identifying atypical development

what 3 factors make atypical development hard to define

• individual differences in rate of development

• individual differences in traits including both strengths + weaknesses —> issues when generalising to whole population

• ‘atypical’ definition is dependent on cultural differences in interpretation

definition of atypical development

‘the extremes of individual differences in development’, including both advanced + delayed development —> equivalent of falling 2/3 SDs from the mean

what are 6 patterns of developmental trajectory

• typical —> steady increase in capability

• delay —> starts at same ability level, but gap increases due to ability not developing at the same rate

• delay with catch-up —> child initially doesn’t develop at the same rate, but ability level eventually increases

• lower starting point —> starts from lower ability level, so develops at same rate as typical, but isn’t catching up

• advanced —> develops ability at a faster rate than typical

• developmental regression —> period where a particular skill initially develops along a typical trajectory, but skill is eventually diminished/lost

in what conditions + which what abilities is developmental regression often observed in

typically seen in children with ASC or an intellectual disability. most commonly effects language skills (may learn vocab but become non-verbal later in development), eye contact motor skills

which 5 main domains does development occur across

• adaptive behaviour

• social development

• cognitive development

• physical development

• motor skills

what are examples of adaptive behaviours that may be assessed

• daily living skills, e.g. ability to work + manage money

• functional decision making skills

• personal safety

• personal responsibility

• independence

what are examples of social behaviours that may be assessed

• language abilities/verbal communication

• understanding social interactions/different types of relationships

• non-verbal communication e.g. facial expressions, gestures, reciprocal eye contact

• conversational turn-taking

• emotional IQ + empathy

what are examples of cognitive abilities that may be assessed

• core/basic cognitive functions e.g. memory, attention + inhibition

• higher-order e.g. IQ, language, EFs + numerical ability

what are examples of physical attributes that may be assessed

more medical than psychological, but may be associated with various neurodevelopmental conditions. includes:

• facial dysmorphism

• micro/macrocephaly

• differences in stature

• organ differences e.g. in heart function/size or muscle tone

what are examples of motor skills that may be assessed

• fine motor skills —> movement of hands/fingers e.g. handwriting/drawing

• gross motor skills —> movement of limbs for whole-body movements e.g. walking/catching a ball

• balance + coordination (commonly affected by neurodevelopmental conditions e.g. William’s syndrome

how we can identify if development is atypical + what 2 things does this require

group comparisons against a representative (normative) sample of the population —> therefore we can see where the individual lies on a normal distribution curve. this requires

• an appropriate control group

• developmental trajectory to be tracked overtime —> gives insight into any changes we can expect later

why it is important to assess a child using appropriate/varied control groups

by using varied control groups (e.g. matched on chronological + mental age), we can assess what a child’s individual strengths/weaknesses relative to these populations

• e.g. child may have poorer than average verbal reasoning abilities matched on chronological age, but average abilities based on mental age

why it is important to consider relative strengths of a child’s developmental profile

we cannot gain full understanding of a child’s abilities without relative strengths —> skills they are good at compared to their other skills, rather than in comparison to other people

• this allows for appropriate interventions to be tailored to the individual based on their relative strengths, e.g. receiving verbal interventions as this is a relative strength in comparison to visuospatial skills

what are two main methods of measuring cognitive development

• specific experimental designs —> designed to target specific behaviours

• standardised tests —> designed to measure broader knowledge or skills

format + examples of specific experimental designs

format varies depending on research question. includes face recognition tasks, theory of mind tasks, EF tasks, online questionnaires, eye tracking + brain scans

• results can be compared with matched control group, e.g. based on age or gender

format + 4 examples of standardised tests

follows a fixed + consistent format with specific instructions, questions + scoring procedures

• participants’ raw scores can be standardised —> assigned a value that indicates how well they performed compared to others who have taken the test

• method allows for broader assumptions to be drawn across large population

• examples include IQ, Weschler Adult Intelligence Scale (WAIS), Weschler Intelligence Scales for Children (WISC) + British Ability Scales (measures adaptive abilities)

what 3 factors are important to consider when deciding between specific vs standardised methods of measurement

• goal → standardised tests aim to measure broader knowledge or skills, while experiments aim to test a specific skill or test hypotheses. 

• scope → standardised tests are broad in scope, covering a range of topics or skills, while experiments are focused on a specific research question

• generalisability → standardised tests aim to generalise results to a larger population, while experiments may have limited generalisability depending on the sample and conditions

what is the WISC and what 5 main indices does it measure

the Weschler Intelligence Scale for Children assesses intelligence in children ages 6-16. tasks start easy, then get progressively harder until participant cannot answer correctly, then test stops. indices assessed include:

• verbal comprehension index (VCI) —> measures a child’s ability to understand + use language as well as verbal reasoning

• visual spatial index (VSI) —> measures child’s ability to perceive, analyse + manipulate abstract visual info

• fluid reasoning index (FRI) —> measures ability to solve novel problems using abstract logic + think flexibly

• working memory index (WMI) —> measures ability to hold information in the mind

• processing speed index (PSI) —> measures ability to quickly + accurately process info

what tasks are necessary to assess full scale IQ (FSIQ) in the WISC

• VCI —> similarities + vocabulary test

• VSI —> block design

• FRI —> matrix reasoning + figure weights

• WMI —> digit span

• PSI —> coding test

what is VABS and what 5 indices does it measure (3,3,3,2,2)

the Vineland Adaptive Behaviour Scales measures adaptive behaviour using a semi-structured interview with the child’s parent, caregiver, teacher etc. its domains include:

• communication —> receptive, expressive + written

• daily living skills —> personal, domestic + community (use of time, money etc.)

