Figure 1.

Experimental design of encoding and retrieval tasks. (a) During encoding, word pairs were presented one by one, and participants were instructed to encode the left word using two encoding strategies of either perceptual or semantic judgments. These encoding strategies were indicated by a cue presented before and during the experimental blocks to indicate whether participants should perform the perceptual or semantic judgments. The cue of “Font” corresponded to an encoding strategy with the perceptual judgments of word pairs, and the cue of “Meaning” referred to an encoding strategy with the semantic judgments. Responses of these judgments were recorded by pressing one of two buttons. In the perceptual judgments, participants were required to press the left button if the font of the target word was the same as that of the cue word and to press the right button if the fonts of two words were different. In the semantic judgments, participants pressed the left button if the target word was semantically close to the cue word and the right button if the target word was semantically distant from the cue word. (b) During retrieval, participants were randomly presented with either a target (old) word that was presented on the left side during encoding or a distracter (new) word, and they were required to judge whether each word was previously learned or not by selecting one of four response options (definitely old: DO, probably old: PO, probably new: PN, and definitely new: DN). In the retrieval phase, participants were required to recognize words in either the High or Low reward condition, which was instructed by a cue before the presentation of the words. All verbal labels were presented in Japanese. English is used here for illustration purposes only.