Prof. Greg Francis 5/23/081Sensory memoryIIE 269: Cognitive PsychologyGreg FrancisLecture 14Why telephone operators seem rude.Memory Humans demonstrate memory when theybehave in a way that could only be basedupon previous experience does not necessarily imply that there arememory systems Memory could be a by-product of othersystems (vision, audition, language,…)Perception to memory Suppose you want to know how muchinformation is available in a single visualglance How would you measure it? It turns out it’s a complicated thing thatinvolves both perception and memoryWhole Report Write down as many letters as you seeWhole Report Write down as many letters as you seeL C X KG B R TV F D JWhole Report Write down as many letters as you seeProf. Greg Francis 5/23/082Whole report results Subjects report 4.5 letters onaverage (Sperling, 1960) Subjects claim they saw moreletters, but lost the percept whilethey reported they cannot report fast enough How can we tell if percept is lost?Partial report Same type of letter matrix Indicate which row to report after the matrixdisappears choice of row is random Suppose the subject reports 3 of 4 letters fromany row =>3/4ths of each row was available ==> entire field was availablePartial report Write down letters from the indicated rowPartial report Write down letters from the indicated rowB R D VK F T XC L G JPartial report Write down letters from the indicated rowSensory memory Temporal characteristics delayProf. Greg Francis 5/23/083Sensory memory Temporal characteristics delayZ X F NI H B EQ L M JSensory memory Temporal characteristics delaySensory memory Temporal characteristics delayResults Vary delay to watch decay from memory compare to CogLab data012340 0.2 0.4 0.6 1Delay of tone (seconds)Number of letters correctResults CogLab data (67 participants)Results But we can test on any row and get essentially thesame result so, the number of letters that actually persist and is available isfound by multiplying by the number of rows02468100 0.2 0.4 0.6 1Delay of tone (seconds)Number of letters availableProf. Greg Francis 5/23/084Iconic/sensory memory02468100 0.2 0.4 0.6 1Delay of tone (seconds)Number of letters available Performance is betterthan the whole-reportprocedure becauseyou can focusattention on just onerow before perceptsfade awayMasking We saw before how attention can modulatemasking effects Masking effects can also influence iconicmemory persistence-based memory is very brief, and iseasily destroyed Iconic memory is brief easily disturbedPartial report with masking Write down letters from the indicated rowPartial report with masking Write down letters from the indicated rowH N S RC Q D AP U T BX X X XX X X XX X X XPartial report with masking Write down letters from the indicated rowMasking With the mask you do not have enough timeto focus attention on the indicated row Iconic memory is so brief (less than asecond) that it probably has little to do with“normal” memory Other systems are more notableProf. Greg Francis 5/23/085Echoic memory Other senses have a similar type ofpersistence or sensory memoryASWDEXFHVEchoic memory Properties Longerduration(seconds) Smallercapacity Significant forsome memorytasks0123450 1 2 3 4Delay (seconds)Number of lettersavailableImmediate serial recall A particular kind of memory task After given a list of items e.g., digits, letters, words,… subject must report them back 1) no delay (immediate) 2) in the correct order (serial) 3) no cues (recall, not recognition) Plot percentage correctly recalled againstposition of item in listSerial position curve Often, subjects recall first and last itemsbest00.20.40.60.811 2 3 4 5 6 7Position in listProbability of recallRecencyPrimacyModality effect Recency depends on the modality ofpresentation00.20.40.60.811 2 3 4 5 6 7AuditoryVisualPosition in listProbability of recallModality effect Explanation: In this task, recency depends on sensory memory It takes time to report all the items in the list, in order in the visual presentation, iconic memory of the last itemis gone before subject tries to report it (poor recall) in the auditory presentation, echoic memory of last itemis still present when subject tries to report it (good recall) Thus, auditory presentation shows recency, butvisual does notProf. Greg Francis 5/23/086Suffix effect Auditory presentation, only Cue to report is either a word or a tone24168792, 4, 1, 6, 8, 7, 9Suffix effect Recency when cue to report is a tone Loss of recency when cue to report is a word00.20.40.60.811 2 3 4 5 6 7ToneWordPosition in listProbability of recallDemonstrationSuffix effect Not affected by practice meaning of cue word common vs. rare word Words are physically different from tones suffix word acts like a mask to wipe out last word inlist from echoic memory the situation is similar to being unable to report theletters in the partial report task with the X-masksPhone operators Call information for a number Operators are very short give the number do not say “goodbye” or “have a nice day” Avoiding the suffix effect! you would forget the last part of the phonenumber if they finished with pleasantriesNeat property Neath et al.(1993) suffix was personsaying “baa” or“woof” subjects told» person’svoice» animal sound00.20.40.60.811 2 3 4 5 6 7animalspeechPosition in listProbability of recallOther suffix effects Tactile suffix effect touch locations on hand, recall order suffix = word or rap on knuckles Lip reading no acoustic signal Mouthing words while reading off a screen Echoic memory cannot account for all of theseresultsProf. Greg Francis 5/23/087Conclusions Sensory memory iconic memory (visual) echoic memory (auditory) Relation to immediate serial recall (recency) modality effect suffix effect significance for phone operatorsNext time Memory Two store model short term memory long term memory Experiments CogLabs on Brown-Peterson and Serial position due! Why it is difficult to win a pizza at Little