{"id":487,"date":"2023-03-03T19:12:49","date_gmt":"2023-03-03T19:12:49","guid":{"rendered":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/reading-storage\/"},"modified":"2025-11-17T22:55:16","modified_gmt":"2025-11-17T22:55:16","slug":"reading-storage","status":"publish","type":"chapter","link":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/chapter\/reading-storage\/","title":{"raw":"How Memory Functions: Learn It 2\u2014Storage: Sensory, Short Term, and Long-Term Memory","rendered":"How Memory Functions: Learn It 2\u2014Storage: Sensory, Short Term, and Long-Term Memory"},"content":{"raw":"<h2>Storing Memories<\/h2>\r\n<p data-start=\"338\" data-end=\"527\">One of the most influential ways psychologists have studied memory is through the <strong data-start=\"420\" data-end=\"452\">information-processing model<\/strong>, which compares the human mind to a computer. Like a computer, your brain:<\/p>\r\n<ol>\r\n\t<li>Receives input from the environment<\/li>\r\n\t<li>Processes and organizes that information<\/li>\r\n\t<li>Produces an output, such as a thought, decision, or action<\/li>\r\n<\/ol>\r\n<h3 data-start=\"890\" data-end=\"923\"><strong data-start=\"892\" data-end=\"923\">The Atkinson\u2013Shiffrin Model<\/strong><\/h3>\r\n<p data-start=\"925\" data-end=\"1031\">Within the information-processing framework, Richard Atkinson and Richard Shiffrin (1968), proposed that memory moves through <strong data-start=\"1005\" data-end=\"1030\">three distinct stages<\/strong>:<\/p>\r\n<ol>\r\n\t<li data-start=\"1036\" data-end=\"1056\">Sensory Memory<\/li>\r\n\t<li data-start=\"1060\" data-end=\"1089\">Short-Term Memory (STM)<\/li>\r\n\t<li data-start=\"1093\" data-end=\"1121\">Long-Term Memory (LTM)<\/li>\r\n<\/ol>\r\n<p>Their model (Figure 1) was the first to describe memory as a system of stages\u2014much like information moving through a computer\u2019s processors. Information (visual, auditory, tactile, etc.) enters from the environment, briefly lingers in sensory memory, moves into short-term memory if we pay attention to it, and may eventually be stored in long-term memory through rehearsal or meaningful processing.<\/p>\r\n<section data-depth=\"1\"><\/section>\r\n<section data-depth=\"1\">\r\n<figure>\r\n[caption id=\"\" align=\"aligncenter\" width=\"649\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/902\/2015\/02\/23224848\/CNX_Psych_08_01_Atkinson.jpg\" alt=\"Atkinson-Shiffrin model of memory. Sensory input flows to Stage 1 \u201cSensory Memory\u201d. Information not transferred is lost. Sensory memory flows to Stage 2 \u201cShort-term memory (STM)\u201d where rehearsal takes place. Information not transferred is lost. Short-term memory flows to Stage 3 \u201cLong-term memory (LTM) which also flows back to Stage 2 \u201cShort-term memory\u201d.\" width=\"649\" height=\"335\" data-media-type=\"image\/jpeg\" \/> <strong>Figure 1<\/strong>. According to the Atkinson-Shiffrin model of memory, information passes through three distinct stages in order for it to be stored in long-term memory.[\/caption]\r\n<\/figure>\r\n<h2>Sensory Memory<\/h2>\r\n<p>In the Atkinson-Shiffrin model, stimuli from the environment are processed first in sensory memory: storage of brief sensory events, such as sights, sounds, and tastes. We are constantly bombarded with sensory information. We cannot absorb all of it, or even most of it. And most of it has no impact on our lives.<\/p>\r\n<p>For example, what was your professor wearing the last time you saw them? Chances are, you don't remember. Sensory information about sights, sounds, smells, and even textures, which we do not view as valuable information, we discard.<\/p>\r\n<p>If light reflects off your cup of coffee hits your eye; the image is transferred through the optic nerve to the sensory register. If you do not attend to it, it fades from this memory store and is lost. In fact, your cup may be on your desk most of the time, and you see it without really \u201cseeing\u201d it many times during the day. If we view something as valuable, the information will move into our short-term memory system.<\/p>\r\n<section class=\"textbox keyTakeaway\">\r\n<h3>sensory memory<\/h3>\r\n<p>Sensory memory is the first and briefest stage of memory. It stores raw sensory input\u2014what you see, hear, smell, taste, and touch\u2014for only a fraction of a second to a few seconds.<\/p>\r\n<\/section>\r\n<h3>Inconic and Echoic Memory<\/h3>\r\n<p>Visual sensory memory is known as <strong>iconic memory<\/strong> (from the word icon or \"image).<\/p>\r\n<p>Iconic memory was first studied by the psychologist George Sperling (1960). In his research, Sperling showed participants a display of letters in rows, similar to that shown in Figure X, \u201cMeasuring Iconic Memory.\u201d However, the display lasted only about 50 milliseconds (1\/20 of a second).<\/p>\r\n<p>Then, Sperling gave his participants a recall test in which they were asked to name all the letters that they could remember. On average, the participants could remember only about one-quarter of the letters that they had seen.