Two are better than one: comparison influences infants' visual recognition memory

Despite a large literature on infants’ memory for visually presented stimuli, the processes underlying visual memory are not well understood. Two studies with 4-month-olds (N = 60) examined the effects of providing opportunities for comparison of items on infants’ memory for those items. Experiment 1 revealed that 4-month-olds failed to show evidence of memory for an item presented during familiarization in a standard task (i.e., when only one item was presented during familiarization). In Experiment 2, infants showed robust memory for one of two different items presented during familiarization. Thus, infants’ memory for the distinctive features of individual items was enhanced when they could compare items.     

The whole is indeed more than the sum of its parts: perceptual averaging in the absence of individual item representation

We tested Ariely's (2001) proposal that the visual system represents the overall statistical properties of sets of objects against alternative accounts of rapid averaging involving sub-sampling strategies. In four experiments, observers could rapidly extract the mean size of a set of circles presented in an RSVP sequence, but could not reliably identify individual members. Experiment 1 contrasted performance on a member identification task with performance on a mean judgment task, and showed that the tasks could be dissociated based on whether the test probe was presented before or after the sequence, suggesting that member identification and mean judgment are subserved by different mechanisms. In Experiment 2, we confirmed that when given a choice between a probe corresponding to the mean size of the set and a foil corresponding to the mean of the smallest and largest items only, the former is preferred to the latter, even when observers are explicitly instructed to average only the smallest and largest items. Experiment 3 showed that a test item corresponding to the mean size of the set could be reliably discriminated from a foil but the largest item in the set, differing by an equivalent amount, could not. In Experiment 4, observers rejected test items dissimilar to the mean size of the set in a member identification task, favoring test items that corresponded to the mean of the set over items that were actually shown. These findings suggest that mean representation is accomplished without explicitly encoding individual items.     

Sense of Time and Executive Functioning in Children and Adults

A number of patient studies suggest that impairments in frontal lobe functions are associated with disorders in temporal information processing. One implication of these findings is that subjective experience of time should be related to executive functions regardless of etiology. In two experiments, we examined sense of time in relation to components of executive functioning in healthy children and adults. In Experiment 1, children between 8 to 12 years completed six experimental tasks that tapped three components of executive functioning: inhibition, updating, and mental shifting. Sense of time was examined in a duration judgment task in which participants reproduced stimulus durations between 4 to 32 s. In Experiment 2, adult participants completed the time reproduction task under varying concurrent task demands. Both experiments showed selective effects in that time reproduction errors were related to the inhibition and updating, but not to the shifting, components of executive functioning. However, the observed effects were modulated by task demands and age-related differences in cognitive competence. We conclude that individual differences in executive functioning are only weakly related to time reproduction performance in healthy children and adults.     

The development of prospective memory in young schoolchildren: The impact of ongoing task absorption,cue salience,and cue centrality

This study presents evidence that 9- and 10-year-old children outperform 6- and 7-year-old children on a measure of event-based prospective memory and that retrieval-based factors systematically influence performance and age differences. All experiments revealed significant age effects in prospective memory even after controlling for ongoing task performance. In addition, the provision of a less absorbing ongoing task (Experiment 1), higher cue salience (Experiment 2), and cues appearing in the center of attention (Experiment 3) were each associated with better performance. Of particular developmental importance was an age by cue centrality (in or outside of the center of attention) interaction that emerged in Experiment 3. Thus, age effects were restricted to prospective memory cues appearing outside of the center of attention, suggesting that the development of prospective memory across early school years may be modulated by whether a cue requires overt monitoring beyond the immediate attentional context. Because whether a cue is in or outside of the center of attention might determine the amount of executive control needed in a prospective memory task, findings suggest that developing executive control resources may drive prospective memory development across primary school age.     

Cyber-dehumanization: Violent video game play diminishes our humanity

Across two studies we show that engaging in violent video game play diminishes perceptions of our own human qualities. In addition, when other players are the targets of this violence it reduces our perceptions of their humanity also. In Study 1, we demonstrate that playing Mortal Kombat against another player reduces the perceived humanity of the self as well as the humanity of one's opponent (compared to playing a non-violent game). In Study 2 we replicate this effect on perceived humanity of the self when playing a violent game with a co-player. However, we find no dehumanization of co-players who are not the targets of violence. We demonstrate these effects cannot be reduced to mood, self-esteem, gender, or other characteristics of the game such as excitement and enjoyment. The findings provide a broader perspective from which to view previous work on the adverse effects of violent video games.     

