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Gaze Direction and
Two-choice Reaction Time:
Multiple Tests of
aTheory
A dissertation presented in partial fulfilment of the requirements
for the degree
of Doctor of Philosophy in
Psychology at
Massey University
�chael Andreasen
1995
Acknowledgements
I would l i ke to express my thanks and appreciat i on t o John Podd for the qual i ty of his supervi s ion . In the beginning he steered me away f rom unreal ambi t ion . Lat er , when s tark rea l i ty loomed , he hauled me back from the abyss o f despa i r . He also showed remarkable pat i ence when L i fe , whi c h i s j us t one damned thing a f t er another , got in the way o f more
important i s sues . Best of a l l , he never ever int erfered but was always there when I needed him .
* * * * * * * * * * * * * *
Thanks are due t o Harvey Jones who did a l l o f the computer p rogramming for my experimen t s . The success ful out come o f my research owes a great dea l t o his c reative and t horough work .
Mike Hughes and Hung That Ton o f the Psychology Department workshop are a l so a cknowl edged for bui lding my equipment t o very high s tandards o f accuracy and workmanship .
Acknowl edgement s L i s t o f figures L i s t of tables Summary
P reface
Introduction
H i s t o rical out l ine
Contents
Theoret ical model s o f CLEMs Model s o f cerebral latera l i ty
Methodological and conceptual problems St rategic probl ems
Def ining CLEMs St imulus quest ions
Psychophys i ological s t udies
Cognit ive s t rategies and lat eral i ty Reverse CLEMs : a di f ferent approach Programme overview and hypotheses
Experimental Programme
Methodologi c a l rat ionale Bas i c experimental procedure
Equipment Arrangement
Trial sequence and control Experimenter-cont ro l l ed t r i a l s S e l f -paced t r i a l s
Analys is
page
J.J.J.
VJ.J.J.
VJ.J.J.
J.X
1
8 1 8
3 0 3 6 3 6 3 7 4 0 4 3 5 0
5 4 6 9
7 9
8 4 8 5 9 0 9 0 9 1 9 2
V
Experiment 1 Method
Resu l t s and Di scus s ion Experiment 2
Method
Resu l t s and Discuss ion Experiment 3
Method
Resu l t s and Discuss ion Experiment 4
Method
Resu l t s and Discuss ion Experiment 5
Method
Resu l t s and Discuss ion
General Discussion
Experimental programme Divi ded field Vert i ca l GPs CVF
Further analy s i s Task di f f i culty Met a analys i s Modal i ty
Explanat i ons Wider i s sues
At t ent i onal gradient Func t ional latera l i ty Modern t rends
Programme evalua t i on
Vl
9 4 1 0 1
1 0 4 1 0 6
1 1 2 1 1 4
1 2 2 1 2 4
1 3 0 1 3 2
1 4 0 1 4 5 1 4 6
1 4 8 1 5 2 1 5 6 1 5 8
1 7 1 1 7 2 1 7 9 1 8 5
Problems, Difficulties and Mistakes
Methodol ogical i s sues S -R compat ibi l i ty Sex
Hand x task interact i ons Fas t hand ef fect s
Handedness
S l ow f inger syndrome
Int rahemi spheric interference
Stat i s t ical problems o f des ign and analy s i s Sta t i s t ical problems of design
S t a t i s t ical problems o f analys i s Di f ference scores
RT ana lys is
Summary stat i s t ics Alpha and Omega Other p roblems
Pract ice ef fect s
Experimental measures Mi s t akes
Future research
References Appendices
L i s t o f abbreviat i ons Notes
1 . St imulus exposure
2 . St imulus l i s t for Experiment 3 El: Tables . RT and ANOVA
E2 : Tables. RT and ANOVA E3 : Tables . RT and ANOVA E4 : Tables. RT and ANOVA E5 : Tables . RT and ANOVA Di f f : Tables . ANOVA
Meta : Tables . ANOVA
frr'lta.
Vl.l.
1 8 7 1 8 8 1 9 1 1 9 1 1 9 2 1 9 3 1 9 3 1 9 4 1 9 5 1 9 6 2 0 1 2 0 3 2 0 5 2 0 7 2 0 9
2 1 7 2 2 0 2 2 2 2 2 5 2 2 8
2 5 9 2 6 0 2 6 1 2 6 2 2 6 3 2 7 0 2 8 3 3 0 0 3 1 1 3 2 4 3 2 8
))J
F i gure 1 . 2 . 3 . 4 . 5 . 6 .
T ab l e 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 .
9 . 1 0 . 1 1 . 1 2 .
1 3 . 1 4 .