• socialisation —> interpersonal relationships, play/leisure time + coping skills (how responsibility + sensitivity to others is shown)

• motor skills (optional) —> gross motor + fine motor

• maladaptive behaviour (optional) —> internalising + externalising behaviour, as well as other undesirable behaviour that may interfere with adaptive functioning, e.g. meltdowns

how does semi-structured interview format used by VABS benefit the test

means the experimenter can follow up questions with prompts to gain more key information —> means test isn’t too rigid and behaviour outside of the norm can be more easily identified (even if parent isn’t aware)

2 possible tests of skills for non-verbal participants (as most tasks rely on giving verbal responses/listening to verbal instruction)

• Weschler Nonverbal Scale of Ability (WNV) —> assesses non-verbal reasoning + problem-solving skills in individuals aged 4-21

• Leiter International Performance Scale - Revised (Leiter-R) —> assessed cognitive abilities in individuals 3-75

what subtests does the WNV contain and who is it suitable for

• subtests include object assembly, block design + picture arrangement

• its use of visual stimuli + minimal verbal instruction make it suitable for non-verbal children/those with language difficulties

what subtests does the Leiter-R contain and who is it suitable for

• uses variety of tasks e.g. matching pictures, completing patterns + solving mazes to capture different aspects of intelligence

• suitable for assessing individuals with autism, language or hearing impairments

2 developmental scales suitable for toddlers/babies

• Bayley Scales of Infant + Toddler Development (Bayley-III) —> assesses cognitive (e.g. attention span), motor (e.g. rolling), language, socio-emotional + adaptive behaviour in infants aged 1-42 months) using observation

• Infant-Toddler Developmental Assessment (IDA) —> assesses cognitive, motor, language, socio-emotional + adaptive behaviour through observation, parent report + standardised tasks

which developmental scale is more often used for infants at risk of developmental delays/conditions

the IDA, as it uses a variety of assessment techniques, so is often used in early intervention programmes to identify children who need additional support

what is a standardised score

generated from raw scores after a standardised test, it’s a value that represents how a participant has performed compared to others in the population (e.g. based on age/gender), without the influence of individual differences

• the value indicates where the score falls on a bell-shaped curve of others in the population

how is a standardised score gained

after a standardised test is administered, the raw score (sum of all scores) can be standardised by using a ‘look-up table’ based on an appropriate representative sample, though there are different ways to create standardised scores (e.g. t-scores)

what are t-scores and how are they scaled

an example of a standardised score —> 50 represents the mean, and each 10 represents 1 standard deviation

• means if someone gets a score of 60, they are 1 standard deviation above the mean on a bell-shaped curve

what are 4 benefits of using standardised scores

• enables researchers/clinicians to compare performance across different populations or tests

• they provide common language for discussing test performance regardless of how actual test is designed (focus on results without method)

• easily interpretable

• though there are different methods of standardisation, they all allow for the same comparison

what did Dale (2021) investigate

whether the WISC-V scores of autistic individuals (with or without a language impairment) differed significantly to that of non-autistic peers —> whether WISC-V is a reliable diagnostic tool

what did previous editions of the WISC often conclude from autistic patients

ASD commonly presented more variability in results than typically-developed peers

• ½ perform 1 SD below the mean, 1/3 perform 2 SDs below mean

• some autistic children have average-to-superior fluid reasoning, VS skills + WM

• often have deficits in VCI + PSI

this meant ASD could be distinguished from other conditions based on cognitive profiles in previous editions

what were Dale et al. (2021)’s main findings in relation to participants with language impairments

study produced 95% accuracy for predicting ASD-LI classification —> shows autistic children with language impairment have strong cognitive profile

• WMI + VCI were the most predictive factors

what were Dale et al. (2021)’s main findings in relation to participants without language impairments

scores for children with ASD-NLI were much more variable, so were not classified as accurately

• WM was often in the normal range

• the comprehension (lower score) subtest + similarities subtest (higher score) were predictive of autism

what was Dale et al. (2021)’s conclusion as to why the WISC-V is less sensitive to classifying cognitive profiles of autism in comparison to previous editions

• the previous ‘perceptual reasoning index’ was separated into the VSI + FRI —> this means the non-verbal strengths + weaknesses of ASD are now included in separate indices, meaning it may be less useful in differentiating ASD

• some subtests that result in significantly different scores between participants, e.g. letter-number sequencing + comprehension tests, are not required in FSIQ administration, meaning cognitive differences may not be picked up