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Desire in a brief autobiography

Desire in a brief autobiography

Professor Frederick Toates
President of OUPS

I obtained my Doctor of Philosophy degree in experimental psychology from the University of Sussex in 1971, researching the biological bases of motivation. In those days, our ideas on motivation were based largely upon a combination of the principles of
(i) homeostasis ('regulation'), coming from biology, and (ii) drive, as advanced by the American behaviourist, Clark Hull (a contemporary and something of a rival of Skinner). Animals were said to be driven to regulate their internal environments, which fitted rather well the motivation to drink water. It fitted less well feeding motivation, and only with much theoretical contortion, sex.

The principle of homeostasis clearly applied to some limited degree to feeding motivation. When we are nutrient deprived, we feel hunger and seek food. After significant ingestion, feeding motivation switches off. However, it was evident that much feeding could not be explained in such terms: people overeat and become obese, where there is clearly no nutrient deficit. Other anomalies also existed but the tendency was to write them off as just that, pathological aberrations to the underlying principles of homeostasis and drive.
Towards the end of my doctorate, I carefully studied the theoretical work of the Indian Canadian psychologist, Dalbir Bindra. I felt that he made a quantum leap in our understanding and allowed a more comprehensive model to be developed. According to Bindra, motivation is triggered by external incentives and cues associated with them (I would add representations in memory). Like so much else, such as the theory of evolution or the earth spinning round the sun, it seems obvious in retrospect. Homeostasis is achieved, such as it is, by internal states modulating the power of external incentives to trigger motivation. So, obesity is not so much to be seen as an aberration, not as an error in a homeostatic system, but rather the natural consequence of the incentive process being overwhelmed in a world very different from that of our evolution. Sex, being non-regulatory, fits just as well as homeostatic systems. I developed Bindra's ideas and demonstrated their very wide explanatory power. Sadly, I never got to meet him, since he died soon after I appeared on the scene.

Then some 12 years later in around 1983, I am now at the OU and an utterly life-changing event happened to me during a conference at the University of Sussex. A young American Ph.D. student, at the University of Pennsylvania, Kent Berridge, came up to me and introduced himself. I bought this 'genius in the making' a drink in the bar and no other drink bought in my life has turned out to be quite such a good investment! Kent said that he had read my work and liked it. He wished to develop the ideas and put some neural flesh on what was otherwise psychological theory. In 1986, Cambridge University Press published my book 'Motivational Systems' and, a year later, I was awarded the degree of Doctor of Science for my contribution to motivation theory.

Fast forward to 1991 and I get a visit from Kent at the O.U. in Milton Keynes. Now an academic at the University of Michigan, he announced some revolutionary and heretical views on the role of the brain chemical messenger dopamine and wanted my opinion. We all knew that dopamine is the brain's pleasure chemical (in addition to its role in movement control, as compromised in Parkinson's disease). Rats depleted in dopamine in the brain regions involved in motivation stop working for food in a Skinner box, since the food was assumed to bring no more pleasure. There was even a pornographic film made with the title 'dopamine'.

Kent announced to me the shock finding that they found evidence that dopamine is not the pleasure chemical. So, how do you know, since we can all agree that dopamine-depleted rats stop working hard for food? The American researchers devised a very cunning piece of apparatus, in which small portions of liquid food are dropped onto rats' tongues and their reactions noted. These reactions are very sensitive to taste hedonics and it was found that rats without dopamine react exactly the same as control rats. So they like the food but don't want it, hence the appearance of the term 'wanting versus liking'. My reaction was one of incredulity "you will tell me next that there is no Father Christmas!" In the evening at our local pub near to the O.U. (The Plough at Simpson), I wined and dined with my American visitor and he added "You should believe this, since our theoretical interpretation is based firmly on your ideas". Kent added "dopamine mediates wanting, your incentive part, but not liking".

