Tag Archives: Behavior

Dopamine: prediction-error vs. incentive salience

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The exact role that dopamine plays in learning remains controversial; some think it acts as a prediction error signal, while Berrdige et al believe that dopamine codes for incentive salience.

A recent paper throws some light on the issue. It uses a simple Pavlovian conditioning paradigm. To recap, US and CS are paired and after some time CS starts predicting the reward ; however the twist to usual Pavlovian conditioning is that when CS is presented before US; some rats become ‘sign trackers’ i.e. as soon as the CS comes start engaging with it; while other are ‘goal trackers’ i.e. as soon as CS comes start engaging with where the US would ultimately appear.

To elaborate, both types of rats are able to learn that CS predicts US , but only sign tracker s attach importance to CS in itself. Also if they are given an option to indulge in instrumental behavior to bring forth the CS (in absence of US) , it seems only the sign trackers are more willing to do work to get the CS and are thus motivated enough by Cs in itself. In other words, while both goal trackers and sign trackers endow CS with predictive capabilities; only sign trackers also endow it with incentive salience.

If all this seems confusing , consider the fact that we are all conditioned to like food/sex; but a secondary reinforcer like money which may predict that food will follow, might become a reward in itself and motivate some of us. while for some money may be as good as it is an indicator of food/sex to come; for other money may acquire an importance/ motivational value in itself.

After that crude analogy, lets return to our sign trackers; these rats are found in wild populations also, but a selectively bred rat breed that has been bred for Novelty preference (bHR) also displays these behaviors prominently. On the other hand those selectively bred not to show novelty preference are goal trackers by large. (bLR)

What the authors of this study showed was a dissociation between the necessity of dopamine for learning and performance in Pavlovian conditioning. they showed that while dopamine is not required for learning the prediction part (i.e. even in absence of dopamine both goal trackers and sign trackers could learn that CS predicts US) , it is indeed required for performance (i.e. in absence of dopamine neither goal trackers or sign trackers would perform the task whereby their learning of CS/US association resulted in overt behavior. ) . Further , it was found that for sign tracker dopamine was required for the sign tracking behavior.

To me, and to the authors too, the results seem to indicate that some individuals are more prone to associate incentive salience to CS and their primary mode of learning is via incentive salience mechanism of dopamine; these are also the one more susceptible to maladaptive behavior. However the learning that results in association of CS with US does not need dopamine; the association can happen without dopamine; but no behavior results if either CS/ US is not able to trigger dopamine release or able to tell the brain that this incentive/stimuli is salient.

To me this bodes victory for the Berridge et al camp of incentive salience theory of dopamine function, to whom I have always been more sympathetic ! do you agree?

Flagel, S., Clark, J., Robinson, T., Mayo, L., Czuj, A., Willuhn, I., Akers, C., Clinton, S., Phillips, P., & Akil, H. (2010). A selective role for dopamine in stimulus–reward learning Nature, 469 (7328), 53-57 DOI: 10.1038/nature09588

Dichotomies; or Psychology in a nutshell

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The field of psychology abounds with dichotomies– some of which are patently false/outdated, as per the grapevine. The familiar ones include Nature-nurture and mind-brain; in the former it is assumed that now everything is a mixture of both nature and nurture while in the latter both mind and brain have been conflated to be the same. However as separate disciplines of neurology and psychology attest , and the naive disorder classification system scientists themselves use, which squarely puts one disorder as psychological while other as more neurological attests, there is some merit in considering things at different level of explanation- at the brain or neuronal level of explanation and at the mind or self/ organism level of explanation,

In this article I argue that not only there is merit in these dichotomies, but that these dichotomies grasp fundamental aspects of being and all provide a glimpse of the proverbial elephant to the blind men that we are.

To begin with , the most fundamental dichotomy I consider is that of BRAIN-MIND or DETERMINISM-FREE WILL. To me the proponents of BRAIN fall on the DETERMINISM side of the table, while those of MIND fall into the FREE WILL camp. Let me elaborate. On the one side is reductive materialism that believes everything can be reduced to and explained in terms of neural firings and that all behavior is predetermined( from say the time of the Big Bang); on the other hand are people who tout the HARD problems and propose that qualia exists, subjectivity exists, agency exists, even if the basis for that be found only in quantum effects, or rather the basis for which will never be found in classical brain based accounts but will always be non-computable/ non -comprehensible but intuitively grasped by phenomenological experiences alone. To me there is merit in both arguments and my personal belief is that we are both determined and free, both brain and mind and that one is not the same as other but entails a different sort of world view. If I can go out on a limb, the first view of BRAIN is mechanistic/autistic in nature; while the second view that of MIND is mentalistic/psychotic in nature. But we are moving ahead of ourselves.