List of Figures
VDU d i s p l ay g r i d
Schemat i c o f t he VDU l ay out S e quence o f t r i a l event s B l o ck di agram o f VDU c ont rol St imu l i u s e d i n Expe riment 5 Met a ana l y s i s RT/GP pro f i les
List of Tables
Expt . 1 Group mean med i an RT s
Expt . 2 S e s s i onal group mean me d i an RTs Expt . 2 Cond i t i on group me an med i an RTs Expt . 2 Ove r a l l gr oup me an me dian RTs Expt . 3 CVF group mean median RT s , by c on di t i on and st imu l i
Expt . 3 D i v i ded f i e l d group me an me di an RT s by c ondit i on
Expt . 3 Ove r a l l group me an median RT s f o r CVF and me an of div ided f i e l ds Expt . 4 CVF gr oup mean median RT s by c ondi t i on
Expt . 4 D i v i de d f i e l d group mean medi ans by c ondi t i on
Expt . 4 D i v i ded f i e l d group me an me di ans by c on di t i on and VF
Expt . 5 CVF group me an me dian RT s by c on di t i on
Expt . 5 D i v i ded f i e l d gr oup mean medi an RT s by c ondi t i on
E xpt . 5 D i v i ded f i e l d group me an med i an RT s by c ondi t i on and VF Compa r i s on s o f a l pha and w2
v i i i
8 0 8 6 9 1 9 3 1 3 1 1 5 4
1 0 2 1 0 7 1 0 8 1 1 0
1 1 7 1 1 8 1 2 0
1 2 5 1 2 7 1 2 8 1 3 4
1 3 5 1 3 6 2 1 2
l.X
Summary
The rel a t ionship between voluntary eye movement s and cog
n i t ion was examined in terms o f Kinsbourne ' s ( 1 9 7 2 ) account o f conj ugate latera l eye movements ( CLEMs ) . Thi s account i s i t sel f based upon hi s ( 1 9 7 0 ) a t tent ional gradient model o f l a tera l i zed cerebra l asymmetry . A novel methodol ogy was devi sed wi th ga ze pos i t ion ( G P ) and visual f ield ( VF ) as the independent variables and manual react i on time ( RT ) as the dependant measure . A divided VF paradigm us ing two -choice RT t asks was used thereby avoiding the ambiguit ies o f o rthodox CLEM methods . The t asks were , let ter ( X , V ) ident i f icat ion , a lexical deci s ion us ing words and non-words , s imple geomet r ical shapes , and a mental rot a t i on task . Five vi sual display uni t s ( VDUs ) arranged in the form of a Maltese cro s s subtend
i ng 5 0 degrees hori z ontal ly and 35 degrees vert ical ly
f unct ioned as tachi s toscopes . Trials were ei ther randomi zed ( R ) over the VDUs or presented in blocks (B) on each VDU in t urn . Under R condit i ons u s i ng verbal tasks , a GP x VF i n teract ion was found for hori zontal GPs . Thi s interact i on was due t o RTs being fastest when the VF and GP hemi space were congruent ( e . g . , LVF and LGP ) . Under B condi t ions , a GP main e f fect was found for verbal tasks . Thi s e f fect was
s hown by RTs being fastest when subjects looked t o the r i ght G P , both VFs producing this e f fect . No rel i able e f fects were
f ound for vi sual - spat ial tasks . The GP ef fect s found under B c ondi t ions were weak and incons is tent and requi red a form o f
meta analys i s t o demons trate the i r reliabi l i ty . No evi dence was found for an interact ion of GP wi th t ask di f f i cu l ty . A number of pos s ible expl anat ions , including Kinsbourne ' s model s , were examined. The direct ion of the GP x VF inter
a c t i on when t r i a l s were randomi zed was contrary to t he predict ions made f rom Kinsbourne ' s model s and the GP main e f fect found under B condi t ions was not predicted by them ; hence " arousal " and " at tent ion " as used by Kinsbourne were rej ec ted . I f eye movement s and cognition were regarded as a
X
dua l task workload , then intrahemi spheri c i nterference could account for t he interact i on . However , it could not account for the GP ef fect under B condi t ions , nor could it a ccount for the absence of any e f fect s wi th visual - spat i a l t asks . Al s o , neuroanat omi c a l cons iderat i ons made global int rahemi spheri c arousa l and interference implausible as exp l anat ions . One poss ible explana t i on was that under both presentat ion condi t i ons , an habi tual bias t owards right hemi space
occurred . But this bias could be reversed i f motor i nterfer
ence occurred in the le f t hemi sphere between saccade control and subvoc a l i z a t i on . Interference would only occur with randomi zed t r i a l s and verbal t asks , producing the GP x VF i nteract ion . Thi s exp l anat ion a l so accounted for the absence o f any e f fect s when visua l - spat ia l tasks were used . The
overal l resul t s were evaluated in relat ion t o other a ccounts o f CLEM product ion and a l so aga inst modern development s in cerebral latera l i ty inve s t i gat i ons .