I was finally, convinced of the correctness of their assumptions when, the next year, Kent sent me a pre-publication copy of a paper written by him and his Michigan colleague, Terry Robinson on drug addiction. They invited my comments. Why, they asked rhetorically, if wanting equals liking, do some people want drugs even though their first experience with them was aversive? How is it that over a period of addiction, wanting drugs ('craving') can go up dramatically, whereas liking them can even come down? Cigarettes can be intensely wanted, even by people in hospital for operations necessitated by smoking (some even sneak illicit smokes). Yet few if any would describe the experience of nicotine as mind-blowingly hedonistic. From reviewing numerous studies, they concluded that dopamine confers what they called 'incentive salience' on things that we want: food, drugs, sex. Stimuli associated with these basic incentives, the smell of baked croissants, the sound of the casino, the hum of the lap-top, the red-lights of a part of town, acquire incentive salience in their own right, a pulling-power. So, liking is mediated by something else: opioids, amongst other brain chemicals. This paper was published in 1993, coining the term 'Bindra-Toates theory' and has become a classic, one of the most cited, if not the most cited, paper of all time in biological psychology.

In around 1994, I received a mysterious fax from a firm of lawyers in New York City, asking me to contact them for a meeting. What could this mean? A distant relative had become an oil billionaire and died leaving me everything? I contacted them and was told that partners were planning a trip to Europe and wanted to talk to me about addiction. The mystery only deepened. Why me? A drugs baron seeking mitigation? A friend told me that I should have played them at their own game and said that my consultancy fee starts at $1000 but academics are a push-over when it concerns money. Two of them arrived in Milton Keynes from Heathrow in a taxi, which waited for them! It soon became evident that they were representing the tobacco industry. But why me? They had read the paper by Robinson and Berridge, in which my model formed a foundation and realized the implications for their industry. There were soon to be Senate hearings on whether nicotine is addictive (which it is) and the last thing that they wanted was a new theory of addiction, which would include nicotine. They were very well informed and subjected me to a monologue on why nicotine is not addictive before departing for their next contact.
In 1997, I was invited to give a lecture and seminars to the students at the University of Michigan. Kent took me to the Tamla Motown museum in Detroit, where I saw Michael Jackson's famous white glove, something which doubtless holds much incentive salience for many fans. I met Aldo Badiani, then one of this research team and a speaker at our desire conference.

Then on to New York, Philadelphia and finally the University of California, Berkeley, and San Francisco, where my wife and I met my vocal/pop-group idols from the 1960s, The Lettermen, at one of their concerts. They took us out to dinner and one member of the group, Bob Engemann, asked us what we did in life. When he discovered what I did, I was asked whether I knew the work of his uncle, Norbert Wiener, the founder of the science of cybernetics. "Yes, indeed", I replied "This comes very near to my psychology. I read his book in New York City, when I was a young undergraduate staying at the YMCA". "Can you explain then what it was all about?" Bob asked "since I could never understand it". So, rather than hearing gossip about Hollywood scandal and groupies, which I might have preferred, it was a somewhat more serious meal. Back in England I had withdrawal symptoms from the visit, doubtless linked to opioid deficiency rebound.

The work of my Michigan colleagues has gone on from strength to strength. Not just drugs, feeding and sex but researchers into attention, autism (seen as a lack of social wanting), bipolar disorder, aggression, Parkinson's disease, schizophrenia and depression are making extensive use of their insights. At least some cases of depression appear to be based upon processes of deficient wanting (dopamine) and liking (opioids), which in principle are dissociable. Traditionally, a core characteristic of schizophrenia was described as 'anhedonia', an inability to experience pleasure. Theorists now see a low wanting as being a more reliable measure. So, for example, a schizophrenic patient might like something as much as a control but lack the wanting to seek it. Kent and Terry won the Award for Research Excellence in 2016, given by the American Psychological Society. Kent has done ground-breaking work identifying pleasure spots in the brain, together with Morten Kringelbach of Oxford University, one of the speakers at our conference.

So how about desire as such, the theme of our conference. We now see desire as being a special sort of wanting, that based upon a conscious goal. Under somewhat artificial conditions, it is possible to show the behaviour of wanting without the conscious goal. Unconscious (or non-conscious) processes can be in the driving-seat (some might like to see a link here with Freud). Whether conscious or not, dopamine appears to play a crucial role in our wanting.

For a short general-interest film that I made on the work of Kent and Terry, termed 'Dopamine: the two-faced molecule behind addiction and Parkinson's disease' you find this by putting 'Dopamine: the two-faced molecule' into a Google search.

This article first appeared in News & Views Spring 2017.


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