Semantic Memory Flashcards
What does semantic memory refer to?
Sometimes our memories do not refer to specific events but are more encyclopedic. This general knowledge is semantic memory.
How does the effect of priming demonstrate a salient characteristic of the semantic memory?
A salient characteristic of semantic memory is its organized and regular structure. Remembering one concept brings related memories closer to awareness. This facilitation of related ideas is priming
How is semantic memory structured? i.e what is it based on
Semantic memory is structured based on shared aspects of meaning metaphorically stored closer together. Because they are more activated, if there is then a need to use them they are now closer to conscious awareness and can be used more readily.
What task are people typically given in a priming study?
A lexical decision task. That is, they are given strings of letters and asked to indicate whether they are words. In these studies, there are pairs of words: a critical item, called a prime, is followed by a target. What is of interest is how fast people respond to the target (such as by pressing a button).
How quickly is priming observed in ERP recordings? Why?
Priming is even observed in ERP recordings as early as 250 ms after the target word is presented. This is because it is easier for the brain to activate that information, so it doesn’t need to work as hard.
Functionally, why does semantic priming occur? (2)
Semantic priming occurs because concepts are not understood in isolation but in terms of how they relate to each other. By activating related concepts, people bring to bear a larger set of knowledge to help them understand and think.
Priming also helps people detect inconsistencies. When people encounter semantically anomalous information, such as hearing the sentence “the doctor listened with his carrot,” ERP recordings show an increased electrical negativity around 400 ms after first seeing it.
What is meant by mediated priming?
When retrieving the concept “lion” it is likely that the concept “tiger” is activated because these are both large, predatory cats. If “tiger” is primed, are concepts related to it also activated, such as “stripes”? This would be mediated priming because the connection between “lion” and “stripes” is mediated by “tiger.”
Does mediated priming actually occur when studied?
In general, mediated priming does occur, as shown by using both response times and ERP recordings. However, mediated priming is more fragile than direct priming. Its priming is smaller in magnitude and it is sometimes not observed
What is the fan effect and how does it relate to the semantic memory?
In episodic memory, increased numbers of associations with a concept can slow down retrieval time, as in the fan effect. Semantic memory is made up of very large numbers of associations among concepts. This interconnectivity can be thought of as a complex network of concepts and associations.
And so, based on the fan effect, one would expect that it should be difficult to retrieve semantic information. However, the opposite is true. Specifically, concepts in semantic memory that have more interconnections are retrieved faster
Why is this different pattern of results regarding the fan effect associated observed?
In semantic memory these associations provide both direct and indirect connections among concepts. Two concepts might be directly associated but also share a number of intermediate concepts, which functionally increases the number of retrieval pathways between them. As a result, there are many ways that concepts can prime one another.
How is inhibition related to semantic memory?
Like episodic memory, inhibition can be used to help narrow a memory search to the appropriate part of semantic memory.
During retrieval, related concepts may be inhibited. For example, people retrieve the concept “salmon” for the category FISH more slowly if they had recently retrieved several other examples of fish.
How long does the conversion of episodic to semantic memory take and how may it be accelerated?
Information requires a great deal of time to move from episodic to semantic memory. For example, in a study by Dagenbach, Horst, and Carr (1990), students at Millersville University did not show
significant priming of newly learned words until after five weeks of practice. Thus, the conversion of knowledge from episodic to semantic memory can be a long process. That said, this process can be accelerated if new learning is done in many different contexts or settings rather than just one
When people process concepts through the semantic memory, do they tend to rely on more associative (what words tend to occur together) or similarity information?
