Science of human behaviour
Empirical guides and essays on behaviour, habits and decision making. Rigorous, readable and independent, from a decade of research and practice.
A list of 79 US behavioral science, behavioral economics and decision science programs by level and delivery, each linked to the official page and read in October 2026.
Anchoring bias explained: Tversky and Kahneman's 1974 evidence, how replication holds up, and where the first number distorts pricing and negotiation decisions.
Which cognitive biases hold up? Bias versus heuristic, the Gigerenzer and Kahneman debate, 15 biases rated by evidence, and why 200-item bias lists mislead.
Confirmation bias explained: Wason's 1960 rule task, Nickerson's review, Lord et al. 1979, business and science examples, and five practical ways to reduce it.
The decoy effect explained: Huber, Payne and Puto (1982), replication caveats, pricing tiers, everyday examples, and how to blunt a third option's pull.
The endowment effect: Kahneman, Knetsch and Thaler's mug study, the Plott and Zeiler replication fight, and what still holds for pricing and retention.
I am writing a book (together with Behavioral Change Specialist Judith Martens from behavior-change.net) about how to change effortless, using habits to shape your behaviour without the need of (an enourmous amount of) motivation. I was writing some chapters, when I realized that I needed to see the preface to really set my focus on […]
Read the essay →It has been postulated (for example see Persons & Miakami) that psycho diagnostic evaluation is an important phase in the treatment of psychopathology. However there is a fierce battle going on between those that argue for a stepped-care model in mental health care and those that argue that we should rather look at the specific […]
Bias in treatment recommendations is a problem health care in general. The focus on my research looks specifically at the biases in mental health care. In this field we find literature that suggests certain disorders are viewed as more “psychological” in nature and others are viewed as more “biological” in nature, and to some degree, […]
This is a reply posted at LinkedIn by Tom Woottoon to the original article: Unconscious perceptual processes. ———— I spoke to 150 mostly doctors and therapists last week and continue to be amazed at how my radical ideas are so well received. Depresssion, Bipolar, and Schizophrenia can be turned into an advantage with professional guidance […]
We know that dieting often does not work. There are many theories why that is the case, and some people say that it actually does work, but not for everyone. However I believe that we do not know much about dieting, because we have been looking for information in the wrong place. Let’s put up […]
This article was inspired by a lecture given by Pamela Smith at the Radboud University Nijmegen. The purpose of perception is to support behaviour. Why do we perceive things in the first place? What is the point of it? Is it so we can understand the world? That sounds logical, but that cannot be the […]
The current study aimed to improve understanding of the behavioral indicators of social anxiety in the Free Speech Task. Building on the current theoretical knowledge about social anxiety, we developed a rating system to maximize the sensitivity of the behavioral anxiety assessment in the Free Speech Task. Participants with social anxiety and a control group […]
RCTs are great and every empirical scientist loves them. Everyone? No there is a small village in the south of France…Well to be honest I believe that RCT’s are just a hype. Of course they were great in reducing a lot of statistical problems and have helped psychology to become a “respected science” and earn […]
The ability to choose an evidence-based psychotherapy on the base of scientific knowledge has been a negligible factor in the evolution of the human brain. One could argue that empirical science itself fosters a style of thinking that is counter-intuitive for many of us. Personally I believe that the human way of trying to identify […]
Internet-based psychotherapy is a hot topic since a few years. The main advantage is money: Computers are much cheaper to run than licensed psychotherapist. So if a computer could achieve the same or nearly the same treatment outcome as a human expert this would be a huge advantage, as computer systems can be replicated almost […]
According to Lars Bergman there are several reasons that keep computerized systems from producing the correct DSM-classification. The most important point might be that diagnosis in psychiatry is just to complex for a fully structured system to reach a good level of validity. Dynamic systems and appropriate statistics might be necessary. According to Dreyfus the […]
[http://www.vrphobia.com](http://www.vrphobia.com) (which turned up as #1 in Google) is an organization that is called Virtual Reality Medical Center. They treat all kinds of anxiety related disorders, but seem to focus mainly on specific phobias. After the intake session the client is taught skills to suppress automatic fear reactions. In the following sessions the client is […]
