PSYCH 258 Lecture 15 PDF Fall 2024

Lecture 15 STM/WM, LTM: Structure Cognitive Psychology PSYCH 258 A3 James Farley, Fall 2024  Working Memory The Central Executive central executive...

Lecture 15 STM/WM, LTM: Structure Cognitive Psychology PSYCH 258 A3 James Farley, Fall 2024  Working Memory The Central Executive central executive Failures of the CE can be associated with perseveration: repeatedly performing the same action or thought even if it is not achieving the desired goal the results you want but you stick to that way of eg) studying a certain way for exams and not getting studying One criticism of the CE is that it resembles an homunculus, meaning it is supposed to do all of these important things though there is very little in the way of specifics to describe/ explain how they are accomplished (i.e. somewhat of a ‘black box’ that lacks formal descriptions, theoretical predictions, etc.) problem with CE ? https://upload.wikimedia.org/wikipedia/commons/1/17/Faust_image_19thcentury.jpg Working Memory An Added Component: The Episodic Buffer place where our mind stores information that we don't need right now but we'll need in the future (information here can also last much longer tha information in the phonological loop The episodic buffer was added to the basic three-piece WM model to account for the fact that we can hold more information than would be expected based on the estimated capacity limits of the other components e.g. we can ‘preload’ into memory a very complicated story that involves far more information than the phonological loop is thought to be able to accommodate This component therefore acts as a sort of backup buffer, temporarily holding information retrieved from LTM until the central executive allocates it to one of the other components  Working Memory An Added Component: The Episodic Buffer http://aspsychologyblackpoolsixth.weebly.com/working-memory-model.html Working Memory and the Brain The Effect of Damage to the Prefrontal Cortex The prefrontal cortex is responsible for processing incoming visual and auditory information Monkeys without a prefrontal cortex have difficulty holding information in working memory monkeys used to be able to easily find food after seeing where it is once but after prefrontal cortex became damaged, they were no longer able to find the food as easily, more of a 50/50 thing up to chance; prefrontal cortex plays big role in WM This can be demonstrated using a delayed-response task Working Memory and the Brain Why Can More Working Memory Be Better? Funahashi et al. (1989) used single cell recordings to examine what happens in the prefrontal cortex during a delay-response task Neurons responded when stimulus was flashed in a particular location Information remains available via these neurons for as long as they continue firing, even if stimuli disappears from screen (see next slide) Working Memory and the Brain Why Can More Working Memory Be Better? Individual differences in WM experiment by Vogel et al. (2005) Participants’ WM capacity was assessed and they were grouped based on that factor (high vs. low capacity) Were shown either simple or complex stimuli (w or w/o distractors, see next slide) while ERP responses recorded What would load theory predict (remember, distractors tend to get automatically processed as long as some residual resources/perceptual capacity are available)? Working Memory and the Brain Why Can More Working Memory Be Better? High-capacity participants demonstrated less of a response to the distractors Suggests the high-capacity participants more efficiently ignored (filtered/inhibited, etc.) the distractors Attributable to central executive?  Chapter 6: LTM Structure https://www.sambrinson.com/digital-brain/ Long-Term Memory (LTM) Questions How does damage to the brain affect memory? How are memories for personal experiences (e.g. what you did over the weekend), different from memories for facts (e.g. knowing what the capital of Canada is) different kinds of memories involve different parts of the brain How do the different types of memory interact in our everyday experience? Long-Term Memory What Is It? Long-term memory (LTM) can be thought of as an ‘archive’ of information about past events and knowledge learned Works closely with STM/WM Storage stretches from a few moments ago to as far back as one can remember More recent memories tend to be more detailed lots of memories are full of mistakes/errors and aren't 100% what actually occurred Serial Position Curve Primacy and Recency Effects Murdoch (1962) studied the distinction between short-term and long-term memories using the serial position curve Participants read stimulus list, then wrote down all the words they could remember Primacy effect: memory better for stimuli presented at beginning Recency effect: memory better for stimuli at the end of the list you remember things better the more recently you've seen them Serial Position Curve dashed blue line, showing frequency of people repeating words to themseklves (while reading a list) Primacy and Recency Effects - this decreases the more you read the list because there are too many words to repeat One explanation for the primacy effect is that it occurs because participants had more time to rehearse the earlier items (and/or experienced less interference while encoding them), making them more likely to enter LTM Differences in how many times each word was rehearsed as a function of serial position (the dashed blue line) support this interpretation Serial Position Curve LTM or STM? One explanation for the recency effect is that it occurs because the stimuli was still active in STM at the point at which participants’ memory was tested Introducing a delay can eliminate this effect, which supports that interpretation Coding in Short-Term and Long-Term Memory Modalities and Coding Coding refers to the form in which stimuli are represented The form a representation takes can have important implications In both STM and LTM, visual, auditory, and semantic coding can be used Auditory coding tends to be the most common form in STM (recall the phonological similarity effect) Semantic coding tends to be the most form in LTM