Retrospective memory is the memory of people, words, and events encountered or experienced in the past. It includes all other types of memory including episodic, semantic and procedural.Baddeley, A., Eysenck, M.W. & Anderson, M.C. (2009) "Memory". New York: Psychology Press. It can be either implicit or explicit. In contrast, prospective memory involves remembering something or remembering to do something after a delay, such as buying groceries on the way home from work. However, it is very closely linked to retrospective memory, since certain aspects of retrospective memory are required for prospective memory.
Relationship with prospective memory Early research on prospective memory and retrospective memory has demonstrated that retrospective memory has a role in prospective memory. It was necessary to create more accurate terms in order to explain the relationship fully. Prospective memory describes more accurately an experimental paradigm, therefore, the term prospective remembering was subsequently used.Burgess, P.W. & Shallice, T.(1997)The relationship between prospective and retrospective memory: neuropsychological evidence. In Conway, M.A. (Ed.), Cognitive Models of Memory(247-272). Cambridge: MIT Press. A review by Burgess and Shallice described studies where patients had impaired prospective memory, but intact retrospective memory, and also studies where the impaired retrospective memory caused an impact on prospective memory. A double dissociation for the two has not been found, therefore concluding they are not independent entities. The role of retrospective memory in prospective memory is suggested to be minimal, and takes the form of the information required to make plans. According to Einstein & McDaniel (1990) the retrospective memory component of the prospective remembering task refers to the ability to retain the basic information about action and context. An example used in the reviews explains this in the following scenario: You are intending to mail a letter on your way home tomorrow evening, at the mailbox that you have used before The basic information of the retrieval context includes time, location and objects, which in combination form the required retrieval context. Each individual representation required is a form of retrospective memory. Despite all the research this issue is still debatable within the scientific community.
Episodic memory Retrospective episodic memory is recollection of past episodes. Significant research in this field looks at the phenomenon of mental time travel.
Mental time travel Mental time travel (MTT) is defined as the ability to mentally project oneself backwards in time to re-live past personal experiences, or forward in time to pre-live possible events in the future.Wheeler, M. A., Stuss, D. T., & Tulving, E. (1997). Toward a theory of episodic memory: The frontal lobes and autonoetic consciousness. Psychological Bulletin,121,331–354. It is a concept created by Canadian psychologist Endel Tulving. It does not simply refer to knowing an event happened, but requires conscious awareness that the individual is indeed reliving the episode. Due to this, it is certain that mental time travel requires central executive functioning, and most often a conscious ability. However new research has found many cases in which mental time travel occurs involuntarily without consciousness. Specifically research shows this occurs for autobiographical events, and as a result these cases are more specific and detail oriented. An example of this would be the phenomenon of scent: How a particular scent can send an individual back to a specific event in their lifetime. There is also evidence that involuntary and voluntary mental time travel differ on activation levels in areas of the brain suggesting that they have different retrieval mechanisms.Bernsten, D. & Jacobsen, A.S. (2008). Involuntary (spontaneous) mental time travel into the past and future. Consciousness and Cognition, 17 1093-1004. Current research has moved away from the retrospective portion and towards the prospective aspect of mental time travel. There is also extensive research on whether mental time travel is unique to humans as there has been some evidence that it may be possible to occur in animalsMendi, M. & Paul, E.S.(2008). Do animals live in the present? Applied Animal Behaviour Science, 113,(4), 357-382.
Episodic Retrospective episodic memory is the memory of moments from the past. It is frequently used in studies of Alzheimer patients and testing their dementia. A study by Livner et al. (2009) compared the effect of the disease on both prospective and retrospective memory. In this case the episodic memory being tested was the ability to remember the testing instructions. To test retrospective memory participants were presented with a list of nouns that had been divided into four categories. The results of retrospective memory were divided into three sections: number of categories, number of items remembered and forgetting ratio, in order to look at the three separate process in creating memory (encoding, retrieval, storage). Using their results and knowledge of episodic memory the researchers were able to find a pattern of functional impairments in the brain.Livner, A, Laukka, E.J., Karlsson, S. & Backman, L. (2009). Prospective and retrospective memory in Alzheimer's disease and vascular dementia: Similar patterns of impairment. Journal of the Neurological Sciences, 283, 235-2009.
Autobiographical Retrospective autobiographical memory is recalling specific events from your own past. Testing of this type of memory has been used when researching the effect of emotion and context on memory. Abenavoli and Henkel (2009) conducted a study looking at childhood events, context and metamemory. They wanted to see if the participants memory of remembering childhood events was accurate. The results showed that when context was recreated metamemory improved as did vividness of the actual event. Besides these topics, it is also used in studying mental time travel and age-related factors.Abenavoli, R. & Henkel, L.A. (2009). Remembering When We Last Remembered Our Childhood Experiences: Effects of Age and Context on Retrospective Metamemory Judgements. Applied Cognitive Psychology, 23, 717-732.
