DevelopmentalChangesinNaturalVisualStatistics

ChristinaDeSerioIndianaUniversity,Bloomington,IN,UnitedStatesMentors:LindaSmith,RowanCandy,JasonGold

Adapted fromHochstein &Ahissar (2002)

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

Visualexperienceoccursintimeanddependsonthebody,behaviorandlocationoftheperceiver

SocialEnvironment

ImmaturevisualsystemEyesBrain

WheretheyareplacedMotorabilities

Mobility

PhysicalEnvironmentBrightnessContrastObjectiveness

#People

IntrinsicDevelopment

Held/carried/bouncedRockedDriven/pushed

HeadTorsoBody

Play(f-f)

Handled

Grabbing/reaching“Interest”

Natural visualstatistics:limitations

Adultperspective:photostakenandframedbyadults

Solution

Developmentally indexed:Egocentricviewsofnaturalscenes

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

Statisticsintime

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

4weeksold:768JPGs 32weeksold:637JPGs

Justfaces

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

FC=3.06SE=2.91

FC=2.31SE=3.41

FC=2.49SE=2.73

FC=6.15SE=4.27

FC=7.80SE=4.21

FC=1.45SE=1.54

ImageSegmentationFelzenszwalb &Huttenlocher (2004)InternationalJournalofComputer

Vision

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

Humancodingà AlgorithmicImplementations

Textureversusacollectionofobjects?

Lowinclutterversushighinclutter?

Howdotheseclassificationsdifferforyoungerandolderbabies?