Gilbert Mohr

Interference in memory for tonal pitch: Implications for a working-memory model

The degree of interference caused by different kinds of stimuli on memory for tonal pitch was studied. Musically trained and untrained subjects heard a sequence of two tones separated by an interval of 5 sec. The tones were either identical in pitch or differed by a semitone. Subjects had to decide whether the tones were identical or not. The interval was filled with tonal, verbal, or visual material under attended and unattended conditions. The results revealed clear group differences. Musically trained subjects’ retention of the first test tone was only affected by the interposition of other tones. In contrast, the performance of musically untrained subjects was also affected by verbal and visual items. The findings are discussed in the framework of Baddeley’s (1986) working-memory model.

Memory of self-performed tasks: Self-performing during recognition

Two experiments focused on whether performing actions described by to-be-remembered phrases during recognition enhances recognition compared with results of a standard verbal recognition test. The enhancement was predicted when the actions described by the phrases had been performed during study, but not when the phrases were verbally encoded by simply listening to and memorizing the material. Both experiments showed that enactment prior to recognition improved memory performance, but only when subjects had encoded by enactment. Experiment 1 also demonstrated that this test-procedure effect was independent of a bizarreness effect, which was observed only with the verbal encoding task. Experiment 2 showed that the effect of enactment during recognition was reduced when subjects used different hands for performing the actions during study and recognition- The findings support the assumption that some kind of motor memory record underlies the enactment effect that occurs when actions are performed during recognition.

Recall and recognition of self-performed acts

SummaryIn Experiment 1, recall and recognition of 80 action phrases were compared under two encoding conditions: verbal and motor (performing the denoted acts). Memory performance was better under motor encoding than under verbal encoding, and more so in recognition than in recall. We assume that this finding is due to the item-specific effect of a specific motor component in the memory trace after enacting. In Experiments 2 and 3 we further investigated whether false-alarm rates are dependent on the motoric similarity of distractor items. The rate of false alarms was lower under motor encoding than under verbal encoding, but the motoric similarity of distractor items to list items did not influence the false alarms. The results were interpreted as support for the assumption that motor encoding enhances item-specific information in relation to verbal encoding, but that during verbal recognition the motoric quality of the depicted movement is not processed.

Memory of imagined actions : imagining oneself or another person

SummaryIn two experiments, three modes of action encoding were compared: overt enactment, self-imagination, and imagination of another person performing the actions. Overt enactment and imagining self-performance of an action are mainly assumed to involve motor-kinesthetic representations, whereas imagining another person is thought to place more demands on the visual representational system. Previous paired-associate learning data on memory of action verbs showed that motor-kinesthetic imagery hinders pair integration, but that pair integration is facilitated by visual imagery. The comparison of free and cued recall of actions learned from lists of concrete nouns supports the assumption that the representational properties of overt enactment and self-imagination differ from those involved in the imagining of another person.

Pair-relational encoding of performed nouns and verbs

SummarySubjects had to learn lists of noun pairs and verb pairs. They were informed in advance about the test types and were tested for free recall (FR) and cued recall (CR). Three classes of encoding instructions were used: standard learning instructions, item-specific enactment instructions (to perform the denoted action of the verb or a typical action for the noun, and to do the same plus finding separate goals for the two elements of each pair), and enactment instructions that were completed by explicit instructions to integrate the word pairs (find a common goal, and find a common goal plus rating your success). There was no effect of encoding instructions on FR of nouns. There was a better FR under all enactment instructions than under standard instructions for verbs. CR decreased after item-specific enactment instructions, in contrast with standard learning instructions, but more for nouns than for verbs. CR increased after the instructions to integrate the pairs, in contrast with item-specific enactment instructions, but more for nouns than for verbs. It was concluded that enactment provides excellent item-specific information that can hardly be enhanced further, and that the item-specific information provided by concrete nouns is fundamentally good and is difficult to enhance by enactment. It is further assumed that enactment not only provides excellent item-specific information, but also hinders pair integration. Therefore, CR decreases after enactment. This decrease can only be overcome when subjects actively try to integrate the word pairs.

Remediation of developmental dyslexia: Tackling a basic memory deficit

Remediation studies of developmental dyslexia are extremely rare. We present a single case study of an 8-year-old German developmental dyslexic boy K.H. who is hypothesized to suffer from a severe memory problem, impeding the development of normal reading functions. The memory problem especially affects the storage and access to letter–sound associations. As a consequence, the boy was initially unable to accurately and quickly name most of the 26 letters of the alphabet. A multiple-baseline across-material design with a high-frequency errorless learning procedure was set up to improve letter–name associations. The intervention improved K.H.s letter reading and even his word reading. We discuss the role of memory deficits in reading acquisition in the context of three different theoretical models. We show how such theoretical considerations can successfully guide remediation programmes.

