Fig. 1: Experimental Procedure for experiments 1 and 2.
a Example of a block with 8 first and 8 second sentences. In each block 8 pairs of sentences were presented. In the first half of each block all eight first sentences were presented, all ending in a different new-word (see above for one congruent and incongruent example sentence pair each). After the presentation of all 8 first sentences, the second sentences for those same new-words were shown in a randomized order relative to the first sentences. b Exemplary overall block structure of the experiment for one participant who started with feedback (blocks 1–5) and switched to no feedback in the second half (block 6–10). Across participants feedback order was counter-balanced, i.e., feedback was present in the first or second half of the blocks (feedback first or no feedback first). All participants received feedback in form of a smiley or frownie and scrambled smileys/frownies (no feedback). c An exemplary congruent trial in the learning session adapted from Ripollés et al.10. In each paired learning trial, two sentences ending in the same new-word were presented. For congruent trials, the two sentences evoke the same congruent meaning (“graveyard”) and thus DA-dependent word learning can occur (i.e., jedin means “graveyard”). Incongruent trials follow the same structure with the difference that the two sentences do not evoke the same meaning (i.e., participants can only learn that this new-word had an two incongruent meanings, DA-independent). After the presentation of the new word, subject’s response and feedback, subjective ratings of pleasantness and arousal were obtained. d An example of a recognition test trial on day 2. All new-words (both congruent and incongruent) from the learning session were presented in a randomized order with two possible meanings to choose from. In addition, participants could indicate that the meaning for that new-word had been incongruent, or that they didn’t know. After indicating their answer, participants again rated their pleasantness and arousal, as well as confidence.
