Levels-of-processing effect
From Wikipedia, the free encyclopedia
The levels-of-processing effect, identified by Fergus I. M. Craik and Robert S. Lockhart in 1972, describes memory recall of stimuli as a function of the depth of mental processing. A stimulus’s mental processing depth is determined by connections with preexisting memory, time spent processing the stimulus, cognitive effort, and sensory input mode. Depth of processing falls on a shallow to deep continuum. Shallow processing (e.g., processing based on phonemic and orthographic components) leads to a fragile memory trace that is susceptible to rapid decay. Conversely, deep processing (e.g., semantic processing) results in a more durable memory trace. This theory contradicts the multi-store Atkinson-Shiffrin memory model in its representation of memory strength as continuously variable.
Contents |
[edit] Modifiers
Familiarity, transfer-appropriate processing, the self-reference effect, and the explicit nature of a stimulus modify the levels-of-processing effect by manipulating mental processing depth factors.
[edit] Familiarity
A stimulus will have a higher recall value if it is highly compatible with preexisting semantic structures (Craik, 1972). According to semantic network theories, this is because such a stimulus will have many connections to other encoded memories, which are activated based on closeness in semantic network structure (Rhodes, 2000). This activation increases cognitive analysis, increasing the strength of the memory representation. The familiarity modifier has been tested in implicit memory experiments, where subjects report false memories when presented with related stimuli (Toth, 1996).
[edit] Specificity of processing
Specificity of processing describes the increased recall value of a stimulus when presented in the method with which it was inputed. For example, auditory stimuli (spoken words and sounds) have the highest recall value when spoken, and visual stimuli have the highest recall value when a subject is presented with images (Vaidya et al., 2002). In lexical (word-based) writing tasks, words are recalled most effectively with semantic cues (asking for words with a particular meaning) if they are encoded semantically (self-generated by the subject as being related to a particular meaning). Words are recalled most effectively with data-driven cues (word completion) if they are read, rather than generated by a subject (Blaxton, 1989).
[edit] Self-reference effect
The self-reference effect describes the greater recall capacity for a particular stimulus if it is related semantically to the subject. This can be thought of as a corollary of the familiarity modifier, because stimuli specifically related to an event in a person’s life will have widespread activation in that person’s semantic network (Symons & Johnson, 1997). For example, the recall value of a personality trait adjective is higher when subjects are asked whether the trait adjective applies to them than when asked whether trait adjective has a meaning similar to another trait (Kelley et al., 2002).
[edit] Implicit memory and levels-of-processing
Implicit memory tests, in contrast with explicit memory tests, measure the recall value of a particular stimulus based on later performance on stimulus-related tasks. During these tasks, the subject does not explicitly recall the stimulus, but the previous stimulus still effects performance (Roediger, 1990). For example, in a word-completion implicit memory task, if a subject reads a list containing the word “dog,” the subject provides this word more readily when asked for three-letter words beginning in “d.” The levels-of-processing effect is only found for explicit memory tests. One study found that word completion tasks were unaffected by levels of semantic encodings achieved using three words with various levels of meaning in common (Schacter & McGlynn, 1989). Another found that typical level-of-processing effects are reversed in word completion tasks; subjects recalled pictures pairs more completely if they were shown a word representing a picture rather than asked to rate a picture for pleasantness (semantic encoding) (Roediger, Stadler, Weldon, & Riegler, 1992). Typical level-of-processing theory would predict that picture encodings would create deeper processing than lexical encoding (see discussion of visual sensory modes below).
[edit] Sensory Modes
Different sensory modes, by their nature, involve different depths of processing, generally producing higher recall value in certain senses than others. However, there is significant room for the modifiers mentioned earlier to affect levels-of-processing to be activated within each sensory mode.
