The cost of a voluntary task switch

Task-switching paradigms are widely used to study executive control. However, standard paradigms may not require active control to switch tasks. We examined voluntary task switching by having subjects choose which task to perform on a series of bivalent stimuli. Subjects performed parity or magnitude judgments on single digits. Instructions were to perform the two tasks equally often and in a random order. The response-to-stimulus interval (RSI) was either 100 or 1,000 ms, manipulated between blocks. Task alternations were slower than task repetitions, and this switch cost was greater at the short RSI than at the long RSI (310 and 94 ms, respectively). Additionally, subjects produced more task repetitions than expected if the tasks were performed in a random sequence. These results show costs associated with a voluntary task switch, when subjects must actively control the choice of the task to be performed.     

The development of a word-learning strategy

Two studies investigated young infants' use of the word-learning principle Mutual Exclusivity. In Experiment 1, a linear relationship between age and performance was discovered. Seventeen-month-old infants successfully used Mutual Exclusivity to map novel labels to novel objects in a preferential looking paradigm. That is, when presented a familiar and a novel object (e.g. car and phototube) and asked to "look at the dax", 17-month-olds increased looking to the novel object (i.e. phototube) above baseline preference. On these trials, 16-month-olds were at chance. And, 14-month-olds systematically increased looking to the familiar object (i.e. car) in response to hearing the novel label "dax". Experiment 2 established that this increase in looking to the car was due solely to hearing the novel label "dax". Several possible interpretations of the surprising form of failure at 14 months are discussed.     

The psychological cost of waiting

The study of any problem involving waiting situations invariably assumes that people dislike having to wait. The analysis of queueing problems usually prescribes that some costs should be associated with the time people spend waiting to be served. These are usually considered to be of an economic nature, though the existence of other costs of a psychological nature is accepted. It is generally accepted that after having to wait for a certain amount of time, anxiety and stress start to build up in an individual, due both to the sense of waste and the uncertainty involved in a waiting situation. This work provides a theoretical basis for analysing this building up process as it occurs during the waiting period. It is proved that, under very general conditions, the resulting psychological stress accumulated during the process is a marginal increasing function of the waiting time, and some strategies to minimise it are developed. The results obtained give theoretical support to the usual assumptions underlying the development of systems to provide “real time” information to people in waiting situations. This is especially important in the operation of public transportation systems. The results also provide theoretical support to the “convex” treatment usually given to the waiting cost function in queueing problems.     

The cost of visual filtering

Speeded choice responses (reading or naming) to a relevant stimulus under conditions of spatial uncertainty are delayed by the simultaneous occurrence of other events. This "filtering cost" occurs despite high discriminability of target and distractors, which allows parallel detection of the target in search through the same displays. Reading is also delayed when the removal of irrelevant objects from the field coincides with the onset of the target. Filtering costs are caused by the processing of events rather than by the mere presence of irrelevant items. They are eliminated by advance information about the location of the target or by advance presentation of maintained distractors.     

The cost of truthmaker maximalism

According to truthmaker theory, particular truths are true in virtue of the existence of particular entities. Truthmaker maximalism holds that this is so for all truths. Negative existential and other ‘negative’ truths threaten the position. Despite this, maximalism is an appealing thesis for truthmaker theorists. This motivates interest in parsimonious maximalist theories, which do not posit extra entities for truthmaker duty. Such theories have been offered by David Lewis and Gideon Rosen, Ross Cameron, and Jonathan Schaffer. However, it will be argued here that these theories cannot be sustained, and hence maximalism comes with a serious ontological cost. Neither Armstrong's invocation of totality facts nor the Martin-Kukso line on absences can meet this cost satisfactorily. I'll claim that negative facts are the best (and perhaps only) way out of the problem for the truthmaker maximalist.     