The first belief system, that based around BRAIN/ DETERMINISM, is not without its own challenges/dichotomies. Consider that the BRAIN is sculpted and so everything is pre-DETERMINED. Who sculpted the BRAIN? NATURE or NURTURE? Both GENES and ENVIRONMENT can be equally strongly deterministic and capable of shaping our brain and predisposing us to act in a particular way. No matter whether you believe in the all-empowering GENES or in the power of SITUATION to elicit behavior, or in the childhood influences that still govern adult REACTIONS, or believe in middle ground of developmental unfolding and epigenetic mechanisms, the predominant theme is that of doom and gloom and predestination. So NATURE-NURTURE is the dichotomy relevant here.

What about the FREE WILL/MIND camp? They too have to answer some tough questions as to what causes agency- is it REASON or PASSION? Does the freedom come from a lifetime of UNCONSCIOUS HABIT that gets engrained as character/PASSION or do we make a CONSCIOUS and REASONED DECISION every time we ACT ? Is it FREE because it is an inbuilt IMPULSE; or is it WILL because it can veto and CONTROL? The focus is squarely on ACTIONS- but Actions driven by PASSIONS or Actions driven by REASON? Note that in the NATURE-NURTURE theme the focus was on REACTIONS- what hidden force (genes/environment) causes us to react so and so; here the focus is on actions and what drives them ; here the focus is on the perennial battle between romanticism and enlightenment /rationalism. We grant that someone acts- but what is the basis of that action- is it PASSION or is it REASON? is it hidden, unconscious and spontaneous or is it deliberate, conscious and planned? the basic dichotomy here is between PASSION and REASON as the drivers of human action.

What about finer levels of dichotomies. Here again , on further analysis one can see that NATURE /GENES has a dichotomy in terms of Paternal genes or Maternal genes (working at cross-purposes at times as per genomic imprinting theory) ? NURTURE/ENVIRONMENT has a dichotomy in terms of SHARED (or PASSIVE) ENV. influences versus nons0hared or ACTIVE (niche constructing) ENV. influences. PASSION has tensions between SPONTANEITY/random/Life force/EROS versus HABIT/ingrained/Death instinct/THANTOS; while REASON has to balance between IRRATIONAL (mythos/chaotic) reasons versus RATIONAL (logos/orderly) reasons .

GENES are historical past facing; ENVIRONMENT is organism past + present facing; PASSION is Present + organism future facing; while REASON is totally future facing.

So where am I getting from here. It is to my ABCD model of psychology. Affect, Behavior , Desire/Motivation and Cognition.

To me, BRAIN-MIND/ DETERMINISM-FREE WILL debate is a manifestation of debates between primacy of Affect/behavior over motivation/cognition. Motivation /cognition are not directly observable/ measurable while in some sense affect and behavior are . Further, in BRAIN side there is tension between Affect (mostly inbuilt or genetic) and Behavior (mostly learned and a result of environmental influences) ; in a similar view, on the MIND side there is tension between Motivation (FREE/ PASSION) and Cognition (WILL/REASON).

Of course, there are finer levels of dichotomies embedded in ABCD as per the eight stage model where each of ABCD splits in two components based around- that of pleasure-pain, active-passive, self-other and broad-narrow. To me these dichotomies make perfect sense now.

To extend to one particular domain of personality psychology: you have deterministic personality theories emphasizing traits or behaviorism and you see a conflict/debate in personality theory in terms of Person (genes/traits) vs. situation(environment) variables. On the other hand are free-will theories of personality centered around Psychoanalytic theories and Phenomenological/existential theories where the fundamental conflicts is between conscious/ and unconscious; between past and future orientation, between passion/libido and reason/actualization.

To extend to another domain – that of psychopathology- Motivation defects in EROS and THANTOS lead to Mania and Depression respectively and remain in conflict with each other; Cognitive deficits in REASONs, that is, in MYTHOS based chaotic/dreamy/irrational reasoning versus LOGOS based orderly/reality-oriented and logical reasoning lead to the opposed and yet conflated phenotypes of Autism spectrum disorders and Psychotic spectrum disorders.

Personality and emotion: take 4

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I’ve written about the relation between personality and emotion from my perspective, but was gladdened when I found Scherer has written on the matter in a very eloquent and apt manner. To quote from him and Revelle:

Personality is the coherent patterning of affect, behavior, cognition, and desires (goals) over time and space. Just as a full blown emotion represents an integration of feeling, action, appraisal and wants at a particular time and location so does personality represent integration over time and space of these components (Ortony et al., 2005). A helpful analogy is to consider that personality is to emotion as climate is to weather. That is, what one expects is personality, what one observes at any particular moment is emotion.

