Goals of the Scientific Approach in Psychology

Goals of the Scientific Approach

• Psychologists and scientists share three sets of interrelated goals: measurement and description, understanding and prediction, and application and control.

Measurement and Description

• Science's commitment to observation requires that an investigator finds a way to measure the phenomenon under study.
• The primary goal is to develop measurement techniques that make it possible to describe behavior clearly and precisely.

Understanding and Prediction

• Comprehension means understanding when one can explain the reasons for the occurrence of the events.
• To evaluate comprehension, scientists make and test predictions, known as hypotheses.
• A hypothesis is a tentative statement about the relationship between two or more variables.
• Variables are measurable conditions, events, characteristics, or behaviors controlled or observed in a study.
• Some research focuses on asking people about their experiences, perceptions, thoughts, and opinions without starting with a hypothesis.
• The research can lead to a testable hypothesis and a deeper understanding of the variables that need to be considered

Application and Control

• Once people understand a phenomenon, they can control it
• Psychologists do not set out just to collect isolated facts about the relationships between variables, they construct theories.
• A theory is a system of interrelated ideas used to explain observations.
• Theories integrate facts and principles into a coherent whole and permit psychologists to make the leap from describing behavior to understanding it.
• Theories guide future research by generating new predictions and suggesting new lines of inquiry
• A scientific theory must be testable.
• Most theories are too complex to be tested all at once and need to be tested one or two specific hypotheses at a time
• If findings support the hypotheses, confidence in that theory grows. If findings fail to support the hypotheses, confidence in the theory diminishes.
• Theory construction is a gradual process that is always subject to revision.

A Scientific Approach

• The aim of the scientific method is to make observations of phenomena of special interest in order to collect data and to improve the quality of human lives.
• In psychology, the observation is either of human or animal behaviour.
• Scientists systematically observe nature and follow the rules of evidence.
• As a science, psychology is empirical and uses direct observation rather than pure intuition or reasoning
• Psychology is the study of behavior and the factors that influence it.
• Psychologists have four goals: to describe how people and animals behave, to understand and explain the causes of these behaviors, to predict how people and animals will behave under certain conditions, and to control behavior through knowledge and control of its causes.
• Neuroscientists produce brain lesions in an animal's brain in order to make inferences about the functions of the damaged region from changes in the animal's behavior.

Steps in a Scientific Investigation

• Steps in a scientific investigation are systematic, logical, and follow an orderly pattern.
• The steps follow from each other, to produce a result that can be tested and replicated through other scientific tests and this makes the results valid and reliable
• The first step begins with identification of a problem ("problem statement").
• It is important to provide motivation on why that problem is worthy of investigation and justify how the study could advance knowledge.
• Develop a scientific research question that can be answered by gathering evidence and specifically focuses on the purpose of the study.
• Step 3 is followed by the formulation of a hypothesis, commonly defined as a tentative statement about the relationship between two or more variables
• A variable is any characteristic that differs or varies from one situation to another, or even from one person to another.
• A good hypothesis is one that can be tested and scientific hypotheses must be formulated precisely, and the variables under study must be identified and clearly defined
• Operational definitions describe the actions or operations that will be used to measure or control a variable, and may be quite different from dictionary definitions
• A hypothesis is an educated, testable prediction about what will happen, and the researcher should be able to prove or disprove the hypothesis.
• Devising a plan makes the hypothesis testable, this plan is referred to as the research design
• A researcher writes a step-by-step procedure of how the research study will be conducted and describes the observations or measurements that will be used.
• The next step entails gathering information, also known as data collection using procedures for making empirical observations and measurements.
• Data collection techniques used in a study depend largely on what is investigated and can often take months/years
• Data collection involves gathering information from a subgroup of people known as a sample.
• A sample is a subgroup of people who are similar in terms of their characteristics and relatively representative of the population a researcher is interested in drawing a conclusion about
• The outcomes of data analysis should provide an answer to the research question posed earlier.
• The last step involves reporting the results, which is a fundamental aspect of the scientific enterprise
• Scientific progress can be achieved only if researchers share findings with one another and the general public
• No matter whether the hypothesis was accepted or refuted, the researcher will report on the results, including any limitations that might have influenced the results, along with a conclusion, for future researchers who wish to replicate or expand on the study
• Researchers prepare a report that is delivered at a scientific meeting and submitted to a journal for publication.
• When articles are submitted to scientific journals, they go through a demanding peer-review process
• Experts thoroughly examine each submission and they carefully evaluate each study's methods, statistical analyses and conclusions, as well as its contribution to knowledge and theory.
• The peer-review process ensures that journals publish reliable findings, based on high-quality research
• The process greatly reduces the likelihood of publishing erroneous findings.