The development of co-representation effects in a joint task: Do children represent a co-actor?

When two adults jointly perform a task, they often show interference effects whereby the other’s task interferes with their own performance (Sebanz, Knoblich, & Prinz, 2003). The current study investigated whether these co-representation effects can be observed in young children. This phenomenon can be used as a criterion for adult-like joint action in children, which has been under debate in existing literature due to the difficulty in identifying what mechanisms underlie the behaviours observed (Brownell, 2011). In Experiment 1, two children performed an adapted Bear Dragon task (Kochanska, Murray, Jacques, Koenig, & Vandegeest, 1996), where children were required to point to a picture when instructed to do so by one puppet and to inhibit pointing when instructed to by the other. In the Same Task condition, both children in a pair were asked to respond to the same puppet, whereas in the Different Task condition, they were asked to respond to different puppets. Children made more errors in the Different Task condition than the Same Task, suggesting that they were experiencing interference from their partner’s task rule. In Experiment 2 children in Different and Same task conditions began with the same task as in Experiment 1 and then switched which puppet to respond to. Switch costs were lower in the Different task condition, consistent with children having already represented the alternative task rule on behalf of their partner during the pre-switch phase. Experiment 3 replicated the effect of Task in a novel computer-based paradigm with children between 4 and 5 years, but not younger. These data provide the first direct evidence that children as young as 4 years co-represent a partner's task during a joint activity, and that younger children may not be capable of co-representation.     

Conflicting desire and the child's theory of mind

We contrast the standard representational theory-of-mind approach to the understanding of mental states with an alternative view that theory-of-mind tasks require executive functioning or the inhibition of more “cognitively salient” information. Two experiments test the hypothesis that 3-year-olds' apparent problems on theory-of-mind tasks are not due to an inability to represent the mental contents of another, but rather lie in the informational structure of the task. In Experiment 1, 3- to 5-year-olds were tested on their understanding of desire in others either when they themselves held a strong and conflicting desire or when they had no strong desire. Results showed that under the condition of having a strong and conflicting desire, only 5-year-olds were able to recognize that another person may desire something different. In contrast, when the children themselves held no strong desire, even 3-year-olds were able to judge another's desire correctly. Experiment 2 compared 3-year-olds' performance on a standard false-belief task with an equivalently structured desire task in which participants had again to inhibit their own strong and conflicting desire. Results showed similar performance on the traditional false-belief task and the new conflicting-desire task.     

Color-object interference: Further tests of an executive control account

Young children are slower in naming the color of a meaningful picture than in naming the color of an abstract form (Stroop-like color-object interference). The current experiments tested an executive control account of this phenomenon. First, color-object interference was observed in 6- and 8-year-olds but not in 12- and 16-year-olds (Experiment 1). Second, meaningful pictures did not interfere in 5- to 7-year-olds’ manual sorting of objects on the basis of color (Experiment 2) or in their naming the number of colored objects in the display, that is, subitizing (Experiment 3). These findings provide support for the view that color-object interference results from the children’s immature inhibition of the prepotent but irrelevant task of object naming.     

Sensitivity to spatial conflict and the development of self‐regulation in children 24–36 months of age

This paper describes a task involving conflict between location and identity, two early developing visual system functions. From 2 years of age, children, like adults, responded more slowly and less accurately when location and identity were in conflict. The ability to resolve conflict appears to be linked to individual differences in effortful control and negative emotionality. Results suggest that this measure of executive attention may reflect the development of a more general capacity for self‐regulation.     

Too exhausted to remember: Ego depletion undermines subsequent event‐based prospective memory

Past research has consistently found that people are likely to do worse on high‐level cognitive tasks after exerting self‐control on previous actions. However, little has been unraveled about to what extent ego depletion affects subsequent prospective memory. Drawing upon the self‐control strength model and the relationship between self‐control resources and executive control, this study proposes that the initial actions of self‐control may undermine subsequent event‐based prospective memory (EBPM). Ego depletion was manipulated through watching a video requiring visual attention (Experiment 1) or completing an incongruent Stroop task (Experiment 2). Participants were then tested on EBPM embedded in an ongoing task. As predicted, the results showed that after ruling out possible intervening variables (e.g. mood, focal and nonfocal cues, and characteristics of ongoing task and ego depletion task), participants in the high‐depletion condition performed significantly worse on EBPM than those in the low‐depletion condition. The results suggested that the effect of ego depletion on EBPM was mainly due to an impaired prospective component rather than to a retrospective component.     

