Context-dependent memory
In psychology, context-dependent memory is the improved recall of specific episodes or information when the context present at encoding and retrieval are the same. In a simpler manner, "when events are represented in memory, contextual information is stored along with memory targets; the context can therefore cue memories containing that contextual information". One particularly common example of context-dependence at work occurs when an individual has lost an item in an unknown location. Typically, people try to systematically "retrace their steps" to determine all of the possible places where the item might be located. Based on the role that context plays in determining recall, it is not at all surprising that individuals often quite easily discover the lost item upon returning to the correct context. This concept is heavily related to the encoding specificity principle.
This example best describes the concept of context-dependent forgetting. However, the research literature on context-dependent memory describes a number of different types of contextual information that may affect recall such as environmental context-dependent memory, state-dependent learning, cognitive context-dependent memory and mood-congruent memory. Research has also shown that context-dependence may play an important role in numerous situations, such as memory for studied material, or events that have occurred following the consumption of alcohol or other drugs.
History
Early research
Some of the earliestresearch on this topic was conducted by researchers in the 1930s who analyzed how changes in context affect an individual's memory for nonsense syllables. These early studies were unable to demonstrate an effect of context-dependent memory. Such non-significant results encouraged the development of new methods, such as a retroactive interference paradigm, to analyze the effect of context on memory. By the 1950s, this technique was used to demonstrate an effect of contextual information on memory recall. However, the validity of using this particular paradigm has been questioned. Indeed, much of the early literature on this topic failed to provide conclusive evidence of any context-dependent effects on memory.
By the end of the 1970s, numerous successful demonstrations of a context-dependent effect appear in the literature. As early as 1971, Jensen et al. found evidence that contradicted previous findings by demonstrating a context-dependent effect on memory for nonsense syllables. In a similar timeframe, Endel Tulving and Donald Thompson proposed their highly influential 'encoding specificity principle', which provided the first framework for understanding how contextual information affects memory and recall. In 1975, the question of whether contextual information influences memory recall was famously investigated with the publication of Godden and Baddeley's paper detailing the well-known 'diving study'. A few years prior to the publication of this study, researchers demonstrated that the memory of deep sea divers for events witnessed underwater was reduced after resurfacing. The authors note in their 1975 paper that this incidental result immediately suggested a possible influence of the contextual environment on recall. To test this hypothesis, Godden and Baddeley had divers learn and recall word lists in two separate environments; under water and on dry land. Their results demonstrated that memory for word lists learned under water was better when recall sessions occurred under water as well, and that a congruent effect existed for words learned and recalled on land. In simplified form: changing the context between encoding and retrieval reduced the divers' ability to recall learned words. The publication of this study likely initiated the current synthesis of context-dependent memory as it is studied by psychologists today.
Certain scholars believe the English philosopher John Locke referenced context-dependent memory in An Essay Concerning Human Understanding, which dates back to the 17th century. In this work, Locke wrote about a man learning a dance routine in a room containing an old wooden trunk. After enough practice, the man learned to avoid the wooden trunk to prevent himself from tripping during said dance routine. Locke wrote, "the idea of this remarkable piece of household stuff had so mixed itself with the turns and steps of all his dances, that though in that chamber he could dance excellently well, yet it was only while that trunk was there; nor could he perform well in any other place unless that or some other trunk had its due place in the room".
Theoretical background
A number of factors are thought to affect how contextual information interacts with memory recall. For example, a meta-analysis of the literature on environmental context-dependent memory by Smith and Vela has suggested that in cases where contextual information is not particularly salient, context-dependent effects on memory are reduced. Similarly, this meta-analysis suggests that reinstatement of context can be achieved not only by physically returning to the encoding environment, but also by mentally visualizing that environment. This study considered only environmental context-dependence.Additionally, other psychological constructs suggest further limits on how context can affect memory. For example, Johnson et al.'s source monitoring framework proposes that the ability of an individual to remember the source of an episode will affect the likelihood of that memory being recalled. Hence, in the case of context-dependent memory, this framework suggests that the effects of context on memory may also be limited by cognitive factors such as the ability of individuals to differentiate between individual contexts.
Context can refer to internal context, referring to state of mind at the time of memory encoding, or temporal context, which refers to the time when a memory was encoded, in addition to external context, or physical and situational surroundings. All of these types of context are incorporated as values into what are known as context vectors, vector representations of multiple context attributes, used in many theories of recall and recognition memory.
In summed similarity theory, the use of a memory matrix includes the context as an attribute in a memory vector. Other attributes of a memory make up the remainder of the memory matrix representation of a particular memory item, in an array model for association. Summed Similarity Theory explains that the theoretical memory matrix is searched and the memory representation with the highest summed similarity of all memory vectors to the probe item is selected. Context plays a large role in this search, especially as more recent items in a memory matrix have closer matching contexts.
The absolute-similarity framework also uses context as an important factor in determining how closely a probe vector and a memory vector match. Contextual drift can be thought of as a random walk, with one unit or step, in a random walk for each item stored in memory. The random walk can be in any direction and is representative of the gradually shifting physical or mental context of encoding. Absolute similarity framework determines whether a probe item is similar enough to a stored memory vector by the use of a threshold. Only those with similarities above threshold, C, are judged to be similar. Context plays a large role in this judgment because of the possibility that a probe item could be matched to a memory vector with a highly similar context rather than the corresponding item itself.
Context effects do differ when it comes to what sort of task is being performed. According to a study by Godden & Baddeley, the effects of context change on memory retrieval are much greater in recall tasks than in recognition tasks.