<\/p>\r\n<p>Auditory sensory memory is called <strong>echoic memory<\/strong>, named after the phenomenon of an echo. Unlike iconic memory that tends to fade quickly, echoic memories have a longer lifespan and can persist for up to four seconds (Cowan, Lichty, &amp; Grove, 1990).<\/p>\r\n<p>This feature is beneficial in various ways, for instance, it enables you to recall the beginning of an extensive sentence when you reach its end, or to jot down your psychology professor's last remark even after they've completed their sentence.<\/p>\r\n<h2>Short-Term Memory<\/h2>\r\n<p><span id=\"term-00016\" data-type=\"term\">Short-term memory (STM)<\/span>\u00a0is a temporary storage system that processes incoming sensory memory. The terms short-term and working memory are sometimes used interchangeably, but they are not exactly the same.<\/p>\r\n<p>Short-term memory is more accurately described as a component of working memory. Short-term memory takes information from sensory memory and sometimes connects that memory to something already in long-term memory.<\/p>\r\n<p>Short-term memory storage lasts 15 to 30 seconds. Think of it as the information you have displayed on your computer screen, such as a document, spreadsheet, or website. Then, information in STM goes to long-term memory (you save it to your hard drive), or it is discarded (you delete a document or close a web browser).<\/p>\r\n<section class=\"textbox keyTakeaway\">\r\n<h3>short-term memory<\/h3>\r\n<p data-start=\"3107\" data-end=\"3285\"><strong data-start=\"3107\" data-end=\"3128\">Short-term memory<\/strong> is a limited-capacity system that holds information you are currently using or thinking about. STM typically lasts <strong data-start=\"3244\" data-end=\"3261\">15\u201330 seconds<\/strong> unless you rehearse it.<\/p>\r\n<p data-start=\"3107\" data-end=\"3285\"><br \/>\r\nFor example, you are trying to remember a phone number that someone just gave you, so you begin repeating it to keep it in STM until you have a chance to write it down or dial it. However, if someone interrupts you to ask you a question while you are rehearsing the number, responding interferes with rehearsal, and the phone number is lost.<\/p>\r\n<\/section>\r\n<section data-depth=\"2\">\r\n<div>\r\n<section class=\"textbox tryIt\">\r\n<h3>Short-Term Memory Practice<\/h3>\r\n\r\nYou may find yourself asking, \u201cHow much information can our memory handle at once?\u201d To explore the capacity and duration of your short-term memory, have a partner read the strings of random numbers out loud to you, beginning each string by saying, \u201cReady?\u201d and ending each by saying, \u201cRecall,\u201d at which point you should try to write down the string of numbers from memory.\r\n\r\n<figure>\r\n[caption id=\"\" align=\"aligncenter\" width=\"487\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/902\/2015\/02\/23224851\/CNX_Psych_08_01_Numbers.jpg\" alt=\"A series of numbers includes two rows, with six numbers in each row. From left to right, the numbers increase from four digits to five, six, seven, eight, and nine digits. The first row includes \u201c9754,\u201d \u201c68259,\u201d \u201c913825,\u201d \u201c5316842,\u201d \u201c86951372,\u201d and \u201c719384273,\u201d and the second row includes \u201c6419,\u201d \u201c67148,\u201d \u201c648327,\u201d \u201c5963827,\u201d \u201c51739826,\u201d and \u201c163875942.\u201d\" width=\"487\" height=\"67\" data-media-type=\"image\/jpeg\" \/> <strong>Figure 2<\/strong>. Work through this series of numbers using the recall exercise explained above to determine the longest string of digits that you can store.[\/caption]\r\n<\/figure>\r\n<p>Note the longest string at which you got the series correct. For most people, the capacity will probably be close to 7 plus or minus 2. In 1956, George Miller reviewed most of the research on the capacity of short-term memory and found that people can retain between 5 and 9 items, so he reported the capacity of short-term memory was the \"magic number\" 7 plus or minus 2. However, more contemporary research has found working memory capacity is 4 plus or minus 1 (Cowan, 2010). Generally, recall is somewhat better for random numbers than for random letters (Jacobs, 1887) and also often slightly better for information we hear (acoustic encoding) rather than information we see (visual encoding) (Anderson, 1969).<\/p>\r\n<\/section>\r\n<\/div>\r\n<h3 data-type=\"title\">From STM to LTM: The Role of Rehearsal<\/h3>\r\n<p><strong>Rehearsal<\/strong> moves information from short-term memory to long-term memory.<\/p>\r\n<section class=\"textbox keyTakeaway\">\r\n<h3>rehearsal<\/h3>\r\n<p><strong>Active rehearsal<\/strong> (or maintenance rehearsal) is a way of attending to information to move it from short-term to long-term memory. During active rehearsal, you repeat (practice) the information to be remembered. If you repeat it enough, it may be moved into long-term memory. For example, this type of active rehearsal is the way many children learn their ABCs by singing the alphabet song.