lecture 1 - Introduction to Psychometrics and Intelligence Tests Flashcards
what are the fundamental aspects of psychological assessment
-Reliability and Validity of tests
-Intellectual ability
-Anxiety and Depression (are you really measuring the level of depression
-Intelligence tests and anxiety and depression scales will be used primarily to illustrate important general points about psychological assessment
-Emphasis will be on getting you to think about what issues a psychologist needs
to consider when using psychological tests
what are assumptions of psychological assessment
-Psychological traits
and states exist
-Psychological traits
can be quantified and
measured.
-Test-related
behaviour predicts
non-test-related
behaviour (we know theres variability etc, , but can use the tests to predict behaviour )
-Test have strengths
and weaknesses
Various sources of
error are part of the
assessment process.
Testing and
assessment can be
conducted in a fair
and unbiased manner
Testing and
assessment benefit
society
what is one of the most valued transferable skills a psychology graduate is expected to have
-knowledge and expertise in assessment and measurement
what to psychological assesments set out to measure
sets out to measure complex
constructs that are hard to capture:
-Mood, intellectual functioning, memory, attitudes
This is a tough ask
But, in general, we do surprisingly well
what is the assumption about ‘soft’ psychological tests compared to ‘hard’ biological tests found in medicine
-what is the truth?
Many assume that “soft” psychological tests are less reliable
and valid as “hard” biological tests found in medicine
Studies comparing psychological to medical testing procedures
(Meyer et al., 2001):
-Psychological tests are as, or more, RELIABLE than many
(biological) medical tests
-Psychological tests are as, or more, VALID than many medical
tests (e.g., have equivalent levels of sensitivity and
specificity)
intelligence testing
-how would you describe and intelligent person
-Learning? Acquiring, remembering lots of information
-Grasps things easily
Good vocabulary – they can find the right words quickly
-Problem solving – applying their knowledge to solve real world
problems.
-Reason logically, plan effectively
-there is no set definition
history
-roots of psychological testing , who and what did they measure (timeline)
-david wechsler definition of intelligence
Psychological testing has its roots in late 19th century
psychological pioneers such as Galton, Wundt, Cattell who were
objectively measuring sensory abilities and reaction times.
Alfred Binet and Theodore Simon published the first modern
intelligence scale in 1905 (used to identify strengths for students, used for educational purposes)
WW2 – screening intellectual ability of new recruits (mobilise large groups, identify who you would want in charge)
One of the most widely used tests is the Wechsler Adult
Intelligence Test developed by David Wechsler in 1939
“A global concept that involves an
individual’s ability to act
purposefully, think rationally, and
deal effectively with the
environment.”
The WAIS-IV
-wechsler adult intelligence scale
-how common is it
-how many psychologists use it
-who was it standardised on
By far the most commonly used measure of adult intelligence
is the Wechsler Adult Intelligence Scale (WAIS)
Typically over 90% of clinical psychologists report they use the
WAIS in their practice
The test is now in its fourth edition (WAIS-IV; Wechsler, 2008)
It was standardized (i.e., normed) in the USA on a sample of
2200 people aged between 16 and 90
The WAIS-IV
-what is the IQ range for the WAIS
The IQ range has been extended each time the WAIS has been re-
standardized
Currently range is 40 to 160; IQ has an SD of 15, therefore measures
from 4 SDs below mean to 4 SDs above
-covers a huge amount of variability in terms of intellectual functioning (can use wais for most people)
in the WAIS-IV why did age range extend upwards each time its standardised
This is partly to reflect increased longevity but also a (belated)
recognition that the elderly are more commonly referred for testing
than other age groups
Quality of norms for the elderly have improved for many
psychological tests in recent years (does it show were getting smarter???) (could be better nutrition)
Wechsler intelligence scale for children
-what age of children does it measure
-WISC-V vs WAIS-IV
There is also a version of the Wechsler Intelligence scale for children
/ adolescents (ages 6 to 16
The WISC is very similar to the WAIS:
◦ Same overall structure
◦ Essentially the same subtests (just simplified)
◦ Very similar psychometric properties (i.e., level of reliability etc)
Thus, most of topics we will be covering apply equally to the WISC
the WAIS-IV
-the importance of wais and standardised instructions
As with all psychological tests, users must administer the WAIS (or
WISC) according to the standardized instructions
A psychologist might think they could give better/clearer instructions
but must resist the temptation to deviate from the standard
instructions.
Test norms were obtained using the standard instructions
Specific feedback not given while the test is administered because
answers are ‘ (just general encouragement)
(the test may have to be used again on the same person again, and so therefore they cant know feedback)
what does the WAIS-IV consist of
-consists of 10 core subtests, arranged into four higher level indexes , and an overall IQ
in the WAIS IV- scores are age corrected - what does this mean and why
-mean and SD of IQs and indexes
The elderly raw score will be lower than the average young/middle
aged individual, but if someone is exactly average for their age, their
IQ will be 100
On some subtests (particularly those involving psychomotor speed)
peak performance is around 17/18 years of age
◦ Peak performance is much later for some subtests (e.g., Vocabulary, as
one would expect)
IQs and Indexes have a mean of 100 and standard deviation of 15
WAIS IV - the 10 tests in core 4
Verbal comprehension - similarity, vocabulry and information , 3 tests used to measure an aspect of verbal comprehension
Perceptual reasoning - block design, matrix reasoning, visual puzzles
working memory - digit span and arithmitac
processing speed- coding , simplesearch
As noted, there are ten core subtests (subtests have a mean of 10 and a
standard deviation of 3)
The subtests are arranged into four Indexes (mean for an Index is 100, SD = 15)
There is also an overall IQ (Full Scale IQ) that is obtained by summing scores on
all the subtests
