The Mystery of the Decline Effect

Text and picture depicting propositions and scienticfi method

(c) 2009 Dave Gray (

There is a very, very strange phenomenon in scientific literature called the decline effect. For some inexplicable reason, many positive scientific effects seem to decline over time as more and more research into the effect is conducted. A theory that seems to be initially supported by overwhelmingly positive evidence can eventually wind up seeming significantly less supported; in some kind of weird way, it may seem like facts are becoming less factual over time.

For example, initial parapsychological research seemed to indicate evidence for psychic ability (ESP in particular), but this effect declined with subsequent studies. A subject of Joseph Banks Rhine who’d initially be able to guess cards vastly over chance in repeated tests gradually became worse at doing so. In fact, over the years this subject became able to guess cards barely above chance.

Jonathan Schooler, who posited the theory of verbal overshadowing, i.e. describing something impairs the ability to remember it more so than just observing something, noticed a similar decline in his results. Since the initial publication of verbal overshadowing theory in 1990, he’s found it increasingly harder to demonstrate positive results. He called it “cosmic habituation”, and joked that the cosmos was interfering in his studies.

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Why do so many people care so little about stealing music?

Cartoon image of a pirate iPod

There’s been a bit of a furore recently over a blog post by Emily White, an intern at NPR All Songs Considered and GM of her college radio station, in which she acknowledges that while she has 11,000 songs in her music library, the vast majority have been obtained through borrowing from friends, mix CDs, ripping music from her college radio station, and – yes – even some from file sharing sites. She’s only ever paid for about 15 CDs in her life.

This isn’t particularly surprising; in the internet age, it is astonishingly easy to access music for free, and a huge number of people do – 95% of music downloads in 2008 were illegal. What has surprised many people is her unashamed tone:

“I honestly don’t think my peers and I will ever pay for albums. I do think we will pay for convenience… What I want is one massive Spotify-like catalog of music that will sync to my phone and various home entertainment devices… All I require is the ability to listen to what I want, when I want and how I want it. Is that too much to ask?”

There have been prominent articles condemning and defending this attitude. I don’t wish to get embroiled in a debate about the morality of her post. What I find interesting are the parallels we can draw with other moral behaviour and what this may say about human moral cognition.

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Mental illness or cognitive style?

I’ve had an interest in clinical psychology for some time, having studied abnormal psychology during A-level and having been diagnosed with depression and social anxiety disorder many years ago. I’m particularly interested in the definition of mental illness and how it is perceived by both the profession and the public. I guess my interest is primarily philosophical: does mental illness really exist? How is it to be differentiated from “normal” suffering? Can it legitimately be compared to other kinds of (much better understood) illness, such as influenza and cholera?

Mental illness ≠ “regular” illness

Long ago I came to the conclusion that mental illness could not exist in the way that influenza or cholera can. Firstly, both these illnesses can be demonstrated to have a specific cause (viral, bacterial) and their mechanisms of action are fully understood. Patients may display different symptoms, but a group of similar symptoms exist for every person who has the illness. Mental illness cannot be traced back to a specific identifiable source, their underlying neural mechanisms are not understood and symptoms may vary wildly between individuals with the same mental illness. Rarely does a patient display symptoms that make them a perfect fit for a diagnostic category.  Major depression, for example, is rarely displayed as just major depression – often various anxieties, phobias, or other disorders such as obsessive-compulsive disorder and post-traumatic stress disorder are also diagnosed.

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On the cognitive origins of religion

(Note: this is a “brief” summary of my MA dissertation. It’s still rather long, but hopefully of interest to those studying the cognitive science of religion)


In this piece I attempt to develop an account of the cognitive origins of religion; firstly, by arguing that the emergence of modern human consciousness during the “creative explosion” of 30,000 – 60,000 years ago caused the fusing of several human cognitive adaptations, an event which led to a sense of personal identity and a susceptibility to certain kinds of cultural ideas, and secondly, by invoking the concept of “memes” to explain why, following the initial emergence of religious ideas (brought on by “sparks” of creativity, i.e. novel multi-modular idea development), certain kinds of ideas become more successful at “exploiting” the susceptibility of the human mind, and hence remained numerous in the meme-pool. My theory is an attempt at a “third-way” – a theory based on the insights of spandrelist arguments, but one which invokes ideas which are generally seen as incompatible with spandrelist arguments (i.e. memes). I argue that such a synthesis is possible, and that the assumption of incompatibility stems from misunderstanding of certain terms.

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