lecture 14 - memory and the senses 2 Flashcards

Question

competing theories of verbal short-term memory

Answer 1

the phonological loop provides a strong account of verbal STM but has limits—especially in explaining serial order and retrieval processes. Alternative models offer different approaches: Feature Model (Nairne, 1988, 1990): Proposes a single memory system using modality-dependent and independent features. Forgetting occurs due to interference. It explains phonological similarity and articulatory suppression but struggles with data like post-stimulus irrelevant sound and mixed word-length lists. SIMPLE Model (Brown et al., 2007): A general model of memory and forgetting based on temporal distinctiveness. Good at explaining free recall, less so for serial recall, and does not address executive functions. SOB Model (Farrell & Lewandowsky, 2002): Maintains serial order using event-based context rather than time-based decay. It models interference as the cause of forgetting. Despite progress, explaining serial order in STM remains challenging—especially for models based solely on activated long-term memory. Repeated items, like in "71216", require temporary distinct representations that simple activation-based models struggle to provide

Answer 2

Most verbal STM research uses small, repeated sets (digits, letters, or words) to isolate serial order recall, minimizing influence from LTM. Using novel items increases LTM effects like word meaning. In free recall, serial order still affects memory. People tend to recall recent (recency effect) and early (primacy effect) items better. Recency is strong unless disrupted by a task (e.g., counting), while primacy is linked to rehearsal, though this isn't always effective. Glanzer & Cunitz (1966) proposed that: Primacy reflects LTM encoding. Recency reflects STM. Delays affect only recency, not early items. LTM-related factors (e.g., word frequency, imageability, age, drugs) affect early list items but not recency. However, Bjork & Whitten (1974) challenged the STM-only view by showing recency persists even with inter-item delays. Baddeley & Hitch (1977) also found long-term recency effects, e.g., in rugby players recalling past games. These effects depend more on intervening events than time. This suggests recency reflects a retrieval strategy—recent items are simply more accessible. Crowder (1976) likened this to visually distinguishing nearby vs. distant telephone poles. The discrimination ratio explains why recent items are easier to recall: they’re more distinct from prior ones

Answer 3

Imagine a sudden power cut in a well-lit room. Would you remember the door’s location? Or recall the box of matches on the desk? These questions concern spatial memory (where?) and object memory (what?). Research suggests you could maintain a general heading towards the door for about 30 seconds, but precise location memory fades more quickly. But is visual STM just for moments like power cuts, or would LTM suffice? Visual STM is more crucial for managing our visual perception. When we scan our environment, we don’t continuously perceive; instead, our eyes make discrete movements, creating snapshots of the world. These glimpses are combined into a coherent representation by visual STM. For effective functioning, visual STM must maintain this representation while allowing constant updates as we move. It must bind perceptual features with spatial context, allowing for actions like targeting an object. This process involves object-based STM (binding features into a single object) and spatial STM (locating the object in space)

Answer 4

As is typical of many areas of experimental psychology, the study of visual STM has largely relied on simple easily specified stimuli such as colored shapes or letters rather than stones or wolves. The reason is that such stimuli are much easier to create, control, and specify and this means that others can repeat your findings; such replication is of course an essential and basic feature of all science. However carefully a study is designed and carried out, it may be subject to chance factors such as a nontypical participant group, or sample of stimulus material, as I myself can testify. Replication with different participants and a different sample of material avoids becoming misled by such problems. Having developed principles and theories using simple and well-controlled material such as colored shapes, the next stage is to take such findings beyond the laboratory, demonstrating in due course what is termed its “ecological validity,” its applicability to the “real world.” A detailed analysis of visual STM has only developed relatively recently, hence most of the work to be described does use quite simple stimuli, although there is a growing interest in studying visual STM using more complex real-world scenes (see Henderson, 2008; Hollingworth, 2008)

Answer 5

Using change detection, Phillips (1974) showed that performance in recalling complex chequerboard patterns declined over time, especially with more intricate patterns, suggesting a limited visual STM capacity. In a later study, Luck and Vogel (1997) used a similar task with colored squares and found that visual STM capacity was limited to three or four items, with performance declining as the number of squares increased. This contrasts with LTM, where capacity appears vast. In a study by Standing et al. (1970), participants correctly identified scenes from 2,560 slides shown briefly, with memory retention even after several days. Despite being less precise, visual LTM can store large amounts of information, though it has limitations when items are highly similar, as shown by the clinical test involving 24 door scenes (Baddeley et al., 1994). The discrepancy in LTM capacity is due to the nature of the test: visual LTM can quickly assess familiarity, but precise comparison of similar items requires more effort. Ultimately, visual LTM’s capacity is far greater than visual STM, which also holds true for visual semantic memory, such as recalling details about familiar objects, faces, or environments

Answer 6

Visual STM benefits from actively maintaining items in focus. McCollough, Machizawa, and Vogel (2007) used ERPs to study brain activity during the delay in a visual STM task. They found increased activation in the contralateral hemisphere, which rose with the number of items up to four, with unsuccessful trials showing lower activation. Vogel, McCollough, and Machizawa (2005) further linked this activation to memory performance, showing a direct correlation between neurophysiological measures and participants' STM abilities

Answer 7

Vogel, Woodman, and Luck (2001) explored how visual STM handles more complex stimuli, finding that people could combine multiple features (e.g., color, shape) into a single object with little difficulty. However, more complex stimuli, like 8 × 8 matrices, are harder to remember, indicating that object complexity impacts visual STM capacity. Binding, the process of combining separate features (e.g., color and shape) into a single object, is key to this. Studies show that binding is largely automatic. In tasks where participants only had to remember colors, shapes, or bound features, binding performance was no worse than recalling single features. Allen, Baddeley, and Hitch (2006) found that even with an attention-demanding task, binding did not require more attention than remembering separate features, suggesting binding operates automatically. While binding itself doesn’t demand executive resources, the overall memory process is affected by executive load. This indicates that while perceptual binding doesn’t rely on executive attention, the broader memory performance does.

