Psych 235 Midterm Two Important terms

All-possible-orders design (Complete counterbalancing)

The conditions of an independent variable are arranged in every possible sequence, and an equal number of participants are assigned to each sequence

Between Subject Designs

different participants are assigned to each of the conditions in the experiment

Block Randomization

We conduct a single round of all the conditions, then another round, then another, for as many rounds as needed to complete the experiment. within each round, the order of conditions is randomly determined

Block Randomization Design

Every participant is exposed to multiple blocks of trials, with each block for each participants containing a newly randomized order of all conditions

Carryover effects

Occur when participant’s responses in one condition are uniquely influenced by the particular condition or conditions that preceded it

Confounding variable

A factor that covaries with the independent variable in such a way that we can no longer determine which one has caused the changes in the dependent variable

Control Condition (control Group)

Participants do not receive the treatment of interest or are exposed to a baseline level of an independent variable

Counterbalancing

A procedure in which the order of conditions is varied so that no condition has an overall advantage relative to the other conditions

Dependent Variable

Refers to the response that is measured to determine whether an independent variable has produced an effect

Experimental Condition (experimental group)

Involves exposing participants to a treatment or an “active” level of the independent variable

Experimental Control

Includes the ability to 1.) Manipulate one or more independent variables; 2.) choose the types of dependent variables that will be measured so that the effect of the independent variable can be assessed; and 3.) regulate other aspects of the research environment, including the manner in which participants are exposed to the various conditions in the experiment

Extraneous Variable

A factor that is not the focus of interest in a particular study, but that could influence the outcome of the study if left uncontrolled

Fatigue Effect

A performance decline that results from becoming tired, inattentive, or less motivated to perform well with repeated exposure to a task

Independent-group design (Random-group design)

Participants are randomly assigned to the various conditions of the experiments

Independent Variable

Refers to the variable manipulated by the researchers

Latin Square

in a n (number of positions in a series) x n (number of orders) matrix in which each condition will appear only once in each column and each row

Matched-groups design

each set of participants that has been matched on one or more attributes is randomly assigned to the various conditions of the experiment

Matching Variable

A characteristics on which we match sets of individuals as closely as possible

Natural-group design

Researcher measures a subject variable, forms different groups based on people’s level of that variable, then measures how different groups respond on other variables

Order Effects (Sequence effects)

Occurs when participants responses are affected by the order of conditions to which they are exposed

Practice Effect

A performance improvement due to greater experience with a task

Progressive Effect

Reflects changes in participant’s responses that result from their cumulative exposure to prior conditions

Random Assignment

a procedure in which each participants has an equal probability of being assigned to any one of the conditions in the experiments

Reverse-counterbalancing design (ABBA-counterbalancing design)

From the entire set of all possible orders, a subset of orders is randomly selected and each order is administered to one participants

Sensitization

In which exposure to multiple conditions increases participant’s awareness of, or sensitivity to, the variable that is being experimentally manipulated

Single factor design

Has only one independent variable

Subject variable

A personal characteristic on which individuals vary from one another

Within-Subject Design

Each participants engages in every condition of the experiment one or more times

Between-subject Factorial Design

A factorial design in which each subject engages in only one conditions

Interaction (Interaction effect)

Occurs when the way in which an independent variable influences a dependent variable differs, depending on the level of another independent variable

Mixed-Factorial Design

A factorial design that includes at least one between-subject variable and at least one within-subjects variable

Person x situation _ (Person x environment) factorial design

An experimental design that incorporates at least one subject variable along with at least one manipulated situational variable

Simple Main effect

Represents the effect of one independent variable at a particular level of another independent variable

Three-way interaction

The interactions of two independent variables depends on the level of a third independent variable

Two way Interaction

Among two independent variable, the way that one independent variable influences a dependent variable depends on the level of the second independent variable

Within-Subject Factorial Design

A factorial Design in which each subject engages in every conditions

Attrition (subject loss)

Occurs when participants fail to complete a study

Ceiling Effect

Occurs when scores on a dependent variable bunch up at the maximum score level

Complete Replication (full replication)

includes all the conditions of the original study

Conceptual Replication

Examines the same questions investigated in the original study, but operationalized the construct differently

Construct validity

Concerns the issue of whether the construct (the conceptual variables) that researchers claim to be studying are, in fact, the construct that they truly are manipulating and measuring

Debriefing

A conversation with the participant that conveys additional information about the study

Demand Characteristics

Refers to cues that influence participants beliefs about the hypothesis being tested and the behaviours expected of them

Differential attrition

Occurs when significantly different attrition rates or reasons for discontinuing exist, overall, across the various conditions

Direct replication (exact replication)

The researchers follow the procedures used in the original study as closely as possible

Double-blind procedure

Which neither the participants nor the experimenters are aware of who is receiving the actual treatment and who is receiving a placebo