For semantic memory, when people process abstract concepts (e.g., barrier) they tend to rely more on associative information (what words tend to occur together), but when they are concrete concepts (e.g., mushroom) people rely more on similarity information
That said, it may be the case that even abstract concepts have an embodied element. Concepts such as horror and beauty have an associated emotional element, and the bodily experience of the emotion may be tied, in some way, to some abstract concepts
Describe a study which demonstrates that semantic knowledge is influenced by how we physically interact with the world
Pecher, Zeelenberg, and Barsalou (2003) gave students a property identification task in which they were shown pairs of words, such as “BLENDER–loud.” The task was to indicate whether the second word was a property of the first. Students were faster when the property was from the same sensory modality as the previous trial. For example, people were faster to respond to “BLENDER– loud” if it immediately followed “LEAVES–rustling” (which also involves sound) than if it followed “CRANBERRIES–tart” (which involves the sense of taste).
What is the purpose of categorisation?
The process of categorization allows us to draw on prior experience in a regular and reliable fashion in new situations. We can assume that some of the elements of the new situation will be like those that were observed previously. (e.g dog)
What are the three levels of categorisation?
basic- The one at which we operate at most often. It is at this level that categories are defined by features that provide enough detail to allow us to treat different members as similar but without providing more detail than is often necessary (saw, dog, chair, drum).
subordinate- Provides detailed information about more specific portions of a basic category. (camping saw, miniature poodle, leather recliner, and kettle drum)
Superordinate- very general information that captures a wide range of basic-level categories ( tool, pet, furniture, and musical instrument)
How does retrieval speed differ between these categories? (3)
In general, basic-level category information is retrieved better than the other two. People can retrieve more attributes for basic level categories and are able to retrieve the names of basic- level categories faster than the others. This suggests that the basic level has some primacy in semantic memory.
Categories have many members. Describe three ways in which their combined influence may manifest themself
First, categories exhibit a central tendency, or averaged category ideal.
Second, categories have graded membership. Some members are thought of as being better members of the category than others (e.g robin vs penguin).
Finally, members of a category might not be defined by a single set of features. Different features may be shared among several category instances. This is called family resemblance.
Describe an important distinction between two classes of categories. Why is a distinction made here?
Artifact categories (things that people make) and natural kind categories (things that are found in nature). These category classes are served by different brain regions.
First, like most semantic memories, the left hemisphere tends to be more involved than the right. Natural kinds, such as animals, tend to involve more of the medial fusiform gyrus (BA 37) and superior temporal gyrus (BA 41).
In comparison, artifacts involve more of the lateral fusiform gyrus (BA 37) and the posterior middle temporal gyrus (BA 21), near brain regions important for verbs and action
Describe two other differences between these classes of categorisation
While both classes of categories show graded membership, this is more evident in artifact categories. This is because people have more certainty about natural kinds (e.g., what makes something a bird), and have more ambiguity about artifacts (e.g., what makes something a tool).
Also, people make perceptual decisions faster when comparing objects from natural kind categories (what something looks like tells you what it is) but make manipulability (how you use it) decisions faster when comparing objects from artifact categories
What is the classical view of categorisation?
The idea that categories are defined by necessary and sufficient features is the classical view of categorization. They are necessary in that those features must be present and they are sufficient in that, as long as they are present, something is a member of a category.
Describe a study providing evidence for the classical view of categorisation
A study by Bruner, Goodnow, and Austin provided support for the classical view. In this study, people were shown figures where items can be identified along four dimensions: the type of objects, their number, their color, and the number of borders. When people are given subsets of items, along with an indication of whether each one is a member of a category, people can derive the category rules.
How is this classical view limited in its explanations?
The classical view cannot explain central tendency, graded membership, and family resemblance.
Part of this rests on the fact that the brain does not work on the either/or principles of a digital computer. Instead, it makes judgments based on loose and shifting collections of cell assemblies, giving the judgments it produces a fuzzier quality
How can elements, features, or properties that define category members can vary in their importance?
Rarer features are more diagnostic than common features in defining a category. For example, “has a trunk” is more defining of an elephant than is “breathes,” although both are needed.
Describe prototype theory
Categories are organized, in part, using unconscious mental statistics. One idea of how this is done is the prototype model. For this view, categories are determined by a mental representation that is an average of all category members. This averaged representation is a prototype, which may or may not correspond to an actual entity in the world.
