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Current time:0:00Total duration:3:39

Semantic networks and spreading activation

Video transcript

in order to solve problems and make decisions you often have to access information already stored in your brain but how is that information stored there are a lot of possibilities but the one we're going to focus on in this video is the semantic network approach which argues that concepts are organized in your mind in terms of connected ideas you can kind of think of this as parallel to how information might be stored in a computer you have different nodes which represent your concepts and those nodes are connected by links depending on how connected the nodes are the links might be shorter for closely related ideas or longer for less related ideas let me show you an example to make this a little more concrete the first semantic Network model was hierarchical meaning that they thought concepts were organized from higher order categories down to lower order categories and their exemplars so let's start with a general category animal so that's this node here animal might be linked to other nodes such as bird or fish and bird might be further link to canary Bluebird or more distantly ostrich ostrich is probably not the first thing you think of when you think of a bird so that's why it's link is longer but simple labels aren't the only type of knowledge that we store we can store characteristics and properties of concepts at each node according to the principle of cognitive economy which just means that our brain is efficient we store these properties at the highest possible node for example then instead of storing can breathe at each animal's node we store that property just at the animal node more specific characteristics such as sings or long legs would be stored at lower level nodes one pretty interesting piece of supporting evidence for this type of hierarchical organization comes from how long it takes people to verify certain statements and this kind of test you say a statement and ask people to tell you if it's true or not as you can imagine people verify a canary as a canary pretty quickly it takes fam a little longer to verify a canary as a bird and even longer to verify that a canary is an animal so this is some support that we store things in a hierarchical manner because the longer it takes us to verify a connection between two nodes then the longer those links are or the more nodes we have to go through to make that link however this isn't true for all types of animals or even all types of categories for example people tend to verify that a pig is an animal faster than a pig as a mammal because of this issue and some other problems Collins and Loftus proposed a modified version of the semantic network rather than a hierarchical organization this model says that every individual semantic network develops based on their experience and knowledge so some links might be longer or shorter for different individuals and there may be direct links from higher-order categories to their exemplars one pretty cool thing about semantic networks is that it means all the ideas in your head are connected together so when you activate one concept you're pulling up related concepts along with it this general elevation and availability is called spreading activation for example if I say fire engine not only do you think of a fire engine but related concepts such as trucks fire even the color red become activated making it easier for you to retrieve or identify those items