<\/p>\r\n<p>&nbsp;<\/p>\r\n<p>Alternatively, <strong>elaborative rehearsa<\/strong>l is the act of linking new information you are trying to learn to existing information that you already know. For example, if you meet someone at a party and your phone is dead but you want to remember his phone number, which starts with area code 203, you might remember that your uncle Abdul lives in Connecticut and has a 203 area code. This way, when you try to remember the phone number of your new prospective friend, you will easily remember the area code.<\/p>\r\n<\/section>\r\n<h3 data-start=\"4526\" data-end=\"4554\"><strong data-start=\"4530\" data-end=\"4554\">Levels of Processing<\/strong><\/h3>\r\n<p data-start=\"4556\" data-end=\"4638\">Craik &amp; Lockhart (1972) proposed the <strong data-start=\"4593\" data-end=\"4623\">Levels of Processing Model<\/strong>, which states that\u00a0the deeper you think about something and the more meaning you can associate with it, the better you remember it.<\/p>\r\n<h3 data-start=\"4556\" data-end=\"4638\">Memory Traces<\/h3>\r\n<p>When memories are encoded and stored in the brain, they have to be stored somewhere, so the brain biochemically alters itself and its neural tissue. Just like you might write yourself a note to remind you of something, the brain \u201cwrites\u201d what's called a <strong>memory trace<\/strong>, or engram, changing its own physical composition to do so.<\/p>\r\n<p>The basic idea is that events (occurrences in our environment) create a memory trace through a process of <strong>consolidation<\/strong>: the neural changes that occur after rehearsal to move a memory into long-term memory. <strong>Memory trace decay,\u00a0<\/strong>when the physical record of a memory fades, and <strong>interference,<\/strong> memory obstruction caused by competing information, are two factors that affect short-term memory retention.<\/p>\r\n<section class=\"textbox connectIt\">\r\n<h3>How long can you remember?<\/h3>\r\n\r\nPeterson and Peterson (1959) investigated short-term memory using the 3 letter sequences called trigrams (e.g., CLS) that had to be recalled after various time intervals between 3 and 18 seconds. Participants remembered about 80% of the trigrams after a 3-second delay, but only 10% after a delay of 18 seconds, which caused them to conclude that short-term memory decayed in 18 seconds. During decay, the memory trace becomes less activated over time, and the information is forgotten. <br \/>\r\n<br \/>\r\nHowever, Keppel and Underwood (1962) examined only the first trials of the trigram task and found that interference, where previously learned trigrams interfered with learning new trigrams, also affected short-term memory retention.<\/section>\r\n<section data-depth=\"2\">\r\n<h2 data-type=\"title\">Long-Term Memory<\/h2>\r\n<section class=\"textbox keyTakeaway\">\r\n<h3>long-term memory<\/h3>\r\n<p data-start=\"5359\" data-end=\"5503\"><strong data-start=\"5359\" data-end=\"5379\">Long-term memory<\/strong> is the system for storing information over long durations\u2014from hours to decades. Its capacity is <strong data-start=\"5477\" data-end=\"5502\">essentially unlimited<\/strong>. It\u00a0holds information that is not in immediate use but needs to be remembered for an extended period of time.<\/p>\r\n<\/section>\r\n<h3 data-start=\"5894\" data-end=\"5934\"><strong data-start=\"5896\" data-end=\"5934\">How Is Long-Term Memory Organized?<\/strong><\/h3>\r\n<p data-start=\"5936\" data-end=\"6088\">Most researchers agree that memories are stored in <strong data-start=\"5987\" data-end=\"6008\">semantic networks<\/strong>, where concepts are linked by meaningful associations (Collins &amp; Loftus, 1975).<\/p>\r\n<p data-start=\"6103\" data-end=\"6152\">For example, hearing \u201cpeanut butter\u201d may immediately activate:<\/p>\r\n<ul>\r\n\t<li>jelly<\/li>\r\n\t<li>sandwich<\/li>\r\n\t<li>lunch<\/li>\r\n\t<li>childhood memories<\/li>\r\n\t<li>American foods<\/li>\r\n<\/ul>\r\n<p data-start=\"6211\" data-end=\"6297\">This is <strong data-start=\"6219\" data-end=\"6243\">spreading activation<\/strong>\u2014one concept activates related concepts automatically. The more connections a memory has, the easier it is to retrieve.<\/p>\r\n<\/section>\r\n<h2>Other Memory Models<\/h2>\r\n<p data-start=\"357\" data-end=\"791\">The Atkinson\u2013Shiffrin model was the first major framework to describe memory as a system of stages, and it remains useful for understanding the movement from sensory memory to short-term and long-term storage. However, psychologists have since developed additional models that refine, expand, or challenge aspects of this early approach. These newer models highlight that memory is far more complex than a simple three-stage pipeline.<\/p>\r\n<h3 data-start=\"793\" data-end=\"854\"><strong data-start=\"797\" data-end=\"852\">Levels of Processing Model (Craik &amp; Lockhart, 1972)<\/strong><\/h3>\r\n<p data-start=\"855\" data-end=\"1003\">Instead of focusing on <em data-start=\"878\" data-end=\"885\">where<\/em> memory is stored, the Levels of Processing model explains memory in terms of <em data-start=\"963\" data-end=\"975\">how deeply<\/em> information is processed.<\/p>\r\n<ul>\r\n\t<li><strong data-start=\"1006\" data-end=\"1028\">Shallow processing<\/strong> (e.g., focusing on how a word looks or sounds) leads to weak, short-lived memory.