Describe a study which attempted to present evidence for prototype theory
An example of prototype extraction using dot patterns: When people first learned the categories, they were shown deviations from the prototypes. The prototypes were never shown during learning. However, when people were later asked to sort both old and new patterns the prototypes were identified and correctly sorted at a high rate of accuracy, suggesting that they were derived and used to make decisions If people can readily derive prototypes from things as meaningless as dot patterns, surely the same mental mechanisms are involved for deriving categories of our everyday experiences with everyday objects.
how is this use of prototypes also seen with meaningful stimuli?
For example, if photographs of faces are used for making preference judgments along with morphed composites of faces, people rate the composite faces, which are closer to the prototype face, as more attractive. That is, people prefer faces that are averages of others. Because they are averages, they have fewer unusual and distinguishing characteristics and so are easier to mentally process. A pretty face is a boring face. This is also part of the reason why attractive faces are harder to remember
What do prototypes provide a clear explanation for?
They provide a clear explanation for the central tendencies of categories (which is the prototype itself) and a graded category structure. The closer an instance is to the prototype, the better a member of the category it is.
What aspects are not accounted for in prototype theory?
For example, people are often aware of a category size —that is, about how many different members are in the category.
Prototypes convey no information about the variability among category members.
Also, a caricature (a category member with exaggerated features) is thought to better represent a category than a prototype when a category is considered in the context of other, related categories. That is because the caricature captures distinctive features and emphasizes them. This helps distinguish one category from other, similar categories.
Name and describe two other approaches to categorisation
Exemplar theory: people use all the category members to make decisions (e.g. thinking of all birds to decide whether something is a bird)
Explanation-based views: people try to have reasons for why things should be grouped together, categories are theories or explanations (feathers and wings tend to go together because feathers are suited for flying).
Describe advantages to exemplar theory
Captures central tendency, graded membership, and family resemblance, as well as information about category size, variability, correlated attributes, and any new information about the category (Because categorization is
always using all of the memory traces, new experiences can have an influence).
They can explain the context sensitivity of categories. For example, the color gray is more similar to white in the context of hair color but is more similar to black in the context of clouds
Previously activated semantic meanings can bias how new information is interpreted. For example, a phrase like “adolescent doctor” is easier to interpret if it follows the phrase “animal doctor” than if it follows “country doctor.”
Do people tend to use prototype or exemplar based processes?
it seems that both are used, though in different circumstances. Specifically, it is more adaptive in a natural environment to move early on from a more exemplar-based form of categorization to a more prototype based form of categorization.
This allows people to deal with the family resemblance of many natural kinds and be less led astray by more peripheral and irrelevant features of individual category members
Describe a serious problem with both prototype and exemplar theories
An inherent circularity. Specifically, categories are defined by experiences with members of that category. That is, the members of the category all contribute to defining it. However, the memory traces that are selected are those that conform to the criteria of the category. In short, how can memory traces be selected to define a category if the category is needed to select them in the first place?
Describe two tendencies which people have that is consistent with the idea that they are creating explanations for what makes something a category
In general, people place an emphasis on causal factors as compared to the effects. For example, knowing that an animal swims is a more fundamental characteristic than knowing that an animal has webbed feet (presumably they have webbed feet because they swim).
Also, categories are defined, in part, by how people interact with things not just statistical regularities. For example, what makes something a chair has more to do with your sitting in it than with the materials used to make it.
What are ad hoc categories? What makes them interesting?
People can make new categories on the fly. These are ad hoc categories. For example, coffee, perfume, leather, and skunks are all members of the category things with a distinctive smell. Ad hoc categories are interesting because people generate them off the cuff but they have many of the same properties as standard categories. They have a central tendency, graded structures, and family resemblance. Thus, some semantic memory structures are generated spontaneously. This raises questions about the stability of semantic memory in general.
