CHAPTER OUTLINE – Unit 12 I. THE NATURE OF MEMORY A. Basic Memory Processes 1. The process of putting information into memory is called encoding. Sensory information is put into memory codes, which are mental representations. a) Acoustic encoding represents information as sequences of sounds. b) Visual encoding represents information in the form of images. c) Semantic encoding represents the meaning of information. 2. Holding information in memory over time is called storage. 3. Pulling information out of memory and into consciousness after it has been stored is called retrieval. Recall is the term for retrieving information without any cues to help. In recognition, cues aid retrieval. B. Types of Memory There are at least three basic types of memory, each of which is named for the type of information it handles. 1. Any memory of a specific event that happened while you were present is an episodic memory. 2. Semantic memory contains generalized knowledge of the world that does not involve memory of a specific event. 3. Procedural memory (skill memory) represents knowledge of how to perform physical tasks. C. Explicit and Implicit Memory Explicit memory is used when you deliberately try to remember something; implicit memory is the unintentional influence of prior experiences. Explicit memory processes are much more negatively affected by the passing of time than are implicit memory processes. E. Models of Memory Currently, there are four models of memory that attempt to explain what and how well items such as processes, episodes, and general information are remembered. 1. Levels of Processing. The levels-of-processing model suggests that what and how well we remember are a function of how deeply information is processed, or rehearsed and encoded, when first experienced. Maintenance rehearsal is simply repeating an item over and over. Elaborative rehearsal is building associations or linkages between new and old information. Elaborative rehearsal requires a deeper level of processing; hence these memories are stronger than those encoded with maintenance rehearsal 2. Transfer-Appropriate Processing. The transfer-appropriate processing model suggests that the most important memory determinant is how well the encoding process matches what is retrieved. 3. Parallel Distributed Processing (PDP). Parallel distributed processing models suggest that new facts change our knowledge base by altering interconnected networks, facts, and associations. These networks allow us to quickly and efficiently draw inferences and generalizations about new and old information. 4. Information Processing. The information processing model states that there are three stages of mental processing required before information can be firmly stored in memory: sensory, short-term, and long-term memory. II. STORING NEW MEMORIES A. Sensory Memory Sensory memory holds information from all the senses in sensory registers for a fraction of a second. Selective attention focuses mental processing on only part of the stimulus field. B. Short-Term Memory and Working Memory Short-term memory (STM) receives the information that was perceived and selectively attended to in sensory memory or retrieved from long-term memory. If no further processing occurs, short-term memory disappears in twenty to thirty seconds. Working memory has two components: maintenance of information in STM and manipulation of that information. 1. Encoding. Across cultures, people tend to use acoustic codes to encode information into short-term memory. Visual codes tend to decay faster than acoustic codes. 2. Storage Capacity of STM. The immediate memory span is the number of items you can recall perfectly after one presentation of a stimulus. It is usually seven plus or minus two chunks of information. 3. The Power of Chunking. Short-term memory can be noticeably improved by creating bigger and bigger chunks, or groups, of information. Efficient chunking requires the interaction of short- and long-term memory. 4. Duration of STM. Brown-Peterson procedure research results indicate that, unless rehearsed, material stays in short-term memory for about eighteen seconds. C. Long-Term Memory 1. Encoding. Encoding information into long-term memory (LTM) is the result of a deep level of conscious processing and usually involves some form of semantic encoding. Visual codes are also used to encode long-term memories. The dual coding theory states that information is remembered better if both semantic and visual codes are used. 2. Storage Capacity of LTM. Most theorists believe that there is no limit to the amount of information that can be stored in long-term memory; however, they realize that our memories can be quite distorted. D. Distinguishing Between Short-Term and Long-Term Memory Psychologists disagree about the differences between short-term and long-term memory. Some believe that short-term and long-term memory are the same; what is referred to as short-term memory is the part of long-term memory that is being used at a particular moment in time. Others claim that short-term and long-term memory obey different laws. 1. Experiments on Recall. Serial position curves show a tendency to recall both the first and last parts of a list (primacy and recency effects) when memory is immediately tested. NOTE: If participants are distracted just prior to being asked to recall a list, the primacy effect remains, but the recency effect disappears. This suggests that the last words were stored in short-term memory, which quickly decays. III. RETRIEVING MEMORIES Retrieval is the ability to bring a memory into consciousness. A. Retrieval Cues and Encoding Specificity Retrieval cues help retrieve information from long-term memory. According to the encoding specificity principle, these cues are more efficient when they reflect the meaning of the originally encoded information. B. Context and State Dependence When people remember more material while in a physical location that is similar to the one where the material was originally learned, the memories are called context dependent. Memories are state dependent when people remember better while in the same psychological state as when the information