A-level psychology comp 1: experiments

what is a hypothesis?

a testable statement that predict the effect that the IV will have on the DV

what is an alternate (experimental)?

tells us that the IV will have an effect on the DV

• this can be one tailed or two tailed

what is a one tailed hypothesis?

when the effect of the IV on the DV is predicted and specified

Uses words like increase, decrease, rise fall

what is a two tailed hypothesis?

when the the effect of the IV on the DV is predicted but not specified

Uses words like affect, change, influence

what is another name for a one tailed hypothesis?

directional

what is another name for a two tailed hypothesis?

non-directional

what is a variable?

anything that can be changed or manipulated

what is a null hypothesis?

when the IV will have no effect on the DV

what is a lab experiment?

an experiment that is done in a highly controlled condition and the IV can be manipulated

what is a field experiment?

an experiment that is done in a real-life environment and the the IV can be manipulated

what is a quasi experiment?

an experiment that can be done in both a controlled and natural setting and the IV cannot be manipulated as it is naturally occurring

what are the advantages of a lab experiment ?

control over variables

can identify cause and effects

reliable

what are the disadvantages of a lab experiment?

low ecological validity

demand characteristics

harder to generalise

what are the advantages of a field experiment?

high ecological validity

less demand characteristics,

what are the disadvantages of a field experiment?

lacks reliability

can't control variables making it harder to establish cause and effect

what are the advantages of a quasi experiment?

high in ecological validity since there's no manipulation of the IV,

what are the disadvantages of a quasi experiment?

no control over variables

what is an independent measure design?

when different participants take part in different condition in the experiment

what is a repeated measure design?

when the same participants take part in the same conditions for the experiment

what is matched pairs design?

when participants are put into groups based on their characteristics

what are the advantages of an independent measure design?

increased external validity

no order effect

what are the disadvantages of an independent measure design?

more participants are needed

individual differences between participant

what are the advantages of a repeated measures design?

individual differences can be eliminated as same participants are doing the same conditions,

has good internal validity,

fewer people are needed

what are the disadvantages of a repeated measure design?

can have an order effect as participants are all doing the exact same conditions,

can have inaccuracy

what are the advantages of a matched pairs design?

no order effects and lower demand characteristics as participants are only tested once

what are the disadvantages of a matched pairs design?

availability of participants that are needed- may not be a match between participants , time consuming

what does it mean to operationalise a variable ?

Making a variable clear, specific and measurable - showing exactly how you are going to manipulate the IV and measure the DV

what do you have to do when operationalising the IV ?

you have to create two or more conditions

eg: if you were manipulating music you would split the participants into two groups, one group will listen to music and the other group will be I'm silence. the ones listening to music will wear headphones and listen to the same song and those in silence will wear noise cancelling headphones

what do you have to do when operationalising the DV?

you must include a clear description of the task, timings and scorings

eg: if you were measuring concentration you would say that the participants would complete a word search puzzle. the word search would have 25 words to find and the participants would have 5 minutes to find as many as they can. the higher the number of words found, the higher the concentration

what does generalisability mean?

to the extent to which findings of a study can be applied to a larger population

what does internal validity mean?

when cause and effect is not influenced by other factors or variables

what is external validity?

when the results of a study can be generalized to other situations and to other people