Dissociating position and heading estimations: Rotated visual orientation cues perceived after walking reset headings but not positions

This project examined the roles of idiothetic cues due to individuals’ movement and allothetic cues independent of individuals’ movement in individuals’ estimations of their position and heading during locomotion. In an immersive virtual environment, participants learned the locations of five objects and then moved along two legs of a path before positioning the origin and the objects. Participants’ estimations of their test position and their test heading were calculated based on the responded objects’ locations, using a method of dissociating position estimation and heading estimation developed in this project. Results showed that when a conflicting visual orientation cue was presented after walking, participants relied on the allothetic cues (i.e., the visual orientation cue) for their heading estimation, but on idiothetic cues for their position estimation. These results indicate that after participants updated their position in terms the origin of the path (homing vector) via path integration, they estimated their heading. These results are inconsistent with the theoretical models stipulating that homing vectors are specified in terms of participants’ body coordinate systems, but are consistent with the models stipulating that both homing vectors and participants’ heading are specified in terms of a fixed reference direction in the environment.     

Nonintentional task set activation: Evidence from implicit task sequence learning

Studies have shown that task sets could be configured endogenously (i.e., on the basis of memory) according to an explicit sequence or exogenously according to a task cue. In two experiments, we examined whether an implicitly learned sequence could facilitate task set configuration without participants’ intention. These experiments led to opposite conclusions regarding this question, but their methodology made it impossible to distinguish between the interpretations. We altered the task-switching paradigm by embedding a hidden task sequence, while randomizing all other aspects, including perceptual (i.e., task cues) and motor elements. We found that a sequence of tasks, proper, was learned implicitly and that the memory of that sequence endogenously facilitated task decision processes without the participants’ explicit knowledge.     

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.     

Learning in noise: Dynamic decision-making in a variable environment

In engineering systems, noise is a curse, obscuring important signals and increasing the uncertainty associated with measurement. However, the negative effects of noise are not universal. In this paper, we examine how people learn sequential control strategies given different sources and amounts of feedback variability. In particular, we consider people’s behavior in a task where short- and long-term rewards are placed in conflict (i.e., the best option in the short-term is worst in the long-term). Consistent with a model based on reinforcement learning principles [Gureckis, T., & Love, B.C. Short term gains, long term pains: How cues about state aid learning in dynamic environments. Cognition (in press)], we find that learners differentially weight information predictive of the current task state. In particular, when cues that signal state are noisy, we find that participants’ ability to identify an optimal strategy is strongly impaired relative to equivalent amounts of noise that obscure the rewards/valuations of those states. In other situations, we find that noise and noise in reward signals may paradoxically improve performance by encouraging exploration. Our results demonstrate how experimentally-manipulated task variability can be used to test predictions about the mechanisms that learners engage in dynamic decision making tasks.     

Social cues for creativity: The impact of behavioral mimicry on convergent and divergent thinking

We present behavioral mimicry as a social cue for creative thinking. Specifically, we argue that being mimicked by an interaction partner cues convergent thinking by signalling a social opportunity for collaboration, while not being mimicked cues divergent thinking by signalling a social demand for improvisation and innovation. To test this theory, we experimentally manipulated whether individuals were subtly mimicked or not by an experimenter during a 5 min social interaction, and subsequently measured participants’ capacity for convergent thinking (Experiment 1) and divergent thinking (Experiment 2). The results point to the importance of understanding how social relationships influence the creative processes and contributes to the growing understanding of the social function of behavioral mimicry.     

Very clever homunculus: Compound stimulus strategies for the explicit task-cuing procedure

In two experiments, subjects were given arbitrary letter cues or meaningful word cues that specified the task to be performed on a subsequent target stimulus. Letter and word cues were presented in separate blocks. There were two cues of each type for each task. Three kinds of transitions separated tasks:cue repetitions, in which both the cue and the task repeated;task repetitions, in which the cue changed but the task repeated; andtask alternations, in which both the cue and the task changed. Responses were faster for cue than for task repetitions for both cue types. With word cues, task repetitions were not reliably faster than task alternations. With letter cues, task repetitions were reliably faster than task alternations in the first block but not in the second block. The results suggest that subjects responded to the compound of the cue and the target rather than switching task set between trials.     

Unconscious activation of task sets

Using an explicit task cuing paradigm, we tested whether masked cues can trigger task-set activation, which would suggest that unconsciously presented stimuli can impact cognitive control processes. Based on a critical assessment of previous findings on the priming of task-set activation, we present two experiments with a new method to approach this subject. Instead of using a prime, we varied the visibility of the cue. These cues either directly signaled particular tasks in Experiment 1, or certain task transitions (i.e., task repetitions or switches) in Experiment 2. While both masked task and transition cues affected task choice, only task cues affected the speed of task performance. This observation suggests that task-specific stimulus–response rules can be activated only by masked cues that are uniquely associated with a particular task. Taken together, these results demonstrate that unconsciously presented stimuli have the power to activate corresponding task sets.     

