Eva Bertha Kemps

Working memory components of the Corsi blocks task

A computerized version of the Corsi blocks task (Milner, 1971) was assessed for standard forward-recall order (Experiments 1 and 3) and for reversed-recall order (Experiments 2 and 3) either in a single-task or in a dual-task design combined with articulatory suppression, matrix-tapping, random-interval generation or fixed-interval generation as concurrent tasks during the encoding stage. Concurrent performance of the matrix-tapping task impaired memory performance for short as well as for longer block sequences. The random-interval generation task, which loads executive processes, impaired memory performance mainly at intermediate- and longer-sequence lengths, while fixed-interval generation, which is presumed to put no load on executive processing, did not show any effect. Articulatory suppression did not impair memory performance on forward-recall order, but it impaired memory for longer sequences in the backward-recall condition in Experiment 2, but not in Experiment 3. The results are discussed within the context of the working-memory model of Baddeley and Hitch (1974).

The phenomenology of food cravings : The role of mental imagery

The study aimed to investigate the role of mental imagery in the experience of food cravings. A sample of 130 undergraduate students was first asked to recall and rate a previous food craving experience. Second, they were asked to imagine themselves eating their favourite food and to rate the involvement of different sensory modalities. It was found that mental imagery was a key element in both the retrospective craving experience and the current food induction. In particular, craving intensity was related to the vividness of the food image (r = .46). The specific sensory modalities most involved were visual (39.7%) and gustatory (30.6%), followed by olfactory (15.8%). There was little involvement of auditory or tactile modalities. It was concluded that cognitive experimental techniques aimed at reducing the vividness of visual, gustatory or olfactory imagery, might usefully be deployed to reduce unwanted food cravings.

The nature of imagery processes underlying food cravings.

OBJECTIVE The study used a working memory approach to examine the nature of the imagery processes underlying food cravings. DESIGN AND METHOD A sample of 60 dieters and 60 non-dieters were asked to imagine either a food induction or a holiday induction scenario. Participants then performed 18 trials of either a visual imagery task (loading the visuo-spatial sketch pad) or auditory imagery task (loading the phonological loop). Food craving was measured before and after the induction scenario, and then after every 6 trials of the imagery task. RESULTS Craving intensity increased following instructions to imagine the food (but not holiday) induction scenario, especially for dieters. As predicted, the visual imagery task was superior to the auditory imagery task in reducing the level of food craving. DISCUSSION The results confirmed the imaginal basis of food cravings. Specifically, they demonstrated that the imagery processes involved in food cravings are predominantly visual in nature. Hence concurrent tasks that load the visuospatial sketch pad of working memory can be used to reduce food cravings. The findings have potential application in the treatment of craving episodes in clinical populations.

Factors That Promote and Prevent Exercise Engagement in Older Adults

Objective: This study aimed to (a) identify factors that motivate or prevent older Australians from exercising; (b) determine how these factors differ as a function of age, gender, and exercise level; and (c) examine how they relate to intentions to exercise in the future. Method: In all, 217 older adults (aged 63 to 86) completed a questionnaire in their own home. Participants rated various motivators and barriers to exercise and indicated future intention to exercise. Results: Health concerns were the strongest motivators to exercise, whereas physical ailments were the most common barrier to exercise. Older Australians were fairly motivated to exercise and experienced few barriers to exercise. Age, gender, and exercise level differentiated between reported motivators and barriers, which in turn were associated with future intentions to exercise. Discussion: Reasons that promote and prevent exercise engagement are quite varied and depend on personal factors. Exercise intervention programs for older adults should incorporate these factors.

Control of interference during working memory updating.

The current study examined the nature of the processes underlying working memory updating. In 4 experiments using the n-back paradigm, the authors demonstrate that continuous updating of items in working memory prevents strong binding of those items to their contexts in working memory, and hence leads to an increased susceptibility to proactive interference. Results of Experiments 1 and 2 show that this interference reflects a competition between a process that reveals the degree of familiarity of an item and a context-sensitive recollection process that depends on the strength of bindings in working memory. Experiment 3 further clarifies the origins of interference during updating by demonstrating that even items that are semantically related to the updated working memory contents but that have not been maintained in working memory before cause proactive interference. Finally, the results of Experiment 4 indicate that the occurrence of interference leads to top-down behavioral adjustments that prioritize recollection over familiarity assessment. The implications of these findings for the construct validity of the n-back task, for the control processes involved in working memory updating, and for the concept of executive control more generally are discussed.

