developmental changes in natural visual statistics -...
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DevelopmentalChangesinNaturalVisualStatistics
ChristinaDeSerioIndianaUniversity,Bloomington,IN,UnitedStatesMentors:LindaSmith,RowanCandy,JasonGold
SleeperEffects
Earlyexperiencestunelater-developingareasofthevisualsystem• Densebilateralcataracts• Correctivesurgeryafewmonthsafterbirth• Normalentry-levelvisionby1to2yearsofage• SleeperEffectsEvidenced:
1. sensitivitytomidspatialfrequencies&highspatialfrequencies2. Holisticfaceprocessing3. Second-orderrelations(recognitionoffacialidentitybasedofthespacing
offeatures)
• Visualinputduringthefirstfewmonthsoflife– beforethereisanysignofsensitivitytothesehigherorderprocesses– istuningupcapabilitiesthatemergelaterindevelopment.
Maurer,Mondloch &Lewis(2007)DevelopmentalScience
Weneedtobeconsideringwhatstatisticsaregettinginandwhatstatisticsareinfluencingthedevelopmentofthesystem.
Thestructureintheinfantvisualenvironmentmatters
Natural visualstatistics
Theoreticallyviewedasthefixedanduniversalpropertiesoftheworld.Mostcommonmethod:Low-levelvisualstatistics(e.g.luminance,contrast,color,orientation,spatialfrequency)averagedacrossanumberofphotographstakenbyadults
SocialEnvironment
ImmaturevisualsystemEyesBrain
WheretheyareplacedMotorabilities
Mobility
PhysicalEnvironmentBrightnessContrastObjectiveness
#People
IntrinsicDevelopment
Held/carried/bouncedRockedDriven/pushed
HeadTorsoBody
Play(f-f)
Handled
Grabbing/reaching“Interest”
Anewwayoflookingatnaturalvisualstatistics
MostcommonmethodLow-levelvisualstatisticsaveragedacrossnumberofphotographstakenbyadults.
MymethodThedistribution of low-levelvisualstatisticsininfant-perspectivescenes obtainedfrombody-worncameras.
Home-viewproject(withthesupportoftheNationalScienceFoundation)
A corpusofdevelopmentallyindexedegocentricscenes• 75infants(todate)• 3weeksto24months• 4to6hoursofhead-cameravideointhehome(noexperimenterspresent,camerasonhats)• Recordedat30Hz• Over5millionimagesextracted
1- to 3-month old infants11 total (5 female, 6 male)
6- to 8-month old infants12 total (7 female, 5 male)
Numberimagessampledat5Hz1- to3-montholds:738,788frames6- to8-montholds:1,082,233frames
Total(bothagegroups):1,821,021frames
Theoverarchinghypothesis:differentstatisticsatdifferentages
1- to3-montholdinfantshavemore…Facescloseinview
Ceiling,wallsandhighcontrastthings
6- to8-montholdinfantshavemore…Touchingobjects
Crowdedscenes
Fausey, Jayaraman &Smith(2016)Cognition;Jayaraman,Fausey &Smith (2015)PLoS ONE
Whatvisualinformationisavailabletothedevelopingsystem?
Whatisphysicallyinfrontofthefaceandhowdoesitchangewithage?
Measures&analyses
Measures
SpatialFrequencyOrientationContrast
Analyses
FourierAnalysis
Subband EntropyFeatureCongestionImageSegmentation
Clutter
Trialrun:subjects&sampling
Four 6- to 8-month old infants at 02 HzFour 1- to 3-month old infants at 02Hz
26weeksold:2,517JPGs28weeksold:2,628JPGs30weeksold:2,500JPGs32weeksold:2,520JPGs
Total:10,175JPGs
4weeksold:2,567JPGs7weeksold:2,187JPGs8weeksold:2,500JPGs11weeksold:2,539JPGs
Total:9,793JPGs
Numberoftested02HzJPGS~20,000framestotal
~2,500framespersubject~10,000framespergroup
Total:19,968frames
02Hzfromthe6-8monthagegroup32weeksold 2,520frames
02Hzfromthe1-3monthagegroup7 weeksold 2,187frames
Frequencyandorientationmap Frequencyandorientationmap
Frequencymap
MeasuresSpatialFrequencyOrientationContrast
Cluttermeasures
FeatureCongestion:visualsalienceofitemsLocalvariabilityinspecificimagefeaturessuchascolor,orientation,andluminance
Subband Entropy:amountofvisualinformationinadisplayameasureoftheefficiencywithwhichanimagecanbeencodedwhilemaintainingperceivedimagequality(similartothemethodusedinJPEGimagecompression)
FC=3.4 FC=4.3 FC=6.1
Empty Clean Messy
Rosenholtz,Li&Nakano(2007)JournalofVision
ComparingFeatureCongestionmeasureofclutterwithWolfe,Oliva,Horowitz,Butcher,andBompas(2002)searchtask
numRegionsSpec =31numRegionsSpec =196
numRegionsSpec =220 numRegionsSpec =25
numRegionsSpec =36numRegionsSpec =107
originals k=800 k=5000
numRegionsSpec =14numRegionsSpec =408
numRegionsSpec =17 numRegionsSpec =10
numRegionsSpec =11numRegionsSpec =34
originals k=800 k=5000