A quantification of robustness

Robustness is an important construct in domains as diverse as evolutionary biology, structural engineering, and decision-making. Unfortunately, in many domains, most relevantly cognitive science, considerations of robustness end with vague semantic references. Little attention is paid to formal analysis. The aim of this paper is to initiate a discussion in the scientific community regarding methods for quantifying and analyzing robustness. To this end, we propose a means for assessing robustness that may supplant the current ambiguous use of the term. We demonstrate our quantitative approach using examples of heuristic-based decision processes, selected due to their explicit association with robustness in the psychological literature. These examples serve to illustrate basic properties of our general methodology for quantifying robustness.     

The relationship between inflated personal responsibility and exaggerated danger expectancies in obsessive-compulsive concerns

The association between responsibility for a negative outcome, perceived severity of the outcome and perceived likelihood of the outcome was examined in a sample of 70 undergraduate students. Participants were asked to rate the likelihood and severity of 10 negative outcomes, five related to contamination and five related to checking. Thirty-eight participants completed a version of the questionnaire that presented the subject as responsible for the action that may lead to a negative outcome ('personally responsible' group). The remaining 32 completed a version of the questionnaire that presented someone else performing the actions that may lead to a negative outcome ('other responsible' group). Significant differences emerged between the personally responsible and other responsible groups for severity of outcome ratings but not for likelihood of outcome ratings. Specifically, for both washing and checking concerns, participants in the personally responsible group rated the severity of the potential negative outcome as greater than did those in the other responsible group. The results support the claimed general tendency for individuals to regard an outcome as more aversive if they are personally responsible for that outcome, rather than someone else being responsible. The results suggest that, in general, increasing perceptions of personal responsibility will increase cost or severity estimates in subjective danger calculations, and that responsibility may influence OCD phenomena in this way. Finally, the results suggest that attempts to manipulate responsibility in the laboratory may be confounded by necessarily impacting on cost estimates, and therefore on danger expectancies.     

Prospective memory and aging: forgetting intentions over short delays

Retrieved intentions often cannot be performed immediately and must be maintained until there is an opportunity to perform them. In 3 experiments, on seeing a target event, younger and older participants were to withhold an action until they encountered the appropriate phase of the experiment. When initial retrieval was made facile by the use of a salient retrieval cue, the age-related decrements were often dramatic, even over unfilled delay intervals as brief as 10 s (Experiments 1 and 2). When initial retrieval was difficult, older adults showed no forgetting over the retention interval (Experiment 3). Several theoretical perspectives were offered as explanations for the age differences observed with salient retrieval cues, including those that focus on age differences in metamemory, the degree to which plans are reformulated, and the ability to nonstrategically maintain current concerns in working memory.     

A sham drug improves a demanding prospective memory task

Every day, people rely on prospective memory--our ability to remember to perform a future action--to carry out myriad tasks. We examined how a sham cognitive enhancing drug might improve people's performance on a prospective memory task. We gave some people (but not others) the sham drug, and asked everyone to perform a high-effort prospective memory task. People who received the sham drug performed better on the prospective memory task. They also took longer to perform their ongoing task, suggesting that they increased their effortful monitoring. These results fit with research showing that suggestions can lead people to increase cognitive effort and increase memory performance.     

Rhesus monkeys (Macaca mulatta) and capuchin monkeys (Cebus apella) remember future responses in a computerized task

Planning is an important aspect of many daily activities for humans. Planning involves forming a strategy in anticipation of a future need. However, evidence that nonhuman animals can plan for future situations is limited, particularly in relation to the many other kinds of cognitive capacities that they appear to share with humans. One critical aspect of planning is the ability to remember future responses, or what is called prospective coding. Two monkey species (Macaca mulatta and Cebus apella) performed a series of computerized tasks that required encoding a future response at the outset of each trial. Monkeys of both species showed competence in all tests that were given, providing evidence that they anticipated future responses and that they appropriately engaged in those responses when the time was right for such responses. In addition, some tests demonstrated that monkeys even remembered future responses that were not as presently motivating as were other aspects of the task environment. These results indicated that monkeys could anticipate future responses and retain and implement those responses when appropriate.     

