Memory-trace theories of remembering suggest that performance in delayed matching-to-sample (DMTS) procedures depends on a memory trace that degrades with time. By contrast, the theory of direct remembering suggests that increasing the delay between sample and comparison stimuli in DMTS procedures is functionally equivalent to decreasing the disparity between sample stimuli. The present dissertation tested this assumption by assessing the degree to which changes in the frequency of reinforcement for correct choices biased the distribution of choice responses in a conditional-discrimination procedure. Seven pigeons responded under a temporal-discrimination procedure in which temporal sample-stimuli were categorized as being of either short or long duration by a response to a corresponding comparison key. In the sample-stimulus disparity condition, the disparity between the sample stimuli (difference between the short and long samples) was manipulated. In the retention-interval condition, the delay between sample offset and presentation of the comparison stimuli was manipulated. Importantly, the same general procedure was used across conditions, facilitating conclusions regarding functional equivalence of the two manipulations. The theory of direct remembering suggests that the relation between sensitivity of behavior to changes in reinforcer frequency and discriminability (accuracy) should be similar in the sample-stimulus disparity and retention-interval condition. The results showed that discriminability decreased with both the sample-stimulus disparity and retention-interval manipulations. Overall estimates of sensitivity were similar to those obtained previously. There was, however, no difference in the estimates of sensitivity as a function of discriminability during either the sample-stimulus disparity or retention-interval conditions; sensitivity was independent of discriminability. These results are in contrast to most previous reports, and are interpreted in terms of the use of temporal-sample stimuli in the current experiment. Further analyses of the choice-response data showed that the effects of variation in reinforcer ratios differed across conditions as a function of trial type and trial difficulty. These results suggest the need for careful consideration of behavioral outcomes at several levels of analysis when assessing functional equivalence of experimental manipulations. The potential benefits and hindrances of characterization of behavioral outcomes in terms of functional equivalence are discussed.

Although much research has been done on how well working memory predicts processing of consciously activated information, research on the possible influences of working memory on automatically activated information is scarce (Barrett, Tugade, & Engle, 2004). Working memory capacity (WMC) may be related to how much information is activated automatically by either aiding ease of access to relevant information or by its role in inhibiting irrelevant thoughts and information (i.e., noise). The purpose of the present study was to examine the contribution of individual differences in WMC on implicit and explicit processes in cued recall. Participants studied target words and recall was cued by associatively related words. Target connectivity was varied in Experiment 1 and target set size was varied in Experiment 2. The cued recall memory test was conducted after various retention intervals (0, 10 and 20 mins). In addition, memory span of all participants was measured with both operation and counting span tasks. Finally, all participants studied a second list of words under divided attention instructions. The present experiments examined 1) the influence of retention interval on cued recall performance, 2) the influence of individual differences in WMC on cued recall after various retention intervals and 3) the role of WMC and divided attention on implicitly activated knowledge (i.e., connectivity and set size effects). The findings revealed that working memory is related to intentional (explicit) types of processes, but not related to implicit processes outside of a person's awareness. WMC also interacted with retention interval. This finding is compatible with an attentional interpretation of WMC that assumes the high span advantage is apparent only when there is interference. Surprisingly, low span participants tended to outperform high span individuals on an immediate test. These findings are explained by differences in maintenance of information and rehearsal, and retrieval strategies.