While research has found differences between novice and expert therapists those differences do not seem to be significant for treatment outcome. A crucial factor in this finding is that certain processes keep the psychotherapist from learning effectively. One of those processes is the lack of good feedback (on the macro and the micro level). If […]
Some time ago I gave my thoughts about the battle of panculturalists vs. universalists with regard to self-enhancement. This is take II, which goes much more in depth and explores the story by examining the two key players in the discussion and there scientific battle in the different journals. Self-enhancement describes a range of psychological […]
Effect size is a parametric test, belonging to the GLM family that allows to compare the size of an effect between two groups (or for that matter two conditions in one group). The test can be used in all kinds of research designs (experimental and non-experimental) that employ different kind of measurements or/and manipulations. Given […]
There seem to be no obvious methodological or statistical issues that could account for the poor inter-rater reliability. Embregts argues that informants might have a different view on presence and severity of behavioral problems depending on the frequency and quality of interaction they have with the client (“biased” data). Secondly both judges might have different […]
Heterotypical continuity means that an underlying (developmental) process or impairment stays the same, but the manifestations do not stay the same. For example a child with autism might first show impairments of non-verbal skills and problems in eye-contact. In a later developmental stage the manifestations would be different, such as stereotypical behaviour or language problems. […]
Idea for an experiment: I proposed to prime therapists with the case of a patient that could easily be identified as one disorder (for example depression or dementia) and then present another case in which the information is ambiguous and thus allowing the possibility for both disorders to be present. Having read the articles by […]
In one of the last posts I summarized three articles that all came to the conclusion that there was no big difference between novice and expert therapists. I came to the conclusion that the tasks used were presenting ready-to-judge material, which was in no way ecological valid. I hypothesised that the true merit of expertise […]
The individual is the smallest entity, that can arise from any group-division. The word individual actually means “that which is un/(in)-dividable”. Thus the meaning of the individual is closely connected to the group, because the individual only gets meaning in the context of the group. In the same way that the individual gains meaning from […]
The study of Hillerbrand and Claiborn is a 2 (level of expertise)x3 (levels of problem structure) design. 17 expert and 15 novice psychologists with good diagnostic abilities read well structured, ill structured or random structured cases. Consistency of the relevance of the information supplied varied between the cases. Relevance was the extend to which information […]
The processes of goal assimilation and goal accommodation refer to different strategies in dealing with goals, that have become unavailable or extremely difficult to reach. Whereas the process of assimilation can be seen as a more active approach to reach a goal, accommodation refers to a more passive, internal cognitive process that changes the valence […]
In medicine, diseases are classified according to the physiological problem that is presumed to have caused the disease. Classification is guided by advanced biological and chemical theories that have proven to have explanatory value. For mental illnesses that is a different story, because the working mechanism is mostly unknown and there is no unified scientific […]
In recent times there has been a lot of discussion with regard to social psychology constructs such as self-esteem, self-determination and self-affirmation. Due to rapidly changing societies and new insights into cognitive processes of memory formation some old theories of self-psychology have recently been challenged. For example Heine, Lehman, Markus and Kitayama (1999) postulated that […]
Charman et al. (2005) found that non-verbal behaviour was relatively robust and reliable on the different measurements over time, whereas the other indicators where not so reliable. In that light non-verbal behaviour might be a good indicator for the development of language and communication skills specifically and quality and frequency of social interactions in general […]
The probabilistic nature of behavioural phenotypes proclaims that people with a specific syndrome will have a heightened probability to exhibit specific behavior or developmental pathways that are different to others, who do not have the specific syndrome. The advantage of probabilistic nature of the construct is that it can account for exceptions and it is […]
A healthy and stable relationship requires both partners to interact on a frequent and regular basis. Different interests need to be discussed, activities need to be planned and coordinated, different tasks need to be done in a joint effort – and if children come into the equation things do not get more relaxed. Recent literature […]
