Efikasnost i efektivnost, kognitivni stil i emocionalne reakcije korisnika s obzirom na model podataka koji stoji u osnovi kompjuterskog interfejsa
Users' efficiency, effectiveness, cognitive style and emotional reactions to computer interface based on different data model
Author
Kovačević, Ivana Z.Mentor
Čizmić, Svetlana
Committee members
Kovačević, PantaŽeželj, Iris

Mihailović, Dobrivoje
Metadata
Show full item recordAbstract
Informaciona usklađenost kompjuterskog sistema i korisnika, kao predmet
kognitivne ergonomije, počiva na dobro osmišljenom korisničkom interfejsu koji
strukturom i informacionim obimom treba da omogući optimalnu interakciju u
složenom sistemu čovek‐računar.
U osnovi vizuelne forme interfejsa stoji, pored ostalog, logika po kojoj su
podaci raspoređeni, međusobno povezani i dostupni za upotrebu, a koja se definiše
modelom podataka. Smatra se da je postizanje veće kompatibilnosti između
predstave koju korisnik ima o sistemu i načina na koji sistem zaista funkcioniše
ključ za efikasno i efektivno korišćenje interaktivnih sistema. U tom smislu, podaci
koji se u bazi mogu predstaviti u obliku zvezdaste sheme (dimenziono modelovani
podaci), gde su veze između objekata i hijerarhijski odnosi načelno dati u okviru
jednog objekta, i podaci koji imaju strukturu u kojoj je svaki hijerarhijski nivo
predstavljen posebnim objektom (transakciono modelovani podaci), za
individualne korisnike mogu biti ...u različitoj meri upotrebljivi.
Brzina i tačnost obavljanja poslovnih zahteva putem dimenziono i
transakciono modelovanih podataka može zavisiti, kako od vrste i složenosti
zadatka, tako i od psiholoških osobenosti korisnika. Kognitivni stil, specifičan način
kognitivnog funkcionisanja, izdvojio se kao relevantan faktor. S druge strane,
isticanje sve većeg značaja afektivne komponente procene sistema i veze sa
objektivnim merama upotrebljivosti, uticalo je na to da se u eksperimentalni nacrt
uvrste i dimenzije emocionalnih reakcija na izgled sistema.
U istraživanju su se, u dva modela podataka, ispitivale brzina i tačnost rada
ispitanika sa u različitom stepenu izraženim metaforičnim, racionalnim i
empiričnim kognitivnim stilom, a s obzirom na izazvane emocionalne reakcije
pobuđenosti, prijatnosti i dominantnosti. U eksperimentu sa ponovljenim nacrtom
učestvovalo je 303 ispitanika, slučajno raspoređenih s obzirom na redosled
izlaganja modela podataka, i ujednačenih po karakteristikama relevantnim za
Mr Ivana Kovačević – DOKTORSKA DISERTACIJA 2
istraživanje. Rezultati govore u prilog bolje upotrebljivosti dimenzionog modela u
kom ispitanici brže obavljaju zadatke. Brzina i tačnost rada nisu u očekivanoj
korelaciji i nejednako variraju s obzirom na različite prediktore, te ih je smisleno
odvojeno posmatrati.
Manipulativna varijabla redosleda izlaganja modela se pokazala
najznačajnijim prediktorom brzine rada. Ispitanici postižu mnogo bolje rezultate
ukoliko prvo koriste dimenzioni model, kao pojavno manje složen, nego u situaciji
kada je transakcioni model prvo korišćen. Ovaj nalaz govori u prilog tome da je
brzina rada zavisna od specifičnog redosleda iskustva. U skladu sa tim su i rezultati
koji pokazuju da kognitivni stil nema naročitog efekta na brzinu rada, za razliku od
emocionalnih reakcija prijatnosti i kontrole koje su negativno povezane sa
potrebnim vremenom da se zadaci obave.