Investigating the time course of tactile reflexive attention using a non-spatial discrimination task

Peripheral cues are thought to facilitate responses to stimuli presented at the same location because they lead to exogenous attention shifts. Facilitation has been observed in numerous studies of visual and auditory attention, but there have been only four demonstrations of tactile facilitation, all in studies with potential confounds. Three studies used a spatial (finger versus thumb) discrimination task, where the cue could have provided a spatial framework that might have assisted the discrimination of subsequent targets presented on the same side as the cue. The final study circumvented this problem by using a non-spatial discrimination; however, the cues were informative and interspersed with visual cues which may have affected the attentional effects observed. In the current study, therefore, we used a non-spatial tactile frequency discrimination task following a non-informative tactile white noise cue. When the target was presented 150 ms after the cue, we observed faster discrimination responses to targets presented on the same side compared to the opposite side as the cue; by 1000 ms, responses were significantly faster to targets presented on the opposite side to the cue. Thus, we demonstrated that tactile attentional facilitation can be observed in a non-spatial discrimination task, under unimodal conditions and with entirely non-predictive cues. Furthermore, we provide the first demonstration of significant tactile facilitation and tactile inhibition of return within a single experiment.     

I see what you’re saying: Voice signals influence children’s judgments of direct and averted gaze

Adults use gaze and voice signals as cues to the mental and emotional states of others. We examined the influence of voice cues on children’s judgments of gaze. In Experiment 1, 6-year-olds, 8-year-olds, and adults viewed photographs of faces fixating the center of the camera lens and a series of positions to the left and right and judged whether gaze was direct or averted. On each trial, participants heard the participant-directed voice cue (e.g., “I see you”), an object-directed voice cue (e.g., “I see that”), or no voice. In 6-year-olds, the range of directions of gaze leading to the perception of eye contact (the cone of gaze) was narrower for trials with object-directed voice cues than for trials with participant-directed voice cues or no voice. This effect was absent in 8-year-olds and adults, both of whom had a narrower cone of gaze than 6-year-olds. In Experiment 2, we investigated whether voice cues would influence adults’ judgments of gaze when the task was made more difficult by limiting the duration of exposure to the face. Adults’ cone of gaze was wider than in Experiment 1, and the effect of voice cues was similar to that observed in 6-year-olds in Experiment 1. Together, the results indicate that object-directed voice cues can decrease the width of the cone of gaze, allowing more adult-like judgments of gaze in young children, and that voice cues may be especially effective when the cone of gaze is wider because of immaturity (Experiment 1) or limited exposure (Experiment 2).     

Uncertainty is associated with increased selective attention and sustained stimulus processing

Uncertainty about future threat has been found to be associated with an overestimation of threat probability and is hypothesized to elicit additional allocation of attention. We used event-related potentials to examine uncertainty-related dynamics in attentional allocation, exploiting brain potentials’ high temporal resolution and sensitivity to attention. Thirty participants performed a picture-viewing task in which cues indicated the subsequent picture valence. A certain-neutral and a certain-aversive cue accurately predicted subsequent picture valence, whereas an uncertain cue did not. Participants overestimated the effective frequency of aversive pictures following the uncertain cue, both during and after the task, signifying expectancy and covariation biases, and they tended to express lower subjective valences for aversive pictures presented after the uncertain cue. Pictures elicited increased P2 and LPP amplitudes when their valence could not be predicted from the cue. For the LPP, this effect was more pronounced in response to neutral pictures. Uncertainty appears to enhance the engagement of early phasic and sustained attention for uncertainly cued targets. Thus, defensive motivation related to uncertainty about future threat elicits specific attentional dynamics implicating prioritization at various processing stages, especially for nonthreatening stimuli that tend to violate expectations.     

Cue–task associations in task switching

Cognitive flexibility can be studied using the task-switching paradigm. This paradigm requires subjects to adapt behaviour to changing contexts as indicated by a cue. In our study, we addressed the question of how cue-based implementation of mental “task sets” occurs. We assumed that cues build up associations to the tasks that they indicate. These associations lead to retrieval of the associated task set once the cue shows up again. In three experiments, we tested this assumption using a negative transfer paradigm. First participants were exposed to one cue–task mapping. After a training phase, the cue–task mapping changed in either of two ways. Whereas one group of participants got new cues, the other experienced a reversal of the learnt cue–task mapping. Our results show that participants build up cue–task associations and that these formerly learnt associations can hamper the implementation of new cue–task mappings (particular with mapping reversal). Prolonged preparation time decreased the cost of changing the cue–task mapping but did not change the overall pattern of results.     