Answer 8

Spatial STM (remembering "where") and object memory (remembering "what") work together but can be tested separately. The Corsi span test, a classic spatial task, involves reproducing a sequence of tapped blocks, typically with a span of around five blocks. Visual span, measured using matrix patterns, involves reproducing a pattern of filled cells, with performance typically breaking down at 16 cells. Studies show that spatial and visual memory are distinct. For example, Corsi span is disrupted by spatial tasks, while visual span is affected by visual tasks (Della Sala et al., 1999). Visual STM includes memory for shapes and colors, as demonstrated by Klauer and Zhao (2004), where spatial memory for a dot was disrupted by spatial tasks, and memory for ideographs was affected by visual tasks involving color processing

Answer 9

We don’t remember everything we see. In one study, people were asked for directions while two confederates carrying a door passed between them, during which the questioner was replaced. Only 50% noticed the change (Levin & Simons, 1997). Similarly, in a video where participants counted basketball passes, half failed to notice a person in a gorilla suit walking through the scene (Simons & Chabris, 1999). These examples highlight how attentional demand can lead to "blindness," with implications for situations like driving while distracted, where critical details may go unnoticed.

Answer 10

Luck and Vogel (1997) found that STM could hold up to three to four objects, regardless of their complexity. This was explained by a slot model, where memory has a limited number of slots for integrated objects. However, later studies suggested that memory capacity decreases as object complexity increases (Fougnie et al., 2010). Wilken and Ma (2004) proposed a continuous report method to measure memory precision, finding that as set size increased, memory precision decreased, but still centered on the correct value. When set size exceeded four, accuracy declined and guessing increased. Some studies argue that a flexible version of the slot model is needed. Alvarez and Cavanagh (2004) found a capacity limit of around four items but showed that the complexity of stimuli affected performance. While the upper limit is around four, the nature of the objects plays a role. Miller’s (1956) concept of "chunks" offers a less rigid model and aligns with research on chunking in verbal STM

Answer 11

The study of patients with specific STM deficits has been crucial in developing the field. Shallice and Warrington (1970) studied patient KF, who had a digit span of only two items and poor recency in free recall. This was later found to be a specific phonological STM deficit, as KF performed better with visual tasks. Similarly, patient PV (Basso et al., 1982; Vallar & Baddeley, 1987) had a specific phonological STM deficit after a stroke, with normal intellect and language. PV’s digit span was also two, and she showed reduced recency effects in verbal recall. However, she demonstrated normal long-term recency in tasks like recalling anagram solutions, suggesting her impairment was in using recency to boost immediate verbal memory

Answer 12

Some patients, like KF and PV, have deficits limited to verbal STM, while others, like LH and LE, show impaired visual or spatial STM but preserve verbal memory. LH, after a head injury, struggled with remembering colors and shapes but had excellent spatial memory. LE, affected by lupus, had impaired visual memory and could no longer visualize her sculptures, despite maintaining spatial memory. Conversely, patients like MV, with right frontal lobe damage, had normal visual memory but impaired spatial memory, as seen in tasks like the Corsi block tapping test. These cases highlight how deficits in visual and spatial STM often affect complex tasks like mental imagery, sculpting, and spatial orientation, linking these issues to broader STM and working memory impairments

Answer 13

The term short-term memory (STM) refers to the temporary storage of relatively small amounts of information whereas working memory (WM) is a complex system that is capable of both storing and manipulating information. * Early approaches to STM involved the digit span and related sequential verbal tasks. * The concept of a phonological loop explains verbal STM by assuming a temporary store and an articulatory rehearsal process. * It gives a simple account of the phonological similarity effect, the word length effect, and the effect on these of subvocal rehearsal. * It is assumed to help in learning new words and also in controlling actions. * Inherent in the memory span task is the problem of serial order and how it is maintained, a problem that has led to a number of detailed models. * Free recall typically shows a marked recency effect which has resulted in a number of influential models applied to both STM and LTM. * Most current studies of visual STM focus on simple stimuli such as colors and shapes and the question of how these are bound into unified colored shapes. * Visual STM has a capacity limit of about four items and has been interpreted as depending on a storage system comprising four slots. * However, it is also the case that the limited available attentional capacity can be used to store fewer items in more detail. * Spatial STM is separable from its visual equivalent and depends on somewhat different neural systems. * Laboratory studies of both verbal and visual STM have been extended and enriched by studies of patients with STM deficits

lecture 14 - memory and the senses 2 Flashcards

(37 cards)