<\/li>\r\n\t<li><strong data-start=\"1115\" data-end=\"1134\">Deep processing<\/strong> (thinking about meaning, making connections, applying information) produces more durable, long-term memories.<br data-start=\"1244\" data-end=\"1247\" \/>\r\nThis model helps explain why elaboration, making personal connections, and studying with meaning-based strategies improve learning.<\/li>\r\n<\/ul>\r\n<h3 data-start=\"1380\" data-end=\"1424\"><strong data-start=\"1384\" data-end=\"1422\">Tulving\u2019s Long-Term Memory Systems<\/strong><\/h3>\r\n<p data-start=\"1425\" data-end=\"1567\">Endel Tulving argued that long-term memory is not one unified system, but several specialized systems supported by different brain networks:<\/p>\r\n<ul>\r\n\t<li data-start=\"1570\" data-end=\"1642\"><strong data-start=\"1570\" data-end=\"1589\">Episodic memory<\/strong> \u2014 personal experiences and autobiographical events<\/li>\r\n\t<li data-start=\"1645\" data-end=\"1707\"><strong data-start=\"1645\" data-end=\"1664\">Semantic memory<\/strong> \u2014 facts, concepts, and general knowledge<\/li>\r\n\t<li data-start=\"1710\" data-end=\"1951\"><strong data-start=\"1710\" data-end=\"1731\">Procedural memory<\/strong> \u2014 skills, habits, and motor abilities<\/li>\r\n<\/ul>\r\n<p>This model is helpful for explaining why someone with amnesia may forget personal events (episodic memory) but still remember how to play piano or ride a bike (procedural memory).<\/p>\r\n<h3 data-start=\"1953\" data-end=\"2012\"><strong data-start=\"1957\" data-end=\"2010\">Baddeley and Hitch Model of Working Memory (1974)<\/strong><\/h3>\r\n<p data-start=\"2013\" data-end=\"2246\">Baddeley and Hitch expanded on the idea of short-term memory by showing that it is not a single \u201cholding tank\u201d but a collection of specialized systems that actively work with information. They proposed that working memory includes:<\/p>\r\n<ul>\r\n\t<li data-start=\"2249\" data-end=\"2310\">A <strong data-start=\"2251\" data-end=\"2272\">phonological loop<\/strong> for verbal and auditory information<\/li>\r\n\t<li data-start=\"2313\" data-end=\"2375\">A <strong data-start=\"2315\" data-end=\"2341\">visuospatial sketchpad<\/strong> for visual and spatial material<\/li>\r\n\t<li data-start=\"2378\" data-end=\"2444\">An <strong data-start=\"2381\" data-end=\"2400\">episodic buffer<\/strong> that integrates information across senses<\/li>\r\n\t<li data-start=\"2447\" data-end=\"2703\">A <strong data-start=\"2449\" data-end=\"2470\">central executive<\/strong> that directs attention and manages all three systems<\/li>\r\n<\/ul>\r\n<p data-start=\"2447\" data-end=\"2703\">This model helps explain everyday experiences\u2014such as why it\u2019s harder to remember a phone number while someone is talking to you (two tasks competing for the phonological loop).<\/p>\r\n<h3 data-start=\"2705\" data-end=\"2775\"><strong data-start=\"2709\" data-end=\"2773\">Connectionist\/Parallel Distributed Processing (PDP) Models<\/strong><\/h3>\r\n<p data-start=\"2776\" data-end=\"2994\">More recent models view memory through the lens of neural networks. In connectionist models, memory is stored as <strong data-start=\"2889\" data-end=\"2915\">patterns of activation<\/strong> across many interconnected nodes, rather than in separate \u201cboxes\u201d or stages.<\/p>\r\n<ul>\r\n\t<li data-start=\"2997\" data-end=\"3050\">Learning strengthens the connections between nodes.<\/li>\r\n\t<li data-start=\"3053\" data-end=\"3268\">Retrieval occurs when a pattern is reactivated.<\/li>\r\n<\/ul>\r\n<p>This approach resembles how modern artificial neural networks learn and helps explain why memories can be fuzzy, reconstructive, and influenced by related knowledge.<\/p>\r\n<section class=\"textbox tryIt\">[ohm2_question height=\"400\"]4205[\/ohm2_question]<\/section>\r\n<\/section>\r\n<\/section>","rendered":"<h2>Storing Memories<\/h2>\n<p data-start=\"338\" data-end=\"527\">One of the most influential ways psychologists have studied memory is through the <strong data-start=\"420\" data-end=\"452\">information-processing model<\/strong>, which compares the human mind to a computer. Like a computer, your brain:<\/p>\n<ol>\n<li>Receives input from the environment<\/li>\n<li>Processes and organizes that information<\/li>\n<li>Produces an output, such as a thought, decision, or action<\/li>\n<\/ol>\n<h3 data-start=\"890\" data-end=\"923\"><strong data-start=\"892\" data-end=\"923\">The Atkinson\u2013Shiffrin Model<\/strong><\/h3>\n<p data-start=\"925\" data-end=\"1031\">Within the information-processing framework, Richard Atkinson and Richard Shiffrin (1968), proposed that memory moves through <strong data-start=\"1005\" data-end=\"1030\">three distinct stages<\/strong>:<\/p>\n<ol>\n<li data-start=\"1036\" data-end=\"1056\">Sensory Memory<\/li>\n<li data-start=\"1060\" data-end=\"1089\">Short-Term Memory (STM)<\/li>\n<li data-start=\"1093\" data-end=\"1121\">Long-Term Memory (LTM)<\/li>\n<\/ol>\n<p>Their model (Figure 1) was the first to describe memory as a system of stages\u2014much like information moving through a computer\u2019s processors. Information (visual, auditory, tactile, etc.) enters from the environment, briefly lingers in sensory memory, moves into short-term memory if we pay attention to it, and may eventually be stored in long-term memory through rehearsal or meaningful processing.