Chapter 1: Research methods in psychologyLearning activity suggested answersLearning Activity 1.1 (p. 18)1 What are two features that best distinguish an experiment from other research methods?
Features may refer to:
• testing a cause–effect relationship between variables of interest
• control of variables (including potential confounds)
• random allocation to groups.
2 Write a definition of each of the following terms as they apply to an experiment:
• variable: any factor that can change (vary) in amount or type over time
• independent variable: a variable in an experiment that is systematically manipulated, changed or varied in some way by the researcher in order to assess its effect on the participants’ responses
• dependent variable: a variable in an experiment that is expected to change as a result of the manipulation of the independent variable; or the aspect of a participant’s behaviour or experience in an experiment that is observed or measured and is expected to change as a result of the manipulation of the independent variable.
3 What do researchers expect to happen to dependent variables when they manipulate independent variables?
Explanation should refer to change in participant behaviour or experience.
4 Identify the IV and DV in each of the following:
a Receiving a reward for studying will increase the amount of time students engage in studying.
IV: reward (for studying)
DV: amount of time spent studying
b People who are in love perceive each other more positively than other people perceive them.
c Recall of information presented early in a list is better than recall of information presented later in a list.
IV: position of information/item in a list
DV: recall accuracy
d People react quicker to sounds than to visual stimuli.
IV: type of stimulus (auditory or visual stimulus)
DV: reaction time
e Using adult language when talking to infants improves their vocabulary.
IV: exposure to adult language
DV: amount of vocabulary/number of words used
f People change their pitch of voice when lying.
IV: lying/telling a lie
DV: voice pitch
g People who suffer from depression recall more negative experiences than positive experiences.
IV: suffering from/diagnosed with depression
DV: number of positive and negative experiences recalled/type of experience recalled
h Daydreaming occurs more frequently during simple tasks than during complex tasks.
IV: task complexity
DV: frequency of daydreaming/daydreams
i Workers on an assembly line are more productive when working alone than in a small group.
IV: work condition (working alone or in a small group)
DV: productivity/level of productivity
Learning Activity 1.2 (p. 19)A researcher noticed that some of her laboratory rats stood on their hind legs for a moment whenever their food was brought into the laboratory. She decided to test whether she could teach the rats to stand on their hind legs when she rang a bell. First she measured the exact amount of time the rats spent standing when the food was brought in. Then she rang a bell just before each meal. The rats eventually started to stand on their hind legs when they heard the bell.
1 What two IVs are being manipulated in the experiment?
IV1: bell ringing
IV2: food presentation/presence of meal
2 What is the DV in this experiment and how is it measured?
3 Why did the researcher measure the rats’ movements before introducing the bell ringing?
Explanation should refer to baseline data for comparison, i.e. she did this in order to compare the change in amount of time spent standing as a consequence of bell conditioning.
Learning Activity 1.3 (p. 22)1 Define the term research hypothesis.
Research hypothesis: a tentative and testable prediction of the relationship between two or more events or characteristics.
2 What does operationalizing of experimental variables involve?
Explanation should refer to operationalization of the IV(s) and DV(s) and stating how these variables will be manipulated and measured.
3 Define the term operational hypothesis.
Definition should refer to a research hypothesis that states:
• how the variables being studied (i.e. the IVs and DVs) will be observed, manipulated and measured; and
• the population
4 List the key characteristics of an operational hypothesis.
Key characteristics are:
• the IV is specified in operationalised terms i.e. how it will be manipulated is stated
• the DV is specified in operationalised terms i.e. how it will be measured is stated
• the population from which the sample will be drawn is stated.
Other characteristics (in common with other research hypothesis) are:
• testable
• an educated guess
• a precisely worded written statement
• expressed in a clear manner
• often written as a single sentence, although it is possible to list a number of hypotheses within a single sentence.
5 Suggest a way that each of the following variables could be operationalised:
• forgetting—number of nonsense syllables that cannot be recalled one hour after learning
• aggression—number of times certain words are used during a specified time period (min)
• crowding—proximity of others to participant (cm) during a specified time period (min)
• anxiety—heart rate, respiration rate and GSR when exposed to a fear-inducing stimulus
• relaxation—heart and respiration rates after X amount of time performing X meditative technique
6 Construct an operational hypothesis for each of the following topics:
a Anxiety causes forgetting.
Adolescents with arachnophobia who are exposed to a live huntsman spider one hour after learning a list of 20 nonsense syllables will recall fewer nonsense syllables than adolescents with arachnophobia who are not exposed to the spider.
b Crowding increases aggression.
Young adults who spend two hours in close proximity to other teenagers in a confined space will use swearwords more often in a subsequent 30-minute period than young adults who don’t spend time in the confined space.
c Relaxation minimises stress.
VCE students will achieve lower scores on a stress-rating scale after practising a meditative technique twice a day for 30 minutes per session.
Learning Activity 1.4 (p. 22)Construct an operational hypothesis for three of the following questions of research interest.
• Does the offer of an incentive result in greater motivation to succeed?
IV: incentive, e.g. access (or no access) to a lolly reward for a correct response
DV: motivation to succeed, e.g. number of correct responses for a novel problem
Hypothesis: Primary school children who are rewarded for correctly solving problems will perform better than primary school children who do not receive a reward.
• Is driving ability affected by the amount of sleep deprivation an individual experiences?