Semantic memory Retrospective semantic memory refers to the collection of knowledge, meaning and concepts that have been acquired over time. It plays a significant role in the study of priming. Jones (2010) researched a pure mediated priming effect and wanted to discover which model accounted for it. Pure priming refers to the connection between two concepts that have a weak or no association with each other. Each of three potential models (spreading activation, compound-cue and semantic matching) were tested with the results concluding that retrospective semantic matching model creates the pure priming effect. This study shows pure priming has more applications than previously thought.Jones, L.J. (2010). Pure Mediated Priming: A Retrospective Semantic Search Model. Journal of Experimental Psychology: Learning, Memory, and Cognition, 36(1), 135-146.
Retrograde amnesia Retrograde amnesia is defined as the loss of memory of events and experiences occurring prior to an illness, accident, injury, or traumatic experience such as rape or assault. The amnesia may cover events over a longer or only a brief period. Typically, it declines with time, with earlier memories returning first.Gordon, M. Retrograde amnesia. A Dictionary of Sociology. 1998. Retrieved March 04, 2010 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O88-retrogradeamnesia.html There are many possible causes of amnesia. The most common include Alzheimer's disease, traumatic brain injury, brain infection (such as encephalitis or meningitis), dementia, seizures, and stroke. Less common causes include a brain tumor or psychiatric disorders (schizophrenia, depression, criminal behavior, or psychogenic amnesia). Psychogenic amnesia usually happens in close association with a stressful event that involves serious threat to life or health. There are two types of retrograde amnesia, one dealing with episodic memory, and one dealing with semantic memory. Semantic retrograde amnesia involves loss of generic, lifelong knowledge, as in the various forms of aphasia or agnosia, and also loss of learned motor skills, as in the various types of apraxia. Its primary focus is on retrograde amnesia for specific, usually time-limited, knowledge. In the case of semantic retrograde amnesia, memory for public events and memory for people have formed the primary corpus of research.Kapur, N. (1999). Syndromes of retrograde amnesia: a conceptual and empirical synthesis. Psychological Bulletin, 125(6), 800-825.
Neuroanatomy Medial prefrontal cortex A study was conducted by Kesner (1989)Kesner, R.P. (1989). Retrospective and prospective coding of information: role of the medial prefrontal cortex. Experimental Brain Research, 74, 163-167. on retrospective memory involving rats. Lesions made to the medial prefrontal cortex of rats led to impairment of retrospective memory, as well as strong impairment to prospective memory on a radial arm task.
Medial temporal lobe Different brain regions in the medial temporal lobe play a unique role in memory. The medial temporal lobe seems to function as a memory system for consciously available events and facts, and is important for the acquisition of new episodic and semantic memory. There is also evidence that the medial temporal lobe automatically encodes memories.Graham, K.S., & Gaffan, D. (2005). The quarterly journal of experimental psychology. New York, NY: Psychology Press, Ltd.
The role of the medial temporal lobe for retrospective memory was assessed by Okuda et al. (2003)Okuda, J., Fujii, T., Ohtake, H., Tukiura, T., Tanji, K., Suzuki, K., et al. (2003). Thinking of the future and the past: the roles of the frontal pole and the medial temporal lobes. Neuroimage, 19, 1369-1380. using Positron Emission Tomography (PET). The PET found that thinking about past events increased blood flow to the medial temporal lobes, emphasizing that this brain area contributes to the activation of retrospective memory. Also, the medial temporal lobe displayed activation levels associated with prospective memories. This finding gives support for the belief that thinking about the future to an extent relies upon thinking about the past, showing a close relationship between retrospective memory and prospective memory.
Hippocampus
The hippocampus plays an important role for remembering specific personal experiences in humans, as well as memory for sequence of events.Fortin, N.J., Agster, K.L., & Eichenbaum, H.B. (2002). Critical role of the hippocampus in memory for sequences of events. Nature Neuroscience, 5(5), 458-562.
A series of lesion studies assessed the role of the hippocampus on retrospective memory. In the first delayed response task, nonhuman primates were shown two food wells. For the primates to get a reward, they had to remember which food well was baited. However, the primate had to retain the information about the two prospects until an apparatus was lowered and raised after a delay interval. The results showed that lesions to the hippocampus impaired performance on this task. In a variation of the study, the primates were required to approach the food well that was empty after a delay. It was found that damage to the thalamus also caused impaired performance on both tasks, but at longer delay intervals. These studies confirmed that damage to the hippocampus and thalamus impaired the recall for episodic memory of previously experienced events.Risberg, J. & Grafman, J. (Ed.). (2006). The frontal lobes: Development, function and pathology. New York, NY: Cambridge University Press.