted by influences such as mood state (anxiety) and context (strange hospital environment).
Therefore, taking a patient's emotional state into account is important when providing health-related information. Patients may have high levels of anxiety and arousal that will distract their attention and impede recall of the message. Alternatively, patients may be unconcerned about the information and not sufficiently aroused to attend to the information (Payne and Walker, 1996).
Interestingly, Yerkes and Dodson (1908) show that while high levels of arousal may impair attention and remembering, small transient doses of anxiety can actually improve memory. A low level of anxiety with a medium level of arousal provides the best state for receiving information (Russell, 2004). The implications are that if a patient is highly anxious then time needs to be taken to identify their concerns and calm them down, whereas if a patient is uninterested in the information then time should be taken to increase arousal levels by alerting them to the importance of the message (Walker et al, 2004).
Stages of memory
There are three stages involved in the processing of memory - encoding, storage and retrieval - and forgetting can take place at any of these stages.
Physical objects, speech, sights and smells have to be encoded to be remembered. A memory trace is created and can be encoded in three separate ways:
- Visual (faces, places);
- Semantic (meaning, knowledge);
- Acoustic (verbal).
Different theories of memory have accounted for the processing of storage of memories. Despite being criticised for its oversimplification of memory, one of the most well-known theories is the multistore model of memory (Atkinson and Schiffrin, 1968). This theory identifies three separate stores for memories: the sensory store, the short-term memory and the long-term memory.
The sensory store or register refers to a brief, relatively unprocessed input that is registered by sensory receptors of sight (iconic memory) and sound (echoic memory). The temporal durability of the sensory register is about 2-4 seconds. Information may be lost at this stage because of interference, lack of attention and decay (Eysenck, 2004).
It is generally believed that information enters the short-term memory as a result of attention being applied to a stimulus that has been momentarily held in this sensory register.
Atkinson and Schiffrin (1968) suggest that short-term memory acts as a system by which information enters long-term memory. Short-term memory is also referred to as working memory (Baddeley, 1986) and is thought to be that part of memory that keeps information active while we are using it. It is used, for example, when remembering the registration number of a car so you can write it down or, in the case of patients receiving complex information, holding the information in short-term memory and therefore keeping it active and rehearsing what is being said helps them to remember the information at a later time.
Forgetting in short-term memory is not clearly understood, but the storage capacity of short-term memory is thought to be limited (Atkinson and Schiffrin, 1968). Short-term memory stores information for about 20-30 seconds and then the information either disappears from consciousness due to decay (information decays over time), or is displaced and replaced by new information because of the limited storage capacity of short-term memory.
Miller (1956) indicated that on average people can remember seven chunks of information (plus or minus two items) at a time in short-term memory. Miller suggested the capacity of short-term memory may be expanded by organising the information, for example putting items into meaningful chunks.
Information already held in short-term memory may be distorted or displaced by new information altering the validity of the initial memory (retroactive inhibition), or existing memory may affect future memories (proactive inhibition). For example, patients who are offered different information from various health professionals become confused about who said what (Payne and Walker, 1996).
Laboratory-based studies such as those by Glanzer and Cunitz (1966) and Bjork and Whitten (1974) have demonstrated that people tend to remember the last piece of information in a message more efficiently than the middle part of the message. This is called the recency effect. The primacy effect has been similarly investigated and shows that people remember the first part of a message because there is more opportunity to rehearse the information than information offered later on in the message and an increased likelihood of it entering long-term memory (Craik and Watkins, 1973).
Long-term memory is a permanent store for memories. The storage of memories is highly organised and the only limitation of long-term memory is one's ability to recall information (Eysenck, 2004). It is generally thought that items entering long-term memory are encoded semantically (based on meanings and knowledge), with memories being stored in networks of association or filed hierarchies (Westen, 1996).
Information is transferred from short-term memory into long-term memory if it is rehearsed adequately and if meaning is applied to the information. Craik and Lockhart (1972) postulated that, rather than there being separate stores for memory, the length of time a memory lasts is directly related to the level of processing of the information. Material may be processed by maintenance or rote-type rehearsal, for example memorising a drug's name by repeating it over and over again, or elaborating the memory so it becomes more meaningful and processed at a deeper level, for example linking the drug with the condition it is used for.
Rehearsal would seem to be as important for effectively recalling items from long-term memory as from short-term memory (for example, studying for examinations). This would imply that the more times a patient is exposed to the information the more likely they are to remember it.
However, a deeper processing of material is required for retention in long-term memory than in short-term memory. This means that health professionals should focus on elaborating the meaning of the message by emphasising the importance of the information to the patient's health and making associations with previously held knowledge to aid recall (Eysenck, 2004).
Forgetting in long-term memory may also be due to decay of the memory through non-use, although there are arguments against this (Cassells, 1991). For example, motor tasks such as applying figure-of-eight dressings can still be performed by nurses even after many years without practice. Interference also has a part to play both in short-term memory and long-term memory, with previously held information interfering with new information and vice versa (Anderson, 1983).
Failure to retrieve information from storage occurs for many reasons (Box 1, p27), but many instances of forgetting are caused by a lack of cues to aid successful recall. To aid recall from short-term memory and long-term memory, information should be presented in an organised fashion with, for example, different sections labelled or signposted for easier retrieval (Salmon, 2000; Wilson, 1989):
- The importance of the information should be emphasised;
- Specific information should be given rather than a general instruction. For example, instructions should say what to do first, second and so on;
- Information should be organised, categorised and labelled according to importance;
- Benefits of treatment and side-effects should be explained and repeated if necessary;
- There should be minimal use of medical and technical jargon.
Cues for retrieving information may be as simple as facilitating reintegration of memory by offering cues to patients. For example, associations can be made between tasks such as self-administering medicine and a daily habit such as drinking a mid-morning cup of tea.
Consultations between patients and health care professionals are often characterised by a lot of information being given in a short space of time. Thus, the patient has a limited opportunity to rehearse or repeat the information to consolidate it into long-term memory. Information may be presented in an unstructured, rushed format and this makes it difficult for the patient to identify the separate pieces of information and make sense of the message.
When giving information, nurses should not overload patients and should present the most important piece of information first, repeating this at the end of the message. If necessary, follow up with a further meeting or provide written information or an audio tape.
Strategies for giving information include:
- Identifying the patient's knowledge before and after information giving;
- Assessing the patient's emotional and intellectual status;
- Offering organised information with clear signposts to different parts of the message, avoiding the use of professional jargon;
- Emphasising important information first and last with follow-up information if necessary;
- Offering strategies for recalling information, for example linking self-medication with daily events.
Presentation of information is an important way in which nurses and health professionals can improve recall of health-related information.
- This article has been double-blind peer-reviewed.
For related articles on this subject and links to relevant websites see www.nursingtimes.net
Each week Nursing Times publishes a guided learning article with reflection points to help you with your CPD. After reading the article you should be able to:
- Identify the different types of memory;
- Know the different stages of memory;
- Be familiar with the functions and capacities of short-term and long-term memory;
- Identify some information-giving skills.
Use the following points to write a reflection for your PREP portfolio:
- Write about your area of work and why this article is relevant;
- Reflect on the last occasion that you had to impart some information to a patient;
- Identify a piece of information in this article that could have helped you ensure
- a patient remembered what you had told her/him;
- Describe how you may use what you have learnt in your future practice;
- Summarise how you will disseminate this information to your colleagues.