<\/p>\n<section data-depth=\"1\"><\/section>\n<section data-depth=\"1\">\n<figure>\n<figure style=\"width: 649px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/902\/2015\/02\/23224848\/CNX_Psych_08_01_Atkinson.jpg\" alt=\"Atkinson-Shiffrin model of memory. Sensory input flows to Stage 1 \u201cSensory Memory\u201d. Information not transferred is lost. Sensory memory flows to Stage 2 \u201cShort-term memory (STM)\u201d where rehearsal takes place. Information not transferred is lost. Short-term memory flows to Stage 3 \u201cLong-term memory (LTM) which also flows back to Stage 2 \u201cShort-term memory\u201d.\" width=\"649\" height=\"335\" data-media-type=\"image\/jpeg\" \/><figcaption class=\"wp-caption-text\"><strong>Figure 1<\/strong>. According to the Atkinson-Shiffrin model of memory, information passes through three distinct stages in order for it to be stored in long-term memory.<\/figcaption><\/figure>\n<\/figure>\n<h2>Sensory Memory<\/h2>\n<p>In the Atkinson-Shiffrin model, stimuli from the environment are processed first in sensory memory: storage of brief sensory events, such as sights, sounds, and tastes. We are constantly bombarded with sensory information. We cannot absorb all of it, or even most of it. And most of it has no impact on our lives.<\/p>\n<p>For example, what was your professor wearing the last time you saw them? Chances are, you don&#8217;t remember. Sensory information about sights, sounds, smells, and even textures, which we do not view as valuable information, we discard.<\/p>\n<p>If light reflects off your cup of coffee hits your eye; the image is transferred through the optic nerve to the sensory register. If you do not attend to it, it fades from this memory store and is lost. In fact, your cup may be on your desk most of the time, and you see it without really \u201cseeing\u201d it many times during the day. If we view something as valuable, the information will move into our short-term memory system.<\/p>\n<section class=\"textbox keyTakeaway\">\n<h3>sensory memory<\/h3>\n<p>Sensory memory is the first and briefest stage of memory. It stores raw sensory input\u2014what you see, hear, smell, taste, and touch\u2014for only a fraction of a second to a few seconds.<\/p>\n<\/section>\n<h3>Inconic and Echoic Memory<\/h3>\n<p>Visual sensory memory is known as <strong>iconic memory<\/strong> (from the word icon or &#8220;image).<\/p>\n<p>Iconic memory was first studied by the psychologist George Sperling (1960). In his research, Sperling showed participants a display of letters in rows, similar to that shown in Figure X, \u201cMeasuring Iconic Memory.\u201d However, the display lasted only about 50 milliseconds (1\/20 of a second).<\/p>\n<p>Then, Sperling gave his participants a recall test in which they were asked to name all the letters that they could remember. On average, the participants could remember only about one-quarter of the letters that they had seen.<\/p>\n<p>Auditory sensory memory is called <strong>echoic memory<\/strong>, named after the phenomenon of an echo. Unlike iconic memory that tends to fade quickly, echoic memories have a longer lifespan and can persist for up to four seconds (Cowan, Lichty, &amp; Grove, 1990).<\/p>\n<p>This feature is beneficial in various ways, for instance, it enables you to recall the beginning of an extensive sentence when you reach its end, or to jot down your psychology professor&#8217;s last remark even after they&#8217;ve completed their sentence.<\/p>\n<h2>Short-Term Memory<\/h2>\n<p><span id=\"term-00016\" data-type=\"term\">Short-term memory (STM)<\/span>\u00a0is a temporary storage system that processes incoming sensory memory. The terms short-term and working memory are sometimes used interchangeably, but they are not exactly the same.<\/p>\n<p>Short-term memory is more accurately described as a component of working memory. Short-term memory takes information from sensory memory and sometimes connects that memory to something already in long-term memory.<\/p>\n<p>Short-term memory storage lasts 15 to 30 seconds. Think of it as the information you have displayed on your computer screen, such as a document, spreadsheet, or website. Then, information in STM goes to long-term memory (you save it to your hard drive), or it is discarded (you delete a document or close a web browser).<\/p>\n<section class=\"textbox keyTakeaway\">\n<h3>short-term memory<\/h3>\n<p data-start=\"3107\" data-end=\"3285\"><strong data-start=\"3107\" data-end=\"3128\">Short-term memory<\/strong> is a limited-capacity system that holds information you are currently using or thinking about. STM typically lasts <strong data-start=\"3244\" data-end=\"3261\">15\u201330 seconds<\/strong> unless you rehearse it.