Hierarchical control of cognitive processes: switching tasks in sequences

Hierarchical control of cognitive processes was studied by examining the relationship between sequence- and task-level processing in the performance of explicit, memorized task sequences. In 4 experiments, switch costs in task-switching performance were perturbed by sequence initiation times that varied with sequence complexity, preparation time, and type of sequence transition (repetition or switch). Hierarchical control was inferred from these sequence initiation time effects and the recurrent finding of no switch cost at the first serial position across sequences, the point at which sequence-level processes are likely active in maintaining or instantiating a hierarchical control structure in working memory. These findings resonate with past research on motor programs and serial memory and provide new insights into the concepts of task set and control.     

On the discrepant results in synchrony judgment and temporal-order judgment tasks: a quantitative model

Research on the perception of temporal order uses either temporal-order judgment (TOJ) tasks or synchrony judgment (SJ) tasks, in both of which two stimuli are presented with some temporal delay and observers must judge the order of presentation. Results generally differ across tasks, raising concerns about whether they measure the same processes. We present a model including sensory and decisional parameters that places these tasks in a common framework that allows studying their implications on observed performance. TOJ tasks imply specific decisional components that explain the discrepancy of results obtained with TOJ and SJ tasks. The model is also tested against published data on audiovisual temporal-order judgments, and the fit is satisfactory, although model parameters are more accurately estimated with SJ tasks. Measures of latent point of subjective simultaneity and latent sensitivity are defined that are invariant across tasks by isolating the sensory parameters governing observed performance, whereas decisional parameters vary across tasks and account for observed differences across them. Our analyses concur with other evidence advising against the use of TOJ tasks in research on perception of temporal order.     

Judgments of relative time-to-contact of more than two approaching objects: Toward a method

Observers reported which of as many as eight computer-generated approaching objects would “hit” them first. Accuracy was above chance probability except when two-object displays contained pictorial relative size information that contradicted relative time-to-contact (TTC) information. Mean d’ and response time was greater, but mean efficiency (Barlow, 1978) was smaller with eight objects than with two. Performance was less effective when global expansion contradicted TTC information than when local expansion contradicted TTC. Results suggest that observers can judge relative TTC with as many as eight objects when certain sources of information are consistent with TTC and that observers rely on information other than, or in conjunction with, optical TTC. Also, the sources of visual information that affect performance may vary with set size, and identification (but not detection) judgments may be constrained by limited-capacity processing.     

Geometrical illusions can affect time-to-contact estimation and mimed prehension

Results indicate that under some conditions the Sander parallelogram illusion can affect time-to-contact (TTC) estimation in a prediction-motion (PM) task and in an interceptive action (IA). The illusion also affected mimed manual prehension. The implication is that the timing of responses in the PM and IA tasks may involve an estimate of TTC that is based on the perceived dimensions of the environment. Further research is warranted in the development of models of perceived collision and of visually guided actions.     

Distinguishing choice and subjective probability estimation processes: Implications for theories of judgment and for cross-cultural comparisons

Research on subjective probability (SP) often focuses on the difference between the fraction of correct binary choices and the SP that they are correct or on the deviation of the calibration curve from the diagonal. On the assumption that choice and SP judgments reflect different, albeit closely related, processes, it is important to analyze the two sources of data separately. This article uses data collected by Yates, Lee, Shinotsuka, Patalano, and Sieck (1998) from Chinese, Japanese, and Americans to demonstrate the advantages of doing so and to yield new conclusions regarding cross-cultural comparisons of judgment. One new result is that a discrete threshold model with an error term best described the choice data of all groups. From their analyses, Yates et al. (1998) had concluded that the Chinese were more overconfident than the American or Japanese. According to the present results, the Chinese appeared either more overconfident or more underconfident, depending on how the data are analyzed. The dual outcome is a consequence of the greater variability both in their SP judgments and in their binary choices. Additionally, the Chinese participants’ choices and SPs were more responsive to the base rate than were those of the other groups.     

Information mispurchase in judgment tasks: A task-driven causal mechanism

Numerous studies of predecisional information purchase indicate that humans are often seriously suboptimal in balancing the costs and benefits of the information they purchase. Underpurchase is reported in some tasks, over-purchase in others, but no convincing account has been offered of the mechanisms producing these patterns of error. The present paper attempts such an account. We first show by computer simulation that simple hill-climbing algorithms reliably reproduce patterns of over-and underpurchase found in earlier studies, and identify the task characteristics that drive this result. We then specify a novel task that should, by this account, yield a new pattern of purchase error and demonstrate that both simulated and real subjects do, in fact, show such error patterns. Implications are drawn both for research strategy in the area and for practical application.     

The effect of body posture on long-range time-to-contact estimation

On Earth, gravity accelerates freely moving objects downward, whereas upward-moving objects are being decelerated. Do humans take internalised knowledge of gravity into account when estimating time-to-contact (TTC, the time remaining before the moving object reaches the observer)? To answer this question, we created a motion-prediction task in which participants saw the initial part of an object's trajectory moving on a collision course prior to an occlusion. Observers had to judge when the object would make contact with them. The visual scene was presented with a head-mounted display. Participants lay either supine (looking up) or prone (looking down), suggestive of the ball either rising up or falling down toward them. Results showed that body posture had a significant effect on time-to-contact estimation, but only when occlusion times were long (2.5 s). The effect was also rather small. This lack of immediacy in the posture effect suggests that TTC estimation is initially robust toward the effect of gravity, which comes to bear only as more time is allowed for post-processing of the visual information.     

