Studying Behaviour Scientifically - Measurement and Confounds

Question 1

Validity

Answer 1

The characteristic of an observation that allows one to draw accurate inferences about it

Ex. Aggression can’t be defined as “the distance you can shoot milk out of you nose while laughing” this lacks validity

Question 2

Validity as a Continuum

Answer 2

Operational definitions are not “valid” or “invalid”. There is a spectrum from “completely irrelevant” to “exactly what I want to measure”

Ex. SAT scores only account for 16% of the variability in college students’ performance, but they are still used as an operational definition of “preparedness for university”

Question 3

Reliability

Answer 3

The tendency for a measurement device to produce the same result when used to measure the same thing on different occasions

Ex. DESCRIBE VISUAL ACUITY

Reliable: minimum threshold of size before you can no longer read letters 10 ft away

Unreliable: number of ducks you can shoot down on a foggy day

Question 4

Bias

Answer 4

The extent to which a measurement consistently differed in a certain direction away from what is supposed to be measuring

Question 5

Power

Answer 5

The tendency for a measurement to produce different results when measuring different things

EXAMPLE

suppose you are interested in styling the difference in happiness between personally getting hurt vs being someone else get hurt

OPERATIONAL DEFINITION

You define happiness as the distance (in mm) the edge of your mouth is pulled backwards

METHOD

Half of participants watch people fall off skateboards, and half are placed on them and are shoved off

RESULTS

You do not observe any differences in happiness between the two groups

You may not see any differences where you expect to because your operational definition lacks power. It produces the same measurement for smiling (seeing someone else get hurt) as it does for wincing (being hurt)

We can tell the difference between smiling and wincing, but operational definition cannot

Question 6

Internal Validity Vs External Validity

Answer 6

Internal:

Logical soundness

External:

Relevance of findings to other situations

Question 7

Cofounds

Answer 7

Cofounds are variables that have incidentally been manipulated along with your independent variable

Presence of confounds affect the internal validity of experiments

Question 8

Demand Characteristics

Answer 8

Sometimes when people think/know they are being observed, their behavior will change

Question 9

Placebo Effects

Answer 9

Sometimes the expectation of receiving treatment has an effect on individuals. This is called the placebo effect.

Question 10

Single Blind Experiments

Answer 10

In single blind experiments, participants are assigned to a treatment condition, but they do not know what that treatment condition is. Single blind experiments are common in medial settings when testing a new therapy or drug.

Single blind experiments are used to allow researchers to separate the effects of an actual treatment from the effects of demand characteristics like placebo effects.

Question 11

Double Blind

Answer 11

In double-blind experiments, neither the participant nor the observer knows what type of treatment or experimental condition the participant is receiving. This helps reduce the effects of demand characteristics and observer bias.