<\/p>\n<p data-start=\"3107\" data-end=\"3285\">\nFor example, you are trying to remember a phone number that someone just gave you, so you begin repeating it to keep it in STM until you have a chance to write it down or dial it. However, if someone interrupts you to ask you a question while you are rehearsing the number, responding interferes with rehearsal, and the phone number is lost.<\/p>\n<\/section>\n<section data-depth=\"2\">\n<div>\n<section class=\"textbox tryIt\">\n<h3>Short-Term Memory Practice<\/h3>\n<p>You may find yourself asking, \u201cHow much information can our memory handle at once?\u201d To explore the capacity and duration of your short-term memory, have a partner read the strings of random numbers out loud to you, beginning each string by saying, \u201cReady?\u201d and ending each by saying, \u201cRecall,\u201d at which point you should try to write down the string of numbers from memory.<\/p>\n<figure>\n<figure style=\"width: 487px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/902\/2015\/02\/23224851\/CNX_Psych_08_01_Numbers.jpg\" alt=\"A series of numbers includes two rows, with six numbers in each row. From left to right, the numbers increase from four digits to five, six, seven, eight, and nine digits. The first row includes \u201c9754,\u201d \u201c68259,\u201d \u201c913825,\u201d \u201c5316842,\u201d \u201c86951372,\u201d and \u201c719384273,\u201d and the second row includes \u201c6419,\u201d \u201c67148,\u201d \u201c648327,\u201d \u201c5963827,\u201d \u201c51739826,\u201d and \u201c163875942.\u201d\" width=\"487\" height=\"67\" data-media-type=\"image\/jpeg\" \/><figcaption class=\"wp-caption-text\"><strong>Figure 2<\/strong>. Work through this series of numbers using the recall exercise explained above to determine the longest string of digits that you can store.<\/figcaption><\/figure>\n<\/figure>\n<p>Note the longest string at which you got the series correct. For most people, the capacity will probably be close to 7 plus or minus 2. In 1956, George Miller reviewed most of the research on the capacity of short-term memory and found that people can retain between 5 and 9 items, so he reported the capacity of short-term memory was the &#8220;magic number&#8221; 7 plus or minus 2. However, more contemporary research has found working memory capacity is 4 plus or minus 1 (Cowan, 2010). Generally, recall is somewhat better for random numbers than for random letters (Jacobs, 1887) and also often slightly better for information we hear (acoustic encoding) rather than information we see (visual encoding) (Anderson, 1969).<\/p>\n<\/section>\n<\/div>\n<h3 data-type=\"title\">From STM to LTM: The Role of Rehearsal<\/h3>\n<p><strong>Rehearsal<\/strong> moves information from short-term memory to long-term memory.<\/p>\n<section class=\"textbox keyTakeaway\">\n<h3>rehearsal<\/h3>\n<p><strong>Active rehearsal<\/strong> (or maintenance rehearsal) is a way of attending to information to move it from short-term to long-term memory. During active rehearsal, you repeat (practice) the information to be remembered. If you repeat it enough, it may be moved into long-term memory. For example, this type of active rehearsal is the way many children learn their ABCs by singing the alphabet song.<\/p>\n<p>&nbsp;<\/p>\n<p>Alternatively, <strong>elaborative rehearsa<\/strong>l is the act of linking new information you are trying to learn to existing information that you already know. For example, if you meet someone at a party and your phone is dead but you want to remember his phone number, which starts with area code 203, you might remember that your uncle Abdul lives in Connecticut and has a 203 area code. This way, when you try to remember the phone number of your new prospective friend, you will easily remember the area code.<\/p>\n<\/section>\n<h3 data-start=\"4526\" data-end=\"4554\"><strong data-start=\"4530\" data-end=\"4554\">Levels of Processing<\/strong><\/h3>\n<p data-start=\"4556\" data-end=\"4638\">Craik &amp; Lockhart (1972) proposed the <strong data-start=\"4593\" data-end=\"4623\">Levels of Processing Model<\/strong>, which states that\u00a0the deeper you think about something and the more meaning you can associate with it, the better you remember it.<\/p>\n<h3 data-start=\"4556\" data-end=\"4638\">Memory Traces<\/h3>\n<p>When memories are encoded and stored in the brain, they have to be stored somewhere, so the brain biochemically alters itself and its neural tissue. Just like you might write yourself a note to remind you of something, the brain \u201cwrites\u201d what&#8217;s called a <strong>memory trace<\/strong>, or engram, changing its own physical composition to do so.<\/p>\n<p>The basic idea is that events (occurrences in our environment) create a memory trace through a process of <strong>consolidation<\/strong>: the neural changes that occur after rehearsal to move a memory into long-term memory. <strong>Memory trace decay,\u00a0<\/strong>when the physical record of a memory fades, and <strong>interference,<\/strong> memory obstruction caused by competing information, are two factors that affect short-term memory retention.<\/p>\n<section class=\"textbox connectIt\">\n<h3>How long can you remember?