The currency of procurement cost

As the number of instrtumental responses required to procure access to food is increased, animals decrease the frequency of initiating meals and increase meal size, conserving total intake while limiting the increase in the overall cost of feeding. In two studies, one using wheel turns and one using bar presses as the instrumental response, we asked whether freely feeding laboratory rats measure cost according to the energy or the time they expend. In each study we varied both the price (i.e., number of wheel turns or bar presses) and the force required to make a response (i.e., torque on the wheel or weight of the bar). Price affected both procurement time (from the first to the last procurement response) and procurement work, whereas torque and bar weight affected work without altering time in most cases. Meal patterns were altered by all manipulations of price, but changes in torque and bar weight had little effect on meal patterns, except in the conditions in which they altered procurement time. These results suggest that time is a critical currency of procurement cost in rats.     

The effects of a response cost treatment tactic on hyperactive children

In a pilot study, a multielement design was used to assess the effectiveness of a response cost procedure on a 7-year-old child's hyperactive behavior and academic performance across days. The procedure was effective in reducing off-task behavior and in increasing academic assignment completion. In Experiment 2, three strategies were compared to a no-treatment baseline in treating an 8-year-old hyperactive child: drug (Ritalin) alone, response cost alone, and drug plus response cost. The cost program alone and the cost program combined with medication were effective in reducing off-task behavior and in increasing academic performance. In both studies, the procedure was viewed by the teachers as practical and effective for use in a classroom setting. The subjects liked the cost system and believed that they completed more academic work when it was operative.     

The contributions of strategy use to working memory span: a comparison of strategy assessment methods

In two experiments, we tested whether individual differences in strategy production account for individual differences in performance on a working memory span task. We measured the strategies used during a standard experimenter-paced operation span (OSPAN) task by having participants make both set-by-set reports of strategy use for individual item sets and global reports of strategy use. In Experiment 1, although normatively effective strategies were self-reported on only a small proportion of OSPAN sets, individual differences in effective strategy use correlated with span performance. Experiment 2 replicated this outcome using a sample of 100 participants but, as important, it demonstrated that individual differences in effective strategy use did not mediate the relationship between OSPAN and measures of verbal ability. Discussion focuses on the interpretation of strategy-span relationships and the relative utility of general reports of strategy use versus the set-by-set reports introduced here for the OSPAN task.     

The Stroop congruency effect is more observable under a speed strategy than an accuracy strategy

Naming the ink color of an incongruent color word (e.g., RED printed in green) usually takes longer than naming the ink color of a color bar. However, when the ink matches the word (e.g., RED printed in red), naming tends to be faster. These phenomena are known as the STroop interference effect and the Stroop congruency effect, respectively. Although the interference effect has been robust and reliable across studies, the congruency effect tends to be elusive. It was hypothesized that this variation in outcomes might be related to subjects' response strategy. The experiment conducted to test this hypothesis induced either a speed or an accuracy strategy in two separate groups of subjects. Significant interference effects were found for both groups and the magnitudes did not differ. At the same time, the congruency effect was observed in the speed group but not in the accuracy group. These results suggest that researchers who wish to observe and study the Stroop congruency and interference effects should place special emphasis on speed. Implications of the study for a model of the Stroop effect are also discussed.     

The omission strategy

People are more willing to bring about morally objectionable outcomes by omission than by commission. Similarly, people condemn others less harshly when a moral offense occurs by omission rather than by commission, even when intentions are controlled. We propose that these two phenomena are related, and that the reduced moral condemnation of omissions causes people to choose omissions in their own behavior to avoid punishment. We report two experiments using an economic game in which one participant (the taker) could take money from another participant (the owner) either by omission or by commission. We manipulated whether or not a third party had the opportunity to punish the taker by reducing the taker's payment. Our results indicated that the frequency of omission increases when punishment is possible. We conclude that people choose omissions to avoid condemnation and that the omission effect is best understood not as a bias, but as a strategy.     