[edit] Vision
Visual input creates the strongest recall value of all senses, and also allows the widest spectrum of levels-of-processing modifiers. It is also one of the most widely studied. Within visual studies, pictures have been shown to have a greater recall value than words. However, semantic associations have the reverse effect in picture memories appear to be reversed to those in other memories. When logical details are stressed, rather than physical details, an image’s recall value becomes lower (Intraub & Nicklos, 1985). Visual word memorization is subject to the standard modifiers mentioned earlier of semantic connection, and was used for Craik & Lockhart’s original work. Craik & Lockhart’s participants in the learning task viewed a series of words on a computer screen and answered simple yes/no questions about those words (e.g., "Is the word printed in capital letters?"). The types of questions the participants were asked to answer were designed to affect the manner in which the words were encoded into memory. Certain questions had participants encode the orthographic aspects of the stimuli (e.g., "Is the word printed in capital letters?"). Other questions had participants encode the phonological properties of the stimuli (e.g., "Does this word rhyme with "DOG"?"). Other questions had participants encode the semantic aspects of the stimuli (e.g., "Does the word fit in the following sentence - "The ________ walked into the house"). In a subsequent memory test, Craik & Lockhart found that participants attending to the physical features of the words had the weakest memory trace, participants attending to the acoustic properties of the words had a moderately strong memory trace, and participants attending to semantic properties of the words had the strongest trace.
[edit] Hearing
Auditory stimuli follow conventional levels-of-processing rules, although are somewhat weaker in general recall value when compared with vision. Some studies suggest that auditory weakness is only present for explicit memory (direct recall), rather than implicit memory (Habib & Nyberg, 1997). When test subjects are presented with auditory versus visual word cues, they only perform worse on directed recall of a spoken word versus a seen word, and perform about equally on implicit free-association tests. Within auditory stimuli, semantic analysis produces the highest levels of recall ability for stimuli. Experiments suggest that levels-of-processing on the auditory level is directly correlated with neural activation (see “Neural Evidence” below) (Fletcher, Shallice, & Dolan, 1998).
[edit] Touch
Tactile memory representations are similar in nature to visual representations, although there is not enough data to reliably compare the strength of the two kinds of stimuli. One study suggests that there is a difference in mental processing level due to innate differences between visual and tactile stimuli representations (Kavitha Srinivas, Greene, & Easton, 1997). In this study, subjects were presented with an object in both visual and tactile form (a subject is shown a sphere but cannot touch it, and later is given a similar sphere to only hold and not view). Subjects had more trouble identifying size difference in visual fields than using tactile feedback. A suggestion for the lower level of size processing in visual fields is that it results from the high variance in viewed object size due to perspective and distance.
[edit] Smell
Odor memory is weaker than visual memory, achieving a successful identification rate of only 70-80% of visual memory (Schab, 1991). Levels-of-processing effects have been found within odor memory if subjects are asked to “visualize” smells and associate them with a particular picture. Subjects who perform this task have a different recall value on explicit memory tests than subjects who memorize smells using self-chosen methods. The difference in recall value, however, depends on the subject, and the subject’s ability to form images from odors. Attributing verbal attributes to odors has similar effects. Semantic processing of odors (e.g. attributing the “mud” odor to “smell like a puddle”) has found to have the most positive effects on recall.
[edit] Neural Evidence
Several brain imaging studies using positron emission tomography and functional magnetic resonance imaging techniques have shown that higher levels of processing correlate with more brain activity and activity in different parts of the brain than lower levels. For example, in a lexical analysis task, subjects showed activity in the left inferior prefrontal cortex only when identifying whether the word represented a living or nonliving object, and not when identifying whether or not the word contained an “a” (Kapur et al., 1994). Similarly, an auditory analysis task showed increased activation in the left inferior prefrontal cortex when subjects performed increasingly semantic word manipulations (Fletcher et al., 1998). Synaptic aspects of word recognition have been correlated with the left frontal operculum and the cortex lining the junction of the inferior frontal and inferior precentral sulcus (Friederici, Opitz, & von Cramon, 2000). The self-reference effect also has neural correlates with a region of the medial prefrontal cortex, which was activated in an experiment where subjects analyzed the relevance of data to themselves (W. M. Kelley et al., 2006). Specificity of processing is explained on a neurological basis by studies that show brain activity in the same location when a visual memory is encoded and retrieved, and lexical memory in a different location (Vaidya, Zhao, Desmond, & Gabrieli, 2002). Visual memory areas were mostly located within the bilateral extrastriate visual cortex.
