The generation and maintenance of visual mental images: evidence from image type and aging

Imagery is a multi-componential process involving different mental operations. This paper addresses whether separate processes underlie the generation, maintenance and transformation of mental images or whether these cognitive processes rely on the same mental functions. We also examine the influence of age on these mental operations for independence of components. In Experiment 1, younger (22 years) and older (69 years) adults generated and maintained general, specific, contextual and autobiographical visual mental images evoked in response to concrete nouns. The older adults had longer generation times, but there was no difference between the two groups on maintenance. Both groups had shortest generation and maintenance times for general images, whereas only the older adults took longest in generating autobiographical images. In Experiment 2, the total maintenance time and number of transformations for each type of image were compared in another group of younger and older adults. General images were less transformed and more subject to decay for both groups. The older people maintained the autobiographical mental images for longest compared to other image types. In conclusion, image generation, maintenance and transformation seem to be differently affected by type of image and aging, supporting a model of their cognitive segregation.     

Reading comprehension in aging: the role of working memory and metacomprehension

This study examines age-related differences in reading comprehension analyzing the role of working memory and metacomprehension components in a sample of young (18-30 years), young-old (65-74 years), and old-old (75-85 years) participants. Text comprehension abilities were measured by a standardized test, including two texts: a narrative and an expository text. The elderly's reading comprehension performance, when compared to the norm, emerged to be adequate. More specifically, the young-old showed an equivalent level of comprehension as the young adults for the narrative text. However, a clear age-related decline was found in the case of the expository text. Hierarchical regression analyses showed that working memory capacity, as well as different metacomprehension components but not age, are the key aspects in explaining the different patterns of changes in the comprehension of narrative and expository texts.     

Cognitive and neuronal processes involved in sequential generation of general and specific mental images

Mental image generation is a complex process mediated by dynamically interrelated components, e.g. image generation and image enrichment of details. This study investigated the cognitive and neural correlates of sequential image generation. An event-related fMRI experiment was carried out in which general and specific images had to be generated sequentially in two different positions. Participants had to generate either a general image first and then a specific one or a specific image first and then a general one, in response to the same word-stimulus. Generation times showed that specific images took shorter to be produced if they had been preceded by the generation of a general image. The fMRI results showed that position of generation and type of image was associated with different patterns of neurofunctional change. When an image was generated as first, areas of activation were found in the parahippocampal, fusiform and occipital regions. These are areas associated with memory retrieval and visual processing. When an image was generated as second, significant activations were found in superior temporal and precuneus areas, brain structures that are involved in the storage of visual memory for object shapes and imagery, respectively. The generation of a general image was supported by frontal areas and by the precuneus. The generation of a specific image involved frontal and thalamic areas (structures associated with visual processing of details) and the posterior cingulate cortex. When shifting from a specific image to a general one, a higher level of activity was found in the middle frontal gyrus involved in global visuo-spatial processing, suggesting that the generation of specific images required the retrieval of an object’s global shape. Altogether, these data suggest that the sequential generation of different types of image is associated with discrete processes but also shares common cognitive and neural components.     

Increases in Intrusion Errors and Working Memory Deficit of Poor Comprehenders

This study tests the hypothesis that the ability to inhibit already processed and actually irrelevant information could influence performance in the listening span test (Daneman & Carpenter, 1980) and have a crucial role in reading comprehension. In two experiments, the listening span test and a new working memory test were given to two groups of young adults, poor and good comprehenders, matched for logical reasoning ability. In Experiment 1, the poor comprehenders had a significantly lower performance in the listening span test associated to a higher number of intrusions-that is, recalled words that, in spite of being in sentence form, were not placed in the last position. In Experiment 2, a new working memory test was devised in order to analyse more effectively the occurrence of intrusions. Subjects were required to listen to a growing series of strings of animal and non-animal words. Whilst listening, they had to detect when an animal word occurred, and at the end of each series they had to recall the last word of each string. The poor comprehenders obtained a significantly lower performance in the memory task and made a higher number of intrusions, particularly of animal words.     