Effects of Social Cues,Task Complexity,and Sex on Intrinsic Motivation and Task Perceptions: A Test of the Task-Instrumentality Hypothesis

This study investigated the interaction of task complexity, social cues, and sex on measures of intrinsic motivation and task perceptions. Social cues were in the form of co-worker statements regarding their preference for intrinsic or extrinsic task outcomes. It was predicted that to the extent the task was instrumental in meeting subjects' expectations (motivational orientation) evoked by the co-worker cue, higher levels of satisfaction, if not intrinsic motivation, would be present. This was called the task-instrumentality hypothesis. To assess sex effects related to the possibility that women may react differently to the task and co-worker cues, sex was included as a factor in the design. The design was a 2 (Cue: Intrinsic vs. Extrinsic) x 2 (Task: Simple vs. Complex) x 2 Sex: (Male vs. Female Subjects) factorial design. Subjects were 81 undergraduate students. The results indicate that for the behavioral measures of intrinsic motivation the instrumentality hypothesis was supported for men only, as evidenced by a significant three-way interaction. In addition, exploratory analyses were also conducted. The results are discussed from a motivational-orientations perspective.     

Processing of probabilistic information in weight perception and motor prediction

We studied the effects of probabilistic cues, i.e., of information of limited certainty, in the context of an action task (GL: grip-lift) and of a perceptual task (WP: weight perception). Normal subjects (n = 22) saw four different probabilistic visual cues, each of which announced the likely weight of an object. In the GL task, the object was grasped and lifted with a pinch grip, and the peak force rates indicated that the grip and load forces were scaled predictively according to the probabilistic information. The WP task provided the expected heaviness related to each probabilistic cue; the participants gradually adjusted the object’s weight until its heaviness matched the expected weight for a given cue. Subjects were randomly assigned to two groups: one started with the GL task and the other one with the WP task. The four different probabilistic cues influenced weight adjustments in the WP task and peak force rates in the GL task in a similar manner. The interpretation and utilization of the probabilistic information was critically influenced by the initial task. Participants who started with the WP task classified the four probabilistic cues into four distinct categories and applied these categories to the subsequent GL task. On the other side, participants who started with the GL task applied three distinct categories to the four cues and retained this classification in the following WP task. The initial strategy, once established, determined the way how the probabilistic information was interpreted and implemented.     

Do people automatically track others’ beliefs? Evidence from a continuous measure

Recent findings suggest that tracking others’ beliefs is not always effortful and slow, but may rely on a fast and implicit system. An untested prediction of the automatic belief tracking account is that own and others’ beliefs should be activated in parallel. We tested this prediction measuring continuous movement trajectories in a task that required deciding between two possible object locations. We independently manipulated whether participants’ belief about the object location was true or false and whether an onlooker’s belief about the object location was true or false. Manipulating whether or not the agent’s belief was ever task relevant allowed us to compare performance in an explicit and implicit version of the same task. Movement parameters revealed an influence of the onlooker’s irrelevant belief in the implicit version of the task. This provides evidence for parallel activation of own and others’ beliefs.     

The effect of newly trained verbal and nonverbal labels for the cues in probabilistic category learning

Learning in a well-established paradigm of probabilistic category learning, the weather prediction task, has been assumed to be mediated by a variety of strategies reflecting explicit learning processes, such as hypothesis testing, when it is administered to young healthy participants. Higher categorization accuracy has been observed in the task when explicit processes are facilitated. We hypothesized that furnishing verbal labels for the cues would boost the formation, testing, and application of verbal rules, leading to higher categorization accuracy. We manipulated the availability of cue names by training separate groups of participants for three consecutive days to associate hard-to-name artificial auditory cues to pseudowords or to hard-to-name ideograms, or to associate stimulus intensity with colors; a fourth group remained unexposed to the cues. Verbal labels, cue individuation, and exposure to the stimulus set each had an additive effect on categorization performance in a subsequent 200-trial session of the weather prediction task using these auditory cues. This study suggests that cue nameability, when controlled for cue individuation and cue familiarity, has an effect on hypothesis-testing processes underlying category learning.     