IV: amount of sleep loss (hours and minutes)
DV: driving ability (number of traffic cones hit on a set course)
Hypothesis: Red P-plate drivers who sleep for eight hours or more on five consecutive days will hit fewer driving cones in a set driving course than red P-platers who sleep for no more than four hours on five consecutive days.
• What is the effect of rote learning of information on a person’s ability to recall that information when needed?
IV: learning technique, e.g. using maintenance rehearsal/rote learning vs elaborative rehearsal/non-rote learning to learn 20 new Latin anatomical terms and definitions
DV: number/percentage of correct answers in a test
Hypothesis: VCE students who use maintenance rehearsal to learn definitions will achieve lower scores on a test of recall than students who use elaborative rehearsal.
• Is our ability to play well in a sports match impaired if we are too anxious?
IV: anxiety, e.g. various physiological measures associated with high anxiety level
DV: performance in a sports match (simulated), e.g. goal shooting accuracy by a forward or corner taking by a hockey or soccer player
Hypothesis: various options depending on IV and DV
• Does being permitted to take a bottle of water into an exam improve performance on that exam?
IV: access (or no access) to a bottle of water during an exam
DV: performance on a specific exam
Hypothesis: various options depending on IV and DV
Learning Activity 1.5 (p. 24)1 Define the meaning of the terms extraneous variable and confounding variable.
• Extraneous variable: any variable other than the IV that can cause a change in the DV and therefore affects the results of the experiment in an unwanted way.
• Confounding variable: any variable other than the IV that has had an unwanted affect on the DV, making it impossible to determine which of the variables has produced the change in the DV.
2 In what key way are extraneous and confounding variables similar and different?
Similarities include:
• both can cause a change in the DV consistent with what was predicted by the hypothesis in addition to the IV
• both cause problems in isolating the real effect of the IV
• presence of either does not necessarily mean that the IV did not cause the change in the DV
• both can compromise interpretation of results or drawing of conclusions
• both may be uncontrolled variables; presence of an influential extraneous variable or a confounding variable suggests lack of control.
Differences include:
• an extraneous variable may or may not affect the DV (i.e. produce a measurable change), whereas a confounding variable produces a measurable change in the DV that is consistent with what was predicted by the hypothesis
• an extraneous variable may affect the DV and not be confused with the IV (i.e. effect can be isolated), whereas a confounding variable produces a measurable change in the DV that is consistent with what was predicted by the hypothesis and that makes it impossible to determine what influenced the DV: the confounding variable or the IV.
3 Give two reasons to explain why it is essential to control extraneous and potential confounding variables in research.
Reasons include:
• isolating and measuring the true effect of the IV
4 A researcher is planning an experiment to investigate the rate of forgetting (how much time it takes) and amount of forgetting (how much information) that occurs when new information (e.g. a list of nonsense ‘words’ such as qab and jir) is learned.
a Identify the IV(s) and DV(s).
IV: new information to be learnt
DV1: rate of forgetting/time taken to forget
DV2: amount of forgetting/number or percentage of words not retained
b Identify two extraneous or potential confounding variables that could affect the DV (in addition to the IV) and therefore need to be controlled.
Variables may include:
• meaningfulness of nonsense words: some nonsense words could have more or less meaning attributed to them as a result of experience with electronic communication, e.g. message texting
• a range of participant variables/individual participant differences, e.g. memory, educational background, motivation/boredom, mood, age.
c Suggest a way that each variable referred to in part (b) could be controlled.
Random allocation of participants (from a reasonably sized random sample) to experimental conditions should control all variables, including prior experience.
5 An experiment was conducted to test whether people make fewer errors in detecting spelling errors in an interesting text than in a boring one. Two groups of randomly selected and allocated participants were used. Group 1 looked for errors in a physics text on string theory (a boring task) and Group 2 looked for errors in the script of a Twilight movie (an interesting task). The results showed that Group 1 detected significantly fewer spelling errors than did Group 2.
Identify the IV, DV and a potential confounding variable in the experiment. Explain your choice of confounding variable.
IV: interest value of the task/type of text
DV: number of errors detected
Potential confounding variable: task difficulty
Explanation: in addition to being less interesting, the physics text might have been more difficult to spellcheck. If so, task difficulty would have been confounded with task interest, making it impossible to determine whether performance differences were caused by task interest or task difficulty.
Learning Activity 1.6 (p. 26)1 In what way can individual participant differences be a source of extraneous or potential
confounding variables? Explain with reference to an example not used in the text.
Explanation should refer to the potential to influence participant responses (i.e. the DV) in an unwanted way and distort the results/effects of the IV.
2 A researcher is planning to conduct an experiment to test the influence of amount of time spent studying on exam performance. Identify three participant variables that are potential confounding variables in this experiment, other than demand characteristics, and explain your choice of each variable.
Suggested variables and explanations should be relevant to the variables of research interest, e.g. specific abilities in relation to the specific exam, prior experience with exams, intelligence, quality of study.
3 Suggest a way of controlling or minimising the influence of participant-related variables such as individual differences in experimental research.
Procedure may refer to the use of random allocation to ensure relatively equitable spread of participant-related variables in different conditions (thereby counterbalancing or ‘neutralising’ effects).
Learning Activity 1.7 (p. 28)1
a What is a placebo in relation to experimental research?
A fake treatment.
b Define the term placebo effect with reference to an example not used in the text.
