Why Psychology cannot be a science

At some point in the future when the science of psychology is well established ideas like this will be taught to undergraduates in the discipline so they can have a good laugh at foolish people who died before they were born, a bit like we do at the moment with Freud, Watson, Eysenck and so forth.

According to the standard, textbook, histories of the discipline psychology overcame the objections of Kant in establishing psychology as a discipline. Kant argued that an empirical science of psychology was impossible for two reasons. The first that psychological phenomena were not open to quantification, and so the only quantity that psychologists would be able to measure was time (either the time psychological phenomena persisted, or the time gaps between psychological phenomena). The second that psychological phenomena were subjective and would not be open to objective measurement.

Now there was a lot more going on than this, and there is a nice overview here with suggestions for further reading. I think one could plausibly argue that psychology has not been successful in meeting the objections of Kant, and one can see the impact of trying to overcome the objections in the way the discipline has changed across time. Those are not the arguments I am going to make.

The argument I am going to make is based on the work of Kurt Danziger, especially the sort of work he does here, and which is also associated with the work of Ian Hacking.

Danziger makes two points, one of which is common to all disciplines, the other of which is only common to a subset of disciplines.

The first point is, that areas of knowledge begin with a vocabulary that comes from the language of the host society, and which contains assumptions, some of which may remain unexamined for some time because they seem natural. In all disciplines the vocabulary of the area of knowledge changes across time, a specialist vocabulary comes into existence, and this specialist vocabulary may feed back to the language of the host societies. In natural sciences, to some extent, as evidence is gathered the nature of concepts and their associated vocabularies may change because of that process. However, the changing vocabulary does not affect the objects being studied; although they may change our understanding of those objects and regardless of language as knowledge increases peoples may gain technologies that can affect the objects of study.

In disciplines like psychology (other examples would include aspects of psychiatry, sociology and economics) things are different, because the description of the object of study can change the object of study.

Danziger in his 1997 book Naming the Mind makes the case for how this has happened for the concepts of intelligence, motivation and personality, attitudes, behaviour and learning; and variables. His more recent book, Marking the Mind makes a similar case for memory.

So what does this mean. I am going to use my usual teaching examples.

Natural Science

Across time our understanding of dinosaurs has changed. During the nineteenth century our understanding of dinosaurs, based on fossil evidence, was often of great lumbering creatures which inevitably became extinct. In the early twenty first century our understanding of dinosaurs is of a complex variety of animals, each superbly suited to their own ecological niche, some of which became extinct through extreme events, some of which through selection pressures evolved into different species, like, for example, chickens.

Neither of these understandings of dinosaurs affected how dinosaurs understood themselves.

Now of course the objection to this example is that dinosaurs (although not their descendants) are no longer with us, so a second example, I normally use Ether theory or Germ theory depending on how I feel.

Across time our understanding of infection and diseases has changed.

Prior to the nineteenth century the predominant theory of disease transmission was miasma theory:

The miasmatic position was that diseases were the product of environmental factors such as contaminated water, foul air, and poor hygienic conditions. Such infection was not passed between individuals but would affect individuals within the locale that gave rise to such vapors. It was identifiable by its foul smell. (wiki)

While there was earlier work leading up to it, in the nineteenth century germ theory developed, with evidence suggesting that for some infectious diseases microorganisms are the cause.

As germ theory developed and came to be accepted, how we reacted to the possibility of infection through germs changed our behaviour, and we developed technologies to ameliorate the possibility of infections.

However diseases did not change because our understanding of them changed, from being contained in Miasmas to being contained in microorganisms.


Disciplines like Psychology

Bystander inaction. People are less likely to act to help someone if they see themselves as one of many witnessing whatever it is that needs help.

There are two general exceptions to this, people who believe they have the professional skills to help, and people who have been thoroughly taught about the bystander inaction effect.

The study of psychology alters the psychology of people. Psychological research alters how people think about themselves and affects their behaviour.

It is not just psychology where this happens, there are other disciplines with similar looping effects. Belief that a certain level of government debt is harmful has led to austerity, which has because it is such a ridiculous mistake, led to government debt growing. Economic theory affects economies.

For a more fun example watch Hysteria.

Does it matter?

Yes and no. There is no point in trying to 'prove' psychology is a science by doing research that gets more and more obtuse.

There is a point in trying to make our measurement tools and theories the best we can so we can best explain what is going on now, without worrying about the universality of findings.

Letting go of a narrow obsession with a limited notion of what psychology should be like because it is a science is I think a good thing. And ironically it might lead to us being better at collecting data, testing hypotheses and building theories.

Brains!

 

Journal of Serendipitous and Unexpected Results, 2010. 1(1):1-5

Unless you are a dualist who believes that consciousness exists apart from the body it will come as no shock that brains are a necessary part of human (and salmon) psychology.

However, there are some issues around what we ought to, and ought not to, say on the basis of techniques such as fMRI (Functional magnetic resonance imaging)

The first point is this is a graph, not a direct image of the brain.

The technique, as explained in the Wiki article, is to compare blood flow across time.

In the case of the graph above the dead salmon was exposed to pictures of human individuals in social situations with a specified emotional valence, either socially inclusive or socially exclusive. The salmon was asked to determine which emotion the individual  in the photo must have been experiencing.

The brain activation graph shows the difference in activation, as detected by fMRI when the dead salmon was exposed to the two types of picture.

Except of course the salmon was dead, the researchers bought it at a supermarket, and unless we have thoroughly misunderstood the difference between dead and alive there was no blood flow.

Which leads to the second point, the need for adjustment for multiple comparisons.