[edit] Mental Disorders
Levels-of-processing effects interact in various ways with mental disorders. In particular, levels-of-processing effects appear to be strengthened in patients with age-related memory degradation, selectively strengthened in panic disorder patients, unaffected in Alzheimer's disease patients, and reversed in autistic patients.
[edit] Age-Related Memory Degradation
Memory encoding strength derived from higher levels-of-processing appears to be conserved despite other losses in memory function with age. Several studies show that, in older individuals, the ability to process semantically in contrast with non-semantically is improved by this disparity (Grady & F. I. Craik, 2000). Neural imagining studies show decreased left-prefrontal cortex activity when words and images are presented to older subjects than with younger subjects, but roughly equal activity when assessing semantic connections (Grady & F. I. Craik, 2000).
[edit] Panic Disorders
Panic disorders appear to modify levels-of-processing by increasing ability to recall words with threatening meanings over positive and neutral words. In one study, both implicit (free recall) and explicit (memory of emotional aspects) memorization of word lists were enhanced by threatening meanings in such patients (Cloitre & Liebowitz, 1991). One possible interpretation of this is that subjects with panic disorders process threatening information more completely and immediately.
[edit] Alzheimer’s Disease
Modern studies show an increased effect of levels-of-processing in Alzheimer patients. Specifically, there is a significantly higher recall value for semantically encoded stimuli over physically encoded stimuli. In one such experiment, subjects maintained a higher recall value in words chosen by meaning over words selected by numerical order (Scott, Wright, Rai, Exton-Smith, & Gardiner, 1991).
[edit] Autism
In autistic patients, levels-of-processing effects are reversed in that semantically presented stimuli have a lower recall value than physically presented stimuli. In one study, phonological and orthographic processing created higher recall value in word list-recall tests (Toichi & Kamio, 2002). Other studies have explicitly found non-semantically processed stimuli to be more accurately processed by autistic patients than in healthy patients (Bertone, Mottron, Jelenic, & Faubert, 2005). No clear conclusions have been drawn as to the cause of this oddity.
[edit] References
- Toth, Jeffrey P (1996-03-01). Conceptual automaticity in recognition memory: Levels-of-processing effects on familiarity. Retrieved on 2007-11-17.
- Matthew G. Rhodes, Jeffery S. Anastasi (2000). The effects of a levels-of-procesing manipulation on false recall. Retrieved on 2007-11-17.
- F. I. M. Craik, R. S. Lockhart (1972). Levels of Processing: A Framework for Memory Research. Retrieved on 2007-11-17.
- Blaxton, Terasa A. (1989). "Investigating Dissociations Among Memory Measures: Support for a Transfer-Appropriate Processing Framework". Journal of Experimental Psychology: Learning, Memory and Cognition 15 (4): 657-668. doi: .
- Vaidya, Chandan J.; Margaret Zhao, John E. Desmond, John D. E. Gabrieli (2002). "Evidence for cortical encoding specificity in episodic memory: memory-induced re-activation of picture processing areas". Neuropsychologia 40: 2136 - 2143. doi: .
- Symons, Cynthia S.; Blair T. Johnson (1997). "The Self-Reference Effect in Memory: A Meta-Analysis". Psychological Bulletin 121 (3): 371-394. doi: .
- Schacter, Daniel L; Susan M McGlynn (1989). "Implicit Memory: Effects of Elaboration Depend on Unitization". The American Journal of Psychology 102 (2): 151-181. doi: . ISSN 00029556.