The Peer-Review Process for Journal Submissions

• An elaborate and rigorous peer-review process determines whether studies merit publication in a technical journal.
• The goal of the process is to maximise the quality and reliability of published scientific findings.

Advantages of the Scientific Approach

• Science is certainly not the only method that can be used to draw conclusions about behaviour
• The scientific approach offers clarity and precision and Scientists are trained to be sceptical and subject their ideas to empirical tests.

Research Approaches

• There are mainly two types of research approaches: qualitative and quantitative studies.
• The purpose of a qualitative research approach is to understand and interpret social interactions.
• Quantitative research aims to test hypotheses, assess cause-and-effect relationships and make predictions.
• Qualitative research tends to have small sample sizes, with data based on open-ended responses, field notes, interviews and observations, analyzed by means of identifying patterns and themes
• Conversely, quantitative research focuses on larger samples, and the data are based on numbers that involve statistical analyses.
• Qualitative approaches provide in-depth knowledge, which it might not be possible to obtain with quantitative approaches so qualitative approaches provide a better understanding of people's meanings.
• Results of a qualitative approach are not generalisable, as the sample size is often small and unrepresentative of the broader population
• Qualitative research is more subjective, while quantitative research is more objective.
• The choice of a research approach is not a neutral choice and Qualitative research is seen as a method of decolonising research,
• Research design is often confused with the methods through which data are gathered

Major types of research designs include:

• Experimental study (quantitative)
• Non-experimental study (quantitative)
• Qualitative study

Quantitative Research Designs:

• Experimental design involves experimentation, in which one or more of the variables or factors are manipulated while the other variables are held constant, so that the effects of the experimentation can be observed.
• The goal is to provide answers to questions of interest by establishing whether cause-and-effect relationships exist between the variables and involves the deliberate manipulation of one or more variables, while trying to keep other variables constant.

Experimental and Control Groups:

• In experimental research, participants are assigned to one of two groups: an experimental (also known as a treatment) group or a control group.
• This will ensure that a comparison can be made.
• The allocation of participants to these conditions is random so that issues of bias can be avoided.
• Random assignment refers to the procedure whereby each of the participants has an equal chance of being assigned to an experimental or a control group

Independent and Dependent Variables:

• The purpose of an experiment is to find out whether changes in one variable (let's call it X) cause changes in another variable (let's call it Y).
• The independent variable is a condition or event that an experimenter varies in order to see its impact on another variable.
• The experiment is conducted to verify this effect.
• The dependent variable is the variable that is thought to be affected by the manipulation of the independent variable.
• In psychology, the dependent variable is usually a measurement of some aspect of the subjects' behavior
• "How X affects Y" is a good shortcut when sorting out the independent and dependent variables

Extraneous Variables:

• A good experiment is one in which the differences between the measurement scores are caused by the actual treatment, and not other extraneous variables
• Therefore, the experiment is regarded to have internal validity and it means to what extent the researcher can precisely state that the independent variable produced the observed outcomes
• If a study demonstrates a high degree of internal validity, then strong evidence of causality

Threats to Internal Validity:

• There are several factors that can affect a good experiment: selection bias, mortality/attrition, instrumentation, history, maturation, and testing.
• Selection bias occurs when there are pre-existing differences between the participants selected for a study or those who volunteered for a study.
• Mortatlity occurs when participants drop out of a study during the follow-up, known as 'attrition' and In order to prevent or minimise mortality, it is important for the researcher to have several ways of contacting each of the participants
• Instrumentation Threat occurs in studies that adopt pre-test to post-test design, is when the observed changes are due to changes in the actual assessment instrument, but not necessarily the effects of the intervention
• History threat occurs when there is an unrelated event during a study that can affect the responses of the participants and usually applies to studies with longitudinal designs involving repeated measures.
• Maturation threat refers to people's internal changes in physiological and psychological conditions that occur with the passage of time
• Testing Threat may occur when there are repeated measurements on the same variable, which can lead to improved performance because of learning and practice.

