Friday, August 29, 2014

Blurred lines: A review of "Intuition Pumps" by Daniel Dennett

Just finished reading "Intuition Pumps" by Daniel Dennett. Although Dennett is perhaps best known as one of the so-called "New Atheists", along with Sam Harris and Richard Dawkins (the latter seems to be a chum of his), he has perhaps made the biggest contribution in the area of philosophy of mind. Besides being a philosopher of mind, Dennett takes a great interest in relevant disciplines such as biology and psychology. He is also a charming, avuncular storyteller, which probably does no harm to his relatively broad appeal, and he aims for a non-specialist audience with this latest offering.

Before grappling with some larger topics, the book opens with some general "thinking tools". I read through this section of the book in no time-it's a great little page-turning pamphlet in itself, even if a few of the ideas (or versions thereof) are probably already in many intelligent people's arsenals. A personal favourite is his point about the phrase surely, which he suggests is often used when someone kind of realises that their argument is just about obvious enough that they shouldn't have to justify/explain it too much (although maybe they should!)

His interest in biology is evident in his discussion of evolution, an engaging enough read (I say this as someone who knows very little about evolution). However, it is his discussion of consciousness (an area I've recently become interested in) that I was most interested in checking out. My first experience of Daniel Dennett was reading (a chunk of) his "Consciousness Explained". With the advent of fMRI allowing researchers to observe blood flow to specific regions of the brain in response to thinking tasks, one might be tempted to look into "pinning" consciousness on a particular part of the brain. Although fMRI has been used to assess whether people are conscious of certain things, in very interesting circumstances, in "Consciousness Explained" Dennett came out against the implication that there is some endpoint in the brain where consciousness occurs, suggesting instead that it is something which is sorta (a word he uses a lot in "Intuition Pumps") present at some level in one part of the brain before becoming more present at a "later" part. This approach to having conscious experience leaves a lot of people cold, as far as I can see, but I must say I'm biased towards Dennett's view on consciousness; when I hears thinkers talk about consciousness as an indivisible, all-or-nothing process it doesn't really appeal to me at an intuitive level-don't we all have experience of our level of awareness diminishing as sleep sets in?

Having been drawn in by the previous book, I was keen to take in the section in this book dealing with consciousness. Here Dennett takes on classic philosophical problems such as zombies (i.e. people who behave as if they are conscious, but are not) and Searle's infamous Chinese Room. Unfortunately, the book gets a little too quick to refer the reader on to other sources at times in this section, although the chapter "The Tuned Deck" may be one of the most entertaining parts of the book (I won't spoil it for you), if a little vague on detail. In some ways this book's section on artificial intelligence seems to say more about consciousness than the section entitled "Tools for thinking about consciousness". Here, Dennett dissects how bits of information, too simplistic by themselves to represent anything in the world, can be gradually combined with extremely simple operators to complete tasks such as addition and subtraction (he even sets a homework assignment to be done using a computer program which allows you to design these types of operations from the bottom up, which I'll admit I didn't do). Reading this section I got a gut feeling for how an incredibly simple process, such as a neuron firing or not, when combined with billions of other neurons in a vast interacting (and sometimes self-referential?...) networks could gradually build up to something complex enough to be capable of self-awareness. I would be curious what Dennett thinks/would say about recent developments in robotics, with robots being created that appear to have some degree of self-awareness.

Turning towards the topic of free will, Dennett takes a compatabilist viewpoint (i.e. that free will and determinism are compatible). Similar to his sorta approach to consciousness, he argues that the idea that determinism rules out free will is based on an idea of free will which is too absolutist. Again, I found this intuitively appealing-I feel that I have a greater amount of free will about things I think of doing tomorrow compared to what I do a few seconds from now. However, I still found this part of the book a little difficult to swallow-I may need to read it a second time, but he seems to put the burden of proof on those who think determinism rules out free will without being 100% clear as to why a sorta free will would allow for determinism-does determinism then become sorta determinism?

Dennett closes with some words on being a philosopher. He suggests that pursuing a more long-term problem in philosophy may be a more fruitful approach in the long run than grappling with a "hot" topic-he quips that these are the quickest to burn out. Probably true in psychology, although this is advice which is easier to give than follow when one is a junior thinker chasing funding/job opportunities...

Sunday, August 10, 2014

The perks of a pack of gum

Besides drinking caffeine-rich beverages, I've heard anecdotally that some long-distance drivers will chew gum behind the wheel to avoid paying an untimely visit to the land of snooze. A recent research article has looked at the potential alerting effect of gum in the lab, looking not only at feelings of alertness and associated attention performance, but also at brain activity and heart rate changes which can give a broader picture of what's happening.

