Individual differences in working memory and reasoning-remembering relationships in solving class-inclusion problems

Verbal working memory capacity modulates semantic and phonological prediction in spoken comprehension

Mounting evidence suggests that people may use multiple cues to predict different levels of representation (e.g., semantic, syntactic, and phonological) during language comprehension. One question that has been less investigated is the relationship between general cognitive processing and the efficiency of prediction at various linguistic levels, such as semantic and phonological levels. To address this research gap, the present study investigated how working memory capacity (WMC) modulates different kinds of prediction behavior (i.e., semantic prediction and phonological prediction) in the visual world. Chinese speakers listened to the highly predictable sentences that contained a highly predictable target word, and viewed a visual display of objects. The visual display of objects contained a target object corresponding to the predictable word, a semantic or a phonological competitor that was semantically or phonologically related to the predictable word, and an unrelated object. We conducted a Chinese version of the reading span task to measure verbal WMC and grouped participants into high- and low-span groups. Participants showed semantic and phonological prediction with comparable size in both groups during language comprehension, with earlier semantic prediction in the high-span group, and a similar time course of phonological prediction in both groups. These results suggest that verbal working memory modulates predictive processing in language comprehension.

How working memory capacity modulates the time course of semantic integration at sentence and discourse level

During comprehension, language users not only immediately integrate information from local sentence context, but also information from global discourse context for full understanding. In the present study, we examined whether the time course of these integration processes is constrained by language users' working memory capacity. Sentence and discourse stimuli were constructed. For the sentence stimuli, each sentence contained a critical word that was either congruent or incongruent with its preceding sentence context. For the discourse stimuli, each discourse contained four sentences with a target word embedded at the final sentence and the target word was either congruent or incongruent with the information provided at the first sentence of the discourse. Participants of high and low working memory span were instructed to read for comprehension. Our results showed that while the high span readers showed the N400 and P600 effects to semantically incongruent words, the low span readers only showed the P600 effect. This pattern was found regardless of whether the incongruent words were placed at sentence or discourse context. These results suggest that the low span readers are relatively delayed than the high span ones at both sentence- and discourse-level semantic integration and indicate that working memory functions have greater influence than context scope on the time course of semantic integration.

Age, memory load, and individual differences in working memory as determinants of class-inclusion reasoning

We studied the effects of individual differences in speak-span scores and variations in memory demands on the class-inclusion performance of 10-, 13-, and 15-year-old children. The speak-span task was an age-appropriate modification of Daneman and Carpenter's (1980) reading-span task and was considered to be a measure of global resources. The age variable was assumed to be a global index of skill development, and some of the specific skills hypothesized to be important in class-inclusion reasoning were estimated using a mathematical model. The results from both regression analyses and the mathematical model indicated that differences in age, speak span, and memory load all affected performance. Surprisingly, the effects of speak span and memory load were independent. However, the effects of each of these variables depended on the age level of the participants. Based on these findings, we argued that (a) resources vary continuously with age, (b) both skill level and global resources should be varied in developmental studies of problem solving, and (c) resource theories (e.g., Norman & Shallice, 1986) should be modified to account for developmental change.