Key Research Questions
- Does congruence between the valence of a decision cue and the to-be-learned value facilitate the acquisition of newly acquired expected values?
- Does value congruence affect learning (of expected value) per se, or "just" the choice of a particular decision cue?
- What are commonalities and specialities of value congruence in different decision domains (perceptual properties, emotional arousal, political convictions)?
The rewards and satisfactions that we encounter every day will endow the cues that predict these rewards with a positive expected values. Likewise the displeasure of punishments that we received from different experiences will lead to negative expected values for the cues predicting these punishments. But these predictive cues are usually not completely neutral. They carry an inherent value that is either innate or las been learned previously, possibly a long time ago in early childhood. Nevertheless, these inherent values can interact with the expected values that are learned from repeated associations with positive or negative outcomes. The phenomenon is quite general and the supposed effect is often employed in advertisement, when an attractive model is presented with a product, or political campaigns ads, when opponent is deliberately shown with negative imagery. The expectation is that the inherent value of the model will make the product more attractive, or that the negative imagery will devalue the political opponent.
This projects investigates one possibility of this interaction between inherent and acquired expected values. Value congruence refers to situation when both the inherent and the acquire value are both positive (an inherently positive cue predicts are reward) or negative (an inherently negative cue predict a punishment). Value incongruence describes the situation in which the inherent value of a cue and the acquired value through learning disagree. We investigate this interaction in great detail and ask whether the inherent value affects the affects the learning of new expected value or the choice of either option. We employ computational modeling, behavioral testing and fMRI, to uncover the behavioral and neural basis of the interaction of inherent and acquired expected values.
Influence of Inherent Values on Associative Learning
In an initial study we used high and low facial attractiveness as a proxy for inherent value and associated each face either with a high or a low probability of winning a small amount of money. When we analyzed the data we found an clear effect of value congruence: very attractive faces that predicted a high probability of winning were selected most frequently, whereas unattractive faces that predicted a high probability of losing were selected least frequently. Furthermore, reaction times to value congruent choices (either high/high or low/low) steadily decreased over time indicating that these cues processed with decreasing effort. For value incongruent trials, reaction times remained the same. Computational modeling revealed that value congruence affected the speed of learning (learning rate) with which the new expected values were learned: learning rates for congruent trials were initially higher (indicating faster initial learning), whereas learning rates for incongruent trials were very small indicating that the new expected values were learned as a slower speed. This suggests that value incongruence lead to more effortful and slow learning of new values that contradict the inherent values of the cue. The fMRI data revealed a hitherto novel neural correlated for a dynamically changing learning rate in the dorsal striatum in close proximity of other striatal regions that encoded important decision-related computations (e.g. prediction errors, reward and punishments). Furthermore, a connectivity analysis demonstrated that these different regions interact in much the same way that out reinforcement learning model updated the expected values.
Value Congruence and Contingency Reversals
In two follow-up studies we are investigating if and how value congruence effects change in face of a reversal con reward contingencies. After new expected values have been learned through cue-outcome associations, we changed the reward probabilities, such that a cue that was previously predicting a high probability of winning is now predicting a high probability of losing. We are interested in whether the value congruence effects on learning rates are reset after such a reversal, whether they are reinstantiated, but at a lower level, or whether learning keep constantly declining. Preliminary findings indicate that learning rates are reset after a reversal, but the magnitude of the initial learning rates after reversal remain complex. Furthermore, in these studies we also switched to cues of emotionally positive and negative valence and to cues of congruent and incongruent political statements. We are therefore also testing the generality of the previously observed value congruence effect with different inherent values.