Modeling icon search in ACT-R/PM

As the use of graphical user interfaces expands into new areas, icons are becoming an increasingly important aspect of GUIs. Oddly, little research has been done into the costs and benefits associated with using icons. One aspect of icons, icon borders, has been proposed as a means of adding information to icons. An experiment was conducted in which the potential cost in response time of using simple icon borders was investigated. Two models were then constructed in ACT-R/PM to carry out the same icon search task as in the experiment. The results of the modeling effort indicated an area where the design of the experiment could be improved. A second, ‘improved’ experiment was carried out, the results of which suggest areas for further improvement in the ACT-R/PM models.     

The failure of deactivating intentions: aftereffects of completed intentions in the repeated prospective memory cue paradigm

We used a newly developed experimental paradigm to investigate aftereffects of completed intentions on subsequent performance that required the maintenance and execution of new intentions. Participants performed an ongoing number categorization task and an additional prospective memory (PM) task, which required them to respond to PM cues that differed from standard stimuli in 1 particular visual feature. Although the feature defining the to-be-acted-upon PM cue changed in each block, the irrelevant PM cue of the previous PM task block was occasionally repeated in the subsequent block. In 4 experiments we found that performance in the ongoing task was substantially slowed for repeated PM cue trials compared to oddball trials, which also differed in a visual feature from standard stimuli but never served as PM cues. This aftereffect decreased as a function of delay after intention completion. These findings indicate that intentions can exhibit persisting activation even after they have been completed and may interfere with the execution of the new relevant task. Possible mechanisms and boundary conditions of this intention deactivation failure are discussed.     

The fate of completed intentions

The goal of this research was to determine whether and how people deactivate prospective memory (PM) intentions after they have been completed. One view proposes that PM intentions can be deactivated after completion, such that they no longer come to mind and interfere with current tasks. Another view is that now irrelevant completed PM intentions exhibit persisting activation, and continue to be retrieved. In Experiment 1, participants were given a PM intention embedded within the ongoing task during Phase 1, after which participants were told either that the PM task had been completed or suspended until later. During Phase 2, participants were instructed to perform only the ongoing task and were periodically prompted to report their thoughts. Critically, the PM targets from Phase 1 reappeared in Phase 2. All of our measures, including thoughts reported about the PM task, supported the existence of persisting activation. In Experiment 2, we varied conditions that were expected to mitigate persisting activation. Despite our best attempts to promote deactivation, we found evidence for the persistence of spontaneous retrieval in all groups after intentions were completed. The theoretical and practical implications of this potential dark side to spontaneous retrieval are discussed.     

Delaying gratification for food and tokens in capuchin monkeys (Cebus apella) and chimpanzees (Pan troglodytes): when quantity is salient, symbolic stimuli do not improve performance

Capuchin monkeys have been tested for the capacity to delay gratification for accumulating rewards in recent studies and have exhibited variable results. Meanwhile, chimpanzees have consistently excelled at this task. However, neither species have ever been tested at accumulating symbolic tokens instead of food items, even though previous reports indicate that tokens sometimes facilitate performance in other self-control tasks. Thus, in the present study, we tested capuchin monkeys and chimpanzees for their capacity to delay gratification in a delay maintenance task, in which an experimenter presented items, one at a time, to within reach of an animal for as long as the animal refrained from taking them. In Experiment 1, we assessed how long capuchin monkeys could accumulate items in the delay maintenance task when items were food rewards or tokens exchangeable for food rewards. Monkeys accumulated more food rewards than they did tokens. In Experiment 2, we tested capuchin monkeys and chimpanzees in a similar accumulation test. Whereas capuchins again accumulated more food than tokens, all chimpanzees but one showed no difference in performance in the two conditions. These findings provide additional evidence that chimpanzees exhibit greater self-control capacity in this task than do capuchin monkeys and indicate that symbolic stimuli fail to facilitate delay maintenance when they do not abstract away from the quantitative dimension of the task. This is consistent with previous findings on the effects of symbols on self-control and illuminates what makes accumulation a particularly challenging task.     

