Summaries based on:
Bowler, D. M., Gaigg, S. B., & Gardiner, J. M. (2014). Binding of multiple features in memory by highfunctioning adults with autism spectrum disorder. Journal of autism and developmental disorders,
44(9), 2355-2362.
Summary 1
Bowler et al (2014) investigated the relationship between Autism Spectrum Disorder (ASD)
and memory, specifically recognition memory. They hypothesised that recognition memory
is difficult for ASD individuals when combinations are involved in the visual stimuli. This is
due to, Chalfonte and Johnson’s (1996) findings that recognition of combinations in older
adults was significantly worse than individual features, as well as, the existing findings of
ASD memory difficulties leading to a prediction of similar diminished combination
recognition, in ASD. In order to test this hypothesis, they conducted two experiments,
involving neurotypical and ASD participants, two groups serving as the independent
variable.
The first experiment involved 18 ASD and 18 neurotypical participants, matched on the
years of formal education they’ve undergone, age and cognitive ability, to avoid
confounding variables. Bowler et al (2004) used line drawings which were randomly placed
in a 6x6 grid. Participants were tested individually and shown a set of coloured drawings
that they were asked to either remember what the drawings were (item condition), the
colours presented (colour condition) or where on the grid the drawings appeared (location
condition). All participated in each condition, with several weeks in between. During the
experiment, participants had a minute to study the grids and were introduced to a test
array, measuring the amount of drawings of each condition, correctly recognised by
participants (dependent variable). Bowler et al (2014) found there were no significant
differences in false alarm rates This suggests that recognition memory in ASD participants is
not as reduced, when features are separate.
The second experiment conducted involved 14 ASD and 15 neurotypical participants, also
matched as in experiment 1. Four study arrays of drawings were randomly allocated in a 6x6
grid. Two used for the Item-Colour condition and two for the Item-Location condition. In the
Item-Colour condition, 10 drawings were the same colour as when studied, whereas 10
were randomly assigned a colour, so there were old and new combinations present. This
was the same for the Item-Location condition, colour replaced by the location of the
drawing, on the grid. When completing the test, the items, colours and locations would
appear as the original or swap with other drawings. Depending on the condition,
participants were asked to remember the combination of what the drawing was and the
colour (Item-Colour condition) or the same but the location instead of colour (Item-Location
condition). As in experiment 1, participants were given a minute to study the grid and
unlimited time to present their responses.
Bowler et al (2014) also conducted a Colour Trials Test (D’Elia et al. 1996) where the time
taken to complete the test was used. They found that there were no differences between
the groups in either of the test measures. They also found that there were no significant
differences in false alarm or corrected recognition rates. However, the experimental group
performed significantly worse for both conditions involving the combination of factors.
Bowler et al (2014) found that although participants showed recognition was better when
the stimuli was presented separately, the difference between the recognition in experiment
1 and 2 is greater in the ASD group, suggesting ASD participants had more difficulty with
recognition memory even though they recognised the stimuli separately and other variables
such as individual differences, e.g. intellectual ability, were controlled. Thus, supporting the
hypothesis that recognition memory is more difficult for ASD individuals when combinations
are involved in visual stimuli.
These findings help to clarify the work of Williams et al (2008), providing potential means of
operationalising dealing with complex memory, which is identified as a characteristic of
ASD. This hasn’t been fully explored, therefore can encourage research into the relationship
between relational binding Bowler et al (2014) addresses and the measures that Williams et
al (2008) argues as including complex memory processes. The findings also prompt research
into the extent that reduced relational binding abilities are related to ASD and the everyday
difficulties individuals on the spectrum face.This article’s findings were also consistent with
Chalfonte and Johnson’s (1996) study, the patterns prompting research into the
effectiveness of relational memory interventions and if this caused other effects on
cognitive functioning. Another possible investigation the findings from the study can
suggest, is the neuropsychological foundations of reduced relational memory, which is
suggested to involve the medial temporal lobe, particularly the hippocampus (Brown and
Aggelton, 2001), both of which are suggested as playing a role in ASD development
(Damasio and Maurer, 1978).
