Module 1 Flashcards
visual acuity
how sharp or clear your vision is.
Challenges in the study of human development
First
first main challenge, it is more difficult to communicate with infants and children.
because their language skills are still developing: a young infant can’t understand anything you’re saying at all and can’t yet talk, but even an older child might have trouble understanding long or complex instructions, and they might have a hard time explaining what they know in words.
Challenges in the study of human development
2nd
children have short attention spans and limited cognitive skills like memory.
need to try to make the study short and interesting
Short attention spans also mean that kids often get distracted easily
Lastly, children’s cognitive skills will limit what kinds of procedures we can use with them,
Most Likert scales have 5 or 7 options because we can hold 7 plus or minus 2 things in memory. Because children’s memory capacities are much smaller, they might only be able to reliably answer questions with two options.
Challenges in the study of human development
3rd
physical limitations
Babies don’t have full control of their heads until about 5 or 6 months, and several of the infant procedures we’ll encounter later depend on being able to sit up with the head supported and turn the head to either side of the body.
Toddlers often understand quite a lot of what is said to them, but the physical movements needed to talk are very precise and hard for them to do, so it can be difficult to understand what words they’re trying to say.
In a similar way, it can be hard to decipher the writing of young children, since the motor movements needed to hold and control a pen or pencil are tricky.
Challenges in the study of human development
4th
competence-performance distinction.
Competence means what you’re capable of, or what the true state of your knowledge is. Performance, on the other hand, is whether you can actually demonstrate that knowledge in a given situation.
competence-performance gap is usually wider in infants and children than it is in adults. Children’s performance is more dramatically affected by their own state—like whether they’re tired or having a bad day—as well as by the task demands, like whether the procedure is too long or too difficult.
Challenges in the study of human development
5th
Ethics.
Infants and children are considered a vulnerable population in research because they’re at a higher risk for harm.
Children cannot provide informed consent, so their parents or guardians have to provide it on their behalf.
Most ethics also require that researchers obtain the child’s verbal assent as well.
This means that we explain to them what we’ll ask to them to do in language that they can understand, and that we ask them if they want to help out.
We also make sure they know that they can stop at any time if they don’t like it or they’re uncomfortable.
Challenges in the study of human development
6th
Attrition,exclusion rates, selection bias
Attrition is the word used when participants drop out of a study before it ends, usually when the study is conducted over a longer term, a design type that is more common in developmental research.
Exclusion happens when participants come in to be tested, but their data has to be excluded because of fussiness, inattention, parent interference, equipment malfunction, or researcher error.
Selection bias happens when only a certain type of participant completes the study, when the researchers were actually targeting a more diverse population.
These tend to be families who come from higher socioeconomic statuses, called SES for short
it is normal to have to exclude up to 50% of the data!
Themes in development
Stability vs change (and shape of change)
1st theme asks whether development is stable, or whether there is a considerable amount of change.
if you’ve ever wondered whether a fussy baby tends to grow up to be a moody adult, then you were wondering about the stability of certain traits.
A related question, when there is change, is what the change look like. Does something like memory capacity grow little-by-little, gradually increasing as children age? This is what we mean by continuous development, where change is quantitative in that there is just “more” of the same.
On the other hand, do some aspects exhibit discontinuous development, which looks like a sudden spurt or change that is qualitatively different than before?
Jean Piaget, the famous child psychologist, thought that cognitive development worked this way and developed a whole theory around it.
Themes in development
nature vs nurture
because genes and environments constantly interact: our genes influence which experiences we have, and our environments influence gene expression, or which genes are turned on or off.
A modern version of this question examines exactly how these things interact to produce a developmental outcome.
Themes in development
Active vs passive development
role of a child in their own development.
Some theories assume that children don’t play much a role – instead, they are at the mercy of the environment that they are exposed to, or their own genetic predispositions.
This is a passive view of child development, where kids are viewed either as sponges, just absorbing experiences that mold them, or as DNA blueprints who mature strictly according to the genetic code.
Piaget who argued for an active view of child development, where children are not just passive sponges or genetic codes.
Instead, he likened kids to little scientists who learned about the world by experimenting and trying different things.
Different kids might experiment differently, and that will affect their outcome in the end.
Under this view, development doesn’t just happen to a child, they play an active part in the outcomes themselves.
Themes in development
Domain specific vs domain general development (connections)
extent to which development is connected across different domains.
A domain is just any aspect where kids change over time, like their physical, emotional, cognitive, or social development.
domain-specific, meaning that development in that area “does its own thing” so-to-speak, and children learn it independently from how they learn other things?
Or is development domain-general, meaning that children’s learning or development in one area is connected to development in another area?
General study designs
Experimental
the true experiment.
When we use that word, we mean a very specific type of study where researchers manipulate one or more independent variables to test their effect on one or more dependent variables that we measure as outcomes of interest.
By “manipulate”, we mean that a researcher decides on the specific conditions or groups that participants will be assigned to, such as a treatment and a control group.
researchers randomly assign ppl to groups
General study designs
between-subjects design
Participants assigned to different conditions.
General study designs
Within-subjects designs
can also be experiments, which is when the same participants complete all conditions, ideally in different orders.
General study designs
quasi- experiments
If there is no random assignment to condition (or to the order of conditions in a within-subjects design), the study is not a true experiment and we can’t make conclusions about causation.
have more in common with correlational designs.
