Brady, Konkle, Alvarez &
Oliva (2008), conducted a study which investigated the information capacity of
visual memory by simultaneously pushing the system in terms of both quantity
and dependability of the representations that must be stored. In this study,
they had participants view pictures of 2,500 objects over five and half hours.
They were then shown pairs of images and had to indicate which of the two
imagines they are being presented with, they had seen prior. The objects which
were presented with prior were paired with either an object from a novel
category, an object of the same basic level category or the same object in a
different state. Results shown that the participants could successfully recall details
about thousands of images after only a single viewing. This study by Brady,
Konkle, Alvarez & Oliva (2008), demonstrates visual imagery in long term
memory, however, the length of the study may be criticised. Not only that, it
can be argued that it does not display or entirely assess retrieval induced
forgetting memory as the study did not utilize the three-main phase (study,
retrieval practice and test).
Ciranni & Shimamura (1999),
believed that the paradigm has only been used to assess interference effects
for information that is already organised in semantic memory therefore the item
interference effects produced with the retrieval-practice paradigm may only appear
for information which is already prearranged prior to the experiment commencing.
Following this belief, they investigated the retrieval induced forgetting paradigm
by conducting three studies were participants learnt the locations of 12
stimuli that were uniquely coloured but could be categorised by shape for an
example four circles, four triangles, four crosses. Subsequently the study
phase, a retrieval practice phase required participants to recall the colours
of a subgroup of the stimuli, for an example two circles, two triangles; using
shape and location as cues. In the test phase participants were required to
recalled the colours of all 12 stimuli. The results shown that in comparison with
the control set of stimuli, memory was facilitated for practiced items but
reduced for related items, which were not practiced but shared the same shape
group. Furthermore, retrieval induced forgetting was detected for different
perceptual groupings and for different cueing procedures across their
experiments. This experiment by Ciranni & Shimamura (1999), presented
retrieval induced forgetting memory by utilising object memory and location; as
in one of the experiments each stimulus had a unique colour and location. Their
findings that dismissing the grouping of stimuli by shape led to memory
interference rather than facilitation.
Retrieval induced forgetting has
been discussed and questioned whether it only occurs in recall tests as this
has been repeatedly investigated. In theory, impaired recognition may be
expected if suppression during retrieval practice weakened the Rp- items. Hicks
& Starns, (2004) reported retrieval induced forgetting impairment of Rp- in
a conventional item recognition test. They adopted a similar design and
procedure as Anderson, Bjork & Bjork (1994). Their findings closely
replicate the finding from previous retrieval induced forgetting studies which
have been done with cued memory recall.
experiments examined whether colour and shape are both generally represented
and contribute to episodic object recognition. If both shape and colour
information for an object produce retrieval induced forgetting it would then it
would display both guide competition effects in memory. The use of retrieval
induced forgetting overpowers any effects of demand characteristics such as attention
to the examined feature and social desirability; this is because completion
during the task is not in the participant’s conscious control.
experiments that investigate memory recall do not utilise visual objects but
commonly use word stimuli. The current experiment being reported employed a
recognition practice paradigm. This is where old-new recognition is performed
during both the practice and the test phases of the retrieval practice paradigm.
Recognition practise with a subgroup of studied objects has shown to be
successful in inducing significant recognition induced forgetting for
unpractised objects; which are Rp- items. Although old-new recognition task is
used in both practice and test phases like the other current studies, in this
study it is the practice phase that is crucial in the paradigm and not the
studies, such as Maxcey & Woodman (2014) and Brady, Konkle, Alvarez &
Oliva (2008), participants had to study everyday/familiar objects by being
shown them on a screen and they were asked to choose between two objects which
object they were presented with prior. This study adopted a similar type of
learning, however in this study participants were shown one object at a time
and asked whether they had seen it before or not.
Target discriminability has
been demonstrated to have powerful effects on visual performance. Target discriminability
is adding distractors which are like the targets which are required to be
learnt. Target discriminability has been used in the past for many reasons. One
of the reasons is that it provides an experimentally controlled similarity of a
certain behaviour (Pashler,
1987). The study being presented utilised this theory by adding distractor
objects with in the practice phase task.
For each of the practiced object (Rp+) there
were four types of matched unpractised objects (Rp-) (Represented in Figure 1).
In the presented study, there are two types of Rp- objects which were the
crucial conditions: Rp- objects that shared the same shape but had a different
colour to the practised objects (Rp- Shape) and Rp- objects which shared the
same colour but had different but had different shape to the practised objects
(Rp- Colour). In addition, Rp- object that shared neither shape or colour (Rp-
Neither) were also included, also objects that shared both shape and colour
with practiced objects (Rp- Both); however, the colour arrangements to the
objects parts were readjusted.