Placebo effect: a change in responses of participants due to their belief that they are receiving some kind of experimental treatment and they respond in accordance with that belief.
Ensure student examples are accurate and discuss a range to clarify conceptual understanding.
c Explain why the placebo effect is a potential confounding variable.
Explanation should refer to the potential for confusing/isolating the respective influences of the IV and placebo effect on the DV/participant responses as both the IV and placebo effect can produce a measurable change in the DV that is consistent with what was predicted by the hypothesis.
2
a Define the meaning of the term experimenter effect.
Experimenter effect: a change in a participant’s response due to the researcher’s expectations, biases or actions rather than to the effect of the IV.
b What is experimenter expectancy?
Experimenter expectancy: an experimenter effect involving a change in a participant’s response due to cues the experimenter/researcher provides about the responses participants should give in the experiment.
i How can it produce a self-fulfilling prophecy?
Explanation should refer to experimenter/researcher expectations about participant responses leading to results/participant responses that accord with their expectations and therefore potentially attributable to their expectations rather than to the effect of the IV.
Explanation should refer to experimenter/researcher expectations about participant responses leading to unintentional biases in their collection and treatment of data.
c Explain why experimenter effects are potential confounding variables.
Explanation should refer to the potential for confusing/isolating the respective influences of the IV and experimenter effect on the DV/participant responses as both the IV and experimenter effect can produce a measurable change in the DV that is consistent with what was predicted by the hypothesis.
3 Suggest a way of controlling or minimising the influence of
a a placebo effect—single-blind procedure
b an experimenter effect—double-blind procedure.
Learning Activity 1.8 (p. 30)1
a Explain the meaning of order effect.
Order effect: when performance, as measured by the DV (i.e. a participant’s response), is influenced by the specific order in which the conditions, treatments or tasks are presented (rather than the IV).
b Distinguish between practice effects and carry-over effects with reference to how these order effects can lead to higher or lower scores on a measure of the DV.
Practice effect: when performance, as measured by the DV (i.e. a participant’s response), is influenced by repeatedly performing an experimental task/treatment.
Carry-over effect: when the effects of a particular experimental manipulation/task/treatment are still present when the DV is measured following another experimental manipulation (i.e. the effect relates to the influence that a particular trial has on subsequent trials and can arise from simply experiencing a trial).
Practice effects result from ‘doing’ and carry-over from the ‘experience’ of a trial (or condition). Both can lead to higher or lower scores, depending on the DV/measure, e.g. practice effect—higher scores due to greater familiarity with a task and lower scores due to fatigue or boredom, and carry-over effect—higher scores due to easier previous trials and lower scores due to a very frustrating previous trial that ‘carries over’ and lowers performance on subsequent trials.
c Explain why order effects are potential confounding variables.
Explanation should refer to the potential for confusing/isolating the respective influences of the IV and of order effects on the DV/participant responses, as both the IV and order effects can produce a measurable change in the DV that is consistent with what was predicted by the hypothesis.
2
a Explain the meaning of the term non-standardised in relation to research procedures.
Non-standardised (in relation to research procedures): when some aspect is not the same for all participants, except for exposure to the IV by participants in the experimental group.
b Give an example of an instruction to participants and one or more experimental procedures that would be considered to be non-standardised.
Instruction: two groups observe a video on road accidents. The first group is asked to rate the severity of the accidents but the other group is unintentionally asked to rate the severity of the smashes. Because an emotive word such as smashes has been used in the instruction, participants of the second group may attribute a higher rating to accidents.
Experimental procedure: two VCE psychology classes are involved in a study of meditation and its effect on anxiety self-ratings. One group completes their activity after recess in a classroom next to the music room; the other group completes their activity at the end of the day in the library. The environment and the time of day when meditation is scheduled could impact on the reported ratings.
c Explain why non-standardised instructions and procedures are potential confounding variables.
Explanation should refer to possibility of producing participant responses consistent with the predicted change in the DV but not due to the IV and therefore potentially confused with the effects of the IV.
Learning Activity 1.9 (p. 34)1
a What is the difference between a sample and a population?
Sample: a group that is a subset or portion of a larger group chosen to be studied for research purposes.
Population: the larger group from which a sample is drawn.
b Why is it important that a sample and the population from which it is drawn share common characteristics?
Explanation should refer to validity of generalisations.
2
a What is convenience sampling?
Convenience sampling: selecting participants who are readily available without any attempt to make the sample representative of a population.
b Why is convenience sampling often described as opportunity sampling?
Explanation should refer to the researcher selecting participants they have the opportunity to study, i.e. anyone who is available or present.
3
a What is random sampling?
Random sampling: a sampling procedure that ensures every member of the population of research interest has an equal chance of being selected as a participant for a study.
b Give an example of an appropriate random sampling procedure.
Examples include:
• random number assignment, e.g. using a random number generator
• coin toss
• lottery method.
4 Give an advantage and a limitation of convenience sampling, as compared to random sampling.
Relative advantages include:
• convenient, opportune
• quick
• easy
• inexpensive.
Relative limitation should refer to bias/non-representativeness and consequential low external validity.
5 Consider the newspaper advertisement shown below.
a Is this an example of convenience sampling or random sampling?
convenience sampling
b Will advertising for research participants and using a gift voucher or incentive payment result in ‘sample bias’? Explain your answer.
