ratwhowouldbeking Reddit top level comment:

Impelled in part by some of the dismissive comments I have seen on /r/science, I thought I would take the opportunity of the new Science Discussion format to wade into the question of whether psychology should be considered a ‘real’ science, but also more broadly about where psychology fits in and what it can tell us about science. 

By way of introduction, I come from the Skinnerian tradition of studying the behaviour of animals based on consequences of behaviour (e.g., reinforcement). This tradition has a storied history of pushing for psychology to be a science. When I apply for funding, I do so through the Natural Sciences and Engineering Research Council of Canada – not through health or social sciences agencies. On the other hand, I also take the principles of behaviourism to study 'unobservable' cognitive phenomena in animals, including time perception and metacognition.

So… is psychology a science? Science is broadly defined as the study of the natural world based on facts learned through experiments or controlled observation. It depends on empirical evidence (observed data, not beliefs), control (that cause and effect can only be determined by minimizing extraneous variables), objective definitions (specific and quantifiable terms) and predictability (that data should be reproduced in similar situations in the future). Does psychological research fit these parameters?

There have been strong questions as to whether psychology can produce objective definitions, reproducible conclusions, and whether the predominant statistical tests used in psychology properly test their claims. Of course, these are questions facing many modern scientific fields (think of evolution or string theory). So rather than asking whether psychology should be considered a science, it’s probably more constructive to ask what psychology still has to learn from the ‘hard’ sciences, and vice versa.

A few related sub-questions that are worth considering as part of this:

1. Is psychology a unitary discipline? The first thing that many freshman undergraduates (hopefully) learn is that there is much more to psychology than Freud. These can range from heavily ‘applied’ disciplines such as clinical, community, or industrial/organizational psychology, to basic science areas like personality psychology or cognitive neuroscience. The ostensible link between all of these is that psychology is the study of behaviour, even though in many cases the behaviour ends up being used to infer unseeable mechanisms proposed to underlie behaviour. Different areas of psychology will gravitate toward different methods (from direct measures of overt behaviours to indirect measures of covert behaviours like Likert scales or EEG) and scientific philosophies. The field is also littered with former philosophers, computer scientists, biologists, sociologists, etc. Different scholars, even in the same area, will often have very different approaches to answering psychological questions.

2. Does psychology provide information of value to other sciences? The functional question, really. Does psychology provide something of value? One of my big pet peeves as a student of animal behaviour is to look at papers in neuroscience, ecology, or medicine that have wonderful biological methods but shabby behavioural measures. You can’t infer anything about the brain, an organism’s function in its environment, or a drug’s effects if you are correlating it with behaviour and using an incorrect behavioural task. These are the sorts of scientific questions where researchers should be collaborating with psychologists. Psychological theories like reinforcement learning can directly inform fields like computing science (machine learning), and form whole subdomains like biopsychology and psychophysics. Likewise, social sciences have produced results that are important for directing money and effort for social programs.

3. Is ‘common sense’ science of value? Psychology in the media faces an issue that is less common in chemistry or physics; the public can generate their own assumptions and anecdotes about expected answers to many psychology questions. There are well-understood issues with believing something ‘obvious’ on face value, however. First, common sense can generate multiple answers to a question, and post-hoc reasoning simply makes the discovered answer the obvious one (referred to as hindsight bias). Second, ‘common sense’ does not necessarily mean ‘correct’, and it is always worth answering a question even if only to verify the common sense reasoning.

4. Can human scientists ever be objective about the human experience? This is a very difficult problem because of how subjective our general experience within the world can be. Being human influences the questions we ask, the way we collect data, and the way we interpret results. It’s likewise a problem in my field, where it is difficult to balance anthropocentrism (believing that humans have special significance as a species) and anthropomorphism (attributing human qualities to animals). A rat is neither a tiny human nor a ‘sub-human’, which makes it very difficult for a human to objectively answer a question like Does a rat have episodic memory, and how would we know if it did?

5. Does a field have to be 'scientific' to be valid? Some psychologists have pushed back against the century-old movement to make psychology more rigorously scientific by trying to return the field to its philosophical, humanistic roots. Examples include using qualitative, introspective processes to look at how individuals experience the world. After all, astrology is arguably more scientific than history, but few would claim it is more true. Is it necessary for psychology to be considered a science for it to produce important conclusions about behaviour?

Finally, in a lighthearted attempt to demonstrate the difficulty in ‘ranking’ the ‘hardness’ or ‘usefulness’ of scientific disciplines, I turn you to two relevant XKCDs: http://xkcd.com/1520/ https://xkcd.com/435/

1000 Reddit comments:

http://reddit.com/r/science/comments/36a0o5/what_is_psychologys_place_in_modern_science/

Soft sciences are such soft targets. Hard sciences make fun of each other too.  One of the best classes I had in college was experimental social psychology.  I learned how to eliminate confounds, set up verifiable experiments with social participants, how to rule out all sorts of experimental biases, etc.  It was very useful. 

An engineer, a physicist, and a mathematician are shown a pasture
with a herd of sheep, and told to put them inside the smallest
possible amount of fence. The engineer is first.  He herds the sheep
into a circle and then puts the fence around them, declaring, "A
circle will use the least fence for a given area, so this is the
best solution." The physicist is next. She creates a circular fence of
infinite radius around the sheep, and then draws the fence tight around
the herd, declaring, "This will give the smallest circular fence around
the herd." The mathematician is last. After giving the problem a little
thought, he puts a small fence around himself and then declares, "I
define myself to be on the outside!"

Ha, those mathematicians are always looking for a theoretical out. :)

Psychology seems to follow the same Scientific Method as other sciences: propose theories, conduct experiments, make observations, and keep expanding the collective knowledge.

And psychology is useful.

So it's interesting that even Reddit itself is conflicted with whether Psychology findings belong in the science subreddit.