was encoded. In the mood congruency effect, recall is facilitated if a person’s emotional state is similar in tone to the information being recalled. C. Retrieval from Semantic Memory 1. Semantic Networks. One theory states that semantic memories are represented in a dense network of hierarchical associations. Strong associations and/or those at the top of the hierarchy are quickly retrieved. Network theory suggests that information is retrieved through a spreading activation process; for example, thinking about concept X spreads neural activity to all other features, attributes, and concepts associated with concept X. 2. Retrieving Incomplete Knowledge. In a phenomenon called incomplete knowledge (such as the tip-of-the-tongue phenomenon or the feeling-of-knowing experience), we often retrieve features and attributes of a concept but can’t access the entire concept. For example, we may not remember the name of a place, but we can remember its physical features. D. Constructing Memories People construct memories from their existing knowledge to fill in gaps in new information that is being encoded. 1. Relating Semantic and Episodic Memory: PDP Models. PDP models allow us to increase our general knowledge of the world by accessing a network of facts and associations. A note of caution: PDP models can facilitate spontaneous generalizations of networks that are based on limited or biased information. 2. Schemas. According to PDP models, the generalized knowledge contained in schemas provides the basis for making inferences about incoming information during the encoding stage. E. Linkages: Memory, Perception and Eyewitness Testimony Witnesses can accurately report what they have seen or heard, but can be biased by the manner in which questions are asked and relevant occurrences are discussed. Jurors may rely too heavily on how witnesses present evidence, such as reporting a great deal of detail or appearing very confident of what they are reporting (i.e., see the misinformation effect). The Department of Justice released a guide for how police and prosecutors should obtain eyewitness evidence. IV. FORGETTING A. How Do We Forget? Ebbinghaus’s contributions to psychology included demonstration of the method of savings and the shape of the forgetting curve. The forgetting curve, which depicts how much and when people forget, stays relatively constant regardless of the type of information learned. B. Why Do We Forget? The Roles of Decay and Interference 1. Decay, the gradual erosion of a memory, is the most common culprit for short-term memory loss. 2. Interference causes forgetting by interrupting the encoding or retrieval process through the presence of other information. In short-term memory, new information displaces old information because of the limited space available. However, in long-term memory, space is not the issue; rather, as the number of stored memories increases, it becomes more and more difficult to “find” one particular memory among the huge number of memories. Interference is the main cause of forgetting in long-term memory. a) Retroactive interference is when learning new information interferes with recall of older information b) Proactive interference is when older information interferes with learning or recall of new information. V. BIOLOGICAL BASES OF MEMORY Brain cells change as memories are formed and stored. An early theory suggested that memories are represented by a set of interconnected neurons called a cell assembly. A. The Biochemistry of Memory Two types of synaptic changes occur during memory formation: New synapses are formed, and communication at existing synapses is improved (long-term potentiation). Neurotransmitters, such as glutamate and acetylcholine, are involved in memory processes. B. Brain Structures and Memory The hippocampus and the thalamus are important in the formation of new memories. Memories are stored in many different areas of the cortex. However, no single brain structure or neurotransmitter is exclusively involved in memory formation or storage. 1. The Impact of Brain Damage. Damage to the hippocampus often results in anterograde amnesia, a loss of memory of events occurring after the injury. Patients cannot transfer new experiences from short-term memory to long-term memory. Retrograde amnesia is the loss of memory of events prior to an injury. Although many injury patients regain most of their memories, few can recall the events just prior to the injury. As a result of the injury, the short-term memories of what happened were never transferred to long-term memory. Memory deficits in several medical conditions support the theory that short-term memory and long-term memory are distinct storage systems. 2. Multiple Storage Areas. Memories are probably stored in and around the cortex, with certain brain areas storing specific aspects of each event. For example, the cerebellum is involved in the storage of procedural memories. VI. APPLICATIONS OF MEMORY RESEARCH A. Improving Your Memory 1. Mnemonics. Mnemonics are strategies for remembering information. The method of loci associates well-known locations with information to be remembered. 2. Guidelines for More Effective Studying. Create a context, such as an outline, for organizing information. Elaborate the new information and associate it with related knowledge you already possess. Remember that distributed practice is more effective than massed practice. 3. Reading a Textbook. Make sure you understand what you are reading before you go on. Use the PQ4R method of preview, question, read, reflect, recite, and review. 4. Lecture Notes. Focus on creating a framework for facts (outline) and expressing major ideas in relatively few words. Finally, work to see and understand the relationship between facts and concepts. Review your notes as soon as possible after a lecture and fill in the gaps. B. Design for Memory The scientific study of memory has influenced the design of electronic and mechanical devices that play important roles in our lives. Two examples are placing only the least- likely-to-be-remembered instructions on a device and using words for toll-free numbers to help people chunk information.