It is important to note that personality/emotion definition has been expanded to include cognition as well as affect; behavior as well as motivation (desires). Traditionally emotions are seen as affective (feeling) in nature but we know that emotional states have different cognitive underpinnings and can affect cognition in subtle and not-so-subtle ways. Similarly though emotions may be more closely related to motivational issues (desires etc) they are also manifested in overt behavioral tendencies. some are energizing while others are calming/soothing.

In one of the last emotion/personality post , I referred to the dimensional emotional model of PAD (Pleasure-Arousal-dominance) as proposed by Meherbain. It is apt to note here that pleasure (pleasantness/unpleasantness) dimension is very much related to affect i.e. subjective feeling or how the emotion is subjectively felt. Also Arousal (Ready/Relaxed) is construct very much related to behavior or action tendencies. Some emotions lead to more vigorous, ready and active engagement with the environment as compared to others wherein one may be relaxed. Similarly Dominance (control/lack of control) is a motivational emotional dimension reflecting whether one wants to control and be in control or be dominated/ lose control in a particular situation.

That leaves us with cognition/appraisals dimension of emotions, but before we get onto that let us revisit the four evolutionary stages of Millon and how opposites on each stage lead to personality variations and disorders. The parallel with emotions will be self-evident.

The first stage is that of Existence and the polarity is of pain/pleasure: again an affective dimension/stage. Stability or life-preservation is coded by predominant disposition towards avoiding feelings of pain- a pain sensitive phenotype; Enhancing or life-enhancement is coded by predominant disposition towards felling pleasure a pleasure sensitive phenotype.

The second stage is that of Adaptation and the polarity is of active-passive: again a behaviorally defined dimension/stage. Modifying the environment to suit ones need is an active strategy, while passively accommodating to environmental niches is the passive strategy. both are defined behaviorally and the actual actions/behavioral tendencies define the personality type.

The third stage of Millon is that of Replication and the polarities are that of Self and Other: this is particularly a motivational dimension…whether one is motivated by selfishness and focus on oneself or by concern for others and selflessness too. There is polarity and tension between self-actualization tendencies and wants and other-nurturing motivational disposition. If focus is on self one would tend to dominate others, if focus is on others one would be willing to become vulnerable and submissive.

The fourth stage of Millon, that he does not relate to personality, but which I find integral to my theory is that of Abstraction and the polarity of information gathering versus information selection/transformation. I call the polarity Broad Versus Narrow and it is reflected in whether one is creative or is rigid and inflexible in thinking, , but the important point to note is that a cognitive dimension has been added to personality at the fourth stage.

Which brings us back to the (missing) cognitive dimension of emotions. I would have gladly taken the credit of discovering/proposing such a cognitive dimension, but it seems I was beaten to the game by Fontaine et al who made the bold statement :“The World of Emotions Is Not Two-Dimensional”.

As per Fonatine/ scherer et al’s analysis, using 144 features (like (a) appraisals of events, (b) psychophysiological changes, (c) motor expressions, (d) action tendencies, (e) subjective experiences, and (f) emotion regulation.) characterizing the 24 prototypical emotion terms, they found that emotions must be specified by at least four dimensions:these dimensions were evaluation-pleasantness, potency-control, activation-arousal, and unpredictability.

Note that the first three dimensions are similar to PAD while the fourth dimension is cognitive(appraisal) in nature- predictability vs unpredictability or certainty vs uncertainty in the appraisal of the situation. this ca be reasonably related to Broad Vs Narrow last stage of Abstraction i.e. whether one is cognitively open to new situations or appraisals or closed to them.

So the relationship between emotions and personality is more or less clear to my naive mind as of now. Of course I’m leaving some parts for the next post that will extend this and correlate with the eight stage process.

For now I’ll like to end with the excellent Scherer et al article quote:

In that personality represents the integration over time of feelings, actions, thoughts and desires, theoretical developments in personality benefit from a greater understanding of emotional processes. At the same time, research in emotion can take advantage of individual differences in sensitivities to situational cues and predispositions to emotional states. The questions of why some people become angry, while others become frightened or depressed in response to threats, and why some become elated while others seem unaffected when given rewards will be better understood by jointly studying the problem of long term coherence (personality) with short term fluctuations in affect, behavior, cognition and desire (emotion).

Fontaine, J., Scherer, K., Roesch, E., & Ellsworth, P. (2007). The World of Emotions is not Two-Dimensional Psychological Science, 18 (12), 1050-1057 DOI: 10.1111/j.1467-9280.2007.02024.x