中国人的群体参照记忆效应

在自我参照效应范式中加入参照认同群体加工任务,比较了中国被试在参照中国人和参照美国人进行记忆加工时的再认率及“记得”与“知道”判断的成绩。两项实验结果一致表明,参照中国人加工的再认成绩显著高于参照美国人,表明记忆加工的认同群体参照效应,而在“记得”与“知道”指标上并无差异;参照中国人加工的再认成绩和“记得”判断成绩显著低于自我参照加工。根据个体自我、关系自我和集体自我的分类方法,自我参照效应反映了个体自我对于记忆加工的影响,群体参照效应则主要反映了集体自我的影响     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Central executive involvement in children's spatial memory

Previous research with adults found that spatial short-term and working memory tasks impose similar demands on executive resources. We administered spatial short-term and working memory tasks to 8- and 11-year-olds in three separate experiments. In Experiments 1 and 2 an executive suppression task (random number generation) was found to impair performances on a short-term memory task (Corsi blocks), a working memory task (letter rotation), and a spatial visualisation task (paper folding). In Experiment 3 an articulatory suppression task only impaired performance on the working memory task. These results suggest that short-term and working memory performances are dependent on executive resources. The degree to which the short-term memory task was dependent on executive resources was expected to be related to the amount of experience children have had with such tasks. Yet we found no significant age-related suppression effects. This was attributed to differences in employment of cognitive strategies by the older children.     

Categorical flexibility in preschoolers: contributions of conceptual knowledge and executive control

The current study evaluated the relative roles of conceptual knowledge and executive control on the development of categorical flexibility, the ability to switch between simultaneously available but conflicting categorical representations of an object. Experiment 1 assessed conceptual knowledge and executive control together; Experiment 2 differentiated conceptual knowledge from costly executive processes. In Experiment 1, 3‐ to 5‐year‐olds were given a three‐choice (taxonomic, thematic, and nonassociate) match‐to‐sample task and asked to match two associates. In Experiment 2, same‐aged children were assessed on another match‐to‐sample task that reduced executive costs by presenting thematic and taxonomic associates on separate trials. By comparing performance across tasks, age‐related changes resulting from conceptual knowledge and executive control indicated that conceptual knowledge of superordinate relations showed gains between 3 and 4 years, whereas gains in executive control were seen between 4 and 5 years, suggesting a décalage in the development of conceptual and executive processes underlying categorical flexibility.     

Are children’s memory illusions created differently from those of adults? Evidence from levels-of-processing and divided attention paradigms

In two experiments, we investigated the robustness and automaticity of adults’ and children’s generation of false memories by using a levels-of-processing paradigm (Experiment 1) and a divided attention paradigm (Experiment 2). The first experiment revealed that when information was encoded at a shallow level, true recognition rates decreased for all ages. For false recognition, when information was encoded on a shallow level, we found a different pattern for young children compared with that for older children and adults. False recognition rates were related to the overall amount of correctly remembered information for 7-year-olds, whereas no such association was found for the other age groups. In the second experiment, divided attention decreased true recognition for all ages. In contrast, children’s (7- and 11-year-olds) false recognition rates were again dependent on the overall amount of correctly remembered information, whereas adults’ false recognition was left unaffected. Overall, children’s false recognition rates changed when levels of processing or divided attention was manipulated in comparison with adults. Together, these results suggest that there may be both quantitative and qualitative changes in false memory rates with age.     

Visual working memory is enhanced by mixed strategy use and semantic coding

Visual working memory is enhanced by processes related to verbalisation. However, the mechanism underlying this enhancement is unclear. Experiment 1 investigated the potential contribution of the phonological loop of working memory, by assessing the effects of articulatory suppression on two versions of the Visual Patterns Test—one low and one high in availability of verbal coding. The lack of interaction suggested that the phonological loop is not responsible; however, active use of combined verbal and visual strategies, as well as activated semantic knowledge, both appear to be related to increased capacity. Experiment 2 assessed the role of central executive resources. Because central executive suppression removed the benefit of the high verbal coding task version, central executive resources, assumed to relate to the temporary maintenance of multimodal codes in the episodic buffer, appear to underlie the benefit associated with verbalisation.     

