Working Memory Influence The Practice Schedule Effect In Category Learning

There are two typical practice schedules: blocked presentation and interleaved presentation.Blocked presentation refers to consecutively presenting stimuli from a single category,whereas interleaved presentation refers to mixing or interleaving stimuli from multiple categories within a block or study session.Most of the previous studies found that when learning new categories,interleaving stimuli across different categories during study enhances classification performance on novel stimuli in comparison with blocking stimuli during study.Why does interleaving stimuli across categories enhance learning? Comparing these two practice schedules,we can find that they differ mainly in two aspects:(1)the category that successively presented stimuli belong to;(2)temporal spacing between stimuli of one category.Researchers asserted the discriminative-contrast hypothesis,the attention attenuation hypothesis and the study-phase retrieval hypothesis based on these two points.The discriminative-contrast hypothesis states that interleaved presentation highlights the differences between categories,facilitating discriminative contrast between categories with high similarity(Kornell & Bjork,2008).According to the attention attenuation hypothesis,when stimuli from the same category are presented consecutively within a block,learners would pay less attention to the stimuli presented latter;however,if mix stimuli from multiple categories within a block,learners would keep attention to the latter stimuli as prior(Kornell et al.,2010).Finally,the study-phase retrieval hypothesis proposes that compared to blocking learning,interleaving learning promotes more effective retrieval practice from long-term memory(LTM)(Dunlosky et al.,2013).These three hypotheses interpret the interleaving effect from attention and retrieval from the LTM.And the working memory(WM)is also composed of the controlled attention and the controlled retrieval from LTM.Does WM affect the practice schedule effects? If it does,how can it make it? This is the issue of concern to this study.The reason why researchers compare learners' performances under different practice schedule conditions is to find the most effective learning way to improve learners' performance.Theoretically,WM affects the practice schedule effects.But especially how does WM work,there are few studies on this issue,and previous studies of WM capacity(WMC)and the interleaving effect have had mixed results.Thus,it is necessary to explore it.In this study,I tested whether WM resources were necessary for the interleaving effect in category learning.In Experiment 1,I examined category learning in the Kornell and Bjork(2008)artistic style task while participants performed the numerical Stroop task as a dual task in order to interfere with WM maintenance and WM dependent executive functions.In addition,I evaluated whether individual differences in WMC,assessed via complex span tasks,would affect learning and interact with the interleaving and dual task manipulations.The results revealed a superiority for interleaved presentation in both single-task and dual-task conditions,as well as superior performance for participants with relatively high WMC.Importantly,there was no interaction between the presence of the dual task and interleaving,or WMC and interleaving,indicating that the benefits of interleaving are independent of WM.Considering that I examined only the artistic style task,which is similar to information integration(II)tasks and which doesn't rely on WM,I used rule-based(RB)organic chemical molecular structure formulas as the experimental materials to repeat Experiment 1.The results showed that for liberal participants,interleaving learning was more effective;however,for science participants,blocking learning was more effective,indicating that subject type affects the practice schedule effects.At the same time,the results also revealed that the practice schedule effects were regulated by WMC——compared with those with higher WMC,participants with lower WMC were more susceptible to the practice schedule.Given that the results of Experiment 2 revealed that the subject type influence the practice schedule effects,in order to exclude the effect of prior knowledge,and in order to compare the effect of WM on the interleaving effect in different category learning structures,I repeat the Experiment 1 and Experiment 2 using the family resemblance(FR)materials.At the same time,in order to prove the discriminative-contrast hypothesis and the attention attenuation hypothesis,participants were asked to make typical judgments.In addition,their eye movement data were recorded by eye-tracking.The results revealed that:(1)when doing observed category learning(Experiment 3a),compared to studying in the blocked condition,participants' performance to the novel stimuli will be better if they study in the interleaved condition.Moreover,in the case of less WM resources(in the dual task condition,or participants with lower WMC),the interleaving effect was more obvious.At the same time,the results showed that participants paid more attention to the non-diagnostic features in the blocked condition,while they paid more attention to the diagnostic features in the interleaved condition.These results were consistent with the discriminative-contrast hypothesis.In addition,the attention decreased with the increase of the position in the blocked condition while the attention did not change too much with the position in the interleaved condition.These findings provided evidence for the attention attenuation hypothesis.And compared with the higher WM condition,when WM is lower,the differences of attention bias and attention retention under the two practice schedules are more obvious.(2)when doing feedback category learning(Experiment 3b),participants did not realize the existence of the practice schedule under the feedback learning condition,thus the advantages of the practice schedules could not be exerted.In the case of lower WM load,participants tended to classify the similarities within the same category,and they were beneficial from blocking;while the WM load was higher,participants tended to identify the difference between categories,and interleaving learning enhanced their performance.The following conclusions can be drawn through above experiments:Fist,whether in the II category learning,RB category learning or family resemblance category learning,when learning new categories,interleaving stimuli across different categories during study enhances classification performance on novel stimuli in comparison with blocking stimuli during study.Second,WM did not affect the practice schedule effects in the II category learning;however,WM affected the practice schedule effects in the RB category learning and family resemblance category learning.Specifically,in the case of lower WM resources,participants were more susceptible to the practice schedule,thus the practice schedule effects were more obvious.Third,learners pay more attention to non-diagnostic features under the blocked condition and they pay more attention to diagnostic features under the interleaved condition.Besides,the attention decreased with the increase of the position in the blocked condition while the attention did not change too much with the position in the interleaved condition.And the above trends do not change due to WM.Results support the discriminative-contrast hypothesis and the attention attenuation hypothesis respectively.And compared with the higher WM condition,when WM is lower,the differences of attention bias and attention retention under the two practice schedules are more obvious.