Robert Rousseau

Time estimation and concurrent nontemporal processing: Specific interference from short-term-memory demands

Previous studies have shown that the effect of concurrent nontempcraLprocessmg on time astimation may vary depending on the level of difficulty of the nontemporal task. This is commonly interpreted within the context of so-called distraction/interruption models of temporal processing, which propose that as concurrent task difficulty or complexity is increased, temporal processing receives less attention. We hypothesize that the effect of nontemporal processing does not depend on the level of difficulty as such, but rather on the extent to which the concurrent nontemporal task specifically involves processing in short-term meraery. Four experiments were run in which the short-term memory requirements of concurrent tasks were systematically varied, although all of the tasks were of comparable levels of difficulty. In the first experiment, the effect of memory search on simultaneous temporal productions was proportional to the number of items to search. As with reaction time, produced intervals were shown to increase linearly with the number of items in the memorized set. In Experiment 2, a visual search involving some load on short-term memory interfered in the same way with time production, although to a lesser extent. The last two experiments showed that performing attention-demanding visual search tasks that did not involve short-term memory did not lengthen simultaneously produced time inter-vals. This suggests that interference of nontemporal processing on time processing may not be a matter of nonspecific general purpose attentional resources, but rather of concurrent short-term-memory processing demands.

Judging the relative duration of multimodal short empty time intervals

Three experiments address the cause of the different performance levels-found in time discrimination of empty intervals with durations near 250 msec. Performance differed according to the kind of sensory modality that marked the intervals. With a procedure in which the type of marker was randomized from trial to trial, it was shown that variability of discrimination judgments could not be attributed entirely to the variability of the criterion on which-a judgment was based. Such a randomization slightly affects discrimination but provokes a reorganization related to marker conditions of the probabilities of judging an interval to be short or long. Moreover, it was shown that within intramodal conditions, physical characteristics of markers influence the discrimination performances. To account for the results generated with different marker-type intervals at 250 msec, we propose that two types of processor may be involved in duration discrimination: one is specifically related to a given sensory modality, whereas the other is aspecific and responsible for discrimination of intermodal intervals.

Time estimation as an index of processing demand in memory search

The influence of cognitive processing on time estimation was investigated. A temporal-interval production and memory-search dual task was devised so that some operations needed by the search took place during the time interval. Subjects were required to produce time intervals concurrently with a memory-search task similar to Sternbergs (1966). On the average, duration increased in proportion to the number of elements in the positive set. In general, temporal-production duration displayed the features previously observed, with speeded responses in memory-search tasks. The additive effect of memory scanning on time estimation made possible an interpretation involving inhibition of timing during concurrent processing in short-term memory. This concurrent processing situation appears to be a fruitful procedure for the study of the interaction between time estimation and cognitive processes. However, since a methodological feature of the search task could favor a successive processing strategy, the possibility that subjects performed the time production and the item-recognition tasks successively makes a conclusive interpretation difficult.

Duration discrimination of empty time intervals marked by intermodal pulses

In 1973, Rousseau and Kristofferson reported that short empty intermodal time intervals marked by a light flash and a brief tone were poorly discriminated by subjects, and that AT,5 was constant over a large range of durations. It led them to suggest that short intramodal empty intervals, marked by stimuli from the same sensory modality, might be handled by a “more efficient mechanism” to which intermodal intervals would not have access. Unfortunately, their study lacked the basic evidence needed to make a strong statement: no direct comparison between inter- and intramodal duration discrimination and no within-subject discrimination function were available. To clarify these two issues, three experiments were performed. The data indicate that intermodal time intervals are discriminated more poorly than intramodal ones, and that intermodal duration discrimination functions follow Weber’s law. Analysis of data from different experiments lead to the conclusion that inter- and intramodal intervals are timed by a common timekeeper and that intermodal intervals induce a large noise component in the timekeeping operation.