Bowler et al (2014) confirm the findings of previous studies, that when stimuli is separate
recognition memory is more intact, showing that when combinations occur within the
stimuli, recognition memory becomes compromised. Therefore, the potential implications
of these findings are important in understanding brain mechanisms for memory.
Summary 2
Research regarding Autistic Spectrum Disorders have illustrated difficulties in
memory patterns. However, the specific details of these patterns remain ambiguous.
Therefore, the researchers aimed to investigate these pattens- through examining and
adopting aspects of amnesia literature. For example, Konkel et al’s experiment of
participants studying abstract shape triplets, inspired this study- as aspects of the stimuli
and procedure was selected. Based on Konkel’s findings and the researchers’ own theories,
it was hypothesised that ‘ASD is characterised by difficulties in relational memory that is
evident in typical ageing’. Relational memory refers to a type of memory that stores and
recalls relationships and associations. Moreover, ASD participants were predicted to exhibit
similar performance to Konkel’s hippocampal patients- who displayed lower performance
rates in relational memory tasks. Additionally, it was hypothesised that the ASD group
would demonstrate intact, item task performance. Furthermore, the researchers aimed to
explore the concept ‘ageing analogy’ (Geurts & Vissers, 2012), as they believed visual
memory declines greater in ASD participants than TD participants. Thus, researchers
predicted through the ageing analogy, that ASD participants maintain similar relational
memory performance to older TD participants- as mental acuity decreases as age increases.
The experiment included 18 TD (4 women/14 men) and 18 ASD (5 women/13 men)
participants-with the age range of 20-62 years. Matched pairs design was used after
participants were randomly selected. TD with a history of neuropsychological or
developmental disorder were excluded from the study- to avoid confounding variables. The
stimuli involved an altered version of the paradigm used in Konkel’s experiment. The
paradigm contained black shapes, displayed on a grey background. The absence of colour
removed the obstacle of ASD participants having difficulty remembering and distinguishing
between colours. The study incorporated two experiments. Experiment 1 required
participants to remember individual features of the paradigm e.g. location, order. Whereas,
Experiment 2 required participants to remember combinations of features of the paradigm
e.g. location and order. It was imperative for participants to remember specific details about
the paradigm (e.g. order) seen in the study phase, as this information would be needed
across the different conditions of the experiment. As the study included an item test,
location test, associative task, order task and relational tests. Furthermore, the procedure
involved participants depicting answers on a keyboard, after the stimuli was illustrated on
the computer screen. Participants were informed to press ‘y’ for yes and ‘n’ for no, in
reference to the familiarity of the items on the screen. For example, in the items test, if
participants had observed all three items during the study phase, they pressed ‘y’- but if one
or two items seemed unfamiliar, they pressed ‘n’. Whereas, the relational task required
participants to distinguish whether items on the screen were the same in the study phase, in
terms of location, order and set in which triplets were presented.
The data gathered for the associative, item, location and order tasks were measured
according to hit-rates (correct answers), false-alarm rates (incorrect answers) and correct
recognition rates (hit-rates minus false-alarm rates). The hit-rates displayed for all four
tasks, illustrated that the TD group provided a greater amount of correct answers
(M=0.60/SD=0.21) compared to the ASD group (M=51/SD=0.23)- with the mean difference
of 9. Whereas, the false-alarm rates for all four tasks, demonstrated that the ASD group
offered a greater number of incorrect answers (M=0.36/SD=0.22) compared to the TD group
(M=21/SD=0.19)- with the mean difference of 15. This data implies that the TD group
performed better in all four tasks, compared to the ASD group- as the TD group obtained
more hit-rates and less false-alarm rates. Therefore, we can assume the hypothesis of
relational memory being poorer in ASD participants is accurate, as ASD participants
exhibited lower performance rates than TD participants.
A methodological strength of the study is the use of a paradigm. The paradigm enabled the
comparison of multiple types of relational memory, through the use of only one paradigm.