Even better than the real thing: Alternative outcome bias affects decision judgements and decision regret

Three experiments demonstrated that decisions resulting in considerable amounts of profit, but missed alternative outcomes of greater profits, were rated lower in quality and produced more regret than did decisions that returned lesser (or equal) amounts of profit but either did not miss or missed only slightly better alternatives. These effects were mediated by upward counterfactuals and moderated by participants’ orientation to the decision context. That decision evaluations were affected by the availability and magnitude of alternative outcomes rather than the positivity of actual outcomes is counter to the outcome bias effect—a bias in which decisions are rated more positively when they led to more positive outcomes (despite a priori probabilities associated with the decision outcomes). Experiment 3 demonstrated that these effects represent a bias that occurs even when it is clear that the process by which decisions were made followed rational decision processes. This research suggests that when alternative worlds are even better than the desirable outcomes experienced, affect and cognition may be more strongly linked to the magnitude of alternative realities than to obtained outcomes.     

Executive functioning by 18‐24‐month‐old children: effects of inhibition,working memory demands and narrative in a novel detour‐reaching task

Infants can inhibit a prepotent but wrong action towards a goal in order to perform a causal means‐action. It is not clear, however, whether infants can perform an arbitrary means‐action while inhibiting a prepotent response. In four experiments, we explore this executive functioning in 18–24‐month‐old children. The working memory and inhibition demands in a novel means‐end problem were systematically varied in terms of the type and combination of means‐action(s) (causal or arbitrary) contained within the task, the number of means‐actions (1 or 2), the goal visual availability and whether the task was accompanied by a narrative. Experiments 1 and 2 showed that children performed tasks that contained causal as opposed to arbitrary information more accurately; accuracy was also higher in tasks containing only one step. Experiment 2 also demonstrated that performance in the arbitrary task improved significantly when all sources of prepotency were removed. In Experiment 3, task performance improved when the two means‐actions were intelligibly linked to the task goal. Experiment 4 demonstrated that the use of a narrative that provided a meaningful (non‐causal) link between the two means‐actions also improved children's performance by assisting their working memory in the generation of a rationale. Findings provide an initial account of executive functioning in the months that bring the end of infancy. Copyright © 2006 John Wiley & Sons, Ltd.     

Spatial breakdown in spatial construction: evidence from eye fixations in children with Williams syndrome

We investigated the role of executive and spatial representational processes in impaired performance of block construction tasks by children with Williams syndrome (WS), a rare genetic defect that results in severely impaired spatial cognition. In Experiment 1, we examined performance in two kinds of block construction tasks, Simple Puzzles, in which block faces contained a single color, and Complex, in which some block faces contained an arrangement of two colors. WS and control children were comparable in their ability to solve simple puzzles, and showed similar eye-fixation patterns, suggesting that basic executive processes were intact. However, WS children were severely impaired in their ability to solve complex puzzles. In these puzzles, WS children fixated the complex puzzle models and checked their partial solutions less often than normal children, but they were comparable in their ability to detect errors in their copies and almost exclusively made repairs to copies that were, in fact, incorrect. We conjecture that the abnormal fixation patterns were a consequence of impoverished spatial representations, rather than a cause of it. This conjecture was tested in Experiment 2, where we examined children's capacity to match and place individual blocks without engaging the complex executive processes required to carry out a complete puzzle solution. We found serious deficiency among WS children in both aspects of spatial representation. Moreover, estimates of the errors in representing the identity and location of model blocks derived from Experiment 2 provided a good account of the observed errors in the block construction task of Experiment 1.     

Motivated semantic control: Exploring the effects of extrinsic reward and self-reference on semantic retrieval in semantic aphasia

Recent insights show that increased motivation can benefit executive control, but this effect has not been explored in relation to semantic cognition. Patients with deficits of controlled semantic retrieval in the context of semantic aphasia (SA) after stroke may benefit from this approach since ‘semantic control’ is considered an executive process. Deficits in this domain are partially distinct from the domain-general deficits of cognitive control. We assessed the effect of both extrinsic and intrinsic motivation in healthy controls and SA patients. Experiment 1 manipulated extrinsic reward using high or low levels of points for correct responses during a semantic association task. Experiment 2 manipulated the intrinsic value of items using self-reference, allocating pictures of items to the participant (‘self’) or researcher (‘other’) in a shopping game before participants retrieved their semantic associations. These experiments revealed that patients, but not controls, showed better performance when given an extrinsic reward, consistent with the view that increased external motivation may help ameliorate patients’ semantic control deficits. However, while self-reference was associated with better episodic memory, there was no effect on semantic retrieval. We conclude that semantic control deficits can be reduced when extrinsic rewards are anticipated; this enhanced motivational state is expected to support proactive control, for example, through the maintenance of task representations. It may be possible to harness this modulatory impact of reward to combat the control demands of semantic tasks in SA patients.