线索聚焦性影响前瞻记忆意向维持与提取：来自眼动追踪的证据

研究以眼动追踪的方法探讨线索聚焦性对前瞻记忆(prospective memory, PM）加工过程的影响。实验1中,28名被试完成了线索聚焦和非聚焦两类PM眼动追踪任务。结果发现,个体在聚焦和非聚焦两类PM任务意向维持、意向提取阶段上均表现出不同的眼动加工特征。实验2中,研究进一步对线索聚焦和非聚焦两个PM任务中PM线索词重复次数进行平衡,并重复了实验1的研究结果,说明实验1所观测到的效应不是PM线索词重复造成的混淆,线索聚焦性影响PM的意向维持、意向提取过程,研究结果支持多重加工理论。     

Capuchin monkeys’ use of human and conspecific cues to solve a hidden object-choice task

Learning by watching others can provide valuable information with adaptive consequences, such as identifying the presence of a predator or locating a food source. The extent to which nonhuman animals can gain information by reading the cues of others is often tested by evaluating responses to human gestures, such as a point, and less often evaluated by examining responses to conspecific cues. We tested whether ten brown capuchin monkeys (Cebus [Sapajus] apella) were able to use cues from monkeys and a pointing cue from a human to obtain hidden rewards. A monkey could gain access to a reward hidden in one of two locations by reading a cue from a conspecific (e.g., reaching) or a human pointing. We then tested whether they could transfer this skill from monkeys to humans, from humans to monkeys, and from one conspecific to another conspecific. One group of monkeys was trained and tested using a conspecific as the cue-giver and was then tested with a human cue-giver. The second group of monkeys was trained and tested with a human cue-giver and was then tested with a monkey cue-giver. Monkeys that were successful with a conspecific cue-giver were also tested with a novel conspecific cue-giver. Monkeys learned to use a human point and conspecific cues to obtain rewards. Monkeys that had learned to use the cues of a conspecific to obtain rewards performed significantly better than expected by chance when they were transferred to the cues of a novel conspecific. Monkeys that learned to use a human point to obtain rewards performed significantly better than expected by chance when tested while observing conspecific cues. Some evidence suggested that transferring between conspecific cue-givers occurred with more facility than transferring across species. Results may be explained by simple rules of association learning and stimulus generalization; however, spontaneous flexible use of gestures across conspecifics and between different species may indicate capuchins can generalize learned social cues within and partially across species.     

The effects of age, enactment, and cue-action relatedness on memory for intentions in the Virtual Week task

ABSTRACT The current study investigated the influence of encoding modality and cue-action relatedness on prospective memory (PM) performance in young and older adults using a modified version of the Virtual Week task. Participants encoded regular and irregular intentions either verbally or by physically performing the action during encoding. For half of the intentions there was a close semantic relation between the retrieval cue and the intended action, while for the remaining intentions the cue and action were semantically unrelated. For irregular tasks, both age groups showed superior PM for related intentions compared to unrelated intentions in both encoding conditions. While older adults retrieved fewer irregular intentions than young adults after verbal encoding, there was no age difference following enactment. Possible mechanisms of enactment and relatedness effects are discussed in the context of current theories of event-based PM.     

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.     

Prospective memory performance across adolescence

In the present study, the authors explored age differences in event-based prospective memory (PM) across adolescence. The tasks consisted of an ongoing task (OT; i.e., personality questionnaire items, math problems) and an embedded prospective task that required participants to remember to make a special response whenever they encountered a PM cue (i.e., a negative word in the OT). The 341 participants (aged 13-22 years) revealed a significant main effect of age, which indicated better PM performance of young adults compared with teenagers. Moreover, when emphasizing the OT versus the PM task, teenagers' PM profited from PM emphasis more than did young adults' PM. The authors discuss the data in the context of limited executive capacity as a factor influencing cognitive development across adolescence.     

The effects of age,enactment, and cue-action relatedness on memory for intentions in the Virtual Week task

ABSTRACT

The current study investigated the influence of encoding modality and cue-action relatedness on prospective memory (PM) performance in young and older adults using a modified version of the Virtual Week task. Participants encoded regular and irregular intentions either verbally or by physically performing the action during encoding. For half of the intentions there was a close semantic relation between the retrieval cue and the intended action, while for the remaining intentions the cue and action were semantically unrelated. For irregular tasks, both age groups showed superior PM for related intentions compared to unrelated intentions in both encoding conditions. While older adults retrieved fewer irregular intentions than young adults after verbal encoding, there was no age difference following enactment. Possible mechanisms of enactment and relatedness effects are discussed in the context of current theories of event-based PM.     

Event-based prospective remembering in a virtual world

Most laboratory-based prospective memory (PM) paradigms pose problems that are very different from those encountered in the real world. Several PM studies have reported conflicting results when comparing laboratory- with naturalistic-based studies (e.g., Bailey, Henry, Rendell, Phillips, & Kliegel, 2010 ). One key contrast is that for the former, how and when the PM cue is encountered typically is determined by the experimenter, whereas in the latter case, cue availability is determined by participant actions. However, participant-driven access to the cue has not been examined in laboratory studies focused on healthy young adults, and its relationship with planned intentions is poorly understood. Here we report a study of PM performance in a controlled, laboratory setting, but with participant-driven actions leading to the availability of the PM cue. This uses a novel PM methodology based upon analysis of participant movements as they attempted a series of errands in a large virtual building on the computer screen. A PM failure was identified as a situation in which a participant entered and exited the "cue" area outside an errand related room without performing the required errand whilst still successfully remembering that errand post test. Additional individual difference measures assessed retrospective and working memory capacity, planning ability and PM. Multiple regression analysis showed that the independent measures of verbal working memory span, planning ability, and PM were significant predictors of PM failure. Correlational analyses with measures of planning suggest that sticking with an original plan (good or bad) is related to better overall PM performance.     

