Do binding deficits account for age-related decline in visual working memory?

Remembering visual material, such as objects, faces, and spatial locations, over a short period of time (seconds) becomes more difficult as we age. We investigated whether these deficits could be explained by a simple reduction in visual working memory capacity or by an impairment in one's ability to form or maintain appropriate associations among pieces of related information. In three experiments, we used recognition and recall tests to address the efficacy with which older adults can create bound object representations by varying the number of features of each object that had to be remembered for a subsequent memory test. Results demonstrated that whereas older adults exhibited reduced memory capacity as compared with that of younger adults, both groups stored integrated object representations in visual working memory. These results are contrasted with other work that suggests that age-related memory decline is due, at least in part, to associative deficits.     

Are attentional resources a mediator for sex differences in memory?

The divided attention paradigm was used to investigate sex differences in encoding and retrieval processes of memory. Participants performed a memory and reaction time (RT) task under full attention and two divided attention conditions, that is, at encoding and retrieval. Results revealed that females recalled significantly more words than males under the full attention and divided attention at encoding conditions. Results further showed that secondary task costs were larger for males than females during divided attention at retrieval. Furthermore, regardless of sex, recall was best under full attention and worst under divided attention at encoding conditions. In relation to the RT task, RTs were shorter under full attention and longer under the divided attention at retrieval condition. Overall, these results show that females recall more words than males possibly due to a more severe effect of reduced attention during encoding than retrieval for males. The current findings thus suggest that a reduction in attentional resources may mediate sex‐related decreases in word recall.     

Who is susceptible in three false memory tasks?

ABSTRACT

Decades of research show that people are susceptible to developing false memories. But if they do so in one task, are they likely to do so in a different one? The answer: “No”. In the current research, a large number of participants took part in three well-established false memory paradigms (a misinformation task, the Deese-Roediger-McDermott [DRM] list learning paradigm, and an imagination inflation exercise) as well as completed several individual difference measures. Results indicate that many correlations between false memory variables in all three inter-paradigm comparisons are null, though some small, positive, significant correlations emerged. Moreover, very few individual difference variables significantly correlated with false memories, and any significant correlations were rather small. It seems likely, therefore, that there is no false memory “trait”. In other words, no one type of person seems especially prone, or especially resilient, to the ubiquity of memory distortion.     

A short‐term perceptual priming account of spacing effects in explicit cued‐memory tasks for unfamiliar stimuli

Memory for repeated items improves when presentations are spaced during study. This effect is found in explicit memory tasks using different types of material, different experimental paradigms, and in different subject populations. Two experiments are described where the spacing effect was assessed on a yes/no recognition memory task using words and nonwords as targets. The main results showed that changing the font between repeated occurrences of targets at study did not affect the spacing effect for words, even under shallow encoding conditions, but effectively removed the spacing effect with nonwords. In both experiments, the font manipulation was made between subjects, ruling out explanations in terms of differential attention to particular font conditions. These results provide further support for short‐term perceptual priming accounts of the spacing effect: Semantically‐based repetition priming affects memory for words; perceptual priming mechanisms affect memory for nonwords.     

Can a temporal processing deficit account for dyslexia?

In this comment, we argue that although Farmer and Klein (1995) have provided a valuable review relating deficits in nonreading tasks and dyslexia, their basic claim that a “temporal processing deficit” is one possible cause of dyslexia is somewhat vague. We argue that “temporal processing deficit” is never clearly defined. Furthermore, we question some of their assumptions concerning an auditory temporal processing deficit related to dyslexia, and we present arguments and data that seem inconsistent with their claims regarding how a visual temporal processing deficit would manifest itself in dyslexic readers. While we agree that some dyslexics have visual problems, we conclude that problems with reading caused by the visual mechanisms that Farmer and Klein postulate are quite rare.     