We had participants complete a task where they watched a stream of 3-digit numbers-generally each number differed from the previous one, but every so often there would be a repetition (a bit like a quality control job on a production line). A vigilance task (i.e. sustained attention to rare target stimuli) such as this tends to be associated with a vigilance decrement (i.e. you perform more poorly at the task as time goes on). A previous paper indicated that chewing gum could improve performance on this type of task, but only after a certain amount of time performing it-that is, as eyes were starting to droop. In this study we looked at chewing gum on the same vigilance task, but this time we also measured electroencephalography (EEG) as well as heart rate, to see what physiological changes might accompany such effects. The vigilance decrement was probably enhanced by the fact that having the EEG equipment set up can take a longish while of sitting still (as anyone who has taken part in this study will attest to).

When participants chewed gum during the first stage of the vigilance task, they showed less of a post-baseline decrement on the vigilance test compared to those who did not chew gum (interestingly enough, this difference was still evident when further vigilance tasks were completed post-chewing). 

The EEG indicated that beta activity (which is associated with an alert state) was heightened at frontal and temporal areas following chewing gum; this effect was strongest straight after chewing, although it seemed to persist post-chewing. Furthermore, chewing gum was also associated with heightened heart rate, although this effect on heart rate seemed to dissipate quite quickly once chewing ended. It may be the case that central nervous system activity is a more likely explanation of ongoing effects of chewing than sympathetic nervous system activity (i.e. heart rate).

The study adds to a growing amount of evidence suggesting that chewing gum can enhance not only subjective alertness but also sustained attention. There has been some evidence that this can occur even in the absence of a vigilance decrement; I would speculate that this may have happened in the linked study as they used a task which I believe requires much more frequent responses to stimuli-this may reduce the extent of the decrement somewhat, compared to the vigilance task we used. (Consider running quality control on a production line where you have to spot the occasional mistake -vigilance- versus an assembly task whereby you have to continuously perform an operation on each passing piece of equipment -continuous performance. I think it's easier to tune out when you only have to do something every so often than when the default mode is responding to stimuli). 

Have I tested this on myself? I can recall attending one lecture where what I'll generously call a vigilance decrement (there was nodding involved) started to set in. This affliction was relieved to some extent by chewing some gum for a few minutes-thereby just about preventing an embarrassing collision of my head and the seat in front of me. Just don't go on an three-night, no-sleep road trip and blame me if anything goes wrong!

Allen, A.P., Jacob, T.J.C., Smith, A.P. (2014). Effects and after-effects of chewing gum on attention, heart rate, EEG and mood. Physiology & Behavior, 133, 244-251. 

Monday, August 4, 2014

Rant: On established validity and good questions

When using psychological tests, it is important to ascertain if they have good validity (i.e. test the concepts they claim to test). Obviously, if a test has already undergone evaluation to show that it has good validity (e.g. it correlates well with other measures assessing the same concept) then this can be a great time saver for you. However, I've recently been struck by a few measures which, while having previously undergone testing to examine validity, seem a priori to either be muddled or downright contradictory. (No doubt more seasoned psychologists than me can think of other examples).

A while back I completed an online survey whereby one was asked to place oneself in an imaginary scenario (stage 1). One is asked to imagine oneself committing a crime (let's say robbing a bank). In this story one is requested to imagine that one feels a sense of excitement and enjoyment in committing this crime. After having read (and presumably daydreamed about) this scenario, there are a series of follow-up questions (stage 2). One of these questions asks you to indicate how much one would enjoy robbing the bank (with the option of saying "not at all"). But you have already been told to imagine that you do enjoy it at stage 1. The question can't really be probing how much the respondent would actually enjoy such an scenario, as the survey as a whole is telling the person that they would enjoy it in this imaginary world. On mentioning this to a researcher using these questions he pointed out that he had previously noticed this shortcoming and was working on re-validating the questions-it annoyed me that he was left doing this as the original designers had not taken more care to ensure that the questions made sense in light of the scenarios that went with them.

A second example is perhaps less irritating, as the question that annoyed me was not necessarily contradictory but rather a bit muddled. However, the response to my griping from the author who used it was telling. An example question they mentioned was a triple-barrel question, let's say along the lines of "In order to enhance economic growth, our nation should cut corporation tax, reduce workers' rights and abolish the minimum wage". When I pointed out that this was a triple-barrel question which didn't allow for people having differing views on the impact of minimum wage versus the impact of corporation tax on economic growth, the person using the scale pointed out that as the validity and reliability of the questionnaire had been assessed in that format, they were sticking with it.

Why rush into spending the time and effort of collecting a large set of data to ensure the validity of a measure when it only takes an intelligent person in a room to see whether or not the questions actually make sense and are clear-cut?