Probably. Explanation should refer to non-likelihood of sample representativeness, e.g. only those who need/want an incentive and responses of such individuals may be different in some way of particular relevance to the DV, such as the influence of a disproportionate number of people in financial need or a tendency for such participants to be overly cooperative or make a greater effort to guess the hypothesis in order to respond ‘appropriately’ (i.e. feeling a need to behave in some way due to payment).
6 You want to compare the lifestyles of VCE students in Melbourne and Mildura.
a Define your population.
Example: VCE students in all Melbourne and Mildura schools, TAFEs and other VCE providers.
b How could you obtain a random sample from each of these populations?
Explanation should refer to a procedure that ensures any VCE student in Melbourne and Mildura has an equal chance of being selected (as any other VCE student), e.g. randomly selecting one or more VCE providers in Melbourne and Mildura and randomly selecting from those providers using their student rolls/administrative records.
7 You want to test short-term memory capacity in preschool children, teenagers and people aged over 65 years.
a Define your population.
For example for preschool children: all children enrolled in a preschool in Richmond, for teenagers: all years 9-12 students enrolled in a secondary school in Richmond, for people
aged over 65 years: all people aged over 65 years residing in a retirement village in Richmond.
b How could you obtain a random sample from each of these populations?
Explanation should refer to a procedure that ensures any individual in each target population has an equal chance of being selected (as any other individual).
8 Explain how the type of sampling procedure used can minimize the influence of extraneous and confounding variables.
Explanation should refer to control of participant variables that can influence the DV (s).
Learning Activity 1.10 (p. 35–6)1 What are random sampling, stratified sampling and stratified-random sampling?
• Random sampling: a sampling procedure that ensures every member of the population of research interest has an equal chance of being selected as a participant for a study.
• Stratified sampling: a sampling procedure that involves dividing the population to be sampled into distinct subgroups/strata, and then selecting a separate sample from each subgroup/stratum in the same proportions as they occur in the target population.
• Stratified-random sampling: a sampling procedure that involves identifying all of the people within each stratum of research interest, then randomly selecting samples of proportionate size from within each stratum.
2 In what way is a random sample and a stratified sample alike? In what way are they different?
• alike: representative of population(s) of interest
• different: stratified sample seeks proportional representation of specific subgroups/strata whereas random does not
3 Suppose that you are required to determine the sleep patterns (e.g. the amount of sleep) of students at your school or college.
a Briefly describe a convenience sampling, random sampling and random-stratified sampling procedure for selecting research participants.
Examples using random numbers:
• convenience sampling (the whole school or college is the population): the first 10 students in the school or college outdoor area at lunchtime who respond to a request for volunteers
• random sampling (the whole school or college is the population): using a current school/college roll, assignment of a number to each student starting with 1 for the first student in the roll, using a random number table/generator to select 10 students
• random-stratified sampling: if the whole school or college is the population and it is believed that one or more participant variables will be influential, determine proportions using relevant data, organise according to strata and randomly select required proportions/ratios as per above.
b Explain which of the three sampling procedures would result in the more representative sample.
Stratified sampling, due to proportional representation of a target population (but must involve random sampling from each stratum).
c Is any of the three procedures unnecessary for this particular research? Briefly explain your answer.
Considering the purpose of the research, convenience sampling is suitable and random sampling unnecessary. Stratified sampling is both unnecessary and irrelevant given the broad purpose.
4 Suppose you are responsible for determining the TV ratings of the viewing audience in Melbourne (or a regional town) for a one-week period. Briefly describe the sampling procedure you could use to select the participants who will receive a recording device. Explain how your procedure would ensure a representative sample of the viewing population.
Explanation should refer to a stratified sampling procedure that takes account of relevant demographics/market segments of interest.
5 Explain why each of the following research studies is likely to have sample bias:
a a survey on binge-drinking behaviour in a popular teenager’s magazine
Explanation may refer to:
• sample is based exclusively on readers of the specific magazine and may not be representative of teenagers/adolescents/target population
• unique characteristics of readers who choose to respond or have or make the time to respond and deliver responses
• readers who choose to respond may have strong beliefs, attitudes etc. about binge-drinking.
b a television or radio call-in survey
as per 5a
c a telephone survey at 6 pm on weeknights using landlines to people’s homes
Explanation should refer to the sample not being representative, e.g includes only those with landlines and listed numbers and excludes people without either or both. Will also represent only people at home at 6 pm on weeknights who answer the phone and give consent. Discuss potential biases.
d a survey at a shopping mall on a weekday in March.
Explanation should refer to the sample not being representative, e.g. convenience sample of people at shopping mall at a specific time who give consent. Discuss potential biases.
Learning Activity 1.11 (p. 36)Consider the article M&M’s Color Distribution Analysis at http://joshmadison.com/2007/12/02/mms-color-distribution-analysis/, which contains data on relative proportions of the lollies and comments relevant to the activity.
1 What is the main difference between participant selection and participant allocation?
• participant selection: choosing participants for a research study, particularly the sampling procedures
• participant allocation: assignment of participants to different conditions/groups of the research study
2 What is random allocation and why is it used in an experiment?
Random allocation: assignment of participants to different conditions/groups of the research study using a procedure that ensures each participant has the same chance of being selected for any condition/group.
Explanation should refer to control of participant variables through equivalence of conditions/groups.