Can emotional content reduce the age gap in visual working memory? Evidence from two tasks

Ageing is associated with declines in several cognitive abilities including working memory (WM). The goal of the present study was to assess whether emotional information could reduce the age gap in the quantity and quality (precision) of representations in visual WM. Young and older adults completed a serial image recognition (SIR) task and a colour-image binding (CIB) task. Results of the SIR task showed worse performance for negative than neutral and positive images within the older group, hence enlarging the age gap in WM. In the CIB task, recall precision was lower in the old than young adults, showing an ageing decline in the quality of WM representations. Positive images tended to improve precision, but this boost was similar for both age groups. In sum, emotional content did not reduce the age gap in visual WM.     

Individual differences for sex differences in achievement attributions?

Past research has found a self-defensive bias in males and a self-derogatory bias in female achievement attributions. Dispositional explanations for these differences were examined in the present study. Subjects completed measures of Need for Achievement, Self-Esteem, Fear of Success, Attitudes Toward Women, and Androgyny. They later competed in same- or mixed-sex pairs on an anagram task which was prearranged in difficulty so that one subject clearly defeated his/her partner. Consistent with past research, males were more likely to attribute their outcomes to ability, and less likely to attribute their outcomes to effort and luck, than were females. Achievement motivation was the most consistently successful predictor of these sex differences.     

Can connectionist models of phonology assembly account for phonology?

Connectionist models have gained considerable success as accounts of how printed words are named. Their success challenges the view of grapheme-to-phoneme correspondences (GPCs) as rules. By extension, however, this challenge is sometimes interpreted also as evidence against linguistic rules and variables. This inference tacitly assumes that the generalizations inherent in reading (specifically, GPCs) are similar in their scope to linguistic generalizations and that they are each reducible to token associations. I examine this assumption by comparing the scope of generalizations required for mapping graphemes to phonemes and several linguistic phonological generalizations. Marcus (1998b) distinguishes between two types of generalizations: those that fall within a model’s training space and those that exceed it. The scope of generalizations is determined by the model’s representational choices— specifically, the implementation of operations over mental variables. An analysis of GPCs suggests that such generalizations do not appeal to variables; hence, they may not exceed the training space. Likewise, certain phonological regularities, such as syllable phonotactic constraints and place assimilation, may be captured by an associative process. In contrast, other phonological processes appeal to variables; hence, such generalizations potentially exceed the training space. I discuss one such case, the obligatory contour principle. I demonstrate that speakers conform to this constraint and that their behavior is inexplicable by the statistical structure of the language. This analysis suggests that, unlike GPCs, phonological generalizations may exceed the training space. Thus, despite their success in modeling GPCs, eliminative connectionist models of phonology assembly may be unable to provide a complete account for phonology. To the extent that reading is subject to phonological constraints, its modeling may require implementing operations over variables.     

What's in a cue? The role of cue orientation in object displacement tasks

The current study looked at two theoretical proposals explaining toddlers’ abilities to use cue information for recovering a hidden object that had rolled down a ramp behind an occluded screen. These two approaches, the theory of object directed attention and a landmark-based account, make different predictions regarding the efficacy of an obliquely aligned cue to object position. Accordingly, the search by forty 24-month olds, forty-two 30-month olds, and forty-one 36-month olds for a hidden toy that was cued using either a short versus a long cue, or a vertically aligned versus an obliquely aligned cue, were compared. Analyses of search accuracy revealed that children were more successful when faced with short as opposed to long cues, and when using vertical as opposed to oblique cues. These findings support a landmark-based approach, as opposed to an object-directed attention account, and are discussed with reference to their implications for spatial orientation more generally.     

Do dogs (Canis familiaris) understand invisible displacement?

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object ended up adjacent to the target box after the displacement. These results suggest that the search behavior of dogs was guided by simple associative rules rather than mental representation of the object's past trajectory. In contrast, Experiment 5 found that on the same task, 18- and 24-month-old children showed no disparity between trials in which the displacement device was adjacent or nonadjacent to the target box.     