Prospective memory: Effects of divided attention on spontaneous retrieval

We examined the effects of divided attention on the spontaneous retrieval of a prospective memory intention. Participants performed an ongoing lexical decision task with an embedded prospective memory demand, and also performed a divided-attention task during some segments of lexical decision trials. In all experiments, monitoring was highly discouraged, and we observed no evidence that participants engaged monitoring processes. In Experiment 1, performing a moderately demanding divided-attention task (a digit detection task) did not affect prospective memory performance. In Experiment 2, performing a more challenging divided-attention task (random number generation) impaired prospective memory. Experiment 3 showed that this impairment was eliminated when the prospective memory cue was perceptually salient. Taken together, the results indicate that spontaneous retrieval is not automatic and that challenging divided-attention tasks interfere with spontaneous retrieval and not with the execution of a retrieved intention.     

Repetition Errors in Habitual Prospective Memory: Elimination of Age Differences via Complex Actions or Appropriate Resource Allocation

ABSTRACT

A challenge in habitual prospective memory tasks (e.g., taking medication) is remembering whether or not one has already performed the action. Einstein, McDaniel, Smith, and Shaw (1998 Einstein, G. O., McDaniel, M. A., Smith, R. E. and Shaw, P. 1998. Habitual prospective memory and aging: Remembering intentions and forgetting actions. Psychological Science, 9: 284–288. [Crossref], [Web of Science ®] , [Google Scholar], Psychological Science, 9, 284) showed that older adults were more likely to incorrectly repeat an action on habitual prospective memory tasks. Extending this research, we (a) biased participants either toward repetition or omission errors, (b) investigated whether performing a more complicated motor action can reduce repetition errors for older adults, and (c) examined participants' resource allocation to the prospective memory task. Older adults committed more repetition errors than younger adults regardless of biasing instructions when ongoing task demands were challenging (Experiment 1). Performing the more complex motor action, however, reduced repetition errors for older adults. Further, when the ongoing task was less demanding, older adults' repetition errors declined to levels of younger adults (Experiment 2). Consistent with this finding, the resource allocation profiles suggested that older participants were monitoring their output (prospective memory execution) in each trial block.     

Importance effects on performance in event-based prospective memory tasks

In the present study we manipulated the importance of performing two event-based prospective memory tasks. In Experiment 1, the event-based task was assumed to rely on relatively automatic processes, whereas in Experiment 2 the event-based task was assumed to rely on a more demanding monitoring process. In contrast to the first experiment, the second experiment showed that importance had a positive effect on prospective memory performance. In addition, the occurrence of an importance effect on prospective memory performance seemed to be mainly due to the features of the prospective memory task itself, and not to the characteristics of the ongoing tasks that only influenced the size of the importance effect. The results suggest that importance instructions may improve prospective memory if the prospective task requires the strategic allocation of attentional monitoring resources.     

Forgetting of intentions in demanding situations is rapid

Demanding work settings often require the deferral of intended actions. In 3 experiments, participants were to withhold a response until they encountered a task change (which occurred 5, 15, or 40 sec later). To approximate highly demanding settings, the experimenters sometimes divided attention during the delay period. During some of the delays the experimenters interrupted the participants with an additional task (Experiment 1). Demanding conditions as well as interruptions revealed rapid forgetting of intentions at levels that would be considered significant in applied settings. Experiments 2 and 3 showed that this rapid forgetting was not reduced by strategic rehearsal and implementation intention strategies. The results suggest that maintaining intentions over brief delays is not a trivial task for the human cognitive system.     

Age-related deficits in prospective memory: the influence of task complexity.

Younger and older subjects were asked to perform an action whenever target words occurred during a short-term memory task. The difficulty of this prospective memory task was manipulated by varying the delay preceding the occurrence of a target event and by varying the number of different target events. Age-related performance differences emerged when there were several different target events but not when there was one target event presented several times. Age-related performance differences, when they occurred, were associated with poorer retrospective memory for the target events. The results were interpreted in terms of a componential analysis of prospective memory, which assumes both similarities and differences between prospective and retrospective memory.