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The Role of Colour in Object

Processing: Developing a

Cognitive Neuroscience Approach

Toby Lloyd!ones



David "ernon

#a$uyo Na%abayashi



& 'o( is infor)ation about object colour and

object shape co)bined in object

identification and )e)ory*

& +hat are the neural processes that

)ediate object colourshape binding*



& Behavioural work: QJEP, 2003

Repetition pri)ing and colour transfor)ation fro)

study to test



& Method



,ti)uli sho(n

in study phase

,ti)uli sho(n

in test phase

,a)e-correct colour

Change-correct colour

Ne(-correct colour

.anana To)ato .roccoli



,ti)uli sho(n

in study phase

,ti)uli sho(n

in test phase

.anana To)ato .roccoli

,a)e-incorrect colour

Change-incorrect colour

Ne( -incorrect colour



/f colour transfor)ation reduces pri)ing then

colour is utili$ed by the syste) )ediating

perfor)ance



Study trial

Na)ing0 Colouredobject Decision0

Rate objectcolour typicality

1e2g20 345not typical at all0 645highly typical78

9iation cross: ;<3)s

,ti)ulus: =ntil response or fied period 1e2g20 ;s8



Test trial

9iation cross ;<3)s

.lan% screen <33)s

,ti)ulus: =ntil response or fied period

1e2g20<33)s8

Response: Na)ing or Colouredobject Decision

%ey press 5Correctly or incorrectly coloured*7



& Results



Na)ing no effect of colour transfor)ation on

pri)ing

COD > (hen colour (as )ade relevant to the tas%

at retrieval0 colour transfor)ation reduced

pri)ing



?2 Object pri)ing is not sensitive to shape alone0

nor does pri)ing facilitate everything that is

encountered

;2 Pri)ing is sensitive to the tas% at hand the

underlying )echanis) is selective and useful fordifferentiating ite)s in ter)s of their current

i)portance

& Co!lusios



@2 ffects of colour on )e)ory are )ediated by a

for) of 5ne(>association pri)ing7: colour and

shape are bound together in a novel

representation (hich benefits perfor)ance



& Patiet work: "l#hei$er%s disease

&euro'sy!holo(y, 200)

Older adults and AD patients (ill have preserved shapebased )e)ory0 but AD patients )ay not be able tointegrate shape and colour into a novel representation(hich can also benefit )e)ory



Patiet dia(osis& AD inclusion > progressive decline0 i)paired

episodic )e)ory 1< or less on CRAD +ord List

Recall80 i)paired in ? other area

& 'C inclusion > BB, ; or greater0 or greater

CRAD +ord List Recall



Patiet !hara!teristi!s



Re!o(itio $e$ory



& Results

Older adult controls



Al$hei)er7s patients



?2 Older adult controls de)onstrate ne(

association pri)ing

;2 AD patients have preserved shapebased

)e)ory0 but an attentional deficit )ay not allo(

shape and colour to be integrated to for) anovel representation (hich can also benefit

)e)ory

& Co!lusios



& Behavioural work: QJEP, i 'ress

=nderstanding the nature of colourshape binding:

Dissociating binding in )e)ory fro) binding in

online identification

,a)e paradig): pri)ing vs2 baseline perfor)ance,tudy colour rating tas%

Test colouredobject decision



S'atial se'aratio o* sha'e ad !olour



& Predi!tios

?2 Reduced pri)ing for transfor)ed sti)uli0

de)onstrating that colour is nor)ally utilisedby the syste) )ediating perfor)ance

;2 /f ne(association pri)ing benefits )e)ory0

then (e epect euivalent pri)ing forcorrectly-incorrectly coloured objects andspatially integrated-separated conditions



@2 9or object identification0 epect )ore efficient

processing of correctly coloured co)pared to

incorrectly coloured objects but only under

spatially integrated conditions

E2 F/f the sa)e )echanis) )ediates effects of

colour in online identification and pri)ing then

epect si)ilar effects of colour but only under

spatially integrated conditions



& Results



& Mai *idi(s

?2 Transfor)ing the colour of an object reduced

pri)ing0 therefore colour infor)ation nor)allycontributes to longter) )e)ory in this tas%

;2 The use of colour infor)ation in object )e)ory

did not depend upon colour falling on the

object surface



@2 The use of colour infor)ation in object )e)ory

(as not influenced by the nature of the object

1i2e20 correctly-incorrectly coloured8

E2 +e observed independent effects of colour:

perfor)ance (as )ore efficient for correctly as

co)pared (ith incorrectly coloured objects but

only (hen colour fell on the object surface



& Co!lusios

Two $e!hais$s o* sha'e+!olour idi(

-. E**e!ts o* !olour o o/e!t $e$ory are$ediated y ew+asso!iatio 'ri$i(

2. E**e!ts o* !olour o o/e!t ideti*i!atio are$ediated y a i'ut re'resetatio whi!h!o$ies o/e!t sha'e ad asso!iated !olour



A and . contribute to online processing during objectidentification

C benefits object )e)ory assessed via pri)ing



& fBR/ study: +iggett0 !ohnson0 Lee%

1.angor8 Reppa 1,(ansea8

E**e!ts o* !olour o o/e!t $e$ory MT1

E**e!ts o* !olour o o/e!t ideti*i!atio etral

te$'oral !orte4le*t *usi*or$ (yrus



• Bethod

,tudy and test tas%s G a series of si)ple

bloc%eddesign eperi)ents as localisers

1LOC0 correctly-incorrectly coloured objects0

fa)iliar-novel objects8



& RP study: 9ouuet0 .urgess 1,(ansea8

Bore pronounced positivity for repeated sti)uli

relative to ne( sti)uli starting around @33)s

after sti)ulus onset 1)ainly over posterior

electrodes8

An attenuation of the repetition positivity for

transfor)ed relative to untransfor)ed sti)uli



Than% you

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