{"id":238,"date":"2016-04-28T20:23:58","date_gmt":"2016-04-28T20:23:58","guid":{"rendered":"http:\/\/labs.la.utexas.edu\/gilden\/?page_id=238"},"modified":"2016-04-28T20:52:18","modified_gmt":"2016-04-28T20:52:18","slug":"measuring-the-course-of-activation-produced-by-concepts","status":"publish","type":"page","link":"https:\/\/labs.la.utexas.edu\/gilden\/measuring-the-course-of-activation-produced-by-concepts\/","title":{"rendered":"Measuring the Course of Activation Produced by Concepts"},"content":{"rendered":"

Measuring the Course of Activation Produced by Concepts<\/em><\/strong><\/p>\n

In the mid 1970\u2019s psychologists found a way to measure the activation of concepts in semantic memory.\u00a0 It is kind of an odd form of measurement but nobody has found a better way to do it in the intervening years. The idea is simple.\u00a0 People are given pairs of words like DOCTOR-NURSE, or DOCTOR-BUTTER or BREAD-BUTTER or BREAD-BLICK.\u00a0 The task, termed lexical decision, is to decide as fast as possible if both letter strings are words or if one of the strings is a nonword like BLICK.\u00a0 The major finding is that people are fastest at reading letter strings and deciding that they are words when the two words are associated.\u00a0 Making a lexical decision about the letter string DOCTOR creates a largely unconscious surge of activation directed towards those parts of semantic memory associated with doctors.\u00a0 This surge is indirectly registered by the behavioral outcome that having seen the word DOCTOR, you will be a little faster to recognize that the letter string NURSE is a word.\u00a0 This is the theory, at least.\u00a0 Thinking about doctors does not activate thoughts of butter and it takes a little longer to recognize that BUTTER is a word.\u00a0 The appearance of personal computers in the 1970\u2019s allowed psychologists to see how activation changed lexical decision times because you need a computer to display all of the letter strings and to obtain precise measurements of reaction time.\u00a0 Association cuts off about 1\/10 of a second (100 milliseconds) in the time to make a decision.\u00a0 This may not seem like a big deal, but 1\/10 of a second is more than enough time to create trains of thought.<\/p>\n

The experiment I did to measure the duration of activation is a slight variation on the original design.\u00a0 Instead of displaying the word pairs at the same time and asking subjects to judge both, I displayed the word pairs one a time with a pause in between.\u00a0 In my design the first string was always a word and the participants had to decide if the second string in each pair was also word.\u00a0 On half the trials the second string was a nonword.\u00a0 On 1\/4 of the trials the second word was associated with the first word.\u00a0 And 1\/4 of the trials it was not. The time delay between the presentation of the first and second word in each pair is the main variable in this experiment.<\/p>\n

The data (averaged over participants) is shown in the adjacent graph and speaks for itself.<\/p>\n

\"priming<\/a><\/p>\n

On the x-axis<\/em> is the time delay between the first and second words of each pair.\u00a0 The delays ranged from 1\/2 to 3 seconds.\u00a0 On the y-axis<\/em> is the time (a reaction time, abbreviated as rt) in milliseconds that it took people to decide if the second letter string was a word.\u00a0 First look at the track labeled by nonword<\/em>.\u00a0 This track is flat within the error bars.\u00a0 It takes about 780 milliseconds to decide that a string is not a word and it does not depend on how long you have been waiting since the first word on that trial appeared.\u00a0 This is because it is not possible to activate a nonword, they don\u2019t mean anything and they are not in semantic memory.\u00a0 The track labeled unrelated<\/em> gives the reaction times for letter strings that were words but had nothing to do with the first word of the pair.\u00a0 These reactions times are also fairly flat within the error bars.\u00a0 It takes about 625 milliseconds to read a word that is unrelated to what just came before.\u00a0 The reason that this track is flat is that unrelated words are not activated either by the first word in the trial.\u00a0 This is the track corresponding to \u201cdoctor \u2013 butter\u201d and it makes no difference how long it takes to get \u201cbutter\u201d because you were not thinking about it anyway.\u00a0 The key finding is in the track labeled associate<\/em>.\u00a0 This is the data corresponding to \u201cdoctor-nurse\u201d.\u00a0 This data has a parabolic shape that arises from two aspects of semantic activation.\u00a0 Activation is not instantaneous.\u00a0 These data suggest DOCTOR does not fully activate its association network until about a second has passed.\u00a0 At this point associates gain about a 80 millisecond advantage over unrelated words.\u00a0 By 3 seconds, there is no advantage for association at all, the activation has completely decayed.\u00a0 A 3 second interval corresponds to 20 bpm, half the metronome limit.\u00a0 2 second time delays gives a good estimation for the activation half life,.\u00a0 When NURSE is delayed by 2\u00a0 seconds, half the priming that DOCTOR created has evaporated, at least as measured by reading time. \u00a02 seconds is also the time delay for notes to begin to lose their musical coherence.<\/p>\n

Previous: Activated Memory<\/a><\/p>\n

Next: Is 2 Seconds a Meaningful Time Scale?<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Measuring the Course of Activation Produced by Concepts In the mid 1970\u2019s psychologists found a way to measure the activation of concepts in semantic memory.\u00a0 It is kind of an odd form of measurement but nobody has found a better way to do it in the intervening years. The idea is simple.\u00a0 People are given […]<\/p>\n","protected":false},"author":107,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","footnotes":""},"class_list":["post-238","page","type-page","status-publish","hentry","entry"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"site-graphic":false},"uagb_author_info":{"display_name":"ecw255","author_link":"https:\/\/labs.la.utexas.edu\/gilden\/author\/ecw255\/"},"uagb_comment_info":0,"uagb_excerpt":"Measuring the Course of Activation Produced by Concepts In the mid 1970\u2019s psychologists found a way to measure the activation of concepts in semantic memory.\u00a0 It is kind of an odd form of measurement but nobody has found a better way to do it in the intervening years. The idea is simple.\u00a0 People are given…","_links":{"self":[{"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/pages\/238","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/users\/107"}],"replies":[{"embeddable":true,"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/comments?post=238"}],"version-history":[{"count":6,"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/pages\/238\/revisions"}],"predecessor-version":[{"id":276,"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/pages\/238\/revisions\/276"}],"wp:attachment":[{"href":"https:\/\/labs.la.utexas.edu\/gilden\/wp-json\/wp\/v2\/media?parent=238"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}