What are Psychological Theories?

Definition  Psychological Theories are general principles that describe and explain behaviour and mental processes based on empirical evidence and enable prediction of outcomes. FOCUS: TRAIT Theory of Personality Development Basic Principle – “Personality is characterised by traits that are stable across situations and over time. The traits have genetic basis. ” Theorists – Allport & Odbert, Hans & Sybil Eysenck, McCrae & Costa

Psychological Theories UNDERSTANDING 1. Theories provide UNDERSTANDING by being  Internally consistent The different parts of a theory do not contradict each other.  Parsimonious They provide the greatest possible explanation in the most economic way.  Orderly Theories are able to organise facts and find regularities and patterns to generate laws. Measurements are valid and reliable. Methods are systematic & can be replicated.  True! Theories should correctly explain reality.

Psychological Theories 2. PREDICTION 2. PREDICTION – allows us to predict behaviour to a certain degree under specific conditions. A good theory should generate lots of bold, precise hypothesis to stimulate research that support or refute the theory. A good theory is falsifiable/refutable – can be disproved using the NULL HYPOTHESIS.

Psychological Theories 3. Control 3. Control – Theories have practical implications that provide solutions to problems and improve the human condition.

Contrast the following Psychological Theories: Psychoanalytic Theory Personality develops from our efforts to resolve the conflict between our primitive pleasure-seeking biological urges (id) and our internalised (super- ego), socialised (ego) reactions to these. Reference: Freud’s Iceberg Trait Theory  Personality is a combination of unique characteristics that are stable over time and across situations.  Individual Differences in Personality can be described using trait dimensions.  Traits have genetic basis. Example: Eysenck’s Wheel (E-S)

How is Psychological Research done?

Steps in a Psychological Research STEP 1. Identify the RESEARCH PROBLEM. Investigate the behavioural, neurological and psychological consequences of surgery wherein the two cerebral hemispheres are deconnected by severing the corpus callosum (‘split-brain’) STEP 2. Formulate the Hypothesis Each hemisphere possess an independent stream of consciousness and memories that are inaccessible to the other.

PSYCHOLOGICAL RESEARCH STEP 3. Design the experimental Method.  Identify research participants (population & sample)  Method of selecting participants (sampling technique)  Method of measurement and data collection?

PSYCHOLOGICAL RESEARCH STEP 4. Collecting the Data. Observation of split-brain patient’s responses STEP 5. Analysing the Data. Two hemispheres of the brain have different abilities and functions One side of the brain does not know what the other side is experiencing.

PSYCHOLOGICAL RESEARCH STEP 6. Interpreting the Data. Hypothesis is supported. Left and right hemispheres have unique functions that are independent of each other but they also share many functions. Application: Treatment for patients with brain damage STEP 7. Reporting Research Findings (publication) Nobel Price Lectures.

How do Psychologists test the quality of studies?  VALIDITY OF A METHOD – Is it measuring what it is supposed to measure? Eg. Personality Test measures Personality and not mood or attitude  RELIABILITY OF A METHOD – How consistent are the measurements? Eg. A participant who takes a personality test this year gets similar results when the same test is given in two year’s time.

TESTING FOR VALIDITY: INTERNAL VALIDITY – Whether the results of a study were really due to the variables identified by the researcher and tested by the experimental method. FACE/CONTENT VALIDITY – the items of the test or method ‘looks like’ it measures what it is supposed to measures. CONSTRUCT VALIDITY – whether the test or method supports the underlying theory. Ex. An intelligence test has items that measures intelligence and not attitude or experience. Ex. Items in a Personality Traits Test contains items in line with the Trait Theory of personality development.

EXTERNAL VALIDITY – whether similar results are obtained if different participants or setting are used CONCURRENT VALIDITY – involves comparing a new method or test with an already established one that measures the same variable/s. PREDICTIVE VALIDITY – whether a test or method will predict future performance as indicated by its results.

ECOLOGICAL VALIDITY – refers to whether a test or method measures behaviour that is representative of naturally occurring behaviour.

TESTING FOR RELIABILITY: INTERNAL Reliability – refers to how consistently a method measures within itself. EXTERNAL Reliability – refers to how consistently a method measures over time when repeated. Ex: Items in a personality test measure personality traits such that if a participant answers only half of the items, he/she will get the same result as when the whole test was answered. (Split-Half Method of Reliability testing) Ex. Results of the test on one occasion is similar to the results obtained in another occasion when given to the same person. (Test- Retest Reliability)

Testing the NULL Hypothesis  Every hypothesis should be capable of being shown to be wrong. (i.e. REFUTABLE or FALSIFIABLE) The null hypothesis proposes that the independent variable will have no significant effect on the dependent variable. Hypothesis: Mothers who adopt a child eventually get pregnant. Become PregnantDo not become pregnant Mothers who adopt(Null Hypothesis) Mothers who do not adopt(Null Hypothesis)

Placebo Effect Placebo – a neutral substance or procedure that looks like and is delivered in a similar way to the real substance or procedure that is being evaluated. Placebo Effect – participants who take inactive substances or undergo useless procedures may feel improved, provided they do not know that the treatment is a fake. Reasons: 1. Belief in the treatment leads to improvement of symptoms (Psychologic Effect) 2. a placebo reduces a person’s anxiety, which causes physiological changes to occur – eg. Heart and lungs return to normal, natural immune system responses increase

Get curedRemain sick Participants taking drugs(proves null hypothesis) Participants taking placebo(Placebo Effect) Testing for Placebo Effect Why? To eliminate the impact of participant expectations and other psychological/physiological factors on treatment Experimental Design: Single-Blind Studies – participants unaware if they are taking a placebo or not. Double-Blind Studies* – participants and researcher are unaware of where placebo is * researcher’s desire for success does not lead to bias in measuring outcomes