6.7 CHAPTER REVIEW

KEY POINTS

• Memory refers to the mental processes that enable us to acquire, retain, and retrieve information. Key memory processes are encoding, storage, and retrieval.

• The stage model of memory describes human memory as the process of transferring information from one memory stage to another. The three stages of memory are sensory memory, short-term memory, and long-term memory.

• Sensory memory briefly stores information about the environment. Information that we attend to is transferred from sensory memory to short-term memory; other information fades quickly.

• George Sperling discovered that visual sensory memory holds information for about half a second before the information fades.

• There is a separate sensory memory for each sense. Visual and auditory sensory memory are the most thoroughly studied. Auditory sensory memory lasts up to a few seconds.

• Short-term memory provides temporary storage for information transferred from sensory memory and information recalled from long-term memory. Maintenance rehearsal keeps information active in short-term memory. Because of either decay or interference, information that is not rehearsed is lost within about 20 seconds.

• The capacity of short-term memory is limited to about seven items, plus or minus two. Chunking can be used to increase the amount of information held in short-term memory.

• Alan Baddeley’s model of working memory has three components: the phonological loop, the visuospatial sketchpad, and the central executive. Working memory is the short-term memory system that involves the active, conscious manipulation of verbal or spatial information.

• Long-term memory stores a limitless amount of information for extended periods of time.

• Encoding transforms information into a form that can be stored and retrieved later. The most effective encoding strategies involve elaborative rehearsal.

• Long-term memory includes procedural, episodic, and semantic memory. Explicit memories can be consciously recalled. Implicit memories cannot be consciously recalled, but affect behavior or performance. Information in long-term memory is clustered into related groups during recall. The semantic network model describes the organization of long-term memory.

• Retrieval refers to the process of accessing information stored in long-term memory.

• Retrieval cues are hints that help us retrieve stored memories. Sometimes stored memories cannot be retrieved because of retrieval cue failure, such as in tip-of-the-tongue (TOT) experiences.

• Retrieval can be tested using recall, cued recall, and recognition measures. The serial position effect is our tendency to remember the first and last items in a series best.

• According to the encoding specificity principle, recreating aspects of the original learning conditions is one way to increase retrieval effectiveness. Examples of the encoding specificity principle include the context effect and mood congruence.

• Memories that are highly unusual tend to be easier to retrieve from long-term memory. Flashbulb memories can be extremely vivid, but, like normal memories, they are not always accurate.

• Forgetting refers to the inability to recall information that was previously available.

• The general pattern of forgetting is reflected in the forgetting curve, which is based on the classic research of Hermann Ebbinghaus.

• Psychologists have identified several factors that contribute to forgetting. Encoding failure, one cause of forgetting, is especially common when attention is divided. Divided attention may contribute to déjà vu experiences. Retrieval cue failure is implicated in prospective memory failures. Decay theory makes sense intuitively but has little research support.

• According to interference theory, forgetting results from retroactive and proactive interference with other information.

• Motivated forgetting can result from suppression or repression. Research support for repression is mixed.

• Misidentification by eyewitnesses is the leading cause of false conviction in rape and murder cases. Because retrieval involves the reconstruction of memories, memory details can become distorted. The misinformation effect and source confusion are both potential causes of eyewitness error and false memories. Schemas and scripts also contribute to memory errors.

• Imagination inflation helps explain how false memories of childhood experiences can be created. Being lost in a shopping mall and putting slime in the teacher’s desk in elementary school are some examples of false memory studies. Imagining vivid sensory details adds greatly to confidence in false memories.

• After extensive research, Karl Lashley concluded that memories are distributed rather than localized as a memory trace. Richard Thompson showed the physical changes that are associated with a simple conditioned reflex in rabbits. Today, it is believed that memories are both localized and distributed. Complex memories involve interrelated changes among many different brain areas.

• Eric Kandel showed that functional and structural changes in neurons are associated with acquiring a conditioned reflex in the sea snail Aplysia. Enduring memories are believed to be stored through long-term potentiation, a long-lasting increase in synaptic strength.

• Retrograde amnesia results when memory consolidation is disrupted. Anterograde amnesia results when the hippocampus is damaged, as in the case of H.M. Amnesia affects episodic memories rather than procedural memories and explicit memory rather than implicit memory. Brain structures involved in memory include the hippocampus, the amygdala, the cerebellum, the frontal lobes, the medial temporal lobes, and the prefrontal cortex.

• Alzheimer’s disease (AD) is the most common cause of dementia, which refers to impairment in memory, reasoning, language, and other cognitive functions.

KEY TERMS

KEY PEOPLE