The old IB Psychology specification placed a huge emphasis on learning a large number of key studies in Psychology. Students could approach the exam having learnt 40-60 studies and feel confident in their ability to answer the majority of short- and extended-response questions… however, they often struggled to evaluate theories or even the studies themselves beyond a superficial level.

The new iteration of the IB specification focuses on a deep understanding of key psychological theories, alongside an ability to critically appraise these. However, underpinning the entire specification are six key concepts that are absolutely fundamental to understanding psychology as a whole.

These concepts are: bias, causality, change, measurement, perspective, and responsibility. Every single one of these is critical when appraising research or theories. A deep understanding is required to reach an IB7 on the exam, as the concepts are fundamental to strong answers on both the 15-mark Paper 1 and Paper 2 essays.

Let´s take one of the most famous studies in Psychology (and the study I read about at age 14 in my school library, which led me to study psychology at university!) – Bandura et al.´s (1961) study on observation and aggression. Bandura was interested in whether, if children viewed an adult model acting aggressively, they would subsequently act aggressively shortly afterwards. We can apply several of the concepts to this study. Firstly, Bandura et al. observed children under different conditions (an aggressive model, a non-aggressive model, and a control group with no model) to establish causality. Bandura et al. also needed to decide how to measure subsequent aggression demonstrated by the children after watching (or not watching) an adult model. This required developing a behavioural checklist to observe the children. To avoid bias, this checklist needed to be standardised across trials, and a second observer was needed to assess inter-rater reliability (one observer´s scores could be correlated with another’s; a high correlation coefficient close to 1 indicated strong inter-rater reliability). The question of responsibility is also raised by this study, as it is important that the children leave the study in the same psychological state as when they arrived. This study was conducted in the 1960s and would likely not pass an ethics committee review today.

The above is very brief; for a Paper 2, Section B essay (where students will be asked to evaluate an unseen study in terms of the concepts), students will need to discuss each issue in much greater detail. However, it should give them an idea of how each of the concept ´lenses´ has an important place in a student´s psychological toolkit when appraising research/theories.

The six concepts individually

Bias is what arises from the fact that nobody looks at anything from nowhere. It is not the same as prejudice, and this distinction is important. A questionnaire worded so that it (maybe accidentally) nudges people towards a particular answer is biased. A study that tested only wealthy university students in Western countries is biased. A journal that prefers to publish striking results over unremarkable ones is biased. In none of these cases does anyone in the chain need to hold a prejudice; the issue is in the instrument rather than the attitude of the person using it. And the sensible response is not to throw the study away but to work out which way it leans and to read it accordingly. A slightly crooked ruler still measures perfectly well as long as a person knows that it is crooked.

Causality concerns causes, which sounds straightforward enough until one tries to establish one. Almost everything that draws people to psychology in the first place is a question about why: why one child comes through hardship while another is broken by it, why a treatment helps some people and not others. Students quickly learn that correlation is not causation, but this is only the beginning. You need to ask what kind of cause is being claimed, at what level the explanation is, whether the explanation is looking at brain chemistry, or for the way a person thinks, or for the family and culture they grew up in, and whether the study was actually built in a way that closes off the other explanations. The aim is never quite to name the single true cause, rather to be honest about how strong the claim really is.

Change is the understanding that people do not stay still. They grow up, they recover or deteriorate, they respond to treatment, and they alter simply as a result of being studied. The concept asks a student to distinguish between change that happens of its own accord and change that has been brought about deliberately, and to look at the shape of the change rather than merely whether it occurred. The clearest illustration is the long-running research on Romanian children who were moved out of institutions and into foster families. They recovered, which is the hopeful part of the story, but they did not all recover in the same way, or across every area of their development, and it mattered a great deal how early in life the move was made. Change is not often a switch that is flipped. It is more often a slope, and sometimes there is a window that does not remain open indefinitely.

Measurement is the most challenging concept within psychology. It tries to take something that cannot be seen: a memory, a mood, the strength of a child’s attachment to its mother, and turn it into a number that can be compared with other numbers. This is extraordinarily challenging and is never quite as neutral as it appears because every test carries within it an idea about the thing it is testing. A depression questionnaire has already decided, before anyone has filled it in, what depression is and what will count as having it. To think clearly about measurement is to always consider the gap between the thing itself and the number standing in for it.

Perspective is the largest of the six, the concept that sits above the others, because before a psychologist has measured anything or gone looking for any cause, they have already decided what to look at and how. A biological psychologist and a sociocultural psychologist studying depression are not really studying the same thing at all: one looks from the perspective of brain chemistry, while the other sees habits of thought and attention, and a third sees culture, stigma and the very different ways in which societies allow their members to speak about sadness. This is where the new course does something important and valuable: it takes ideas from outside the familiar Western textbooks as different perspectives. Frameworks such as Kapwa in Filipino psychology or Indigenous models of social and emotional wellbeing are not bolted onto the course; they are distinct viewpoints that are often left out of psychology.

Responsibility is the concept most often mistaken for the ethics section at the end of the chapter, and it encompasses much more than that. We need to untangle the word, which carries several quite different meanings at once. To say that trauma is responsible for a man’s behaviour is to make a claim about cause. To say that a young child is not responsible for what he does is to make a claim about whether he is even the kind of person who can be held to account. To say that a researcher is responsible for the safety of her participants is to describe the duties of a role. And to say that a company is responsible for having made its app addictive is to apportion blame. Understanding the different facets of responsibility shows that a student actually understands what they are discussing.

How the six interact

It may be tempting to treat the concepts as six separate subjects. However, they interact, and good critical thinking requires understanding how they do.

One way to picture the arrangement is in layers. Perspective sits at the top, because the lens a psychologist chooses shapes everything that comes afterwards. Beneath it lie the three concepts that govern how psychology actually does its work: measurement, bias and causality, which, between them, turn the world into evidence. Then, beneath those lie the two concepts that deal with what comes next: change, which is what our knowledge allows us to do, and responsibility, which is what our knowledge obliges us to do. From top to bottom, the arrangement of the concepts traces the journey of psychology, from the choice of where to look, through the gathering of evidence, and out into the world where that evidence finally matters.

There is a second way of viewing as well. The six fall into three pairs that compete with one another. Perspective is necessary, but if a researcher isn´t careful, this can turn into bias. Causality is the explanation a researcher is looking for, while change is the reality that keeps complicating it. Measurement is the act of capturing something, while responsibility is being careful with what, and with whom, one has captured data on.

This is why the concepts should not be taught in separate boxes, and students can show excellent critical thinking by discussing how they interact.