Threats to External Validity:

• It is concerned with the extent to which the results of a study can be generalised to the larger target population or across environments
• There are several threats to external validity.
• Multiple Treatment Effect: occurs frequently in studies with three or more treatments and The effect may be the result of more than one treatment given consecutively or in combination, rather than the result of the final treatment independently
• Small Sample Size: Conclusions derived from small sample sizes can be more susceptible to individual deviations and anomalies, which can skew the results.

Advantages and Disadvantages of Experimental Research:

• One advantage is that the researcher can identify cause and effect as well as to distinguish placebo effects
• A potential disadvantage is that the results obtained are sometimes difficult to generalise beyond the laboratory settings because the situation is artificial
• The main advantage of manipulating two or three independent variables is that the experimenter can whether two variables interact
• Interaction means that the effect of one variable relies on the effect of another variable.

Quasi-Experimental Research Design:

• The term 'quasi' means 'partly' or 'to some degree'.
• It shares many features with the experimental design and it is commonly adopted in natural settings when it is impractical to carry out true experiments
• A quasi-experimental research design is an experimental design where the independent variable is manipulated, but it does not provide for full control of less important variables because the participants are not randomly assigned to groups.
• It is, however, stronger than correlational and descriptive designs

Descriptive Research Design:

• Descriptive research provides a snapshot or summary of the present thoughts, feelings or behaviour of individuals regarding a particular phenomenon.
• The focus of descriptive research designs is on determining how often a particular variable occurs, or the extent to which two variables are associated or 'co-vary'

Survey Design:

• Survey research is a type of descriptive research that involves asking a large sample of people questions about their perceptions, attitudes and behaviour.
• The purpose of surveys is to gather information about the prevalence, distribution and associations between the variables within a sample of interest.

Correlational Research Design:

• Correlational research describes the strength of the relation between two or more variables or characteristics.
• The purpose of correlational research is to determine whether a relationship exists among variables and to predict future events from present knowledge
• Although correlational research permits researchers to test the relationships between variables and allows them to make predictions, its weakness is that it cannot be used to draw inferences about the causal relationships between variables.

Qualitative Research Designs:

• Observational research involves the direct observation of individuals in their natural setting' and the researcher passively observes as nature takes its course and systematically collects data without manipulating or altering any variables.
• Case study design involves the in-depth observation of an individual or a small group of individuals
• Phenomenology is based on the understanding that the world and reality are not objective but are socially constructed by people

Types of Data Collection Methods:

• Data used in research are gathered by either primary or secondary data collection methods.
• Primary data collection methods include information collected through methods such as surveys, questionnaires, interviews and experiments.
• Secondary data collection methods are indirect ways of collecting data and comprise sourcing information from a range of sources including documents.
• Quantitative and qualitative research approaches use different methods to collect data

Quantitative data collection methods:

• Standardised tests enable researchers to examine the participants' ability to solve problems.
• A questionnaire is a data collection instrument that is used to elicit participants' feelings, perceptions, beliefs or attitudes toward a particular issue that is of interest to the researcher.

Qualitative data collection methods:

• Interviews are among the most commonly used techniques for collecting qualitative data and they are helpful in gathering information about a participant's experiences and opinions.
• Observational research involves the direct observation of individuals in their natural setting.
• 'Documents' refers to different kinds of material that people generate while carrying out their daily activities and, in the context of research methods, documents (both historical and contemporary) provide sources of information.

