The Big Picture: Chapter Overview

Memory is the retention of information over time; it involves three domains: encoding, storage, and retrieval. This chapter discusses variables that influence each of these three memory processes as well as research on forgetting and optimal studying strategies based on memory research.

Encoding is the process of getting information into memory. Selective attention, a concept discussed in Chapter Five, explains why we may encode some stimuli and not others. Encoding is also affected by divided attention, which occurs when a person is paying attention to more than one thing at the same time. There are different levels at which we may encode: shallow level, intermediate level, and deepest level. The more in-depth our processing of the information, the more likely we are to place it in memory. Encoding also depends on elaboration, which refers to how extensively the information is processed at any given depth in memory. Encoding information in images, as illustrated in this chapter's opening story, can also improve our recollection of information.

Storage consists of retention of information over time and the representation of information in memory. According to the popular Atkinson-Shiffrin theory, we can accumulate information in three main stores that vary according to time frames: sensory memory, short-term memory, and long-term memory. Information is stored very briefly in the sensory memory. Visual sensory memory is called iconic memory, whereas auditory sensory memory is referred to as echoic memory. Short-term memory has a limited capacity of 7 ± 2 items, which can be illustrated by memory span. The capacity of the short-term memory can be expanded with chunking. Short-term memory lasts up to 30 seconds, but this can also be expanded by maintenance rehearsal. In a revision of the Atkinson-Shiffrin model, psychologist Alan Baddeley proposed the concept of working memory, a system that holds information while we are thinking. From this perspective, working memory has three components: phonological loop, visuospatial working memory, and the central executive. Long-term memory can retain enormous amounts of information up to a lifetime, and we can efficiently retrieve information from long-term memory.

Long-term memory has been classified into many types of memories, based on the content and purpose of the information. Information in long-term memory that can be verbally communicated is called declarative memory or explicit memory. Episodic memory is the retention of information about the where and when of life's happenings; semantic memory is a person's knowledge about the world. Prospective memory involves remembering information about doing something in the future, while retrospective memory refers to remembering the past. Nondeclarative memory, also called implicit memory, refers to memory in which behavior is affected by prior experience without that experience being consciously recollected. Three types of implicit memory are procedural, priming, and classical conditioning. Four main theories describe how long-term memory is organized: hierarchies, semantic networks, schemas, and connectionist network. The hierarchies approach argues that memory is organized on a hierarchy from general to specific types of things. The semantic networks approach claims that long-term memory is organized in a network of interconnected concepts. While the original semantic networks approach was hierarchical, more recent versions argue that concepts are organized in irregular networks of concepts connected based on the meaning and relationships that we have learned through experiences. New material is placed in the network by connecting it to appropriate nodes. The schema approach suggests that our memories are not precise and that we reconstruct our past. A schema framework already exists in a person's memory, and that framework influences how new information is interpreted and integrated into memory. Finally, the connectionist networks view takes into consideration the role of the brain in memory and argues that memory is stored throughout the brain in connections between neurons, several of which may work together to process a single memory. Long-term potentiation contributes to memory at the level of the neurons. Brain structures that have been associated with memory include the hippocampus, the amygdala, and the cerebellum.

Retrieval is the process of getting information out of memory. Much of the interest in retrieval has focused on long-term memory. The serial position effect refers to how recall is superior for items at the beginning (primacy effect) and at the end of the list (recency effect). Retrieval is also influenced by the presence of cues and the nature of the task. Two different types of memory retrieval are recall and recognition. Recall is a memory measure where information must be retrieved from previously learned information, whereas in recognition one only has to identify learned items. The encoding specificity principle states that associations formed at the time of encoding or learning tend to be effective retrieval cues. Retrieval also is influenced by priming, which involves activating particular connections or associations in memory. Research on the tip-of-the-tongue phenomenon suggests that good retrieval cues are helpful in retrieving information from memory. Context-dependent memory is the process through which people remember better when they try to recall information in the same context in which they learned it. Autobiographical memory consists of a person's recollections of his or her life experiences. Emotional memories may be flashbulb memories, which are memories of emotionally significant events that people often recall with more accuracy and vivid imagery than everyday events. Many people have flashbulb memories of personal events and their accuracy is far more durable and accurate than memories of everyday events. Memory of personal trauma is usually more accurate than memory for ordinary events; however, personal trauma can also result in the repression of the memory, a process of pushing the event into the unconscious mind. The recall of repressed memories is a controversial issue in psychology because research indicates that memories may be implanted, especially using hypnosis.

Forgetting may occur because of interference and decay. Proactive interference occurs when material learned earlier interferes with the recall of material learned later. Retroactive interference occurs when material learned later interferes with material learned earlier. Decay theory suggests that a memory trace, formed when something new is learned, can disintegrate with the passage of time. Anterograde amnesia affects memory for new information, whereas retrograde amnesia is memory loss for a segment of the past.

Optimal studying strategies may be developed based on memory research. To improve encoding, the strategies include managing study time effectively, paying attention and minimizing distraction, understanding the material rather than simply memorizing it, asking yourself questions, taking good notes, and using mnemonic strategies. Mnemonics are techniques for improving memory and include the method of loci, acronyms, and the keyword method. To enhance the storage of the information studied, it is recommended to consciously organize the information being memorized and spread out the study sessions. To improve the retrieval of the material studied, retrieval cues and the PQ4R method are recommended.