The anomalous graph is caused because there is no (or inadequate) adjustment made to the null hypothesis statistical tests used to 'detect' the difference given the (large) number of multiple comparisons being made.

This issue is so well documented at this point that any researcher who publishes research based on fMRI data who has failed to do appropriate adjustments for multiple comparisons ought to be seen as fraudulent. Although that may not have been as apparent in the early years of this century, and there is a technical argument about the correct way of doing these adjustments for multiple comparison.

So there we have the basics, however seductive it is to think we are looking at something akin to an X-ray of brain activation we are actually looking at a graph. Beware of any research which does not robustly adjust for multiple comparisons.

Just because it appears in brain imaging it doesn't mean it is just a biological phenomena

In the next post I will address some of the issues around the philosophy of what I am discussing, and thereafter will post something more concrete about the relationships between brains, bodies and the environment for human psychology. For right now hold on to the idea (unless you are a substance dualist) that anything that happens in the mind also happens in the brain.

So if I have learnt to fear dentistry, which I have, then that fear of dentists is materially represented in my body and brain. That is not the same as saying that my fear of dentistry is caused by my biology.

This blog post by Neurocritic illustrates the problems of inadequate reporting of research to make it sound like once a psychological issue can be 'brain scanned' it is biological and open to straightforward intervention with drug therapies. However, it is not only the reporting that is at fault here, it also appears to be a default position of at least some psychology and neuroscience authors that the 'brain scan' (graph of difference in blood flow) shows a biological reality for psychological phenomena.

Beware of the dichotomy that biological is real, not biological is false (or constructed).

This is a particular issue in sex and gender research, where if a graph of difference in blood flow can be   shown for men and women then that particular difference is seen as biological in origin. Despite the possibility that the differences between men and women, for a particular difference, can be at least as plausibly be explained by social process.

Just showing a graph of differences in blood flow in the brains of two categories of people does not equal an explanation of the differences between those categories of people.

Psychology, methods and science, why worry?

Over the last couple of months I have been toying with ideas around Psychology, methods and science.

I suspect that what I want to say will be a bit bigger than one blog post, so I intend to do a series of posts.

This installment is about why I think we have a problem.

As someone with an interest in conceptual and historical issues I tend to range a bit more freely over the psychological literature than specialists in a particular area. Some of the problems which are acknowledged in one aspect of psychology seem to be mirrored in other areas of the discipline. If the problems are even more widespread than that it seems to implicate the whole discipline.

We do not routinely test for similarity instead of difference

One of the outstanding issues in Psychology is something I first became aware of with the Psychology of Sex and Gender.

While most of us, most of the time, act and talk as if there are psychological differences between men and women the scientific evidence for those differences is at best contested, at worst none existent.

What tends to happen is that an area of possible, psychological, difference is opened up by a statistically significant difference being published. Over time a bunch of other people do similar (although not identical) work. After some more time a meta analysis is carried out on the findings, and the results of the meta analysis suggest that the original difference is small and inconsistent. This may lead us to believe that the genders are more (psychologically) similar than different.

However, while I strongly believe that psychological differences that we can detect using our current methods are small and inconsistent, that is not the same thing as saying the men and women are psychologically similar. We simply have not been testing for similarity, and lack of evidence for difference is not the same as evidence in favour of similarity.

Psychology studies are routinely under powered

In the paper Cohen, J. (1994). The earth is round (p < .05). American Psychologist, 49, 997-1003. Cohen argues that there are a number of problems with null hypothesis significance testing. One of the problems highlighted is that psychology studies are routinely under powered.

This suggested teaching exercise might help you grasp what this means, and may act as a useful teaching resource if you ever have to teach statistics.

One trouble with having a routine of under powered studies (studies with too few participants for a given effect size) is that we get studies published followed by a number of failures to replicate. After some time someone will do a meta analysis and suggest that the original finding is smaller and more inconsistent than originally thought. All this strikes me as a huge waste of resources.

We do not routinely try to replicate results

While the recent controversies around Bem may have put this into focus in psychology it is very difficult to get a straightforward replication published. Psychologists work around this by doing "conceptual replications" replicating the idea, but not the study. However, this is surely missing the point. When researchers do meta analyses of psychology studies they try to include unpublished studies (normally Ph.D. dissertations) that did attempt replication. Unfortunately we do not know about the missing studies because of the next problem.

We do not routinely register studies before they are run

We simply don't know how big the 'file drawer' of studies is, people occasionally try to make a guess but without routinely registering studies before they run we cannot know so fairly important information about whether an apparently interesting finding has been extensively tested.   

We do not know the relationship between our studies and the world outside of the laboratory

In order to carry out science like investigations of human psychology it is necessary to simplify phenomena so that we can test for some of the things that might affect human psychology, while concentrating on a sub-set of things that might affect human psychology. What psychologists mean when they talk about 'controlling unwanted variables'.

One of the questions is can we do that in a meaningful way. I suspect we can but all too often we do not try to. There is a famous talk given by the physicist Richard Feynman on Cargo Cult Science.

All too often we don't know what our laboratory studies, with humans, actually mean because we haven't done the basic work (Feynman also makes some points about replication, which means the problem of lack of replications stretches back at least to the mid twentieth century).

Most psychometric tests have not been tested for predictive validity

Which is ultimately the same problem as above, but for personality tests.

We routinely use poor sampling methods

Psychologists routinely use undergraduate students, self selecting samples, and samples drawn purely from clinical populations. That they/we then go on to make universal claims about human psychology from these samples is just bizarre.

Next episode being careful with 'brain scans'