GLOSARIO

The current experiment fills a gap among the existing literature on massed versus spaced learning within a pair-association paradigm by investigating the robust massing and spacing effect found in participants without brain damage and in people with aphasia. Overall, the patterns of learning generated by PWA were reduced but not to distinct from their age-matched controls and young participants. The difference among PWA and the two control groups lay in the performance on the delayed recognition task, which taps implicit memory. In this section, existing theories for spacing as well as massing hypotheses are discussed from the perspective(s) of what might account for the similarities and differences between PWA and the other two groups of participants.

Spacing over massing on long-term retention has been tackled by different accounts of memory and processing. The majority of these accounts argue that massed retrieval practice results in insufficient processing or encoding of a newly learnt item compared to spaced retrieval practice. Explanation(s) for the massing and spacing effect includes, first of all, which memory system is involved in retrieval. Having cued-retrieval practice

newly learnt information from short-term memory instead of (long-term) episodic memory. Information recalled from short-term memory does not always transfer into long-term retention (Craik, 1970; Craik & Watkins, 1973; Watkins, 1977); consequently, massed practice only benefits immediate retrieval but not the spaced one.

Secondly, deficit processing theory suggests that the amount of focus an information received changes based on learners’ familiarity of the particular information. Therefore, when information is repeated in massed fashion, learners allocate less attention or time for rehearsal due to the immediate increase of familiarity of the information. Derived from deficit processing theory, the attention-attenuation theory further claims that massed practice impairs recollection because of the difficulty paying full attention to the subsequent presentation of the same item (Kornell et al., 2010). That is, when the inter- stimuli interval is relatively short, processing of the second presentation is reduced in quality as well as quantity.

Thirdly, encoding variability theory (Martin, 1968, Melton, 1970) has been previously employed by Balota et al. (2006) to account for the effect of spacing. According to the theory, performance on memory tests depends on the interval between the time of study and the time of retrieval. The two factors correlate with one another; the shorter the interval between study and time of retrieval the greater success rate. However, when recall/retrieval occurs immediately after study or the previous opportunity of recall/retrieval, the time for the information to drift between study/first retrieval and subsequent retrieval is limited;

consequently, it results in relatively poor retention. The theory suggests that spacing out the study/retrieval opportunities creates higher probability of later recall because it allows the newly learnt information to fluctuate to a greater extent compared to massing. Therefore, the likelihood that information activated during study overlaps with information activated at the time of retrieval.

The above theories can account for the findings of the current

experiment that massed practice benefits immediate retrieval but not delayed recollection. All three groups of participants performed better with massed- practiced pairs than spaced-practiced pairs during the study phase. However, the current experiment only involved a relatively short spacing schedule (four

not much lower than massed pairs. It is plausible to claim that, at least, with the current spacing schedule, PWA learnt in the same fashion as the two control groups during pair-association learning of word-pairs as well as picture-pairs.

Spaced pairs, on the other hand, may facilitate cued-recall after a short (ten minutes) delay as well as a relatively long (two days) delay. The robust spacing effect previously reported in healthy participants (Carpenter & DeLosh, 2005; Karpicke & Roediger, 2007a) and other groups of people with cognitive deficits (Balota et al., 2006; Middleton & Schwartz, 2012; Sumowski et al., 2010) is observed in PWA and has been shown to facilitate learning within the pair- association paradigm involving word-pairs and picture-pairs. Despite the overall reduced performance, PWA employed the same memory process in pair-

association learning as the two control groups of participants; hence, they also benefit from spacing. Furthermore, the efficacy of spacing did not restrict to word-pair learning; the spacing effect was also evident in pair-association learning of picture-pairs. The finding contradicts the deficient semantic

processing hypothesis (Challis, 1993), which suggests that spacing improves performance on pair-association learning only when a pair is processed

semantically. That is, based on the level of processing (Craik & Tulving, 1975), the spacing effect on a pair depends on the level of processing it received during study; therefore, the effect should not be evident when learning of pairs containing complex semantic information for encoding or non-linguistic pairs, such as pictures. Nonetheless, in the current experiment, on average, all three groups of participants performed better on spaced-practiced picture-pairs

compared to not only massed-practiced picture-pairs but also massed-practiced word-pairs. Accordingly, the deficit processing hypothesis fails to account for the current findings, which suggests that the effect of the amount of semantic information the stimuli carries was independent from the effect of spacing schedule. Although the higher success rate in cued-recall of word-pairs than picture-pairs indicates that the amount of semantic information the stimuli carries did affect learning outcome(s) and retention, no sufficient evidence supports that it is a relevant factor to the spacing effect observed.

One of the tasks involved in the experiment was delayed recognition, which was designed to tap potential implicit learning occurring during the study phase. The participants in the two control groups benefited from spaced

practice in delayed recognition; yet, spacing did not facilitate recognition for PWA. This finding points out that although PWA generated similar outcomes of cued-recall tasks, the process of learning might not be exactly the same as the controls. Alternatively, it is possible that other cognitive functions rather than language influenced the outcomes of the delayed recognition task. Besides, across all three groups of participants, words and pictures had equal rates of accuracy in delayed recognition, suggesting that, again, spacing effect and the amount of information the stimuli carry did not co-occur as claimed by the deficit processing hypothesis. The difference in performance between PWA and the two control groups indicates that spacing did not boost implicit learning, at least in the current experiment, in PWA.