Stop-reaction time and the internal clock

In astop-reaction-time (stop-RT) task, a subject is presented with a regular, isochronous sequence of brief signals separated by a constant time interval, orstimulus onset asynchrony (SOA). His/her task is to press a response key as fast as possible when the sequence stops. As the sequence unfolds, an internal representation of the SOA duration builds up. Stop-RT is assumed to be triggered when aninternal clock, operating as an “alarm clock,” reaches a time criterion. Criterion setting is contingent upon variability in the SOA’s internal representation. In Experiment 1A, stop-RT was measured for isochronous sequences of brief tones, light flashes, and also sequences of tones and flashes presented in regular alternation (tone-light-tone…). Stop-RT was a linear function of SOA duration (ranging from 250 to 1,000 msec), regardless of modality, supporting a “central-clock” hypothesis. On the other hand, taken together, the results of Experiments 1A, 1B, 2, and 3 suggest that no internal representation of thebimodal (tone-light) SOA of alternating sequences builds up. Indeed, an alternating sequence is physically equivalent to two interlaced isochronous subsequences, one auditory and one visual. So,two internal representations, one for the auditory (tone-tone) and one for the visual (light-light) SOA, could build up, andtwo time criteria running “in parallel” could thus support stop-RT. To provide a critical test of parallel timing, stop-RT was measured for bimodal 5∶3 polyrhythms formed by the superposition of auditory and visual isochronous sequences that haddifferent SOA durations (Experiment 4). Parallel timing accounted for a large proportion of variance in polyrhythmic stop-RT data. Overall findings can be accounted for by assuming a functional architecture of an internal clock in which pulses emitted by acentral pacemaker are available in parallel with twomodality-specific switch-accumulator “timing modules.”

An Adaptive Counter Model for Time Estimation

The main objection to Poisson counter models for time estimation originates from their prediction that VAR(T) = KT, since empirical data generally show SD(T) = K T (at least up to T = 2 sec). Furthermore, as is the case for other psychophysical models, Poisson models do not account for the effect of cognitive variables on time estimation. FIGURE 1 is a description of a modified Poisson counter model compatible with Weber’s law and able to take into account selective attention. The model has been tested with two experiments in which subjects produce temporal intervals (by finger-tapping) adjusted by feedback around a target duration, T.

Object permanence and working memory in cats (Felis catus).

Cats (Felis catus) find an object when it is visibly moved behind a succession of screens. However, when the object is moved behind a container and is invisibly transferred from the container to the back of a screen, cats try to find the object at or near the container rather than at the true hiding place. Four experiments were conducted to study search behavior and working memory in visible and invisible displacement tests of object permanence. Experiment 1 compared performance in single and in double visible displacement trials. Experiment 2 analyzed search behavior in invisible displacement tests and in analogs using a transparent container. Experiments 3 and 4 tested predictions made from Experiment 1 and 2 in a new situation of object permanence. Results showed that only the position changes that cats have directly perceived are encoded and activated in working memory, because they are unable to represent or infer invisible movements.

The role of metacognition in the relationship between objective and subjective measures of situation awareness

The present paper is concerned with the relationship between subjective and objective measures of situation awareness (SA) within the context of a realistic command and control (C2) scenario. A 2-day scenario involved a joint military–civilian C2 exercise relating to the (crisis) management of a large event held in a metropolitan area. The role of participants comprised both the acquisition and maintenance of SA of each crisis event and the coordination of an appropriate course of action. Two measures of SA were collected at the end of each day–Situation Awareness Rating Technique (SART) and Quantitative Assessment of Situation Awareness (QUASA). No correlation was found between QUASA confidence and accuracy scores. However, SART SA, SART S(upply) and SART U(nderstanding) scores showed a negative correlation with QUASA accuracy scores. These results are interpreted in light of Koriat et al.s (Koriat, A., et al., 2008. Information-based and experience-based metacognitive judgement: evidence from subjective confidence. In: J. Dunlosky and R.A. Bjork, eds. Handbook of metamemory and memory. New York: Taylor & Francis, 117–135) framework of information- and experience-based metacognitive judgements and practical implications for the subjective measurement of SA are discussed. SA is a critical real-world concept, yet its measurement remains ambiguous. The relationship between subjective and objective SA measures was examined within the context of a realistic C2 scenario. Using theories of metacognition, unique insights were gained into how subjective SA plays a strategic role in the acquisition of SA.

Decision Analysis Using Policy Capturing and Process Tracing Techniques in a Simulated Naval Air-Defense Task:

Research in cognitive systems engineering (CSE) and decision support requires an understanding of the psychological processes involved in a given task. The purpose of the present study is to investigate how policy capturing and process tracing may help understand the decision mechanisms involved in a naval air-defense task and characterize how human decision making effectiveness can be improved. We report results from a study in which participants performed a threat evaluation and weapons assignment task within a naval air-defense microworld. Policy capturing and process tracing techniques provide both converging perspectives and complementary insights into complex decision making processes.

Assessing temporal support for dynamic decision making in C2

Temporal awareness is key to successful decision making in a wide range of command and control situations, yet little explicit support to maintaining temporal awareness is provided by Decision Support Systems (DSS) for time-critical decisions. In the context of simulated weapon-target scheduling, the present study compared the decision support gained from two display formats: typical geospatial display and temporal display. The results demonstrated that the temporal display facilitates scheduling performance though its beneficial impact seems to require greater familiarization.