Moreover, the paradigm illustrated which relational information is more challenging for the
ASD participants to process. For example, the hit-rates for the ASD group was the lowest in
the order task (M=0.46/SD=0.22) and the false-alarm rate was the highest for the
associative task (M=0.44/SD=0.22). Nevertheless, a caveat of the investigation is the small
sample size. The study contained only 36 participants (18 TD/18 ASD). Thus, diminishing the
representativeness of the research population and hindering the generalisability of the
findings. On the other hand, the researchers recommended that their study should be
replicated with a larger sample to overcome this limitation.
Summary 3
Bowler, Gaigg and Gardiner (2008) were interested in investigating the relation between
episodic and semantic memory, and relational binding of elements of complex stimuli in
people with autism spectrum disorder (ASD).
They hypothesised that participants with ASD would have reduced recognition for episodic
combinations of features of visual stimuli but would have normal recognition of the features
separately.
In the first experiment, thirteen male and five female participants with ASD (all of whom
were clinically diagnosed according to the DSM-IV) and fourteen male and four female
‘typical’ participants (control group) were matched in terms of number of years of formal
education and cognitive ability (measured by the Wechsler adult intelligence scale). As the
study was an independent design, each participant took part in all three conditions which
were separated by several weeks to reduce interference effects. In order the reduce the
influence of order effects, counterbalancing measures were enacted, meaning that
participants took part in the three conditions in different orders so that participants’
learning did not influence the results. The three conditions were; item condition, where
participants were instructed to remember what the line drawings were, colour condition,
where participants were instructed to remember what colours they saw, or location
condition, where participants were instructed to remember the locations in the grid filled
with a drawing.
The independent variable was the focus of the participants, either to remember what the
line drawings, colours or location of the drawings were, and the dependent variable was the
accuracy of recognition. The grids presented were 6 x 6 and the stimuli for each condition
(item, location and colour) was randomly allocated. Participants took part individually in
each condition and were instructed to remember the variable of each condition, either to
remember the items, colours or locations after studying for 1 minute, and participants were
given as much time as needed for recall.
In experiment 1, the researchers found that participants with higher-functioning ASD
demonstrated relatively undiminished recognition in the item, colour and location drawings.
The mean recognition for the ASD participants in the item, colour and location conditions
respectively are .77 (SD = .23), .14 (SD = .23), and .26 (SD = .34) in comparison to the mean
recognition for the ‘typical’ participants in the item, colour and location conditions
respectively are .89 (SD = .15), .17 (SD = .23), and .24 (SD = .39).
In the second experiment, eleven male and three females participants with ASD, and two
female and thirteen male ‘typical’ participants, as well as nineteen participants (nine with
ASD and ten ‘typical’) who had previously participated in experiment 1 were all matched on
number of years of formal education and cognitive ability, and took part in experiment 2.
The two conditions of the experiment were, item-colour condition, where participants were
instructed to remember both the lines of the drawing and the colour, and item-location
condition, where participants were instructed to remember both the lines of the drawing
and their locations.
The independent variable was the focus of the participants, either to remember the item
and colour, or the item and location, and the dependent variable was the accuracy of
recognition. In this experiment, the grids presented were generated in the same way as the
first experiment, and counterbalancing measures were put in place to reduce the influence
of order effects. Participants were instructed to remember the respective stimuli of their
condition (either the items and colours or items and locations) after studying each grid for 1
minute, and were allowed as much time as needed to recall.
In experiment 2, results found that the participants with ASD had reduced recognition than
the comparison ‘typical’ participants in both the item-colour and item-location conditions.
The mean recognition for participants with ASD for the item-colour and item-location
conditions respectively was .25 (SD = .26) and .37 (SD = .22) in comparison to the ‘typical’
participants with mean scores of .56 (SD = .27) and .60 (SD = .27).