- Challis, Bradford H.; Boris M. Velichkovsky, Fergus I. M. Craik (1996-03). "Levels-of-Processing Effects on a Variety of Memory Tasks: New Findings and Theoretical Implications". Consciousness and Cognition 5 (1-2): 142-164. doi: .
- Intraub, H; S Nicklos (1985-04). "Levels of processing and picture memory: the physical superiority effect". Journal of experimental psychology. Learning, memory, and cognition 11 (2): 284-98. doi: . ISSN 02787393.
- Fletcher, PC; T Shallice, RJ Dolan (1998-07-01). "The functional roles of prefrontal cortex in episodic memory. I. Encoding" (abstract). Brain 121 (7): 1239-1248. doi: .
- Roediger III, Henry L.; David A. Gallo, Lia Geraci (2002). "Processing approaches to cognition: The impetus from the levels-of-processing framework". Memory 10 (5/6): 319-332.
- Habib, Reza; Lars Nyberg (1997). "Incidental retrieval processes influence explicit test performance with data-limited cues". Psychonomic Bulletin & Review 4 (1): 130-133.
- Kavitha Srinivas; Anthony J. Greene, Randolph D. Easton (1997). "Visual and tactile memory for 2-D patterns: Effects of changes in size and lef-right orientation". Psychonomic Bulletin & Review 4 (4): 535-540.
- Schab, F R (1991-03). "Odor memory: taking stock". Psychological bulletin 109 (2): 242-51. doi: . ISSN 00332909.
- Kapur, S; FIM Craik, E Tulving, AA Wilson, S Houle, GM Brown (1994-03-15). "Neuroanatomical Correlates of Encoding in Episodic Memory: Levels of Processing Effect" (abstract). Proceedings of the National Academy of Sciences 91 (6): 2008-2011. doi: .
- Friederici, Angela D.; Bertram Opitz, D. Yves von Cramon (2000-07-01). "Segregating Semantic and Syntactic Aspects of Processing in the Human Brain: an fMRI Investigation of Different Word Types" (abstract). Cereb. Cortex 10 (7): 698-705. doi: .
- W. M. Kelley; C. N. Macrae, C. L. Wyland, S. Caglar, S. Inati, T. F. Heatherton (2006-03-13). Finding the Self? An Event-Related fMRI Study (research-article). Retrieved on 2007-11-18.
- Kelley, W. M.; C. N. Macrae, C. L. Wyland, S. Caglar, S. Inati, T. F. Heatherton (2002). "Finding the Self? An Event-Related fMRI Study". Journal of Cognitive Neuroscience 14 (5): 785-794. doi: .
- Roediger, H. L. (1990). "Implicit memory". American Psychologist 45: 1043-1056. doi: .
- ROEDIGER, HL; ML STADLER, MS WELDON, GL RIEGLER (1992). "Direct comparison of two implicit memory tests: word fragment and word stem completion". Journal of experimental psychology. Learning, memory, and cognition 18 (6): 1251-1269. doi: .
- Scott, L. C.; G. K. Wright, G. S. Rai, A. N. Exton-Smith, J. M. Gardiner (1991). "Further evidence of preserved memory function in Alzheimer's disease". International Journal of Geriatric Psychiatry 6 (8): 583-588. doi: .
- Grady, Cheryl L; Fergus IM Craik (2000-04-01). "Changes in memory processing with age". Current Opinion in Neurobiology 10 (2): 224-231. doi: .
- Cloitre; Liebowitz (1991-10-01). "Memory bias in panic disorder: An investigation of the cognitive avoidance hypothesis". Cognitive Therapy and Research 15 (5): 371-386. doi: .
- Toichi, Motomi; Yoko Kamio (2002). "Long-term memory and levels-of-processing in autism". Neuropsychologia 40 (7): 964-969. doi: .
- Bertone, Armando; Laurent Mottron, Patricia Jelenic, Jocelyn Faubert (2005-10-01). "Enhanced and diminished visuo-spatial information processing in autism depends on stimulus complexity" (abstract). Brain 128 (10): 2430-2441. doi: .