3 How are random allocation and random sampling different?
• random allocation: participant assignment procedure
• random sampling: participant selection procedure
4
a What is an experimental group? A control group?
• experimental group: participants exposed to the IV/experimental condition in which the IV under investigation is present
• control group: participants not exposed to the IV/ exposed to the control condition in which the IV is absent
b Why is a control group used in an experiment?
Explanation should refer to comparison with experimental group responses to the IV, i.e. provides a standard against which performance/results of the experimental group/s can be compared in order to determine whether the IV has caused change in the DV.
Learning Activity 1.14 (p. 42)1 Explain what the counterbalancing procedure is and what it attempts to control.
Explanation should refer to counterbalancing as a procedure that involves systematically varying the order of experimental treatments or tasks within or across participants to control order or counter the balance of order effect influence.
2
a A researcher believes that the gender of participants is a potential confounding variable. Explain how counterbalancing could be used to control this variable.
Explanation should refer to random allocation for equivalence of gender in groups then refer to an example such as Group A experience condition 1 first, then 2 and group B experience condition 2 first then 1.
b The researcher will use a number of research assistants to conduct the study and also believes that their gender is a potential confounding variable. Explain how counterbalancing could be used to control this variable.
Explanation should refer to male research assistants testing half the participants in each condition and female research assistants testing the other half.
3 Suggest a randomisation or random allocation procedure that could be used to counterbalance order effects in an experiment.
Explanation should refer to any systematic randomisation procedure for balancing of order effects by randomly creating different orders under which different participants are tested or exposed to different conditions, e.g. tossing a coin separately for each participant to determine whether he or she does condition 1 or 2 first or randomising the order of trials within a condition.
4
a In what way is the single-blind procedure similar and different to the double-blind procedure?
Similarity: subjects are not aware whether they are in an experimental or control group
Difference: in a double-blind procedure, the experimenter is also unaware of whether subjects are in a control or experimental group, whereas they have that information in a single-blind procedure.
b Which of the two procedures is more advantageous and why?
Double-blind provides a tighter control on unwanted experimenter effects.
5
a What is a placebo?
a fake treatment
b Explain how a placebo can be used to control or minimise the influence of expectations or beliefs associated with the specific treatment received by participants in experimental and control groups.
Explanation should refer to use of an appropriate placebo in a control group so that participants form the same beliefs/expectations about the IV as the experimental group, so any difference relevant to the DV can be assumed to be due to the IV.
6
a What are standardised instructions and procedures? Explain with reference to relevant examples.
Standardised instructions and procedures: use and administration of the same procedures/techniques for participants, as relevant to the specific group (condition) to which they have been assigned.
Ensure student examples are accurate and discuss a range to clarify conceptual understanding.
b Explain how standardised instructions and procedures can be used to control or minimise the influence of participant variables and experimenter effects.
• participant variables: control by ensuring all participants have the same experience as relevant to their type of experimental condition, but first identifying and preventing cues in instructions and other procedures that can bias participants’ responses.
• experimenter effects: control by ensuring all researchers use the same instructions and follow the same pre-determined procedures, all of which have been devised to control experimenter effects and ensure participants have the same experience as relevant to their experimental condition.
Learning Activity 1.15 (p. 42)1 What is the IV in Mardi’s experiment?
type of feeding bottle
2 How many experimental groups does Mardi have in her experiment?
five (one group for each coloured bottle)
3 Which participants make up the control group?
newborn babies feeding from regular, transparent bottles
4 What is the DV?
colour preference
5 How could Mardi randomly allocate the participants to different groups?
Ensure student examples are accurate and discuss a range to clarify conceptual understanding, e.g. lottery method using mothers’ names for allocation to each condition.
6 Identify two extraneous or potential confounding variables that should be controlled and explain why.
Variables may include:
• limited colour perception of newborn babies
• developmental or maturational differences of newborn babies
• mothers’ behaviour during feeding such as eye-contact, soothing pats, soothing sounds, cuddles, rocking, smiles, chatter and songs.
Learning Activity 1.16 (p. 49)1 Complete the table including at least two strengths and two limitations for each experimental
design.
Experimental design
Features Strengths Limitations
repeated-measures
• each participant is involved in all conditions of the experiment
• strict control of relevant participant variables/individual participant differences (including known and unknown variables)
• order effects that can be confounded and need control are more common
• requires a relatively smaller number of participants when compared with other experimental designs as same participants are in all conditions
beliefs about experimental procedures can be more difficult to control due to cues from experiencing different conditions
• participant attrition
matched-participants
• pairs of participants are matched on the basis of relevant personal characteristics that can influence the DV, then one member of each pair is randomly allocated to different conditions/groups
• ensures each condition/group is fairly equivalent in spread of relevant personal characteristics that can influence the DV
• participant attrition less likely
• difficulty identifying all relevant variables (to be matched)
• practical problems, e.g. time-consuming to identify and recruit participants who are sufficiently alike in the variable, pre-testing may be required and can lead to order effects requiring control
independent-groups
• each participant is randomly allocated to either the experimental or control group and is in one group only
• no order effects across conditions to control
• participant attrition less likely
• less control over participant characteristics than repeated-measures and matched-participants
• often need a larger group of participants in order to lessen any differences between groups
2 For each of the following extraneous or potential confounding variables, rank the three experimental designs from 1 to 3 to indicate the extent to which the design controls the variable, as compared to the other designs. A ranking of 1 indicates greatest control and a ranking of 3 indicates least control. If appropriate, more than one design may be given the same ranking. Explain your choice of rankings.