Who remembers best? Individual differences in memory for events that occurred in a science museum

Individual differences in memory and suggestibility were assessed in an experiment involving 1989 people who attended the Exploratorium, a science museum located in San Francisco. Subjects watched a brief film clip of an assault and later answered questions about it. Approximately half received misinformation about some critical items. Four demographic variables (gender, educational level, age, and occupation) were examined to determine their impact on memory performance. The principle of discrepancy detection predicts that, compared to individuals with a good memory, people who have poor memory to begin with will be relatively suggestible (that is susceptible to misinformation). Some of our findings were consistent with this principle. For example, children (5–10 years) and elderly (over 65) were relatively inaccurate and also relatively suggestible. Other findings were not consistent with the principle, for example the finding that artists and architects were relatively accurate, but they were also highly suggestible.     

Do chimpanzees (Pan troglodytes) understand single invisible displacement?

Previous research suggests that chimpanzees understand single invisible displacement. However, this Piagetian task may be solvable through the use of simple search strategies rather than through mentally representing the past trajectory of an object. Four control conditions were thus administered to two chimpanzees in order to separate associative search strategies from performance based on mental representation. Strategies involving experimenter cue-use, search at the last or first box visited by the displacement device, and search at boxes adjacent to the displacement device were systematically controlled for. Chimpanzees showed no indications of utilizing these simple strategies, suggesting that their capacity to mentally represent single invisible displacements is comparable to that of 18-24-month-old children.     

How does processing affect storage in working memory tasks? Evidence for both domain-general and domain-specific effects

Two studies that examine whether the forgetting caused by the processing demands of working memory tasks is domain-general or domain-specific are presented. In each, separate groups of adult participants were asked to carry out either verbal or nonverbal operations on exactly the same processing materials while maintaining verbal storage items. The imposition of verbal processing tended to produce greater forgetting even though verbal processing operations took no longer to complete than did nonverbal processing operations. However, nonverbal processing did cause forgetting relative to baseline control conditions, and evidence from the timing of individuals' processing responses suggests that individuals in both processing groups slowed their responses in order to "refresh" the memoranda. Taken together the data suggest that processing has a domain-general effect on working memory performance by impeding refreshment of memoranda but can also cause effects that appear domain-specific and that result from either blocking of rehearsal or interference.     

Age differences in memory retrieval shift: governed by feeling-of-knowing?

The noun-pair lookup (NP) task was used to evaluate strategic shift from visual scanning to retrieval. We investigated whether age differences in feeling-of-knowing (FOK) account for older adults' delayed retrieval shift. Participants were randomly assigned to one of three conditions: (1) standard NP learning, (2) fast binary FOK judgments, or (3) Choice, where participants had to choose in advance whether to see the look-up table or respond from memory. We found small age differences in FOK magnitudes but major age differences in memory retrieval choices that mirrored retrieval use in the standard NP task. Older adults showed lower resolution in their confidence judgments (CJs) for recognition memory tests on the NP items, and this difference appeared to influence rates of retrieval shift, given that retrieval use was correlated with CJ magnitudes in both age groups. Older adults had particular difficulty with accuracy and confidence for rearranged pairs, relative to intact pairs. Older adults' slowed retrieval shift appears to be attributable to (1) impaired associative learning early in practice, not just a lower FOK; but also (2) retrieval reluctance later in practice after the degree of associative learning would afford memory-based responding.     

Commission errors in delay–execute prospective memory tasks

Individuals frequently retrieve an intention, but the execution of the task needs to be delayed due to ongoing task demands - so-called delay-execute prospective memory (PM) tasks. We investigated commission errors in the delay-execute paradigm. Participants were told that a PM task is finished (PM task has been executed and is now finished for a final phase) or cancelled (PM task has been cancelled immediately after introduction). We observed commission errors and ongoing task performance in the final phase which included several irrelevant PM cues. In two experiments, we observed significantly more commission errors for cancelled compared to the finished intentions. In Experiment 2, commission errors were eliminated if the final phase required divided attention, regardless of PM task status. In addition, we observed significantly more PM cue interference on the ongoing task in the cancelled compared to the finished group, indicating that the PM task was retrieved in the cancelled group but not in the finished group. As retrieval and execution of the PM task were separated by a delay, the results indicate that commission errors are not always the result of a quick, spontaneous retrieval-execution sequence and may also occur when retrieval and execution are temporally separated.     

