Module 1 Psychology as a science (NEUR1020)

1.1

The scientific method in psychology

The scientific method

Observations: things that we notice

Explanations: Help us understand the data (why is that so? why do things appear as they seem to be?)

Prediction: explanations about things we have not observed but could observe if theory is correct

Property of scientific theories

Testable: does the theory generate hypotheses that can be evaluated against data?

Falsibility: Capacity to show that theory is fundamentally incorrect

= allows formation of hypotheses

Refining scientific knowledge

If theoretical prediction is confirmed by an observation = theory is provisionally accepted and another hypothesis is tested

Theoretical adjustments can be made to see if the theory can be brought in accord with disconforming results

Disconforming results can result in the theory rejection in favor of an alternative that is consistent with data

Paradigm

Widely accepted set of beliefs, theories, and practices that guide research and understanding

• set of background assumptions

Dictate how:

• we are meant to construct explanations

• we are meant to understand the world around us,

• to identify means of how one can achieve an understanding

Miasma theory

Fundamental assumption of illness is that people get sick because they are exposed to miasma

Disease believed to be caused by particles suspended in foul odours – miasma – emanating from rotting organic material

Watson’s Methodological Behaviourism

• rejected the study of unobservable “private” phenomena as unscientific

• only publicly observable phenomena such as overt behaviours could be studied scientifically

• prompted a shift in focusing on relationships between publicly observable stimuli and their behavioural consequences

• PRIVATE THOUGHTS OFF LIMITS

Skinner’s Radical Behaviourism

• Broadened the definition of “behaviour” to include “private events” → thoughts and feelings - as legitimate scientific topics of study

• Argued that external environment was the determinant of observable and unobservable behaviours

• Mental events, therefore, are not causes of behaviour but are themselves behaviours caused by environment

• PRIVATE THOUGHTS AND FEELINGS ARE LEGITIMATE STUDY TOPICS

• MENTAL EVENTS ARE CAUSED BY EXTERNAL ENVIRONMENT

• PRIVATE EVENTS DON’T HAVE CAUSAL ROLE IN TERMS OF BEHAVIOUR

Cognitive Paradigm

• Placed mental events and representations at the centre of psychology – mental events could be studied as causal determinants of behaviour

• Rather than viewing the mind as a black box, the cognitive paradigm seeks to understand processes that “transform” stimuli into behaviours

• MENTAL EVENTS = CAUSAL DETERMINANTS OF BEHAVIOUR

Biological Paradigm

• Does not focus on exclusively on abstract functional relationships between cognitive processes

• Seeks to explain cognition and behaviour in terms of biological processes

  • E.g patterns of neural activity

• Synergistic with, and extends, work within the Cognitive and Behaviourist paradigms

• What brain regions are responsible for performing particular cognitive functions?

• How are cognitive functions performed by neurobiological mechanisms?

• How are patterns of behaviour or psychological processes influenced by genetics?

1.2

Paradigms and research methods

Psychology definition

Commonly defined as the scientific study of mind, brain, and behaviour

Features of a cience

Grounded in observation

• data needed to confirm and disconfirm ideas

Cumulative

• body of knowledge that grows and is refined through time

Self-correcting

• errors/misconceptions are eventually removed

Achieves explanation and understanding

• a singular theory can account from a multitude of findings

Falsification and the Logic of Scientific Discovery

The scientific method implies incremental refinement

• Our knowledge progressively becomes a closer approximation to truth/reality

Scientific interference requires critical thinking

Real scientific interference requires exercising judgement at many levels

• How trustworthy are the data upon which inferences are based?

• → Judgements about the data quality

Is the theoretical explanation a general one, or is it limited to this specific instance?

• → Judgements about the theory adequacy

Does the experiment show the effect what the researcher thinks it does?

• → Judgements about alternative explanations.

Reliability

How repeatable/consistent a measure is

• If you were to assess the same construct in the same way using the same method of measurement, do you tend to get the same results?

Validity

The degree to which a measure assesses the thing it is purported to assess

• Is the construct you seek to measure actually related to the measurement?

Judgements about theory

Is the theory general?

• A scientific explanation should apply to more than just one specific case

Can the theory be tested?

• Does the theory predict novel observations?

• Are there results that would falsify the theory?

Is the theory parsimonious?

• A parsimonious theory provides the simplest possible explanation that suffices to explain all relevant observations

• Principle of Ockham’s Razor

Can we rule out alternative explanations?

• If multiple explanations can explain the data, is there a way to distinguish them?