A comparison of results between both of the experiments found that both groups had
improved recognition in the single-focus conditions of experiment 1 (item, colour, and
location conditions), but the difference between the two experiments’ recognition was
greater for participants with ASD than the ‘typical’ participants. These findings support the
researchers’ hypothesis that those with ASD possess difficulties with complex features of
episodic memory and they are consistent with the view that memory difficulties for those
with ASD are a result of diminished relational binding. The results of this study has
implications for future research; this includes the under researched area of cognitive aging
of those with ASD, the level of association between diminished relational binding and
symptoms of ASD, as well as the effectiveness of interventions on relational memory
performance, and finally the exploration of neural and neuropsychological explanations of
impaired relational memory.
Summary 4
Bowler, et al. hypothesis was if weakened episodic memory (recollection of personal
experience) and reduced use of semantic information (information involving signs, words and
phrases) to aid recall by people with ASD (autism spectrum disorder) are both thought to
occur due to reduced relational binding of elements (fitting pieces of information together to
construct a memory) of complex stimuli. Autism can cause many difficulties in daily life such
as struggles with social interactions. They are known as high-functioning individuals. Evidence
through many studies have shown that they struggle with free recall tasks (presented words
for an amount of time and asked to recall as many as they can). The researchers tested the
hypothesis by completing two different experiments. The findings of this experiment are key
in gaining more information on ASD and to understand the areas of the brain that are
functioning at a lower level than in a typical participant. The results of this experiment show
in detail the severity ASD has on certain areas of the brain. The underlying meaning of the
article was whether there was a reduced relational binding of elements in people with ASD
then typical participants. This was tested through two experiments of this study.
In the first experiment there was eighteen participants with ASD; 5 females and 13 males
along with 18 typical participants 4 females and 14 males who all participated in experiment
1. Participants were matched closely on years of education and cognitive ability. ASD
participants were recruited from autism research group at City University. The independent
variable were two groups (typical participants and the ASD participants). The dependent
variable was how many correctly recognised item, colour and locations they got on the study
array. The procedure for experiment 1 was they were shown a 6x6 grid and coloured line
drawings would be on random locations. There were three different conditions every
participant completed the different conditions over several weeks. When given the 6x6 grid
they were asked to remember one of the three conditions either the colour condition, the
item condition, or the location condition. They were given 1 minute to study the grid. Every
participant went through a brief description of the recognition procedure and shown the grid
again, and asked to say which items, colours or locations they could remember depending on
the condition they were in. Results from this experiment showed that all three conditions
(item, colour and location) had virtually the same results for both the ASD group and the
typical participant group. This experiment shows that verbal recognition is not affected by
ASD and were almost exactly the same as typical participants.
In the second experiment there were 14 participants with ASD (3 female and 11 male) and
fifteen typical participants (2 female and 13 male), there were more participants then the
previous experiment (9 ASD and 10 Typical participants). They were all matched in the same
way as in experiment one. The independent variable again was the two participant groups
the ASD group and the typical participant group. The dependent variable was how many items
they correctly identified in the two conditions. In this experiment there were two conditions.
The first condition was item-colour the other condition was item-location. There were two
grids in the item-colour condition one which the participants studied. The other grid was to
create false memories or to inhibit retrieval of correct memories. This was the same for the
second condition (item-location). However, in experiment 2 all participants were
counterbalanced (half did one grid then the other studied the other grid to minimise order
effects). The procedure was the exact same for experiment 1, however the difference was
participants had to remember both item and the colour and also for the item and location.
Just like in experiment 1 they also had to study the grid for 1 minute. Results from experiment
2 showed that the ASD participants were drastically lower than the typical participants on the
2 combination conditions. Therefore experiment 2 shows that ASD participants struggled
reciting combinations, this was the same in both conditions.
In conclusion, the hypothesis of this study has evidence particularly in experiment 2 that
individuals with ASD struggle with recognition memory of episodically defined
combinations. However, experiment 1 contradicts the hypothesis slightly in the way they
are able to recall the same amount of a single features as the typical participants. In
addition, Bowler produced a hypothesis known as the “TSH” this is known as the task
support hypothesis which predicts that ASD group performances will not be hindered in the
two experiments. Experiment 2 goes against this theory as ASD participants struggle to
recall combinations of information. Overall, the results help to build on our knowledge and
experience, so we understand more about individuals with ASD and how their complex
memory is severely affected.