Chapter 10 Memory

The Evolution of Multiple Memory Systems The ability to store memories and memes is adaptive, although memories may or may not contribute directly to fitness. Most of us suffer from inaccurate memories and false memories, which can compromise an individual's fitness.

The Information-Processing Model of Memory Memory may be thought of as a three-stage process, in which information in each stage lasts longer than in the preceding one.

Measuring the Duration of Sensory Memory George Sperling measured the duration of an icon. Sperling projected three rows of four letters each onto a screen for one-twentieth of a second. By "viewing" a visual afterimage of the icon, subjects could report 3 or 4 of the 12 letters correctly. Sperling estimated that their iconic memory of the image lasted about one-third to a one-half second.

The Cocktail Party Phenomenon The process of moving information from the sensory store to short-term memory is called selective attention. The cocktail party phenomenon is an example: the ability to pick out and selectively hear one voice among many.

Dichotic Listening Task A person can pay attention to only one of two different messages played into the ears. In dichotic listening, a subject shadows, or repeats back, the message in one ear. Typically, subjects can detect the physical characteristics of sounds presented to the other ear, but not their meaning.

Chunking Chunking a 20-digit telephone number into six chunks helps in memorizing it.

The Duration of Short-term Memory Three to 18 seconds after hearing three consonants and being unable to rehearse them, subjects were asked to recall them. As the time interval between hearing and recall increased, the percentage of consonants the subjects recalled decreased.

Long-term Memory for Spanish Researchers measured how much Spanish people retained years after they had studied the language. Surprisingly, people who had taken several semesters of high-school Spanish retained 40 percent of what they had learned, even after 50 years.

The Serial Position Effect After hearing a list of 20 words, subjects immediately wrote down as many as they could remember, in any order. With few exceptions, they remembered more words from the beginning and end of the list than from the middle, producing this u-shaped function.

The Phonological Loop Polysyllabic words are read at a slower rate than shorter words, and recalled less often in tests of memory. In this experiment, subjects read one-syllable words at a rate of about 2 per second, but four-syllable words at about half that rate. Likewise, they recalled 90 percent of the one-syllable words, but less than 50 percent of the four- syllable words.

The Primacy Effect The tendency for items at the beginning of a list to be remembered better than items in the middle. The primacy effect may be caused by maintenance rehearsal: silent repetition of each item as it is processed.

The Process of Encoding Two Types of Encoding Intentional Encoding Example: studying (deep processing) Automatic Encoding Example: information having to do with time and place (shallow processing)

Levels of Processing In one experiment (Craik & Tulving, 1975), subjects who rehearsed words in terms of their physical characteristics did not remember them well. Subjects who rehearsed them in the form of rhymes or used them in sentences remembered them better.

Elaborative Rehearsal A strategy of associating a target stimulus with other information at the time of encoding.

Implicit Memory The phenomenon of being influenced by the memory of a past experience, even though you have no conscious memory of it.

Implicit Memories Lasts Longer than Explicit Memories Subjects often do not remember the words that prime their responses, suggesting that implicit (unconscious) memories last longer than explicit (conscious) memories.

Schemas A series of ten subjects viewed and later redrew an image from memory. By the tenth drawing, the original drawing of an owl had been transformed into a cat through a series

The Effect of Leading Questions Which view is correct? Subjects viewed one of these scenes in a series of photos showing the events leading up to an accident. When asked later which of the nearly identical scenes they saw, their recollections were influenced by verbal instructions that confirmed or disconfirmed the photo's content.of encoding distortions.

Tulving's Multiple Memory Systems

The Mental Lexicon: Words in Categories

The Forgetting Function

Theories of Forgetting Decay Theory: the theory that existing memories interfere with the encoding and retrieval of memories. Interference Theory: –Proactive interference - interference in the learning of new information caused by existing memories. –Retroactive interference - interference in the retrieval of old memories caused by newly learned information.

The Process of Retrieval from Memory Retrieval cues –Retrieval cues help people solve problems by using available bits of information, including mnemonics, rhymes, and songs, to direct memory searches. Context effects –Context effects on memory can occur when retrieval cues match encoding cues. State-dependency effects –State-dependency effects on memory can occur when a subject's physiological or psychological state at the time of retrieval matches the state at the time of encoding.

Brain Areas Involved in the Formation of Memory

Amnesia Two types: –Retrograde amnesia - the loss of memory for events that preceded a brain injury. –Anterograde amnesia - the inability to form new memories following an injury to the brain.