General study designs
correlational designs
we measure two or more naturally-existing variables and examine whether they’re related to each other.
main issue with correlational designs is that we can’t make firm conclusions about what caused what, which is why we repeat that mantra “correlation does not equal causation.”
Another possibility, sometimes called the third variable problem, is that any number of other variables could cause both of the other two.
General study designs
Longitudinal designs
Are usually the gold standard for measuring change over time, which is when the same children or adults are tested at more than one timepoint.
benefits is that they’re the only way to test certain questions, like whether development is continuous or discontinuous.
The drawback is that longitudinal research is really difficult to conduct.
First, it’s common to have attrition as participants move away or become too busy or disinterested to continue with the study.
Second, it’s expensive, partly because you need a large enough sample size to account for expected attrition, and partly because it takes a lot of money to fund the amount of testing and record-keeping that is needed.
Third, time-consuming.
Finally, some longitudinal designs can have issues with practice effects, which is when participants get better at a test each time they take it, not because they’re better at the skill that is being measured, but because they’re becoming more familiar with the test itself.
General study designs
cross-sectional design
where different groups of different- aged children are tested in the same timeframe and compared.
The main drawback with this design is that you can’t answer questions about continuous and discontinuous development that longitudinal designs are best at tackling.
But if you just want to know what kids can do, on average, at different ages, this type of design is quite a bit easier, cheaper, and less time consuming.
General study designs
longitudinal- sequential design.
Here, children of more than one age group are tested twice or more, such as both when 6- and 9-year-olds are tested 3 years later when they are now 9 and 12 respectively.
These designs have the same benefits as longitudinal designs, but they can test the same developmental span—6 to 12 years of age in this example—in less time and with fewer expenses.
Infant procedures
Habituation
use to answer questions about discrimination—whether babies can tell things apart—of visual stimuli, although it has sometimes been modified to test other things like auditory (hearing) and tactile (touch) perception.
Get infants completely bored-–or habituated—by presenting them with the same thing over and over again, measuring how long they look at it on each trial.
This is called the habituation phase, and we end each trial after infants look away from the display for 2 or more seconds.
move on to the test phase, where infants are presented with yet another instance of the old thing—the familiar stimulus—or a new thing, which is the novel stimulus.
If their interest is suddenly piqued to the novel display causing them to look at it longer, it means that they can probably tell the difference between the old stimulus and the new stimulus. We call this renewed interest dishabituation.
Infant procedures
Preferential looking
is another procedure that examines infants’ understanding of visual stimuli, but it is usually used to answer different kinds of research questions.
Specifically, is used to test whether infants recognize something as familiar from their everyday environment, or whether they have a natural interest in one thing over another thing.
On each trial, you show infants two images, side-by-side. measure which image the infant looks at longer, or which image they look at first. They will tend to look longer at the image they’re familiar with, or at the image that they naturally prefer.
conduct at least two trials and swap the right-left placement of each image, because sometimes infants have a side bias causing them to tend to prefer one side over the other.
If you’re wondering why infants looked longer at the novel stimulus in the habituation procedure, but longer at the familiar stimulus in preferential looking, it has to do with when infants were familiarized with something. Infants tend to prefer familiarity in general, unless they’ve been saturated with it over and over in that particular moment, like in habituation.
Infant procedures
preferential listening/head turn preference
For auditory recognition and natural preferences,
only issue is that unlike visual stimuli, which you can present simultaneously at the same time, you have to present sounds sequentially, one-at-a-time. Otherwise, you wouldn’t really be able to tell which sound the infant is paying more attention to.
get the infant’s attention to one side by flashing a light or playing a short sound like a beep. Once the infant is looking in that direction, you play one of the two stimuli.
Once they get bored and look away for 2 or more seconds, you get their attention on the other side, and repeat the procedure with the other stimulus.
You alternate back and forth for a set number of trials or some other predetermined rule, and then tally up how long the infant listened to each stimulus over the course of the experiment.
That way, you can see if infants recognized the familiar stimulus or showed a natural preference.
Infant procedures
conditioned head-turn procedure
auditory discrimination
infants are conditioned to turn their head whenever they hear a change in an auditory stimulus, assuming they can hear the difference.
starting the procedure with a conditioning or training phase. In this phase, one stimulus repeats over and over in the background while the infant looks straight ahead.
Every time a change is presented – like from one speech sound to another – a toy lights up and dances to one side of the infant, attracting their attention and acting as a reward for head-turning.
Soon, the infant begins to associate the change with the reward, which is delayed a couple of seconds after the change to give the infant a chance to turn in anticipation of the reward, rather than as a reaction to it.
In the test phase, this delay is kept, and a new set of stimuli are used: the ones the experimenter is actually interested in testing.
To figure out whether infants can discriminate the stimuli, there are a number of things researchers can calculate, but only two things matter.
hits are when there was a change and the infant turned their head, as they are supposed to.
Misses occur when the infant failed to notice a change and did not turn his head.
False alarms occur when there was no change—it was just the same repeating background stimulus—but the infant jumped the gun and turned their head anyway.
Correct rejections occur when there was no change, and the infant correctly showed no head turn.
hits and false alarms that matter most.
Infant procedures summary
Visual stimuli + discrimination = habituation
Visual stimuli + recognition = preferential looking
Auditory stimuli + discrimination = conditioned head turn
Auditory stimuli + recognition = preferential listening