Advantage for emotional words in immediate and delayed memory tasks: could it be explained in terms of processing capacity?

Emotional stimuli are better remembered and recognized than neutral ones. This advantage for emotional stimuli has been repeatedly obtained when testing long-term retention. However, there are contradictory results concerning retention of emotional information when short retention intervals are used. The aim of the present study was, on the one hand, to test the effect of retention interval on memory for emotional stimuli (Experiment 1). The results showed that emotional information is better remembered than neutral information in both immediate and delayed memory tests, suggesting that the advantage for emotional information is not limited to long retention intervals. On the other hand, I tried to test the proposals made by Christianson and Nilsson (1984) and Bower (1992). These authors suggested that the advantage for emotional stimuli could be explained as emotional stimuli spending more processing capacity during acquisition, thus rendering less capacity available to encode simultaneously presented information (Experiments 2 and 3). Results showed that concurrent presentation of emotional stimuli did not inhibit the recall of neutral stimuli. These findings do not seem to support the proposals of Christianson and Nilsson (1984) and Bower (1992). According to these results, some mechanisms other than a greater spending of processing capacity have to be involved in the advantage for emotional information in memory.     

Developmental differences in working memory: Where do they come from?

Several models assume that working memory development depends on age-related increases in efficiency and speed of processing. However, age-related increases in the efficiency of the mechanisms that counteract forgetting and restore memory traces may also be important. This hypothesis was tested in three experiments by manipulating both the processing duration within a working memory task and the time available to restore memory traces. Third- and sixth-grade children performed a complex span task in which they maintained series of letters while adding numbers to series of digits. When we equated processing and restoration times between ages, the developmental difference in working memory span was reduced but remained significant. However, this residual difference was eliminated when the time available to reactivate memory traces was tailored to the processing speed of each age group. This indicates that children employ active mechanisms for maintenance and restoration of memory traces that develop with age.     

Can young children integrate premises in transitivity and serial order tasks?

An analysis is presented of the relational information needed for premise integration in transitivity and simple serial order tasks. The tasks are divided into those where an ordering decision can be made by considering a single binary relation, and those where two binary relations must be considered. Four experiments are reported, the principal purpose of which is to manipulate the number of relations which must be considered in making decisions about the order of a small set of elements. In every test it was found that preschool children succeeded if decisions could be made by considering one relation, but failed if two relations had to be considered. Children over 5 almost always succeeded in both cases. It is concluded that preschool children cannot integrate relational premise information, and therefore cannot understand transitivity or serial order. This would impose limitations on their understanding of quantification and a number of other concepts. It is also suggested that the amount of information required to make a single decision may be an important factor determining cognitive complexity generally.     

Increased distractibility in schizotypy: Independent of individual differences in working memory capacity?

Individuals with schizophrenia typically show increased levels of distractibility. This has been attributed to impaired working memory capacity (WMC), since lower WMC is typically associated with higher distractibility, and schizophrenia is typically associated with impoverished WMC. Here, participants performed verbal and spatial serial recall tasks that were accompanied by to-be-ignored speech tokens. For the few trials wherein one speech token was replaced with a different token, impairment was produced to task scores (a deviation effect). Participants subsequently completed a schizotypy questionnaire and a WMC measure. Higher schizotypy scores were associated with lower WMC (as measured with operation span, OSPAN), but WMC and schizotypy scores explained unique variance in relation to the mean magnitude of the deviation effect. These results suggest that schizotypy is associated with heightened domain-general distractibility, but that this is independent of its relationship with WMC.