In recognition memory, participants often fail to change their criterion for making a “studied” response from one trial to the next based on learning strength, even when they are given obvious cues to identify each test item as studied often (“strong”) or studied a single time (“weak”) (e.g., Stretch & Wixted, 1998). In three experiments we tested the hypothesis that participants produce robust item-by-item shifts only when responding did not involve significant response interference (Simon, Acosta, Mewaldt, & Speidel, 1976). In our three experiments, participants studied lists of words studied once (weak) or five times (strong). In Experiment 1, both strong and weak words appeared at test under the questions “Was this studied at all?” or “Was this studied five times?” Participants were randomly assigned to conditions using two keys to respond “yes” or “no”, or using four keys with one set of “yes” and “no” per question. Four-key participants were expected to shift their criteria while 2-key participants could not due to response interference, though results showed that both conditions were capable of criterion-shifting. In Experiment 2 test items appeared on either the left or the right side of the screen; only strong words appeared on the right and only weak words on the left. Participants went through one study-test cycle with four response keys, and one with two. Regardless of the testing conditions, participants did not shift their criteria in the 2-key condition while participants in the 4-key condition did shift their criteria. Finally, Experiment 3 fully crossed 2 or 4 key conditions with blocked or unblocked presentation of test items. Previous experiments have found both number of response keys and blocking of presentations to have an effect on ability to criterion-shift (Hicks & Starns, 2014; Starns & Olchowski, submitted; Verde & Rotello, 2007). Experiment 3 confirmed that number of response keys has a significant effect on criterion-shifting and that it is separate from any effect of blocking. All three experiments suggest that response interference is not the driving force behind criterion-shifting. A new explanation is proposed.

A primary goal of education is the acquisition of durable knowledge which challenges the use of efficient pedagogical methods of how to best facilitate learning. Research in cognitive psychology has demonstrated that repeated testing during the learning phase improves performance on later retention tests compared to restudy of material. This empirical phenomenon is called the testing effect. The testing effect has shown to be robust across different kinds of material and when compared to different pedagogical methods. Despite the extensive number of published papers on the testing effect, the majority of the studies have been conducted in the laboratory. More specific, few studies have examined the testing effect in authentic settings when using course material during the progress of a course. Further, few studies have investigated the beneficial effects with test-enhanced learning by the use of neuroimaging methods (e.g. fMRI). The aim with the thesis was to investigate the effects of test-enhanced learning in an authentic educational context and how this is related to individual differences in working memory capacity (Study I and II) as well as changes in brain activity involved in successful repeated testing and long term retention (Study III). In study I, we examined whether repeated testing with feedback benefitted learning compared to rereading of introductory psychology key concepts in a sample of undergraduate students. The results revealed that repeated testing with feedback was superior compared to rereading both immediate after practice and at longer delays. The effect of repeated testing was beneficial for students irrespectively of WMC. In Study II, we investigated test-enhanced learning in relation to the encoding variability hypothesis for the learning of mathematics in a sample of fifth-grade children. Learning was examined in relation to both practiced and transfer tasks. No differences were found for the practiced tasks. Regarding the transfer tasks, the results gave support for the encoding variability hypothesis, but only at the immediate test. In contrast, when we followed up the durability of learning across time, the results showed that taking the same questions over and over again during the intervention resulted in better performance across time compared to variable encoding. Individual differences in WMC predicted performance on the transfer tasks, but only at the immediate test, regardless of group. Together, the results from Study I and Study II clearly indicate that testenhanced learning is effective in authentic settings, across age-groups and also produces transfer. Integrate current findings from cognitive science, in terms of test-enhanced learning, by the use of authentic materials and assessments relevant for educational goals can be rather easily done with vi computer based tasks. The observed influence of individual differences in WMC between the studies warrant further study of its specific contribution to be able to optimize the learning procedure. In Study III, we tested the complementary hypothesis regarding the mechanisms behind memory retrieval. Recurrent retrieval may be efficient because it induces representational consistency or, alternatively, because it induces representational variability - the altering or adding of underlying representations as a function of successful repeated retrieval. A cluster in right superior parietal cortex was identified as important for items successfully repeatedly retrieved Day 1, and also correctly remembered Day 7, compared to those successfully repeatedly retrieved Day 1 but forgotten Day 7. Representational similarity analysis in this region gave support for the theoretical explanations that emphasis semantic elaboration.