S druge strane, tačnost je relativno nezavisna od redosleda izlaganja, i
konzistentna karakteristika u oba modela. Ispitanici koji teže tačnosti, to čine bez
obzira na prethodna ili trenutna iskustva, stoga se čini da je tačnost rada
inherentna karakteristika korisnika. Tako su nađene i veze metaforičnosti,
racionalnosti i empiričnosti sa tačnošću rada. Tačnost opada pri prelasku sa
transakcionog na dimenzioni model podataka, u funkciji porasta metaforičnosti
(moguć efekat zamora), dok se prelaskom sa dimenzionog na transakcioni,
povećava u transakcionom u funkciji povećanja skora na racionalnosti (moguć
efekat uvežbanosti). Empiričnost je povezana sa slabijom tačnošću rada u
transakcionom modelu, kada je on prvi model u kom se radi (moguć efekat
neuvežbanosti).
Pojednostavljeno rečeno, ukoliko težimo efikasnosti (većoj brzini rada),
insistiraćemo na jednostavnijim ili pak postupno usložnjavajućim interfejsima.
Ukoliko težimo efektivnosti (većoj tačnosti rada), rešenja ćemo tražiti u
personalizaciji korisničkih interfejsa.
Informational compatibility of computer system and user, as the subject of
cognitive ergonomics, depends on the characteristics of user interface. Well
conceived user interface, with its structure and amount of information, provides
optimal interaction in complex computer‐user system.
Visual form of interface is based on logics in which data are displayed
(arranged), interconnected and available for use, defined by data models. It is
assumed that achieving higher compatibility between user perception of the
system and the manner in which it really operates is the key for effectiveness and
efficacy in using interactive systems. There are at least two different data base
arrangements with different usability level for individual users.
Dimensionally modeled data are arranged in a shape of star schema, where all
relations between objects and all hierarchical associations are given within one
object. Transactionallly modeled data have structure within which every
hierarchical level is repr...esented with particular object.
Speed and accuracy of performing tasks by using dimensionally or
transactionally modeled data are dependent on type and complexity of tasks, as
well as on psychological characteristics of users. Cognitive style, as the specific
manner of cognitive functioning, and dimensions of emotional reactions on system
appearance, are seen as relevant factors.
Research consisted of experimentally measuring the speed and accuracy of
performing tasks in two data environments (dimensional and transactional data
models) by participants with different levels of metaphorical, rational and
empirical cognitive styles. Emotional reactions of arousal, pleasure and dominance
provoked during the experience of using data models were assessed as well.
In this experiment 303 participants, balanced by relevant characteristics,
were randomly assigned in groups according to the order of exposing to data
models. Results proved better overall performance of dimensionally modeled data
Mr Ivana Kovačević – DOKTORSKA DISERTACIJA 4
which is seen as a data model with higher usability. Speed and accuracy of
performance are shown not to be in expected correlation, varying differently
according to the different predictors. Therefore, it was concluded it is plausible to
consider them as separate entities.
Manipulative variable, the order of data model display, proved to be the
most important predictor of speed performance. Participants achieved better
results when using dimensionally modeled data first, with its appearance less
complex, than in situation when the transactional model was primarily used. This
result showed that performance speed was dependent on specific order of user
experience. Accordingly, it was found that cognitive style had no particular effect
on speed, while emotional reactions of pleasure and dominance were negatively
related to the time required for task completion.
On the other hand, accuracy was relatively independent of data model order
and it is a consistent characteristic within subject in both models. Participants who
tended to be accurate, did that regardless of their previous or current experience
with data model, thus it appeared that performance accuracy was user`s inherent
quality. Relations between accuracy and metaphorical, rational and empirical
cognitive styles were also found. Accuracy of dimensionally modeled data
performance was poorer when using the transactional model first, in function of
higher level of metaphorical style (possible effect of fatigue). Conversely, when
using the dimensional model first, accuracy is higher in the transactional model in
function of increasing the score on rational dimension (possible effect of training).
Empirical cognitive style is correlated with lower accuracy in the transactional
model, when it was a the first model of choice (possible effect of lack of practice).
Generally, abridged implications of findings were the following, if we strive
to achieve efficacy (speed), we should insist on simplifying, or at least gradually
building more complexity in user interfaces. Otherwise, if we are looking for
effectiveness (accuracy), we should try to find a solution in the personalization of
user interface.