Choice-induced preferences in the absence of choice: Evidence from a blind two choice paradigm with young children and capuchin monkeys

In two studies, we provide a test of the revealed-preferences account of choice-induced preferences. To do so, we introduce a blind two-choice task in which preferences cannot guide choices. Children chose between two similar objects while ignorant of the objects’ identities, and then chose between the rejected alternative and a third similar object. Monkeys were given an illusion of choice between two similar objects, and then chose between the rejected object and a third similar object. Both children and monkeys preferred the third object, indicating that they devalued the rejected object. This response pattern did not occur when the children and monkeys were not given the opportunity to choose between the two initial items. These results provide evidence against a revealed-preferences account of choice-induced preferences and demonstrate that the process of making a choice itself induces preferences.     

Evidence for spontaneous retrieval of suspended but not finished prospective memories

McDaniel and Einstein (2007) argued that prospective memories can be retrieved through spontaneous retrieval processes stimulated by the presence of a target cue. To test this claim, we investigated whether presenting a prospective memory cue during a task that did not require an intention to be performed spontaneously triggered remembering of that intention. In two experiments, participants performed an image-rating task in which a prospective memory task (to press the “Q” key when a target word appeared) was embedded. Then, participants were told that their intention was finished or suspended. Finally, participants performed a lexical decision task in which each target (and a matched control) word appeared. RTs were slower to target words than to control words when the intention was suspended but not when it was finished. These results suggest that target cues associated with suspended intentions can spontaneously trigger remembering but that finished intentions are quickly deactivated.     

Cooperative problem solving by tufted capuchin monkeys (Cebus apella): spontaneous division of labor, communication, and reciprocal altruism

Using an experimentally induced cooperation task, the authors investigated whether tufted capuchin monkeys (Cebus apella) share the following 3 characteristics of cooperation with humans: division of labor, communication, and reciprocal altruism. In Experiment 1, the authors trained individual monkeys to perform the necessary sequence of actions for rewards and tested them in pairs to assess whether they could solve the task by spontaneously dividing the sequence of actions. All pairs solved this task. In Experiment 2, monkeys worked in the cooperation task and a task requiring no partner help. They looked at the partner significantly longer in the former task than in the latter, but communicative intent could not be determined. In Experiment 3, only 1 of 2 participants obtained a reward on each trial. Monkeys maintained cooperation when their roles were reversed on alternate trials. Their cooperative performances demonstrated division of labor; results suggest task-related communication and reciprocal altruism.     

Change detection by rhesus monkeys (Macaca mulatta) and pigeons (Columba livia)

Two monkeys (Macaca mulatta) learned a color change-detection task where two colored circles (selected from a 4-color set) were presented on a 4 × 4 invisible matrix. Following a delay, the correct response was to touch the changed colored circle. The monkeys' learning, color transfer, and delay transfer were compared to a similar experiment with pigeons. Monkeys, like pigeons (Columba livia), showed full transfer to four novel colors, and to delays as long as 6.4 s, suggesting they remembered the colors as opposed to perceptual based attentional capture process that may work at very short delays. The monkeys and pigeons were further tested to compare transfer with other dimensions. Monkeys transferred to shape and location changes, unlike the pigeons, but neither species transferred to size changes. Thus, monkeys were less restricted in their domain to detect change than pigeons, but both species learned the basic task and appear suitable for comparative studies of visual short-term memory. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Time-based prospective remembering: Interference and facilitation in a dual task

The aim of this study was to analyse prospective memory behaviour when people have to fulfil two different intentions whose retention intervals partially overlapped. More specifically, the purpose of the study was to explore the effects of a secondary PM task (either time-based or event-based) on performance of a main time-based PM task. Four embedded conditions were tested: two event-based ones and two time-based ones. The time- and event-based interpolated tasks differed in how closely their target time was to the 20-minute response required by the main time-based task (16th and 19th min., respectively). The results indicated that when a main time-based prospective memory task shares a portion of the retention interval with a second time-based prospective task, this overlapping facilitated performance on the main task. However, the interpolated tasks appeared to be affected by the moment in which they were administered during the execution of the main time-based task. More specifically, a decrease in the interpolated task performance was observed when this was time-based and had to be executed very closely to the target time of the main task. On the contrary, when the two tasks were different (event-based vs. time-based), there was neither interference, nor facilitation.     