1—strict control as same participants used in both conditions
3—one or more relevant characteristics may not be identified
2—strict control through random allocation but arguably less than repeated-measures
placebo effect 2—not necessarily more or less control but repetition of procedure(s) may be more likely to result in participants accessing cues about the treatment
1—strict control as exposed to the fake treatment once
1—strict control as exposed to fake treatment once
order effects 3—more likely due to exposure to different conditions (but may be controlled through counterbalancing)
2. pre-testing participants to match on specific characteristics may create order effects(but may be controlled through time-delay)
1—no between-condition order effects
experimenter effects
1—not necessarily more or less control
1—not necessarily more or less control
1—not necessarily more or less control
3 A researcher wants to investigate the effects on aggressive behaviour of observing violence on television. The researcher is specifically interested in the effects on young children who watch violent scenes in cartoons during after-school viewing hours.
a Identify the IV(s) and DV.
IV: observing violence (in cartoons on TV aired during after school hours)
DV: aggressive behaviour
b Briefly describe an appropriate participant selection procedure and explain why the researcher should use this procedure.
A random selection procedure may be described but description will also depend on whether a matched-participants design is used, e.g. matching on standard personality and intelligence tests for very strict control (but not essential as random allocation using independent-groups with sufficient numbers would also control).
c Briefly describe an appropriate participant allocation procedure and explain why the researcher should use this procedure.
Any common random allocation may be used, with the specific type depending on sample size.
d Identify three participant characteristics that would need to be controlled and explain your choices.
Relevant personal characteristics based on research findings include:
• pre-disposition to aggression, e.g. as measured by rating scales, teacher reports, pre-testing etc.
• prior experience to observed violence on TV
• cultural background.
e Briefly describe how the experiment could be conducted using each of the three experimental designs. You may use a diagram such as a flow chart for each design to assist your explanation.
Examples:
• repeated-measures—Participants are randomly allocated into two groups. In the two conditions, participants would watch either the violent cartoons or another cartoon of the same duration that is non-violent and their behaviour would be observed afterwards to determine if there was any aggressive play etc. After an interval, the two groups would return to the experiment and swap conditions. Counterbalancing would enable control of order effects.
• matched-participants—Participants could be matched on one or more personal characteristics of interest following pre-testing. Each pair member is then randomly allocated to one of the conditions. In the two identical conditions other than the IV, participants would watch either the violent cartoons or another non-violent cartoon of the same duration and their behaviour would be subsequently observed so that aggressive responses can be tallied.
• independent-groups—Participants are randomly allocated to one of the conditions. In the two identical conditions other than the IV, participants would watch either the violent cartoons or another non-violent cartoon of the same duration and their behaviour would be subsequently observed so that aggressive responses can be tallied.
f Identify and explain which of the three designs would be most appropriate and which would be least appropriate for this experiment.
Each of the three designs could be used but the Bandura, Ross and Ross experiments in the 1960s (see pp. 511–17) show that independent-groups is suitable.
Use student responses to clarify understanding of the designs and their relative strengths and limitations (but taking account of the research topic and resources available).
Learning Activity 1.19 (p. 52)1 Define and distinguish between qualitative data and quantitative data with reference to an
example that is not used in the text.
• Qualitative data: information about the qualities or characteristics of what is being studied, e.g. an adolescent’s verbal description of a friend.
• Qquantitative data: information about the quantities or amounts of what is being studied, e.g. an adolescent’s ratings of a friend.
2 Identify whether the data collected in each of the following research studies are likely to be qualitative or quantitative. Explain your answers.
a A researcher compares the detail in paintings by people with a phobia and people with paranoid schizophrenia.
• Qualitative—assessments of details/characteristics/qualities of paintings and reported as words, meanings etc.
• Quantitative—comparisons are criteria-based and rating scales are used for each criterion.
b A researcher compares the differences in visual perceptual abilities of kittens with and without damage to the visual cortex in the brain.
• Quantitative—most likely uses a quantitative measure, e.g. orientation response shown or not shown and its duration, response times across trials.
c A researcher observes how much time male and female adolescents take to get ready for a deb ball.
• Quantitative—the measure is time taken to get ready and data are likely to be statistically summarised, described and reported.
d A researcher uses diary records kept by people hospitalised with a mood disorder to study their mental experiences.
• Qualitative—personal assessments of aspects of thoughts, feelings and behaviour etc. recorded in words/sentences, doodles/sketches.
e A researcher compares how infants who can walk independently respond when left alone with a stranger in a laboratory setting with infants who can crawl but are unable to walk independently.
• Qualitative—assessments of responses under different conditions and reported as words, meanings etc.
• Quantitative—observation checklist is used for presence/absence of pre-determined response types, responses and ratings.
f A researcher analyses participant scores on a test of recall in a study on long-term memory decline and ageing.
• Quantitative—the measure is scores on a test of recall and data are likely to be statistically summarised, described and reported.
