 |
Psychology, 5/e Wortman, Loftus & Weaver | |||||
|---|---|---|---|---|---|---|
| Online Learning Center |
 |
|||||
|
Psychology, 5/e Wortman, Loftus & Weaver | |||||
|---|---|---|---|---|---|---|
| Online Learning Center |
|
|||||
John Dean confidently gave detailed testimony at the Watergate hearings; however, tape recordings released later showed that many of the details Dean provided were inaccurate. This and other historical examples illustrate the reconstructive (i.e., active and dynamic) rather than reproductive processes of thought and cognition (Theme 4).
Inspired by the associationism of classic Greek philosophers, Hermann Ebbinghaus studied memory in his laboratory. Studying his own memory for nonsense syllables, Ebbinghaus discovered a forgetting function, in which forgetting was initially very rapid, but the rate eventually leveled off. Researchers have since found that this function generalizes to a number of "real world" situations. As cognitive research progressed, Atkinson and Shiffrin proposed the information-processing model of memory, which differentiated among some properties of memory.
The information-processing model of memory divides memory into three types: sensory, short-term, and long-term. Sensory memory is the momentary memory (no more than 1/2 second for vision, slightly longer for audition) of sensory information after a stimulus has been removed. Selective attention is the brain’s ability to screen out some information entering a particular sensory channel and focus on one aspect of the information entering that channel. To study the type of selective attention involved in the "cocktail party phenomenon," E. C. Cherry developed the dichotic listening technique, which involves using the simultaneous input of different information in each ear.
Short-term memory has a limited duration (about 20 seconds), but information can be maintained in short-term memory through rehearsal, or repetition. Short-term memory rehearsal is believed to be acoustical--that is, the sound of the words are repeated and stored. Our short-term memory generally holds "seven plus or minus two" (that is, five to nine) pieces of information at any one time, according to George Miller and most other psychologists. Furthermore, if we use chunking--that is, organize information into a smaller number of units--we can increase the capacity of our short-term memory.
Long-term memory is the permanent, unlimited-capacity part of our memory; it is the repository of all our accumulated information. Long-term memory encompasses three processes: encoding, storage, and retrieval. Through encoding, sensory information is converted into a form that can be remembered. The way in which we encode stimuli has tremendous implications for our memories. For example, Nickerson and Adams (1982) found that only 1 in 20 participants was able to correctly place eight characteristics on a penny. The reason for their poor performance is that cognition, thought, and memory are dynamic, active processes, best considered reconstructive, not reproductive (Theme 4). Thus, only those characteristics of a penny that are important to know for typical functioning are likely to be remembered accurately. Automatic encoding occurs without intentional effort and is distinguished from effortful encoding, or deliberate encoding. Storage is the way in which information is kept in memory for later use. Shallow processing, or maintenance rehearsal, is more likely to reinforce short-term memory. Deep processing, or elaborative rehearsal, is more likely to produce long-term storage. Thus, when elaboration stresses meaning, memory is enhanced. Through retrieval, stored memories are found and made available for use. Retrieval from long-term memory can be in the form of recognition (you are presented with a stimulus and asked if you encountered it before) or recall (you are asked to remember an event). Recognition is generally easier than recall since it involves only a matching rather than a memory search process. Retrieval cues (hints) are also helpful in recall. In addition, recall can be enhanced by utilizing encoding specificity, the phenomenon whereby memory is enhanced by matching conditions during retrieval with the conditions dur ing encoding. When memories are stored, we typically create a number of retrieval pathways we can use to access the memory. This fact is demonstrated in the tip-of-the-tongue phenomenon, where participants feel they know a correct response, but cannot quite access it.
Endel Tulving has proposed a theory of multiple memory systems, which consists of his proposal that memory is a hierarchy of systems composed of three parts. First, procedural memories are learned associations between stimuli and responses that allow a person to perform motor skills. Second, semantic memories are mental representations of objects, states, and qualities in a person’s world. Third, episodic memories consist of recollections of events an individual has personally experienced.
Evidence supporting this theory of multiple memory systems comes from research on amnesia, memory systems in normal people, and neural structures. Anterograde amnesia involves a loss of memory for only new events and information. Retrograde amnesia involves a loss of memory for only a segment of the past. Hence, the existence of these two types of amnesia can be taken as evidence of separate memory systems. Using direct tests (which measure conscious awareness) and indirect tests (tests that do not require conscious awareness) on people with normal memory, researchers have been able to empirically distinguish between explicit memories (memories that refer to conscious awareness) and implicit memories (memories independent of conscious awareness). Furthermore, researchers have found that even implicit memories can influence behavior. In addition, researchers have found neurological evidence of implicit and explicit memories being proce ssed by different brain structures. Therefore, by studying the abnormal (viz., people with amnesia), researchers have been able to learn about the normal (Theme 2). Therefore, both people with normal and abnormal memory seem to have separate memory systems--multiple memory systems.
Nevertheless, Roediger has proposed that rather than reflecting different memory systems, results showing differences between implicit and explicit memory performance may actually reflect differences in the tests being used. Perhaps memory is being used differently on explicit and implicit memory tests.
Autobiographical memories are personal, individual memories that pertain to one’s own life. Rather than being evenly distributed across a lifetime, these memories tend to be more prevalent for one’s early 20s than for any other period in life. Memories of extraordinary events are referred to as flashbulb memories. Generally, as affect increases memory improves, but this relationship breaks down at very high levels of emotion. Moreover, people’s memories tend to match their current mood. One such bias in retrieving memories is illustrated by mood-dependent memory, memory that is easier to retrieve when in the same psychological state as the state in which memory was stored. Another such bias, called mood-congruent recall, may involve a positive mood screening out a negative thought or situation or vice versa.
The process of remembering or piecing together the past is often prone to distortion. Schemas, mental representations of objects and events against which incoming data can be compared and interpreted, are one potential source of such distortions.
Other distortions in memory have been highlighted by research on eyewitness testimony. One common finding of this research is that people may unconsciously adopt untruths after the fact, which is called misinformation acceptance.
Contrary to the popular belief that memory is a trait, Ericsson’s memory skill hypothesis states that memory is an improvable skill and is characterized by: (1) meaningful, redundant encoding; (2) rich, highly associated retrieval cues stored with items; and (3) increased performance through tremendous practice, called the speedup principle.
External aids and internals aids (mnemonic devices) can be used to improve memory. One such mnemonic device, the method of loci, involves associating the items to be remembered with a series of places, or loci, already firmly fixed in memory. Another method, the word peg method, involves associating the items to be learned with appropriate key words that are easily visualized.
Repression, a defense mechanism first described by Freud, involves pushing unacceptable, anxiety-provoking thoughts and impulses into the unconscious to avoid confronting them directly. This concept has partly led therapists to try to recover memories of early childhood abuse. These possibly recovered memories have been used as evidence in court. However, in most cases, checking the validity of these memories is impossible. Moreover, in some experiments, memories have been induced through suggestion. Overall, there is little empirical support for the accuracy of repressed memories. Recent research has found that brain scans may be able to help distinguish between true and false memories.
MHHE Home | About MHHE | Help Desk | Legal Policies and Info | Order Info | What's New | Get Involved