Many would agree that learning occurs when new information is stored in memory. Therefore, most learning efforts typically focus on encoding processes, such as additional study or other forms of repetition. However, as I will outline in this thesis, there are other means by which to improve memory, such as retrieval practice in the form of tests. Testing memory has a reinforcing effect on memory, and it improves retention more than an equal amount of repeated study – referred to as the testing effect – and it has been assumed that retrieval processes drive this effect. Recently, however, this assumption has been called into question because of findings that suggest that articulation, that is, the act of providing an explicit response on a memory test, may play a role in determining the magnitude of the testing effect. Therefore, in three studies, I have examined the effects of retrieval and articulation on later retention, in an attempt to ascertain whether the testing effect is entirely driven by retrieval, or if there are additive effects of articulation. I have also explored possible boundary conditions that may determine when, and if, the effects of retrieval and articulation become selective with respect to memory performance. In all three studies, participants studied paired associates and were tested in a cued recall paradigm after a short (~5 min) and a long (1 week) retention interval, and retrieval was either covert (i.e., responses were retrieved but not articulated) or overt (i.e., responses were retrieved and articulated).  In Study I, I demonstrated that uninstructed covert retrieval practice (by means of delayed judgments of learning) produced a testing effect (i.e., improved memory relative to a study-only condition) similar to that of explicit testing, which supports the idea that the testing effect is mainly the result of retrieval processes. In study II, I compared memory performance for covert and overt testing, and found partial support for a relative efficacy in favor of overt retrieval, compared to covert retrieval, although the effect size was small. In Study III, I further explored the distinction between different response formats (i.e., covert retrieval vs. various forms of overt testing), specifically handwriting and keyboard typing. I also examined the relative efficacy of covert versus overt retrieval as a function of list order (i.e., whether covert and overt retrieval is practiced in blocks or random order) and its manipulation within or between subjects. The results of Study III were inconclusive insofar as a relative efficacy of covert versus overt retrieval, with respect to later retention, could not be demonstrated reliably. The list order manipulations did not appear to affect covert and overt retrieval selectively. More importantly, in cases where a relative efficacy was found, the effect size was again small. Taken together, the three studies that of thesis indicate that the benefit of testing memory appears to be almost entirely the result of retrieval processes, and that articulation alone adds very little – if anything – to the magnitude of the testing effect, at least in cued-recall paradigms. These findings are discussed in terms of their theoretical implications, as well as their importance for the development of optimal teaching and learning practices in educational settings. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Accepted.</p>

False Memories (FM\'s) are memory errors that occur when people remember situations that did not happen, events not witnessed, or when the memory of the facts are distorted. The aim of this study was to evaluate the occurrence of false memories in a short-term task using the Deese-Roediger-McDermott (DRM) procedure. We planned out two experiments: the first experiment is an adaptation based on the Coane, McBride, Raulerson and Jordan (2007) experiments and it was performed by 12 participants. Sets of memorized words (CPM) composed of 3, 5 or 7 items and type of test (target, critical distractor and distractor not related) were manipulated within subjects. The main dependent variable was the reaction time (RT). The variable type of test was statistically significant, while the interaction between CPM and CPM x type of test were not statistically significant. The second experiment was performed by two groups of 12 participants. In the group 1 the retention interval was 750ms, while in the group 2 the retention interval was 1500ms. We also manipulated the CPM, the type of test and the emotionality / valence (positive, neutral and negative) of the words. The retention interval was not statistically significant, while the type of test and the CPM were statistically significant. The variable emotionality / valence (positive, neutral and negative) was not statistically significant. In general, the data replicate the Coane et al\'s work, except in the experiment 1, in which the CPM was not significant. The presence of FMs in the two experiments shows the generality and robustness of this phenomenon, widely found in the literature. The results were discussed in terms of the main theories about the phenomenon of false memories. / As Falsas Memórias (FM s) são erros de memória e ocorrem quando as pessoas lembram-se de situações que não aconteceram, eventos não presenciados, ou então, quando as lembranças dos fatos ocorridos são distorcidas. O objetivo geral deste trabalho foi testar a ocorrência de falsas memórias em uma tarefa de curto prazo utilizando o procedimento de Palavras Associadas (DRM). Foram realizados dois experimentos: o experimento 1 é uma adaptação baseada no experimento de Coane, McBride, Raulerson e Jordan (2007) e foi aplicado em 12 participantes. Foram manipulados os fatores conjuntos de palavras memorizadas (CPM) compostos por 3, 5 ou 7 itens e o tipo de prova (alvo, distrator crítico e distrator não relacionado). A variável dependente principal foi o tempo de reação (TR). A variável tipo de prova foi estatisticamente significativa, enquanto o CPM e a interação tipo de prova x CPM não foram estatisticamente significativos. O experimento 2 foi realizado por dois grupos iguais de 12 participantes, nas quais um grupo respondia ao experimento com intervalo de retenção de 750ms e o outro respondia com intervalo de retenção de 1500ms. Foram manipulados também o CPM, o tipo de prova e a emocionalidade/valência (positiva, neutra e negativa) das palavras. O intervalo de retenção não foi estatisticamente significativa, enquanto o tipo de prova e o CPM foram estatisticamente significativos. A variável emocionalidade/valência (positiva, neutra e negativa) não foi estatisticamente significativa. No geral os dados replicam o trabalho de Coane et al., exceto no experimento 1, no qual o CPM não foi significativo, mas a presença de FMs nos dois experimentos mostra a generalidade e a robustez desse fenômeno, amplamente encontrado na literatura. Os resultados foram discutidos em termos das principais teorias sobre o fenômeno das falsas memórias. / Mestre em Psicologia Aplicada

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