Judgements about alternative explanations

correlation vs. causation

• Because 2 variables are related to each other does not mean that one causes the other

Uncertainty and quantitative measurement

Allows us to put a numeral value on a measurement

• Quantifies our uncertainty

• “Tall” is no longer subjective or relative

• Permits objective measurement by others

Paradigms define:

• Concepts and constructs invoked by theories

• Research questions that are worth investigating

• Methodologies used to assess these questions

Provides a template for expressing theories. Encompasses the set of backgorund assumptions that provide a general frame of reference for explaining things.

Behavioural Paradigm

Our behaviours are wholly determined by our environment

Key concepts of history of reinforcement and learning

• Law of Effect – Behaviours that are rewarded tend to be repeated

• Rejection of unobservable processes as unscientific (mental events)

 Questions about how contingencies (relationship/association) pairing stimuli with reward/punishment affect subsequent behaviour

Cognitive Paradigm

Inputs are processed and transformed into outputs

• Presented with things that happen in the environment and we produce behaviours

Key concepts of mental representations and mental states

• Focus on unobservable mental processes and their (observable) effects

• Attention, memory, and decision-making

• We can observe something in our environment and the way we conceptualise that objective stimulus from environment might be different from the physical properties of the stimulus

Questions about the mental processes that give rise to behaviour

The Biological Paradigm

What are the physical bases of thought and behaviour?

What is physically happening in the brain that allows you to perform mental acts?

Key concepts of evolution, genetics, and physiological functions

• Focus on identifying physiological correlates of specific behaviours/cognition

• Measurement of brain activity and identification of genetic contributions to behaviours or psychological disorders

Questions about how mental processes are physically realised in the brain and how such functionality evolved

DSM-V: Major Depressive Disorder

Experience 5 or more of the following within a 2-week period:

 

1.        Depressed mood most of the day, nearly every day.

2.        Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day.

3.        Significant weight loss when not dieting or weight gain, or decrease or increase in appetite nearly every day.

4.        A slowing down of thought and reduction of physical movement (observable by others, not merely subjective feelings of restlessness or being slowed down).

5.        Fatigue or loss of energy every day.

6.        Feelings of worthlessness or excessive or inappropriate guilt nearly every day.

7.        Diminished ability to think or concentrate, or indecisiveness, nearly every day.

8.        Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, or a suicide attempt or a specific plan for committing suicide.

Why are research methods important?

People have a tendency to see what they want to see

Confirmation bias

People often seek out information that confirms their beliefs

• Occurrence of expected or favoured events are highlighted

• Occurrence of unexpected or unfavourable events are minimised

Benefits of Research Methodologies

Impose control, or structure, over the observations we make

The more structure there is, the more confident we can be about the causal status between events

Specific way of acquiring data

• Introspection (less control) ↑

• Natural observation

• Case history

• Surveys

• Correlational designs

• Experiments (more control) ↓

A variety of methods are often used to provide converging evidence for a theory

Experimental designs

Specifically set up to support causal inference

Manipulate (i.e.  systematically vary) an independent variable while measuring the effect on another dependent variable

• introducing a difference in 2 groups

• different “levels” of independent variable create different experimental conditions

• All other factors are held constant across conditions by either being allowed to vary randomly or by being deliberately equated

If dependent variable changes significantly across conditions = may infer that the change was caused by manipulation of the independent variable

eg. IV = level of rest, DV = response time

Bias in research

Factors that affect the data that are obtained in a study

• Can have follow-on effects on conclusions and theoretical inferences

• If bias is not detected, conclusions/inferences can be compromised

Sampling Bias

When the study sample is not representative of the population to which you wish to generalise the study conclusions to

eg. adjusting weekly employee wages to study the effect of income on worker happiness for rich people

Expectation effects

Bias from participant expectations

• placebo effect

• hawthorne effect

• stereotype threat

• demand effects

Single-blind research can restrict participant knowledge of study aims

Double-blind researh can restrict experimenter knowledge of participant groups

Placebo Effect

the improvement in a person’s condition resulting from the belief that they are receiving treatment, even if the treatment has no therapeutic effect

Hawthorne effect

the change in behaviour that occurs when individuals are aware they are being observed or studied

Stereotype threat

The risk of conforming to negative stereotypes about one’s social group, which can negatively impact performance and behaviour

Demand effects

when participants alter their behaviour in response to perceived expectations or cues from the researcher during a study

Operational Effects

Defining variables in terms of the operations/methods used to observe/measure/manipulate them

• Difference in Response Time are identified with the amount of conflict information that is being processed

Defining a concept or variable in measurable terms so it can be observed and tested

Not all equally valid

• Some measures are more clearly linked to theoretical concepts than others