Statistics in Psychological Research:

• Statistics are commonly divided into two main areas: descriptive and inferential statistics.
• Both provide insights into the nature of the data collected

Descriptive Statistics:

• Descriptive statistics include statistical procedures used to analyze data and are concerned with the presentation of numerical facts, or data.
• The purpose is to help researchers to describe, show or summarise data in a meaningful way but they do not permit the researcher to make conclusions beyond the analyzed data.

Measures of Central Tendency:

• There is a tendency for the observed values (scores/numbers) to group themselves about the central point within a data set, referred to as central tendency.
• Measures of central tendency are ways of describing the central position of a frequency distribution
• There are three measures of central tendency: the median, the mean and the mode.
• The mode (Mo) is the most frequently occurring value (number).
• The median (Mdn) is defined as the middle value of all given observations arranged in numerical order.
• The mean is the sum of a set of data divided by the number of data.

Measures of Spread:

• A measure of spread is used to describe the variability or spread of data in a sample or population.
• The range is the difference between the highest and lowest values in a data set.
• Variance and standard deviation are measures of how values are spread or dispersed about their mean.

Correlation:

• Correlation examines whether there is a relationship between two or more variables.
• Perfect positive correlation occurs when the values of the X variable have a tendency to increase with the values of the Y variable.
• In a perfect negative correlation, when the values of the X variable increase, the values of the Y variable decrease.
• Correlation is a robust statistical tool used to measure the strength of a relationship.
• The closer the correlation coefficients are to +1.0 and -1.0, the greater the strength of the relationship

Inferential Statistics:

• After researchers have summarised their data with descriptive statistics, they still need to decide whether their data support their hypotheses
• Inferential statistics are used to interpret data and draw conclusions by Working with the laws of probability
• They are concerned with making predictions or inferences, about a population from observations and analyses of a sample.
• Statistically significant findings are likely to yield accurate conclusions, but they are never a sure thing.
• Statistical significance is said to exist when the probability that the observed findings are due to chance is very low

Ethics in Psychological Research:

• All psychological research introduces some ethical issues, which should be identified and resolved before starting a research study
• Guidelines include: voluntary participation, informed consent, confidentiality, debriefing and deception.
• voluntary participation gives participants power whether they want to participate or not
• The researcher should not force, coerce or bribe participants into participating in the study
• Researchers are required to obtain informed consent freely, without the coercion of the participants, based on a clear understanding of what 'participation' entails
• Researchers have a duty to inform participants of the nature of the research and that they are free to participate or to withdraw from the study without being penalised or losing benefits.
• Confidentiality is defined as an explicit or implied guarantee given by the researcher to a research participant that steps will be taken to protect the identity of the participant.
• Research ethics committees evaluate to determine the study's safety through the ethical clearance process.

The Question of Animal Research:

• Psychology's other major ethics controversy concerns the use of animals in research.
• Some people maintain that it is wrong to subject animals to harm or pain for research purposes

Evaluating Research:

• Flawed studies make their way into the body of scientific literature so one of the reasons that scientists often try to replicate studies

Bias in Research:

• Bias is a form of systematic error that can affect scientific investigations and alter the measurement process
• Few common categories of bias that can negatively impact the validity of research include selection bias, measurement bias, intervention bias and social desirability bias.

Selection Bias:

• Selection bias occurs when potential research participants, selected to take part in a study, are not representative of the population of interest.

Sampling Bias:

• Sampling bias is a type of selection bias, and refers to a particular error that occurs due to the sample selection.

Measurement Bias:

• Measurement bias involves a systematic error that can occur during the collection of data

Instrument bias:

• Occurs when the instrument used to assess a particular phenomenon gives incorrect information because of a communication barrier between the researcher and the participant.

Distortions in Self-Report Data:

• Researchers use self-report measures such as interviews or questionnaires to collect data about people's beliefs, experiences or behaviour.

The Placebo Effect:

• is commonly used in medical research, and it refers to an inactive or inert substance.
• Occur when participants' expectations lead them to experience some change even though they receive empty, fake or ineffectual treatment
• A double-blind procedure is often seen as a solution to placebo and experimenter bias because then experimenter and participants are unaware participants get a drug or placebo.