The attentional cost of inattentional blindness

When our attention is engaged in a visual task, we can be blind to events which would otherwise not be missed. In three experiments, 97 out of the 165 observers performing a visual attention task failed to notice an unexpected, irrelevant object moving across the display. Surprisingly, this object significantly lowered accuracy in the primary task when, and only when, it failed to reach awareness. We suggest that an unexpected stimulus causes a state of alert that would normally generate an attentional shift; if this response is prevented by an attention-consuming task, a portion of the attentional resources remains allocated to the object. Such a portion is large enough to disturb performance, but not so large that the object can be recognized as task-irrelevant and accordingly ignored. Our findings have one counterintuitive implication: irrelevant stimuli might hamper some types of performance only when perceived subliminally.     

The emotional cost of charitable donations

Donations in support of a charitable cause can create a conflict between moral intuitions (e.g., fulfilling moral obligations and helping as many individuals in need as possible) and the cost entailed by following one's moral intuitions (e.g., spending money). The present paper investigates this conflict by putting people in a situation in which they must choose whether to help three women by giving more money or help one woman by giving less. In addition, the paper uses the attraction effect paradigm to counteract the single victim effect and reduce the conflict. Experiment 1 demonstrates that in a two-alternative context the majority of participants choose to help one woman by giving €150 instead of helping three women by giving €450. Experiment 2 replicates this finding and highlights the role of emotion regulation strategies in the management of the emotional conflict arising in the two-alternative condition. In both studies, the introduction of a third, dominated alternative reduces the conflict and makes it easier to choose the programme asking for a higher donation and helping three women. Implications for charitable donations and the role of the conflict between moral intuitions and economic costs are discussed.     

The cost of forfeiting causal inheritance

Jaegwon Kim’s causal inheritance principle says that the causal powers of a mental property instance are identical with the causal powers of its particular physical realizer. Sydney Shoemaker’s subset account of realization is at odds with Kim’s principle: it says that a mental property instance has fewer causal powers than Kim’s principle entails. In this paper, I argue that the subset account should be rejected because it has intolerable consequences for mental causation, consequences that are avoided by accepting causal inheritance. I develop my argument in part by drawing on one of the central debates that has arisen regarding the extended mind hypothesis defended by Andy Clark and David Chalmers.     

The emotional cost of charitable donations

Donations in support of a charitable cause can create a conflict between moral intuitions (e.g., fulfilling moral obligations and helping as many individuals in need as possible) and the cost entailed by following one's moral intuitions (e.g., spending money). The present paper investigates this conflict by putting people in a situation in which they must choose whether to help three women by giving more money or help one woman by giving less. In addition, the paper uses the attraction effect paradigm to counteract the single victim effect and reduce the conflict. Experiment 1 demonstrates that in a two-alternative context the majority of participants choose to help one woman by giving €150 instead of helping three women by giving €450. Experiment 2 replicates this finding and highlights the role of emotion regulation strategies in the management of the emotional conflict arising in the two-alternative condition. In both studies, the introduction of a third, dominated alternative reduces the conflict and makes it easier to choose the programme asking for a higher donation and helping three women. Implications for charitable donations and the role of the conflict between moral intuitions and economic costs are discussed.     

The role of a guessing strategy in the Bransford-Franks paradigm

Within the framework of the Bransford-Franks paradigm, variations of two memory models and a guessing strategy hypothesis were evaluated using concepts that differed in the number of atomic units each contained (‘concept size’). Results showed that, though the precise patterns of recognition for concept size were not completely consistent with any of the explanations, the changes in the patterns across concept size agreed with the guessing strategy hypothesis. It was argued that the subject's interpretation of the guessing strategy is likely to be a similar but simpler version of the experimenter-theorist's formal model, with the consequence that, while less sensitive to the finer details of the formal model, it will still reflect coarser differences.     

The use of feedback in education: a complex instructional strategy

The use of feedback to improve students' academic performance involves complex instructional strategies. There are a number of instructional problems within these strategies that may be overlooked. These include the influence of emotional responses, interactions between teacher and student, and levels of cognitive processing involved. Feedback should be viewed as an interactive, empirically driven, problem-solving process.