Components of attentional bias for food cues among restrained eaters

The study aimed to investigate attentional bias for food cues among restrained eaters. In particular, the roles of speeded detection (enhanced orientation of attention toward food stimuli) and slowed disengagement (trouble disengaging attention from food stimuli) were examined. Participants were 78 female undergraduate students aged 18-25 years, classified as restrained (N=38) or unrestrained eaters (N=40). Attentional bias was assessed by a visual search task which required participants to locate the position of an odd-one-out target word in a matrix of 19 distractor words. Restrained eaters were disproportionately faster than unrestrained eaters to detect a food word within a neutral matrix compared to a neutral word within a neutral distractor matrix. Restrained eaters were also disproportionately faster, rather than slower, than unrestrained eaters to detect a neutral word within a food matrix compared to a neutral word within a neutral distractor matrix. Thus restrained eaters show a heightened vigilance for food cues, but no slower disengagement from such cues.

Response selection involves executive control: Evidence from the selective interference paradigm

In the present study, we investigated whether response selection involves executive control, using the selective interference paradigm within Baddeley’s (1986) working memory framework. The interference from response selection was estimated by comparing the patterns of dual-task interference of simple and choice RT tasks with those of a number of established working memory tasks. In Experiment 1, we compared impairment of forward and backward verbal serial recall from the RT tasks and articulatory suppression. Experiment 2 measured the adverse effects of the RT tasks and matrix tapping on forward and backward visuospatial serial recall. Finally, in Experiment 3, we examined the impairment from the RT tasks with two measures of executive control—namely, letter and category fluency. Altogether, the three experiments demonstrated that response selection interferes with executive control and that the interference is not produced at the level of working memory’s slave systems, which supports the assumption of executive involvement in response selection.

Attentional bias for craving-related (chocolate) food cues.

In this study, we investigated attentional biases for craving-related food cues. A pictorial dot probe task was used to assess selective attentional processing of one particular highly desired food, namely chocolate, relative to that of other highly desired foods. In Experiment 1, we examined biased processing of chocolate cues in habitual (trait) chocolate cravers, whereas in Experiment 2 we investigated the effect of experimentally induced (state) chocolate cravings on such processing. As predicted, habitual chocolate cravers (Experiment 1) and individuals in whom a craving for chocolate was temporarily induced (Experiment 2) showed speeded detection of probes replacing chocolate-related pictures, demonstrating an attentional bias for chocolate cues. Subsequent examination indicated that in both experiments the observed attentional biases stemmed from difficulty in disengaging attention from chocolate cues rather than from a shift of attention toward such cues. The findings have important theoretical and practical implications.

Food cravings consume limited cognitive resources.

Using Tiffanys (1990) cognitive model of drug use and craving as a theoretical basis, the present experiments investigated whether cravings for food expend limited cognitive resources. Cognitive performance was assessed by simple reaction time (Experiment 1) and an established measure of working memory capacity, the operation span task (Experiment 2). In each experiment, female undergraduate students were randomly assigned to a craving or control condition. Participants in the craving condition abstained from eating chocolate for 24 hours prior to testing and performed the cognitive task in the presence of chocolate, a manipulation that successfully elicited chocolate cravings. In both experiments, there was no main effect of craving condition on cognition, but there was a significant interaction between condition and trait chocolate craving. In support of Tiffanys model, our results show that habitual food cravers direct limited cognitive resources to craving-related cues, at the cost of competing cognitive demands.

Working memory performance and preoccupying thoughts in female dieters : Evidence for a selective central executive impairment

OBJECTIVE The study aimed to extend previous research into the impaired cognitive performance of spontaneous dieters by employing the Double Span Memory Task to investigate the relationship between weight-loss dieting and performance simultaneously on the three subsystems of working memory. METHOD A sample of 33 dieting and 33 non-dieting women were presented with increasingly longer sequences of common objects, displayed successively in different, randomly chosen locations of a 4 x 4 grid. Participants were then asked to name the objects (phonological loop), point to the locations (visuospatial sketch pad), or both (central executive). Participants also completed self-report measures of preoccupying cognitions, dietary restraint, depressed affect, and verbal intelligence. RESULTS Current dieters performed more poorly than non-dieters on combined recall, but not on the single recall of objects or locations. They also scored more highly on self-rated preoccupying cognitions. CONCLUSION Dieting to lose weight selectively impairs central executive functioning, rather than the storage capacity of the two slave systems. This dieting-related central executive deficit is at best partly attributable to the preoccupying thoughts about food, weight, and body shape accompanying dieting.