Mapping Effects in the Lexical-Decision Task

The data files contain raw data from a publication entitled “Mapping effects in choice-response and go/nogo variants of the lexical-decision task: A case for polarity correspondence”, authored by Peter Wühr and Herbert Heuer, and published in the Quarterly Journal of Experimental Psychology in 2021. In this study, we investigated how different types of Stimulus-Response (S-R) mappings affect performance in the lexical-decision task (LDT). In the LDT, participants have to decide as quickly as possible whether a letter-string stimulus is a word or a nonword. In a choice-response variant of the LDT, participants press one key (e.g., a left key) to words, and another key (e.g., a right key) to nonwords. In a go-nogo variant of the LDT, participants press a key (e.g., a left key) to words, and refrain from responding to nonwords. Previous studies had shown that performance in the LDT is superior with a particular variant of the go-nogo LDT (i.e., when participants respond to words, and refrain from responding to nonwords) over choice-response variants of the LDT. In our experiment, we tested whether the superiority is confined to this particular S-R mapping of the LDT, or occurs with all possible S-R mappings of the LDT. In the experiment participants performed both a choice-response variant of the LDT (with one mapping) and go-nogo variants of the LDT (with two different mappings, to obtain RT measurements for both responses used in the choice-response task). Results showed a strong mapping effect in the go-nogo variant of the LDT: performance was much better with responses to words and nonresponses to nonwords, than with responses to nonwords and nonresponses to words. A smaller mapping effect was also observed in the choice-response variant of the LDT: responses to words were faster and more accurate than responses to nonwords. We attributed the mapping effects in both tasks to an effect of polarity correspondence versus noncorrespondence. According to this account, words and active responses have both positive polarities, whereas nonwords and nonresponses have both negative polarities, in each dichotomous set of stimuli/responses. Hence, polarity correspondence facilitates performance when participants respond to words, and refrain from responding to nonword, whereas polarity noncorrespondence impairs performance when participants respond to nonwords, and refrain from responding to words. Additional evidence for polarity correspondence was obtained in a second task, in which participants rated the valence of each stimulus (words, and nonwords) on a nine-point rating scale. Results from this valence-rating task showed higher (average) valence ratings for words than for nonwords, consistent with the notion of positive polarity of words and negative polarity of nonwords.