PSY 217 Lecture Notes - Lecture 2: Environmental Psychology, Random Assignment, Dependent And Independent Variables
5 May 2018
School
Department
Course
Professor
Research Methods
●Psychologists are interested in the relationship between variables
●Variables are things to be measured that can take on different values e.g.
room temperature, noise level, math test performance, “liking” ratings,
etc
●Environmental psychology: goals are to understand how people’s
behaviour is shaped by their environment - understand how people
shape their environment to suit their needs
●Hope is that designers will apply these finding towards better design
●3 research methods:
1. Experiments
2. Correlational research
3. Descriptive research
●Experiments: 2 defining features of experiments;
1. Manipulation of variable(s)
2. Random assignment
●In experiments, at least one variable is manipulated by the experimenter
e.g. I’m interested in how room temperature affects math test
performance -> put some people in a 30°C room, put some people in a
20°C room and get them to do the same math test
●Independent variable (IV): the variable that is manipulated by the
experimenter
●Actual values are called the levels
●Dependent variable (DV): what the researcher measures to determine
how much effect the IV had -> Sometimes called the outcome variable
e.g., room temperature study
●Random assignment to different levels of the IV minimizes the possibility
of differences between groups being due to some other confounding
variable
●Confounding of variables: occurs when two variables are linked together
in a way that makes it difficult to sort out their specific effects
●If confounding variables have been carefully controlled, an experiment
has high internal validity i.e. we can be confident that any differences in
DV between groups is due to the IV and not some other factor
●More importantly, we can be confident about cause e.g., room
temperature caused 30°C group to do worse on the math test than 20°C
group
●“Lab” experiments can lack external validity
●External validity: extent to which findings can be generalized to the “real
world” e.g., different people, different situations, etc
●Ulrich (1984) - Post-op patients with a window view -> shorter stay, fewer
negative notes from nurses, needed fewer drugs
●Field experiments can sometimes be impractical e.g., researching
people’s green space preferences
●Simulating the environment in the lab can be a compromise e.g.,
showing participants pictures of different spaces
●Correlational Research: aims to specify the relationship between two
variables
●Sometimes experiments would be impossible to do and unethical so
some research is done by carefully measuring variables i.e. no
manipulation or random assignment and no IVs or DVs
●Correlational coefficient: "a statistic that indicates whether two variables
are related in a systematic way” i.e. number between -1 and +1,
represented by the letter R, direction and strength of relationship ->
direction can be positive or negative
●Positive correlation (+): as x increases so does y
●Negative correlation (-): as x increases y decreases
Document Summary
Ps(cid:629)(cid:428)holo(cid:469)ists a(cid:568)e inte(cid:568)ested in the (cid:568)elationship (cid:427)et(cid:623)een (cid:622)a(cid:568)ia(cid:427)les. Va(cid:568)ia(cid:427)les a(cid:568)e thin(cid:469)s to (cid:427)e measu(cid:568)ed that (cid:428)an take on di(cid:468)(cid:468)e(cid:568)ent (cid:622)alues e. (cid:469). (cid:568)oom tempe(cid:568)atu(cid:568)e, noise le(cid:622)el, math test pe(cid:568)(cid:468)o(cid:568)man(cid:428)e, (cid:1657)likin(cid:469)(cid:1658) (cid:568)atin(cid:469)s, et(cid:428) En(cid:622)i(cid:568)onmental ps(cid:629)(cid:428)holo(cid:469)(cid:629): (cid:469)oals a(cid:568)e to unde(cid:568)stand ho(cid:623) people"s (cid:427)eha(cid:622)iou(cid:568) is shaped (cid:427)(cid:629) thei(cid:568) en(cid:622)i(cid:568)onment - unde(cid:568)stand ho(cid:623) people shape thei(cid:568) en(cid:622)i(cid:568)onment to suit thei(cid:568) needs. Hope is that desi(cid:469)ne(cid:568)s (cid:623)ill appl(cid:629) these (cid:468)indin(cid:469) to(cid:623)a(cid:568)ds (cid:427)ette(cid:568) desi(cid:469)n. E(cid:628)pe(cid:568)iments: (cid:1488) de(cid:468)inin(cid:469) (cid:468)eatu(cid:568)es o(cid:468) e(cid:628)pe(cid:568)iments; (cid:1487). In e(cid:628)pe(cid:568)iments, at least one (cid:622)a(cid:568)ia(cid:427)le is manipulated (cid:427)(cid:629) the e(cid:628)pe(cid:568)imente(cid:568) e. (cid:469). I"m inte(cid:568)ested in ho(cid:623) (cid:568)oom tempe(cid:568)atu(cid:568)e a(cid:468)(cid:468)e(cid:428)ts math test pe(cid:568)(cid:468)o(cid:568)man(cid:428)e -> put some people in a (cid:1489)(cid:1486) c (cid:568)oom, put some people in a (cid:1488)(cid:1486) c (cid:568)oom and (cid:469)et them to do the same math test. Independent (cid:622)a(cid:568)ia(cid:427)le (cid:1634)iv(cid:1635): the (cid:622)a(cid:568)ia(cid:427)le that is manipulated (cid:427)(cid:629) the e(cid:628)pe(cid:568)imente(cid:568) Dependent (cid:622)a(cid:568)ia(cid:427)le (cid:1634)dv(cid:1635): (cid:623)hat the (cid:568)esea(cid:568)(cid:428)he(cid:568) measu(cid:568)es to dete(cid:568)mine ho(cid:623) mu(cid:428)h e(cid:468)(cid:468)e(cid:428)t the iv had -> sometimes (cid:428)alled the out(cid:428)ome (cid:622)a(cid:568)ia(cid:427)le e. (cid:469). , (cid:568)oom tempe(cid:568)atu(cid:568)e stud(cid:629)
