別紙41 (課程博士(英文))January lolh、 2020

Date of submission (month day, yeal')
Departmenlofcomputer
StudentlD Numbcr

D123359

Science 肌d En8inccring

Shigeki Naka11Chi
Supervlsors

Tetsuto Mlnami
APP11Canl's name

YujiNihei

Abstract Doctor
Title ofThesis

Investigating the face pareidolia neul'ahnechanism(顔パレイドリア現象の;斬鑑機序の解明)

Approx.80O W01'dsイ

弓

Humans havc an cxceⅡent abilily to facc percePⅡon. For examplc, CYcn a casual pal[ern such as a cloud may appear like a face.1hc
Phcnomenon that is secing objccls as a face is ca11Cd "pareidolia." HO、VCYer,1he details of the mecharlism of 山is phenomenon havenot becn clarined.1hc purposc of lhis thesis is to darify thc representation in lhe brain involvcd in the face pareidolia phenomenon,、vhich is an 訓Usion of facc pel'ception, by psych010gical, elec[roencephal0套ram (鷲1三G). and P11Pil diametcr measurements.1nParticular,、vc focus on thc differences in 山e brain and behavior before and aftel'the face pareidolia phcnomenon
firsl,、vc inves[igated 、V11e[her lhe inversion e仟ed index of the N170 componcnt renected facc・1ikeness by observinσ lhe
Correlalion beいVeen the eYent‑relaled polential (EIW) components and l)el]avioral rcports of face‑1ikeness. previous ERp studies
Showcd that the pl componen[(early visual processing),1he N 170 comp()ncnl(face derection), and lhe N250 component (pcrsonaldcleclion) Nned the neural processing 01' faces.1nYerted faces 、vcre reported to cnhance the amplilude and delay lhc latcncy of pland N170.10 jnvestioatc face‑1ikeness processino in the brain,、ve explored the face‑related componenls of thc ERp through aface‑1ike evalualion task usino nalural faces、 cars,insecls, and Arcimboldo paintinos presenled uprioht or inverted. we found aSiσnificant conclaⅡon l)eいVecn [he inYersion effcct indcx and face・Ⅱkc scorcs in pl h〕 both hemispheres and N170 in the rioht
hemisphere.1hesc rcsU11S suggestthat thcjudoment of face‑1ikeness occurs in a relatively early slage of face processinσNext, we lnveS11galed how b〔)th aspects of botlom・up proccssing and top・down modulatlon conlrlbute to facc‑1ikencss perception
Humans can immediately judge 、vha[ kind of objcd H is 、、 10OMng althc objed.互Specia11y for the facc,山C abili【y is shal'penedIhjs ability to quickly group cxpcricnccd slimuliinto mcanjngful calegorics (perceplual categorization) is undoubledly one of themost flmdamental high・1Cvcl brain functions. h〕 thc Yisual domain、the melhod of investigaⅡno lhe pcrccplual cateoori2ation process
is to combine visual pcriodicity 、vith a dired recordino of neural actiYily、 for hlstancc、 using EEG. we considered thisCategory・seleclivc responsC 加ght be gcl〕eraled or modulated by race‑1ikeness.圦le recorded EEG while p】'esenting naluralimaoes ofObjccls al a fasl・periodic ratc of 12 HZ.圦le compared ncurophysi010σical responses lo periodic and non・periodic facc and facc・1ike
Objcd stimuliin a fasl・visual slream. MoreoYel', we presented an inYerled face and face・1ikc object stimuli as a contr01. As a rcsult,CalcgⅨ'y d'ace・1ike objecl)・selecliYe E竪G responses did nol elicit in a fast・peri()dic slrcam, TMs resU11indjcatcs tl】a1 山e facc、1ike
Calegory dNs not gcnel'ale a unlque category‑seledlYe resp()nse unconsclously、 This rcsU11 Suggestcd that the parcidolia
Phcnomenon dNs not occurln lhe l)ottom‑up process
Moreovcr,、ve 】nvest唱ated face pareldoha uslng puP1Ⅱary rcsp〔)nse.1hc pupiⅡary response was su08ested to bc innuenccd byhigh‑1eYel c0旦nltlon. Therefore、、Ye predlcted lhat the changc of puP11 dlamcler mi01〕t be induced by racc parcidolia、 wc measured
that pupil diameter 、vhen stimuli were pcrcciYcd as faces.1he stimuli consisted of five cirdes、induding a l)ig cirdc and four smaⅡCircles. The subjects performed いVo lasks (facc‑1ikc and symmetry) t0 小e same stimuliin the block dcsign. As a result, pupil
dilation in face‑1ikc condjtkms sho、Ycd differcnccs be〔、Yccn lhe face・1ike task and symmetry task. HO、vevcr, pupil dilation in 山eSymmetry condilion sho、ved no diffcrenccs beいVccn rasks.'1、hese Nsults suggeslthat thjs pupj11ιlry effcd is specific for lhe face‑1ikeProcesslng by lhc top・do、vn proccss and nol speci"c f01'the symmetry processlng
Lastly,、Yc darlned prcference chanσes 、vith the pareidolia phenomenon.圦,1e hypotl〕csizcd thal a face‑1ike objecl eliciled anOncntln旦 response,1ikc a facc、 and attracted more attention tharl other visual stim111i. HO、vcver、it is prcdicted from past studies thatthe effect docs not affed 山〕1ess a face‑1ike obiect is recoonized as a face. we inYestioated 、vhcthcr seeino objects as a face 、YouldInnucncc prefercnce.1n the expcrlment, we used a pare】d011C lmage that could be pcrceived as a face or abs[racts palntlng,1hcse
images arc prcsented upright or inverled.1he partiCゆants perl、ormed いVo lasks. D to selccunorc prefened in the いVo alternativcs
forced・choicc lask.2)facc・1ike evaluation tasks.い,1e diYjded lhe pal'1icipants int0 いVo groups in the order in 、Yhich thc tasks 、verc
Pcrformed. ThC 旦roup tl〕al first perrormed "Face‑1ikeness evalualion lask," and dlcn pcrformed "preference task"、vas dcfined as"Facc biascd group." Anolher group named "No face blased group" pel'formed thc first "preference task" and thcn "face・1ikcness
CYalualion task." As a rcsult,1he Face biased sroup preferred the upnght 山an 11]c lnvcrtcd imaoes、 althougl] anothcr oroup did n01
Prcfcr lhc upnghtlmages. This result suggesled lhatthe pareld011a phenomcnon a仟CCIS PNference
Xvc darincd the differences in Ⅱle brain and be1旧Vior bcfore and をlfler the facc pa】'eidolia phenomenon. Besjdes、 wc identified
tinling、 area,ιmd puP11 response assoc】ated pal'eld011a phenomenon.1n lhe fuluN、 11〕e flndmgs of the study might be of usc lo
Pcrson‑10・machine communlca110n or socla1 Ⅱfe