What is Short-Term Memory?

STM Task vs. ST Processing An Important Distinction!! Each memory model will have its own account of processing for STM Tasks

The Modal Model Vs. The Working Memory Model

The phonological loop The visuospatial sketchpad The central executive The episodic buffer Modules in the Modified WM Model

Approaches to Testing the Model Dual tasks including concurrent vocalization, repeating random digits, visual scanning, etc. Double Dissociations Both with case studies & in normal populations using a concurrent task Delays Converging Operations

Some Examples Clinical Cases Some patients do poorly on STM tasks but well on LTM tasks Others do well on STM tasks but poorly on LTM tasks A Double Dissociation!! Inferences to Best Explanation?? Some patients do well on digit span but poorly on the Corsi spatial span Others do poorly on digit span but well on the Corsi spatial span Another Double Dissociation!!

Concurrent memory task effects on verbal reasoning Concurrent task: repeating sequences of random numbers Verbal reasoning example: A follows B BA (true/false?) Error rate unaffected Inference to Best Explanation?

Baddley study using a pursuit rotor A spot of light moves along a circular path & the subject has to track it with a stylus This tracking became the concurrent task Subjects had to learn a list of words using either an imagery technique or a verbal rote memory technique Imagery better except when performing the concurrent tracking task Inference to Best Explanation??

Daneman & Carpenter, 1980 Measuring working memory span using prose memory Task: verify a sequence of sentences & then recall the last word of each Inference to Best Explanation? The episodic buffer

Baddeley et al, 1975 The word length effect Task: immediate memory for sequences of words Results: 1) memory declines as words become longer 2) subjects who rehearse rapidly tend to have longer spans 3) disappears with articulatory suppression Inference to Best Explanation? The rehearsal process operates in real time. Memory span set by two factors: the rate at which the memory trace fades the speed at which items can be rehearsed

Chess Research Moderate vs. Expert Chess players viewed chess boards with pieces places on the board & then had to recall them Dual task methodology used: articulatory suppression spatial tapping generation of number sequences none Results: Memory highly correlated with chess skill Both groups showed no interruption from articulatory suppression Both groups showed a moderate degree of interruption from spatial task Both groups showed a substantial drop when random number generation was required Inference to Best Explanation? Attentional control through the central executive is limited in capacity

The Case of Jeremy How well does the working memory model vs. the modal model account for Jeremy’s problems?