Methodological and empirical issues when dissociating cue-related from task-related processes in the explicit task-cuing procedure

In the explicit cuing version of the task-switching paradigm, each individual task is indicated by a unique task cue. Consequently, a task switch is accompanied by a cue switch. Recently, it has been proposed that priming of cue encoding contributes to the empirically observed switch costs. This proposal was experimentally supported by using a 2:1 mapping of cues to tasks, so that a cue switch does not necessarily imply a task switch. The results indeed suggested a substantial contribution of “cue-switch costs” to task-switch costs. Here we argue that the 2:1 mapping potentially leads to an underestimation of “pure” task-switch costs. To support this argument, we report the results of a new study in which we used “transition cues” that indicate the identity of the current task based on the identity of the preceding task. This new type of cue allows a full factorial manipulation of cue switches and task switches because it includes the condition in which a cue repetition can also indicate a task switch (i.e., when the “switch” cue is repeated). We discuss the methodological implications and argue that the present approach has merits relative to the previously used 2:1 mapping of cues to tasks.     

Tiger salamanders’ (<Emphasis Type="Italic">Ambystoma tigrinum</Emphasis>) response learning and usage of visual cues

We explored tiger salamanders’ (Ambystoma tigrinum) learning to execute a response within a maze as proximal visual cue conditions varied. In Experiment 1, salamanders learned to turn consistently in a T-maze for reinforcement before the maze was rotated. All learned the initial task and executed the trained turn during test, suggesting that they learned to demonstrate the reinforced response during training and continued to perform it during test. In a second experiment utilizing a similar procedure, two visual cues were placed consistently at the maze junction. Salamanders were reinforced for turning towards one cue. Cue placement was reversed during test. All learned the initial task, but executed the trained turn rather than turning towards the visual cue during test, evidencing response learning. In Experiment 3, we investigated whether a compound visual cue could control salamanders’ behaviour when it was the only cue predictive of reinforcement in a cross-maze by varying start position and cue placement. All learned to turn in the direction indicated by the compound visual cue, indicating that visual cues can come to control their behaviour. Following training, testing revealed that salamanders attended to stimuli foreground over background features. Overall, these results suggest that salamanders learn to execute responses over learning to use visual cues but can use visual cues if required. Our success with this paradigm offers the potential in future studies to explore salamanders’ cognition further, as well as to shed light on how features of the tiger salamanders’ life history (e.g. hibernation and metamorphosis) impact cognition.     

Navigating through abstract decision spaces: Evaluating the role of state generalization in a dynamic decision-making task

Research on dynamic decision-making tasks, in which the payoffs associated with each choice vary with participants’ recent choice history, shows that humans have difficulty making long-term optimal choices in the presence of attractive immediate rewards. However, a number of recent studies have shown that simple cues providing information about the underlying state of the task environment may facilitate optimal responding. In this study, we examined the mechanism by which this state knowledge influences choice behavior. We examined the possibility that participants use state information in conjunction with changing payoffs to extrapolate payoffs in future states. We found support for this hypothesis in an experiment in which generalizations based on this state information worked to the benefit or detriment of task performance, depending on the task’s payoff structure.     

Switch detection in preschoolers' cognitive flexibility

The current study addressed the role of switch detection in cognitive flexibility by testing the effect of transition cues (i.e., cues that directly signal the need to switch or maintain a given task goal) in a cued set-shifting paradigm at 5 years of age. Children performed better, especially on switch trials, when transition cues were combined with traditional task cues (i.e., cues that directly signal the relevant task on a given trial) relative to conditions without transition cues. This effect was not influenced by explicit knowledge of transition cues or transition cue transparency, suggesting that transition cues did not need to be semantically processed to be beneficial. These findings reveal that young children’s difficulties in set-shifting situations stem partially from failures to monitor for the need to switch.     

The hidden persuaders break into the tired brain

There is a long-lasting debate on whether subliminal advertising actually works. In this context there are some studies suggesting that subjects’ motivation is a crucial point. Karremans et al. [Karremans, J. C., Stroebe, W., & Claus, J. (2006). Beyond Vicary’s fantasies: The impact of subliminal priming and brand choice. Journal of Experimental Social Psychology, 42, 792-798] showed that subjects were influenced in their intention to drink a specific brand of soft drink by a subliminally presented brand prime, but only if they were thirsty. In the present study, we adapted their paradigm to the concept of ‘concentration’ and embedded the subliminal presentation of a brand logo into a computer game. Actual subsequent consumption of dextrose pills (of the presented or a not presented brand) was measured dependent on the level of participants’ tiredness and the subliminally presented logo. We found the same pattern as Karremans et al. (2006): only tired participants consumed more of the subliminally presented than the not presented brand. Therefore, the findings confirm that subjects are influenced by subliminally presented stimuli if these stimuli are need-related and if subjects are in the matching motivational state.