Learning Activity 1.20 (p. 56)1 What is a case study?
an intensive, in-depth investigation of some behaviour or event of interest in an individual, small group or situation
2 What type of data can be collected in a case study?
different types of quantitative and qualitative data, including data from interviews, school and medical reports, psychological tests, behavioural observations, results from participation in experiments
3 Suggest a reason to explain why case studies often involve the use of several data-collection techniques.
Reasons may refer to:
• case studies often focussing on rare or unusual conditions or situations and need detailed information from different sources to enhance understanding
• the often subjective nature of data (e.g. through interview) requiring validation through other sources.
4 Are demand characteristics and experimenter effects relevant to case studies? Explain your answers.
Yes. They tend to be more susceptible to bias from both the participant and researcher, so demand characteristics and experimenter effects are relevant.
5 Describe three advantages and three limitations of case studies when used for research purposes.
Advantages include:
• appropriate and useful way of obtaining detailed and valuable information on mental processes and behaviour, particularly in relation to rare or unusual disorders
• avoiding artificiality and providing a ‘snapshot’ of the actual or real-life experience of one or more individuals at a particular time in a particular situation
• valuable source of hypotheses for further research.
Limitations include:
• process of analysing, summarising and reporting these data can be a painstaking and time-consuming process
• can be difficult to generalise findings, e.g. case studies usually focus on rare or unusual individuals or situations and the often ‘extraordinary’ mental experiences,
processes or behaviours of such individuals may not reflect typical ways of thinking, feeling or behaving
• more susceptible to biased information from the participant or the researcher, affecting accuracy of information obtained and the conclusions drawn.
1 How is observation defined in psychology? Explain with reference to examples.
any means by which a phenomenon/observable event is studied, including the data that represent a phenomenon (such as spoken or written responses, test scores and brain wave recordings)
2 What is an observational study?
collection of data by carefully watching and recording behaviour as it occurs
3 What type of data can be collected in an observational study?
qualitative and quantitative
4 What are the key features of naturalistic observation?
Key features:
• observation of a naturally occurring behaviour of interest
• do not directly influence/interfere with the behaviour being observed
• systematic data collection and record-keeping.
5 Distinguish between participant and non-participant observation with reference to examples not used in the text.
• participant observation: observers take part in what is being observed, do not conceal presence
• non-participant observation: observers do not take part in what is being observed, do not disclose presence
6 Give an example of an observational study in which artificiality and demand characteristics may be potential extraneous or confounding variables.
Use student examples to clarify understanding of the concepts.
7 Describe three advantages and three limitations of observational studies.
Advantages include:
• researchers can watch and record behaviours in their natural real-life settings; overcomes artificiality
• enable study of human behaviour that would be inappropriate or impractical to study them in a laboratory situation
• do not require the cooperation of participants being observed
• demand characteristics are not relevant.
Limitations include:
• difficult to determine the causes of observed behaviour
• observer bias can occur
• ethical dilemma, i.e. violation of privacy when participant observation is used without informed consent.
participant’s written or spoken responses to questions, statements or instructions presented by the researcher
2 What type of data can be collected through self-reports?
both qualitative and quantitative, depending on the data collection technique
3 Distinguish between free-response and fixed-response questions with reference to an advantage and a limitation of each question type.
• Free-response questions do not specify pre-determined answer options, enable unrestricted responses and encourage participants to use their own words to describe their thoughts, feelings and behaviour, thus generating qualitative data. An advantage is the breadth of information and the detail that can be gained from this questioning style. A limitation is the difficulty researchers can have in summarising or rating answers.
• Fixed-response questions provide pre-determined answer options from which the participant is required to select. An advantage is that the obtained data are quantitative and therefore more easily summarised and statistically analysed. A limitation is the lack of detail underlying and/or within individual responses.
4 Describe two advantages and two limitations of self-reports.
Advantages include:
• range of techniques from which the research can select for data collection
• can be used to collect qualitative or quantitative data
• some techniques provide means of collecting data from large groups
• some techniques provide means of collecting data that people are not willing to disclose publicly.
Limitations include:
• data often biased
• data often subjective/not objective
• require certain level of language skills by participants
• difficult to control demand characteristics
• free-response questions often difficult to analyse, rate or summarise.
Learning Activity 1.23 (p. 71)1 A researcher conducts an experiment and obtains statistically significant results. What does the
term statistically significant mean?
when the difference in the results obtained for the experimental and control groups is a real difference due to the IV and probably not due to chance factors alone
2 Explain the meaning of the term p value, with reference to an example.
p value is the probability value that indicates the probability of the results obtained in a statistical test being due to chance.
Use student examples to clarify understanding of the concept.
3 Write the meaning of the following p values as they apply to the findings of an experiment: p ≤0.001, p ≤0.01, p ≤0.10. Make sure that you refer to the probable roles of chance and the independent variable.
• p ≤0.001: probability of results being due to chance is less than or equal to 0.1% or 1 or fewer times in 1000 repetitions of the same study, meaning that chance is at an acceptable level and the results may be due to effect of the IV.
• p ≤0.01: probability of results being due to chance is less than or equal to 1% or 1 or fewer times in 100 repetitions of the same study, meaning that chance is at an acceptable level and the results may be due to effect of the IV.
• p ≤0.10: probability of results being due to chance is less than or equal to 10% or 10 or fewer times in 100 repetitions of the same study, meaning that chance is at an unacceptable level and it is extremely unlikely that the results are due to effect of the IV.