Memory for size relations and selective interference

Abstract Memory for ordinal size information was studied in two experiments using a selective interference paradigm. Subjects were to learn five-term series either with verbal stimuli or with pictorial stimuli which were presented pairwise in ascending size order. They were tested with a comparative judgement task. Study and test modality were always congruent. The series were learned and tested in a control condition (without interference), concurrently with articulatory suppression, and concurrently with hand movement (tapping). In addition, task difficulty was varied. There was a clear increase in error rates under articulatory suppression with pictures as well as with words as stimuli. However, tapping increased the error rates only with pictures as stimuli, not with words. These findings were independent of task difficulty. The results are discussed in the context of working memory theory.

Leistungsbegrenzungen im verbalen Arbeitsgedächtnis: Argumente gegen energetische Ressourcenkonzepte

SummaryLimitations in Verbal Working Memory: Arguments Against Energetic Resource Concepts Summary. Limitations of cognitive performance are explained either by a limited energetic resource that is available to the human processing system or by characteristics of the mental architecture and the processes that are effective in a specific task. We argue in favor of the processing-oriented approach, and we illustrate the problems of energetic concepts by contrasting two models of working memory. We argue (1) that the energetic resource conception does not really explain the limitations because it is often formulated in a circular manner and does not specify what the to-be-allocated resource is, (2) that it hinders the development of functional models that decompose processing because the energetic explanation is considered to be sufficient, (3) that, when looked at closely, the energetic approach is seen to require processing assumptions to be formulated, and (4) that often cognitive activation is equated with physiological activation, which is not acceptable without additional evidence. We think that an energetic approach only explains performance limitations if the resource in question is a physical one; in all other cases, it is at best useful, for example, insofar as it allows us to predict behavior, but it does not explain the limitations.ZusammenfassungBegrenzungen kognitiver Leistungen werden entweder durch die Annahme erklärt, daß dem Verarbeitungssystem eine begrenzte Energiemenge zur Verfügung steht oder daß die beteiligten Architekturkomponenten and Prozesse Eigenschaften haben, die begrenzend wirken. Wir argumentieren für die prozeßorientierten Ansätze and wir illustrieren die Probleme der energetischen Zugangsweise anhand zweier Modelle des Arbeitsgedächtnisses. Gegen die energetischen Modelle des Arbeitsgedächtnisses bringen wir vor: (1) daß sie oft keinen Erkldrungswert haben, weil sie zirkulär sind and offen lassen, worum es sich bei den sich erschöpfenden Ressourcen handelt; (2) daß sie die funktionelle Dekomposition kognitiver Anforderungen behindern, weil bereits die energetische Begründung als hinreichend erscheint and deshalb Hypothesen zur Architektur and der auf dieser Architektur ablaufenden Prozesse gar nicht erst gebildet werden; (3) da13 energetische Konzeptionen streng genommen eine funktionale and prozeßorientierte Betrachtung voraussetzen and (4) daß kognitive Aktivierung oft unbegründet and deshalb voreilig mit physiologischer Aktivierung gleichgesetzt wird. Wir halten energetische Ansätze nur dann für eine Erklarung für Verarbeitungsbeschrankungen ‚wenn kognitive‘ Energie physikalisch oder physiologisch operationalisierbar ist. Ist dies nicht der Fall, sind sie allenfalls nützlich, z. B. wenn es darum geht, Verhalten vorherzusagen. Verarbeitungsbeschränkungen können auf diese Weise nicht erklärt werden.

Storing and accessing ordinal size relations in episodic memory: Effects of stimulus modality

Abstract Episodic memory for ordinal size relations was investigated addressing the question whether the speed of access to such information is influenced by the stimulus modality employed during acquisition and test. Pictorial material was contrasted with verbal material. Congruent and incongruent study and test conditions were realized. Subjects had to encode six-term series with size as the relevant dimension. They were tested by a comparative judgement task after a five-second retention interval. Experiment 1 and 2 showed a distinct picture superiority effect with the presentation of pictorial test stimuli. Study modality did not affect the response times. In addition, the test modality effect and the ordinal distance effect proved to be additive. A third experiment was set up to demonstrate the test modality effect with a forced choice recognition task. Although the recognition task did not involve a dimensional comparison, a distinct test modality effect emerged, indicating that access to dimensional information is not the decisive variable for the pattern of results obtained in the first two experiments. The implications of the results for theories hypothesizing specific memory codes are discussed.

On the independence of modality effects and end-term and distance effects in episodic comparative judgement: Dissociations of errors and reaction times

The experiments reported in this paper explore the effect of modality variations on end-term and distance effects in an episodic comparative judgement task. In each experiment, subjects were to store serial orders of objects on a size dimension. Memory was tested after a brief retention interval by a comparative judgement task, in which subjects were presented with two elements of an order and had to point to the formerly larger one. Regarding the response times, we hypothesized that modality variations affect speed of stimulus identification and code access processes. We further hypothesized that distance variations and end-term variations affect processing components that are independent of the component affected by the modality variation. Finally, we assumed that end-term and distance effects interact in a predictable way, because they mirror competing response selection strategies. The latency data clearly support these hypotheses. As regards the accuracy data, we argued that modality and end-term effects, if they show up within the accuracy data, very likely have a different basis than the effects within the latency data. Again, the data support this assumption showing clear dissociations of accuracy and latency data. With respect to the stimulus modality variation, the whole data pattern shows that explanations which rely on modality-specific codings are not justifiable.