Spontaneous discounting of availability in frequency judgment tasks

Discounting is a causal-reasoning phenomenon in which increasing confidence in the likelihood of a particular cause decreases confidence in the likelihood of all other causes. This article provides evidence that individuals apply discounting principles to making causal attributions about internal cognitive states. In particular, the three studies reported show that individuals will fail to use the availability heuristic in frequency estimations when salient causal explanations for availability exist. Experiment 1 shows that fame is used as a cue for discounting in estimates of surname frequency. Experiment 2 demonstrates that individuals discount the availability of their own last name. Experiment 3, which used individuals' initials in a letter-frequency estimation task, demonstrates that simple priming of alternative causal models leads to discounting of availability. Discounting of cognitive states can occur spontaneously, even when alternative causal models are never explicitly provided.     

Perceptual hysteresis in the judgment of auditory pitch shift

Perceptual hysteresis can be defined as the enduring influence of the recent past on current perception. Here, hysteresis was investigated in a basic auditory task: pitch comparisons between successive tones. On each trial, listeners were presented with pairs of tones and asked to report the direction of subjective pitch shift, as either “up” or “down.” All tones were complexes known as Shepard tones (Shepard, 1964), which comprise several frequency components at octave multiples of a base frequency. The results showed that perceptual judgments were determined both by stimulus-related factors (the interval ratio between the base frequencies within a pair) and by recent context (the intervals in the two previous trials). When tones were presented in ordered sequences, for which the frequency interval between tones was varied in a progressive manner, strong hysteresis was found. In particular, ambiguous stimuli that led to equal probabilities of “up” and “down” responses within a randomized context were almost fully determined within an ordered context. Moreover, hysteresis did not act on the direction of the reported pitch shift, but rather on the perceptual representation of each tone. Thus, hysteresis could be observed within sequences in which listeners varied between “up” and “down” responses, enabling us to largely rule out confounds related to response bias. The strength of the perceptual hysteresis observed suggests that the ongoing context may have a substantial influence on fundamental aspects of auditory perception, such as how we perceive the changes in pitch between successive sounds.     

A theory of relative judgment

This paper is concerned with the scaling method of “ratio estimation.” The simple theory that equates reported ratio judgments to ratios of psychological magnitudes is first considered, then two close relatives of this theory are formulated, each of which places weaker constraints on the structure of the data. Structural conditions are stated that express the relations that must hold among observed ratio judgments for each of the models. The models proposed are “cumulative” in the sense that the second is a weakened version of the first, and the third a weakened version of the second. A special feature of the models is that they may be tested entirely in terms of observables, avoiding the necessity of scale construction prior to testing. Tests were carried out on data from 9 published studies. The strongest model, typically used in scale construction using ratio estimation data, was generally inadequate, showing large systematic errors. However, the weakest version generally passed the tests of internal consistency, and the model equation provided a basis for constructing ratio scales utilizing bias parameters.     

Comparison processes in social judgment: mechanisms and consequences

This article proposes an informational perspective on comparison consequences in social judgment. It is argued that to understand the variable consequences of comparison, one has to examine what target knowledge is activated during the comparison process. These informational underpinnings are conceptualized in a selective accessibility model that distinguishes 2 fundamental comparison processes. Similarity testing selectively makes accessible knowledge indicating target-standard similarity, whereas dissimilarity testing selectively makes accessible knowledge indicating target-standard dissimilarity. These respective subsets of target knowledge build the basis for subsequent target evaluations, so that similarity testing typically leads to assimilation whereas dissimilarity testing typically leads to contrast. The model is proposed as a unifying conceptual framework that integrates diverse findings on comparison consequences in social judgment.     

Selectional processes in causality judgment

Two experiments illustrate the way in which competition between potential causes occurs when subjects are asked to judge the extent to which an action is the cause of an outcome. In the first experiment, it was found that introducing occurrences of the outcome in the absence of the action reduced causality judgments, but this effect was attenuated if these outcomes were signaled by another stimulus. In the second experiment, a delay between the action and the outcome reduced judgments, but this could be abolished by inserting a stimulus between the action and the outcome. The results are discussed in terms of a view of causality judgment that assumes that such judgments are based on associations between the mental representations of the action and the outcome.     

Comparison and expectancy processes in human judgment

This work explored a judgment model proposed by Manis and Paskewitz (1984a). The model suggests that prior experience with the members of a given category affects the assessment of other category members in 2 ways: (a) by providing a basis for comparison and (b) by leading the judge to expect that new exemplars will resemble those previously encountered. In 4 experiments, respondents judged the height of different people on the basis of full-length photographs. The height of the models in an induction series constituted the main independent variable. The effects of contrasting inductions (e.g., short vs. tall women) affected the judges' subsequent assessments in a test series. Both comparison and expectancy processes played a significant role, sometimes opposing one another and sometimes acting in parallel (i.e., supporting one another).     

Explicit and implicit processes in multicue judgment

In two experiments, a multicue probability learning task was used to train participants in relating judgments to a criterion, on the basis of several cues that could or could not be relevant. The outcome feedback had 25% added noise to simulate real-world experience-based learning. Judgmental strategies acquired were measured by individual multiple linear regression analyses of a test phase (with no feedback) and were compared with self-ratings of cue relevance. In a third experiment, participants were instructed explicitly on cue relevance, with no training phase. The pattern of results suggested that both implicit and explicit cognitive processes influenced judgments and that they may have been sensitive to different task manipulations in the learning phase. On more complex tasks, despite weak explicit learning, explicit processes continued to influence judgments, producing a decrement in performance. These findings explain why studies of expert judgment often show only moderate levels of self-insight, since people have only partial access to the processes determining their judgments.