<\/h3>\n<p>Peterson and Peterson (1959) investigated short-term memory using the 3 letter sequences called trigrams (e.g., CLS) that had to be recalled after various time intervals between 3 and 18 seconds. Participants remembered about 80% of the trigrams after a 3-second delay, but only 10% after a delay of 18 seconds, which caused them to conclude that short-term memory decayed in 18 seconds. During decay, the memory trace becomes less activated over time, and the information is forgotten. <\/p>\n<p>However, Keppel and Underwood (1962) examined only the first trials of the trigram task and found that interference, where previously learned trigrams interfered with learning new trigrams, also affected short-term memory retention.<\/section>\n<section data-depth=\"2\">\n<h2 data-type=\"title\">Long-Term Memory<\/h2>\n<section class=\"textbox keyTakeaway\">\n<h3>long-term memory<\/h3>\n<p data-start=\"5359\" data-end=\"5503\"><strong data-start=\"5359\" data-end=\"5379\">Long-term memory<\/strong> is the system for storing information over long durations\u2014from hours to decades. Its capacity is <strong data-start=\"5477\" data-end=\"5502\">essentially unlimited<\/strong>. It\u00a0holds information that is not in immediate use but needs to be remembered for an extended period of time.<\/p>\n<\/section>\n<h3 data-start=\"5894\" data-end=\"5934\"><strong data-start=\"5896\" data-end=\"5934\">How Is Long-Term Memory Organized?<\/strong><\/h3>\n<p data-start=\"5936\" data-end=\"6088\">Most researchers agree that memories are stored in <strong data-start=\"5987\" data-end=\"6008\">semantic networks<\/strong>, where concepts are linked by meaningful associations (Collins &amp; Loftus, 1975).<\/p>\n<p data-start=\"6103\" data-end=\"6152\">For example, hearing \u201cpeanut butter\u201d may immediately activate:<\/p>\n<ul>\n<li>jelly<\/li>\n<li>sandwich<\/li>\n<li>lunch<\/li>\n<li>childhood memories<\/li>\n<li>American foods<\/li>\n<\/ul>\n<p data-start=\"6211\" data-end=\"6297\">This is <strong data-start=\"6219\" data-end=\"6243\">spreading activation<\/strong>\u2014one concept activates related concepts automatically. The more connections a memory has, the easier it is to retrieve.<\/p>\n<\/section>\n<h2>Other Memory Models<\/h2>\n<p data-start=\"357\" data-end=\"791\">The Atkinson\u2013Shiffrin model was the first major framework to describe memory as a system of stages, and it remains useful for understanding the movement from sensory memory to short-term and long-term storage. However, psychologists have since developed additional models that refine, expand, or challenge aspects of this early approach. These newer models highlight that memory is far more complex than a simple three-stage pipeline.<\/p>\n<h3 data-start=\"793\" data-end=\"854\"><strong data-start=\"797\" data-end=\"852\">Levels of Processing Model (Craik &amp; Lockhart, 1972)<\/strong><\/h3>\n<p data-start=\"855\" data-end=\"1003\">Instead of focusing on <em data-start=\"878\" data-end=\"885\">where<\/em> memory is stored, the Levels of Processing model explains memory in terms of <em data-start=\"963\" data-end=\"975\">how deeply<\/em> information is processed.<\/p>\n<ul>\n<li><strong data-start=\"1006\" data-end=\"1028\">Shallow processing<\/strong> (e.g., focusing on how a word looks or sounds) leads to weak, short-lived memory.<\/li>\n<li><strong data-start=\"1115\" data-end=\"1134\">Deep processing<\/strong> (thinking about meaning, making connections, applying information) produces more durable, long-term memories.<br data-start=\"1244\" data-end=\"1247\" \/><br \/>\nThis model helps explain why elaboration, making personal connections, and studying with meaning-based strategies improve learning.<\/li>\n<\/ul>\n<h3 data-start=\"1380\" data-end=\"1424\"><strong data-start=\"1384\" data-end=\"1422\">Tulving\u2019s Long-Term Memory Systems<\/strong><\/h3>\n<p data-start=\"1425\" data-end=\"1567\">Endel Tulving argued that long-term memory is not one unified system, but several specialized systems supported by different brain networks:<\/p>\n<ul>\n<li data-start=\"1570\" data-end=\"1642\"><strong data-start=\"1570\" data-end=\"1589\">Episodic memory<\/strong> \u2014 personal experiences and autobiographical events<\/li>\n<li data-start=\"1645\" data-end=\"1707\"><strong data-start=\"1645\" data-end=\"1664\">Semantic memory<\/strong> \u2014 facts, concepts, and general knowledge<\/li>\n<li data-start=\"1710\" data-end=\"1951\"><strong data-start=\"1710\" data-end=\"1731\">Procedural memory<\/strong> \u2014 skills, habits, and motor abilities<\/li>\n<\/ul>\n<p>This model is helpful for explaining why someone with amnesia may forget personal events (episodic memory) but still remember how to play piano or ride a bike (procedural memory).