Dissociation of visual localization and visual detection in rhesus monkeys (Macaca mulatta)

Conscious and unconscious cognitive processes contribute independently to human behavior and can be dissociated. For example, humans report failing to see objects clearly in the periphery while simultaneously being able to grasp those objects accurately (Milner in Proc R Soc B Biol Sci 279:2289–2298, 2012). Knowing whether similar dissociations are present in nonverbal species is critical to our understanding of comparative psychology and the evolution of brains. However, such dissociations are difficult to detect in nonhumans because verbal reports of experience are the main way we discriminate putative conscious from unconscious processing. We trained monkeys in a localization task in which they responded to the location where a target appeared, and a matched detection task in which they reported the presence or absence of the same target. We used masking to manipulate the visibility of targets. Accuracy was high in both tasks when stimuli were unmasked and was attenuated by visual masking. At the strongest level of masking, performance in the detection task was at chance, while localization remained significantly above chance. Critically, errors in the detection task were predominantly misses, indicating that the monkeys’ behavior remained under stimulus control, but that the monkeys did not detect the target despite above-chance localization. While these results cannot establish the existence of phenomenal vision in monkeys, the dissociation of visually guided action from detection parallels the dissociation of conscious and unconscious vision seen in humans.     

The influence of high and low cue–action association on prospective memory performance

Recent discoveries in the field of prospective memory (PM) show higher accuracy for remembering intentions in which prospective cue and action are strongly associated. In two experiments presented in this paper, participants encoded both high and low association cue–action pairs and were later tested on both prospective and retrospective PM components. Results of both studies show higher PM accuracy for the low association pairs, compared to high association ones, but only for the prospective component (across both Experiments) and only when a high association cue was presented first (Experiment 2). This finding was accompanied by longer study times for the low association pairs and study times were functionally related to later performance (across both Experiments). In the retrospective component, higher accuracy was observed for pairs with high level of association (but only in the first Experiment). Data are discussed in the context of metacognitive processes possibly related to the encoding of an intention as well as cue monitoring in case of PM tasks with high memory load and varying task difficulty.     

Irrational choice behavior in human and nonhuman primates

Choice behavior in humans has motivated a large body of research with a focus on whether decisions can be considered to be rational. In general, humans prefer having choice, as do a number of other species that have been tested, even though having increased choice does not necessarily yield a positive outcome. Humans have been found to choose an option more often only because the opportunity to select it was diminishing, an example of a deviation from economic rationality. Here we extend this paradigm to nonhuman primates in an effort to understand the mechanisms underlying this finding. In this study, we presented two groups of laboratory monkeys, capuchins (Cebus apella) and rhesus macaques (Macaca mulatta), as well as human subjects, with a computerized task in which subjects were presented with two differently colored icons. When the subject selected an icon, differing numbers of food pellets were dispensed (or points were assigned), making each icon correspond to a certain level of risk (one icon yielded 1 or 4 pellets/points and the other yielded 2 or 3). Initially, both options remained constantly available and we established choice preference scores for each subject. Then, we assessed preference patterns once the options were not continuously available. Specifically, choosing one icon would cause the other to shrink in size on the screen and eventually disappear if never selected. Selecting it would restore it to its full size. As predicted, humans shifted their risk preferences in the diminishing options phase, choosing to click on both icons more equally in order to keep both options available. At the group level, capuchin monkeys showed this pattern as well, but there was a great deal of individual variability in both capuchins and macaques. The present work suggests that there is some degree of continuity between human and nonhuman primates in the desire to have choice simply for the sake of having choice.     

Not all same-different discriminations are created equal: Evidence contrary to a unidimensional account of same-different learning

In Experiment 1, we trained four pigeons to concurrently discriminate displays of 16 same icons (16S) from displays of 16 different icons (16D) as well as between displays of same icons (16S) from displays that contained 15 same icons and one different icon (15S:1D). The birds rapidly learned to discriminate 16S vs. 16D displays, but they failed to learn to discriminate 16S vs. 15S:1D displays. In Experiment 2, the same pigeons acquired the 16S vs. 15S:1D task after being required to locate and peck at the odd-item in the 15S:1D displays. Acquisition of the 16S vs. 15S:1D task had little effect on discriminative performance in the concurrent 16S:16D task, suggesting that a unidimensional entropy explanation for mastery of these two same-different tasks is not viable. During testing, the birds transferred discriminative performance in both tasks to displays composed of different visual stimuli. Such concurrent discrimination learning, performance, and transfer suggest that pigeons are flexible in the way they process the displays seen in these two same-different tasks.