4
a Which of the p values stated in question 3 can be interpreted as being most significant? Explain your answer.
p ≤0.001—probability of results being due to chance is less than or equal to 0.1%, which is a very stringent standard for the probability of results being due to chance.
b Which of the p values stated in question 3 can be interpreted as being least significant ? Explain your answer.
p ≤0.1—probability of results being due to chance is less than or equal to 10%, which is an unacceptable standard for the probability of results being due to chance.
5 Suppose you conducted a study and obtained results with a p value that is not ≤0.05. What would you conclude about the results?
If the required level of significance is p ≤0.05, the probability that the results may be due to chance is at an unacceptable level/not statistically significant and it can therefore be concluded that the results do not support the hypothesis.
Learning Activity 1.24 (p. 72)1 What kind of judgment is made about the hypothesis for a study after the results have been
obtained and analysed?
whether the hypothesis is supported or rejected
2
a What is the meaning of the term conclusion?
a decision or judgment about what the results obtained from an investigation mean
b Why must confounding and extraneous variables be considered when drawing conclusions from results obtained in a study?
• alternative explanations attributable to uncontrolled extraneous variables and potential confounding variables.
• internal validity/possible limitations of/problems with the study, e.g. sample size, whether sample is sufficiently representative
• what the results may actually mean, e.g. avoid making errors and overstating what the results mean.
3
a What is the meaning of the term generalisation?
a decision or judgment about how widely the findings of a study can be applied, particularly to other members of the population from which the sample was drawn
b What are the important considerations in making generalisations from the findings of a study?
Considerations include:
• uncontrolled extraneous variables and potential confounding variables, i.e. alternative explanations
• internal validity/possible limitations of/problems with the study, e.g. sample size, whether sample is sufficiently representative
• what the results may actually mean, e.g. avoid making errors and overstating what the results mean
• specific topic studied.
4 Distinguish between the terms conclusion and generalisation as they apply in research studies.
A conclusion relates to the specific results of a study, whereas a generalisation relates to the application of the results to the population from which the sample was drawn and often beyond that population.
Learning Activity 1.25 (p. 73)Outline the design of an experiment that could be undertaken to test the following hypothesis: ‘If a newborn infant has extra contact with their mother soon after birth, then the bond formed between the mother and infant will be stronger.’ Twelve mothers who are about to give birth have volunteered to be participants in your experiment for two years. In designing your experiment, make sure that you address the following:
• What groups will be used?
• Experimental group: extra contact time with newborn
• Control group: standard hospital allotted contact time with newborn
• What are the independent and dependent variables?
• Bond – needs to be measurable, i.e. an attachment scale
• Contact – Skin-to-skin? Breastfeeding?
• What is your operational hypothesis for the experiment?
• Newborns exposed to 30 minutes more skin-to-skin contact time with their mothers immediately after birth than the standard hospital time allotted will demonstrate a higher score on the X Attachment Scale.
• What potential extraneous or confounding variables will it be important to control?
• This small sample is not representative of the population.
• willing to involve themselves in an experiment about their birth experience are also not representative of the population.
• Are the mothers experienced mums or is this their first baby?
• The nature of the birth may complicate the experience of attachment – natural, drugs, complications such as breech position, multiple births, caesarean.
• What type of experimental design will you use? Explain your choice of design.
• Independent groups would be the only feasible design here. The sample is too small for Matched-pairs and repeated-measures is out of the question due to the nature of birth!
• If you find an acceptable significant difference in the results for the two groups (say, p ≤ 0.05), what conclusion would you draw? What generalisation would you make?
• Conclusion – Newborns exposed to 30 minutes more skin-to-skin contact time with their mothers immediately after birth than the standard hospital time allotted have demonstrated a significantly higher score on the X Attachment Scale.
• Generalisation – extra bonding time enhances attachment
Learning Activity 1.26 (p. 78-9)Study 1• voluntary participation, i.e. participants must freely choose to take part in research; must not be
pressured to participate or experience negative consequences if choose not to
• informed consent procedures, i.e. consent must be based on information about the nature and purpose of the research; use of an appropriate consent form etc.
• professional conduct, i.e. the ‘lecturer’ who is responsible for the research must ensure all ethical guidelines are considered and followed (and is therefore responsible for the assistant’s conduct).
Study 2 • use of deception: this is likely to be justifiable to ensure validity of the results but it also makes
• professional conduct: must ensure all ethical guidelines are considered and followed; must not place any participant at risk of physical or psychological harm; respect and ensure participant rights
• informed consent procedures: consent must be based on information about the nature and purpose of the research; use of an appropriate consent form outlining purpose, methods, demands, risks, inconveniences, discomforts and possible outcomes
• withdrawal rights: participants must know they can withdraw from the research at any time, without giving a reason and with no negative consequences
• debriefing: after research is conducted, clarify participants’ understanding of the study; if necessary provide information about services available to treat any distress due to participation
• use of deception: cannot be used when distress is possible.
Study 4• professional conduct, i.e. the student’s teacher is responsible for the research and must ensure
all ethical guidelines are considered and followed (and is therefore responsible for the student’s conduct). Note additional guidelines in the study design for teachers, i.e. teachers and schools have a legal and moral responsibility to ensure that students follow ethical principles at all times when undertaking psychological research (Box 1.13, p. 81-82).
• informed consent procedures: no justification for non-adherence; participant’s and parents of child participants have the right to be fully informed of all aspects of the research
• use of deception: although no risk of harm is involved, not justified