Who are you? Okay…easy enough question, but get this one: How do you know who you are? Do you get it right? So many times I meet people that tell me all about them and how they are and when I finally get to know them, they seem to do quite the opposite of what […]
These are my notes of the discussion during the third European workshop on causal reasoning in clinical decision making. The workshop took place on April, 25th and some experts from different European countries were present. My notes are not at all complete, they were rather meant to help me remember the interesting points that were […]
Normative models require the data to be linear. Each case should be weighted linearly and combined additively. That is certainly not the case in clinical settings. Not all therapists have clear guidelines for themselves on what to base a categorical decision. When comparing the data at hand they rely on statistical models that are fallible. […]
The study of explanatory diagnosis can best be conducted with an experiment, manipulating the data in a way so that an ambiguous, specific cause for mental illness is rendered more active in the mind of the clinician. This could be a for example a case about psychotic behaviour that could be attributed to a depression […]
The study of developmental psychopathology is a multidisciplinary approach for studying factors that contribute or impede mental health. These factors can be internal (for example genes) or external (environment) and are conceptualized not as directly influencing mental health, but as building vulnerabilities or enhance adaptation. It is assumed these factors differ in their mechanics according […]
In the article “When Prejudice does not pay: Effects of Interracial Contact on Executive Functioning”, Richeson and Shelton found that people who score high on an implicit racial bias test, show the highest impairment on executive functioning, after interaction with a black experimenter. They state that this effect occurs when a member of the majority-group […]
Imagine walking into a library. All objects in that building are based on the same principle, they all use paper with letters printed on it to deliver a specific message. So should we just put all the books, articles and newspapers on one pile? No – it makes sense to structure the objects according to […]
In terms of psychopharmacology, nicotine acts directly on nicotine cholinergic receptors, which are located in part on mesolimbic dopamine neurons. By stimulating the nicotine receptor, dopamine is released from the mesolimbic neurons, accompanied by a sense of reward and pleasure. Whereas other drugs, such as cocaine, that act on the same neurons, block the dopamine […]
It is interesting to note that most of models for behaviour have a focus on the automatic, impulsive part of behavioural regulation. However, deliberation has not disappeared from the scene and makes up a part of some models. The Mode-Model by Fazio consists of two different classes of processes that can regulate behaviour. The spontaneous […]
1. Short Summary of the research proposal This study investigates the role of affect in consciously created automatic behaviour tendencies (implementation intentions). The general hypothesis is that the frequency of a behaviour is closely connected to the activation of a specific behaviour tendency, but this model often fails when implementation intentions are used to change […]
The topic of free will has been a central issue since the beginning of philosophy: How do rational agents exercise control over one’s actions and decisions. In “the precise of the illusion of conscious will” (2004), Daniel M. Wegner explores the idea of apparent mental causation. He argues that if a thought arises just before […]
Where are all the Eskimos gone? The question of language and though and its reciprocal influence has been discussed countless times. It goes back all the way to the Greeks and probably even further. In the last 30s of last century the businessman and linguist Benjamin Whorf postulated what would be know as the Whorfian-Hypothesis. […]
Executive functioning is the mental ability to control and manage cognitive processes. It is a theoretical cognitive system that involves processes such as attention, abstract thinking, rule acquisition, initiating appropriate actions and inhibiting inappropriate actions and selecting relevant sensory information. Executive functioning is sometimes called central executive or cognitive control and plays an important role […]
The term Embodiment refers to the idea that the internal milieu of the body (such as hormone levels or other homeostatic functions) plays an important role in the processes usually attributed to more higher cognitive processes. This influence is probably achieved through manipulation of emotional states, as suggested by Damasio (1994). “Embedded” describes the quality […]
I will first demonstrate that in behavioural science there is no alternative explanation to evolution when exploring the whole causal chain that leads to a specific behaviour. Secondly I will show that the implication of this perspective yield results also in studies that focus on a more narrow subject. Last I hope to refuse the […]