CPS613 – 2-6 MEMORY 1 ATKINSON-SHIFFRIN MULTI-STORE MEMORY MODEL SENSORY MEMORIES = SENSORY REGISTERS Definition: Buffers for stimuli received through the senses Sensory “trace” of the stimulus remains after it is gone. They are constantly overwritten by new stimuli coming through channels Types: Iconic memory for visual stimuli: 0.5 seconds Echoic memory for aural stimuli: about 4 seconds Haptic memory for touch: longer SHORT-TERM MEMORY = WORKING MEMORY Scratchpad for temporary recall of information Can be accessed rapidly (around 70 ms) Duration: decays rapidly: information stays there for about 30s to 5mns Limited capacity Information does not have to be in same modality as sensory input (e.g. visual information can be stored as auditory information) CPS613 – 2-6 MEMORY 2 LONG-TERM MEMORY = MAIN MEMORY Definition: main memory used to store everything we know Knowledge Stored: Declarative Knowledge: (what) . factual knowledge concerning the nature of the world, in both its physical and its social aspects; it includes: o knowledge about what words, numbers, and other symbols mean; o knowledge about what attributes objects possess; what categories they belong to; o knowledge of events, and the contexts in which they take place. Can be perception-based or meaning-based Procedural Knowledge: (how) . rules and skills used to manipulate and transform declarative knowledge; . includes the rules of mathematical and logical operations; the rules of grammar, inference, and judgment; . includes strategies for encoding and retrieving memories; . includes motor skills. Properties Huge capacity (limits not known) Slow access time: 1/10 seconds Little decay: long-term recall same after minutes, hours or days Types of memory: Episodic memory: memory of events and experiences in a serial form, including a description of the episodic context (time and place) Semantic memory: context-free structured record of facts, concepts, and skills acquired Information in semantic memory can be derived from episodic memory: we learn new facts from experience Semantic Memory Structure: Semantic Network (Collins and Quillian 1969) Frames (Minsky 1974) Scripts (Tomkins 1979) Production systems CPS613 – 2-6 MEMORY 3 INFORMATION FLOW: Attention Definition: concentration of the mind on one out of a number of competing stimuli or thoughts. Attention is necessary to avoid stimulation overload. Attention is voluntary: it can be focused involuntary: stronger stimuli can change focus Attention is based on level of interest or need Attention can be divided Rehearsal Processes for retaining information in memory All involve repetition of information Maintenance Rehearsal: to retain information in short-term memory simple repetition of information Elaborative Rehearsal: to transfer information into long-term memory repetition of information augmented with o related semantic information o unrelated semantic information (mnemonics) o sensory associations Retrieval Recall: information reproduced from memory Recognition: selection of information from given information Recognition easier than recall Forgetting Decay is logarithmic: information lost very quickly and then more slowly Retroactive Interference: new information causes loss of old information Proactive inhibition: old information masks new .