Ecological Validity

Concerns the degree to which responses obtained in a research context generalize to behaviour in natural settings

floor effect

Occurs when scores on a dependent variable bunch up at the minimum score level

independent Replication

a Replication conducted by researchers who were not part of the original research group

Instrumentation

Refers to changes that occur in a measuring instrument during the course of data collection. (As long as random assignment (combined with block randomization) or proper counterbalancing procedures are used

Internal Replication

Occurs when researchers follow up their initial study with one or more replications and present this series of studies in a single research report

Internal Validity

Concerns the degree to which we can be confident that a study demonstrated that one variable had a causal effect on another variable

Manipulation check

Measures to assess whether the procedures used to manipulate an independent variable successfully captured the construct that was intended

Masking (blinding)

A procedure in which the parties involved in an experiment are kept unaware of: the hypothesis being tested, and/or the condition to which each participant has been assigned

Maturation

Refers to ways that people naturally change over time, independent of their participation in a study. random assignment is a way to fix this

Partial Replication

Only includes some of the original conditions

Pilot Study

is a trial run, usually conducted with a smaller number of participants, prior to initiating the actual experiment

Placebo Control Group

In which participants do not receive the core treatment, but are led to believe that they are (may be) receiving it

Placebo effect

People’s expectations about how a treatment will affect them influence their responses (on the dependent variable) to that treatment

Randomized controlled trial (Randomized clinical Trial)

An experiment in which participants are randomly assigned to different conditions for the purpose of examining the effectiveness of an interventions

Regression to the mean

Is the statistical concept that when two variables are not perfectly correlated, more extreme scores on one variable will be associated overall with less extreme scores on the other variables. should be equivalent across conditions as long as participants are randomly assigned.

Replication and extension (replication with extension)

Is a replication that adds a new design element to the original study

Selection

Refers to situations in which, at the start if a study, participants in the various conditions already differ on a characteristic that can partly or fully account for the eventual results. (Experiments involve multiple conditions, and when between-subjects designs are used, the key to prevent this confound is to create equivalent groups at the start. This is achieved by randomly assigning participants to conditions)

Sensitivity

Refers to the ability to detect an effect that actually is present

Single-blind procedure

Either the participants or experimenters, but not both, are masked to the participants condition

Statisitcal Conclusion Validity Testing

Concerns the proper statistical treatment of data and the soundness of the researcher’s statistical conclusion

Wait-list control group

A group of randomly selected participants who do not receive a treatment, but expect to and do receive it after treatment of the experimental groups ends

Yoked control group

In which each control group member is procedurally linked (i.e, yoked) to a particular experimental group member, whose behaviour will determine how both of them are treated

Efficiency Assessment

Weighs the program’s benefits and effectiveness in relation to its cost, to determine whether it is an efficient method for addressing the problem

Program Diffusion

Implementing and maintaining effective programs in other settings or with other groups

Quasi-experiment

Has some features of an experiment but lacks key aspects of experimental control

One-group posttest-only design

Treatment occurs and and afterward the dependent variable is measured once

one-group pretest-posttest design

A dependent variable is measured once before and once after a treatment occurs

Simple interrupted time-series design

A dependent variable is repeatedly measured at periodic intervals before and after a treatment

Selection Interactions

The interaction of selection with another threat to internal validity

Posttest-only design with a nonequivalent control group

Participants in one condition are exposed to a treatment, a nonequivalent group is not exposed to the treatment, and scores from both groups are obtained after the treatment ends

pretest-posttest design with a nonequivalent control group

Pre- and posttreatment scores are obtained for a treatment group and a nonequivalent control group

Interrupted time - series with a nonequivalent control group

A series of pre- and posttreatment scores are obtained for a treatment group and a nonequivalent control group

Switching replication design

One group receives a treatment and a nonequivalent group initially does not receive the treatment but is then exposed (i.e., switched) to it at a later point in time

Program evaluation

Involves the use of research methods to assess the need for, and the design, implementation, and effectiveness of, a social intervention

needs assessment

Determines whether there is a need for a social program and the general steps required to meet that need

program theory and design assessment

Evaluates the rationale for why a program has been, or will be, designed in a particular way

Process evaluation

Determines whether a program is being implemented as intended

Outcome evaluation

Assesses a program effectiveness

Contamination

Which occurs when knowledge, services or other experiences intended for one group are unintentionally received by another grouo

Factorial Design

Includes two or more independent variables and crosses (i.e., combines) every level of each independent variable

External Validity

Concerns the generalizability of the findings beyond the present study

Replication

refers to the process of repeating a study in order to determine whether the original findings will be upheld

History

Refers to events that occur while a study is being conducted, and that are not a part of the experimental manipulation or treatment Block randomization will render this.

Testing

Concerns whether the act of measuring participants response affect how they respond on subsequent measures.  (Many experiments do not include a pretest because due to random assignment, the participants in the various conditions are, overall, assumed to be equivalent at the start of the experiment)

Experimenter expectancy Effects

Unintentional ways in which researchers influence their participants to respond in a manner consistent with the researcher’s hypothesis