<\/p>\n<h3 data-start=\"1953\" data-end=\"2012\"><strong data-start=\"1957\" data-end=\"2010\">Baddeley and Hitch Model of Working Memory (1974)<\/strong><\/h3>\n<p data-start=\"2013\" data-end=\"2246\">Baddeley and Hitch expanded on the idea of short-term memory by showing that it is not a single \u201cholding tank\u201d but a collection of specialized systems that actively work with information. They proposed that working memory includes:<\/p>\n<ul>\n<li data-start=\"2249\" data-end=\"2310\">A <strong data-start=\"2251\" data-end=\"2272\">phonological loop<\/strong> for verbal and auditory information<\/li>\n<li data-start=\"2313\" data-end=\"2375\">A <strong data-start=\"2315\" data-end=\"2341\">visuospatial sketchpad<\/strong> for visual and spatial material<\/li>\n<li data-start=\"2378\" data-end=\"2444\">An <strong data-start=\"2381\" data-end=\"2400\">episodic buffer<\/strong> that integrates information across senses<\/li>\n<li data-start=\"2447\" data-end=\"2703\">A <strong data-start=\"2449\" data-end=\"2470\">central executive<\/strong> that directs attention and manages all three systems<\/li>\n<\/ul>\n<p data-start=\"2447\" data-end=\"2703\">This model helps explain everyday experiences\u2014such as why it\u2019s harder to remember a phone number while someone is talking to you (two tasks competing for the phonological loop).<\/p>\n<h3 data-start=\"2705\" data-end=\"2775\"><strong data-start=\"2709\" data-end=\"2773\">Connectionist\/Parallel Distributed Processing (PDP) Models<\/strong><\/h3>\n<p data-start=\"2776\" data-end=\"2994\">More recent models view memory through the lens of neural networks. In connectionist models, memory is stored as <strong data-start=\"2889\" data-end=\"2915\">patterns of activation<\/strong> across many interconnected nodes, rather than in separate \u201cboxes\u201d or stages.<\/p>\n<ul>\n<li data-start=\"2997\" data-end=\"3050\">Learning strengthens the connections between nodes.<\/li>\n<li data-start=\"3053\" data-end=\"3268\">Retrieval occurs when a pattern is reactivated.<\/li>\n<\/ul>\n<p>This approach resembles how modern artificial neural networks learn and helps explain why memories can be fuzzy, reconstructive, and influenced by related knowledge.<\/p>\n<section class=\"textbox tryIt\"><iframe loading=\"lazy\" id=\"ohm4205\" class=\"resizable\" src=\"https:\/\/ohm.one.lumenlearning.com\/multiembedq.php?id=4205&theme=lumen&iframe_resize_id=ohm4205&source=tnh&show_question_numbers\" width=\"100%\" height=\"400\"><\/iframe><\/section>\n<\/section>\n<\/section>\n","protected":false},"author":20,"menu_order":5,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"How Memory Functions\",\"author\":\"OpenStax College\",\"organization\":\"\",\"url\":\"https:\/\/openstax.org\/books\/psychology-2e\/pages\/8-1-how-memory-functions\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Download for free at https:\/\/openstax.org\/books\/psychology-2e\/pages\/1-introduction\"},{\"type\":\"copyrighted_video\",\"description\":\"Why Is Riding a Bike Just Like Riding a Bike?\",\"author\":\"\",\"organization\":\"SciShow Psych\",\"url\":\"https:\/\/www.youtube.com\/watch?v=Q0wfm9wrhXA&list=PL73K_0Mtyy1_Gf07IuKSc24_yh3tNyDXW&index=13\",\"project\":\"\",\"license\":\"arr\",\"license_terms\":\"\"},{\"type\":\"copyrighted_video\",\"description\":\"Endless Memory, Part 1\",\"author\":\"\",\"organization\":\"CBS News\",\"url\":\"https:\/\/www.youtube.com\/watch?v=2zTkBgHNsWM\",\"project\":\"\",\"license\":\"arr\",\"license_terms\":\"Standard YouTube License\"}]","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"part":628,"module-header":"learn_it","content_attributions":[{"type":"cc","description":"How Memory Functions","author":"OpenStax College","organization":"","url":"https:\/\/openstax.org\/books\/psychology-2e\/pages\/8-1-how-memory-functions","project":"","license":"cc-by","license_terms":"Download for free at https:\/\/openstax.org\/books\/psychology-2e\/pages\/1-introduction"},{"type":"copyrighted_video","description":"Why Is Riding a Bike Just Like Riding a Bike?","author":"","organization":"SciShow Psych","url":"https:\/\/www.youtube.com\/watch?v=Q0wfm9wrhXA&list=PL73K_0Mtyy1_Gf07IuKSc24_yh3tNyDXW&index=13","project":"","license":"arr","license_terms":""},{"type":"copyrighted_video","description":"Endless Memory, Part 1","author":"","organization":"CBS News","url":"https:\/\/www.youtube.com\/watch?v=2zTkBgHNsWM","project":"","license":"arr","license_terms":"Standard YouTube License"}],"internal_book_links":[],"video_content":null,"cc_video_embed_content":{"cc_scripts":"","media_targets":[]},"try_it_collection":null,"_links":{"self":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/487"}],"collection":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/users\/20"}],"version-history":[{"count":29,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/487\/revisions"}],"predecessor-version":[{"id":7228,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/487\/revisions\/7228"}],"part":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/parts\/628"}],"metadata":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapters\/487\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/media?parent=487"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/pressbooks\/v2\/chapter-type?post=487"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/contributor?post=487"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/content.one.lumenlearning.com\/introductiontopsychology\/wp-json\/wp\/v2\/license?post=487"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}