Learning a map of environment: The role of visuo‐spatial abilities in young and older adults

The present study examines age‐related differences between young and older adults in spatial mental representation derived from learning a realistic city map. A sample of 30 young (20–30‐years) and 30 older (60–72 years) adults learned a simplified map of a city; afterwards participants performed map‐drawing and pointing‐aligned and counter‐aligned tasks. Tasks measuring visuo‐spatial abilities were also administered to explore their relationship with map learning. Results showed an age‐related impairment in older adults in both map tasks, as well as in visuo‐spatial ones. Furthermore, performance on counter‐aligned pointing was poorer than on aligned pointing in young and older adults, and its relationship with visuo‐spatial abilities changed as a function of age group: The performance of counter‐aligned pointing in older adults was related to all visuo‐spatial abilities, and in young adults with perspective‐taking measures only. Copyright © 2011 John Wiley & Sons, Ltd.     

The relative importance of two different mathematical abilities to mathematical achievement

Background. Two distinct abilities, mathematical reasoning and arithmetic skill, might make separate and specific contributions to mathematical achievement. However, there is little evidence to inform theory and educational practice on this matter. Aims. The aims of this study were (1) to assess whether mathematical reasoning and arithmetic make independent contributions to the longitudinal prediction of mathematical achievement over 5 years and (2) to test the specificity of this prediction. Sample. Data from Avon Longitudinal Study of Parents and Children (ALSPAC) were available on 2,579 participants for analyses of KS2 achievement and on 1,680 for the analyses of KS3 achievement. Method. Hierarchical regression analyses were used to assess the independence and specificity of the contribution of mathematical reasoning and arithmetic skill to the prediction of achievement in KS2 and KS3 mathematics, science, and English. Age, intelligence, and working memory (WM) were controls in these analyses. Results. Mathematical reasoning and arithmetic did make independent contributions to the prediction of mathematical achievement; mathematical reasoning was by far the stronger predictor of the two. These predictions were specific in so far as these measures were more strongly related to mathematics than to science or English. Intelligence and WM were non‐specific predictors; intelligence contributed more to the prediction of science than of maths, and WM predicted maths and English equally well. Conclusions. There is clear justification for making a distinction between mathematical reasoning and arithmetic skills. The implication is that schools must plan explicitly to improve mathematical reasoning as well as arithmetic skills.     

Decline in working memory updating through ageing: Intrusion error analyses

The present research examines the decline in working memory updating through age. Two experiments compared groups of participants in different age ranges (young‐old, 55–65 years, old, 66–75 years and old‐old, more than 75 years and, in Experiment 2 only, young, 20–30 years). Memory updating tasks were administered, which required participants to remember the smallest items in each list. To perform the task correctly, participants had to update information efficiently, reducing interference from items no longer relevant. Intrusion errors were computed and in the first experiment these were described as “intrusions of irrelevant items” (immediate exclusion) and “intrusions of once relevant items” (delayed exclusion). The oldest adults performed worse in memory updating and made a greater number of intrusion errors of once relevant information. In the second experiment results showed that increases in memory load (number of items that had to be remembered) and updating demand (number of potentially relevant items) impaired performance. The oldest adults had greater difficulty when the task demand was increased. Furthermore, they produced a higher number of intrusion errors, particularly when the updating demand was increased. It therefore appears that elderly people have specific difficulty in updating information in working memory by excluding irrelevant information.     

Memory for discourse: Loci mnemonics and the oral presentation effect

The help given by loci mnemonics in memorizing isolated items is widely known, whereas there is no doubt as to whether mnemonics are useful for learning meaningful passages. In the present research it is argued that past failures to find a loci effect with text may have been due to the limited range of conditions explored during analysis of the problem. In the present research the modality of presentation of the text was hypothesized to be particularly relevant. In two experiments groups of trained and non-trained students were asked to memorize two different passages, either using loci mnemonics or not. Loci mnemonics facilitated memory of passages, the increase being greater for oral presentation of text than after private study of a written text.