Biomedical subjects

Pierre Jolicoeur

Publications and source records attributed to Pierre Jolicoeur.

10 recordsLinked to original sources

PubMed2003

Recognition thresholds for plane-rotated pictures of familiar objects.

We investigated picture plane rotation effects on the minimum stimulus duration required to recognise pictures of familiar objects in a picture-word verification task. Participants made unspeeded responses, selecting from 126 written alternatives. Longer stimulus durations were needed to identify plane-misoriented views. These orientation effects were non-linear, arguing against a simple mental rotation account of compensation for plane misorientation in identification tasks. Orientation effects were found for almost all items, in particular including those labelled at the basic level (cf. Hamm, McMullen, 1998, Journal of Experimental Psychology: Human Perception and Performance 24, 413-426). We suggest that plane misorientation increases the difficulty of basic level as well as subordinate level identification unless only a small, visually dissimilar set of stimuli are presented. Errors in the task were analysed to provide an alternative, objective measure of perceived visual similarity, by assessing the number and nature of mistaken identifications made to a given target object. We propose that misorientation effects are best understood in terms of the effects of the perceived visual similarity of a target to its set of response alternatives rather than in terms of the level (basic or subordinate) at which the target is to be identified.

Humans↗

PubMed2003

Congruency-induced blindness: a cost-benefit analysis.

Targets are identified more accurately when they are presented during an incongruent response (e.g., a left-pointing arrowhead presented during a right key press) than during a congruent response (e.g., a left-pointing arrowhead presented during a left key press). This effect, referred to here as congruency-induced blindness, has been hypothesised to result from the occupation of feature codes. According to the code occupation hypothesis (Behav. Brain Sci.; J. Experim. Psychol.: Human Percept. Perform.; Vis. Cogn., in press), only costs of congruency between features of a planned or executed action and a to-be-perceived target should be observed; neither costs nor benefits of incongruency are predicted by this account. In the present study, we investigated costs and benefits in identifying left and right targets directly by manipulating neutral response type and the symbols used to cue the neutral response, which produced four neutral conditions. Three important results emerged: (1). a significant main effect of RSI (suggesting that increasing temporal overlap between a planned action and target presentation interferes with perceptual reports of the target), (2). a significant main effect of congruency (showing that impairment is code-specific), and (3). clear-cut costs with little evidence for benefits. Other complex patterns of results provided additional information relevant for extant theories of perception-action interactions.

Adolescent↗

PubMed2003

A central capacity sharing model of dual-task performance.

The authors present the central capacity sharing (CCS) model and derive equations describing its behaviors to explain results from dual-task situations. The predictions of the CCS model are contrasted with those of the central bottleneck model. The CCS model predicts all of the hallmark effects of the psychological refractory period (PRP) pardigm: -1 slope of the PRP effect at short stimulus onset asynchronies (SOAs), underadditivity of precentral Task 2 manipulations, additivity of central or postcentral Task 2 manipulations with SOA, and carry forward to Task 2 of Task 1 precentral or central manipulations at short SOAs. The CCS model also predicts that Task 1 response times increase with decreasing SOA. The model is a viable alternative to the central bottleneck model.

Humans↗

PubMed2003

Can blindness to response-compatible stimuli be observed in the absence of a response?

Blindness to response-compatible stimuli is the finding that targets are identified less accurately when presented during the planning or execution of a congruent response (e.g., right arrow presented during a right keypress) versus an incongruent response (e.g., right arrow presented during a left keypress). Accounts of this effect suggest the planning and execution of a response are critical to its observation. Five experiments investigated whether a blindness effect would be observed in the absence of a planned response. Results suggest that a planned response is not necessary to observe a content-specific blindness effect and that the blindness effect may actually comprise both an action-related component and a symbolic component that is distinct from the action-planning system.

Adult↗

PubMed2003

Lengthening the duration of response execution does not modulate blindness to action-compatible stimuli.

Action-compatible blindness refers to the finding that target stimuli are perceived less frequently if they are presented during the planning or execution of a compatible action (e.g., a left arrow presented during a left manual key press) than during an incompatible action (Müsseler & Hommel, 1997 a, b). We investigated the effect of lengthening the response execution phase in the action-compatible blindness paradigm by requiring subjects to tap a response key once or three times on the assumption that tapping three times would increase the duration of the execution phase of the response. Prior research (e.g., Stevanovski, Oriet, & Jolicoeur, 2002; Wühr & Müsseler, 2001) has shown that larger blindness effects are observed for targets presented during the execution phase of a response than after the response has been made. We investigated whether a larger blindness effect would be observed in the three-tap condition than in the one-tap condition, or whether lengthening the duration of the response would extend the time course of the blindness effect. Neither of these possibilities was supported by the data irrespective of whether the number of taps to be made was blocked or mixed within a block of trials. The results are discussed in terms of current accounts of action-compatible blindness and the possible cognitive differences between making a single response and repeating a response.

Adolescent↗

PubMed2002

All-or-none bottleneck versus capacity sharing accounts of the psychological refractory period phenomenon.

The goal of the present experiment was to test the predictions of Central Bottleneck and Central Capacity Sharing models. According to the Central Bottleneck model, dual task interference, as observed in the PRP paradigm, is caused by an all-or-none bottleneck in information processing. The Central Capacity Sharing model postulates that dual task interference is caused by a capacity limited process that can allocate capacity in a graded fashion. The Central Bottleneck model predicts no change in RT1 with decreasing SOA, whereas the Central Capacity Sharing model predicts that RT1 will increase with decreasing SOA and that the slope of the RT1 SOA effect will depend upon the difficulty of task 2. Subjects were required to perform a tone pitch judgement and shape-matching task in rapid succession. Task order was randomized and the SOA between the first and second stimulus varied from 50 to 1250 ms. Results from this experiment favour the Central Capacity Sharing model. The results were then run through simulations of both the Central Bottleneck and Central Capacity Sharing models. Results from the simulations also favoured the Central Capacity Sharing model. As the difficulty of the second task increased, more capacity was allocated to it, confirming the prediction that as task 2 difficulty increases, the RT1 SOA slope increases. The proportion of capacity allocated to the first task varied from.78 to.91 indicating that capacity can be allocated in a graded fashion.

Analysis of Variance↗

PubMed2002

Fractionating the preview benefit in search: dual-task decomposition of visual marking by timing and modality.

Providing participants with a preview of half the distractors in a visual search task facilitates performance. The present study examined the effects of secondary tasks on the preview benefit in search. Participants had to attend to a visual or an auditory stream of digits that began either (a) at the onset of the preview or (b) after the preview. Secondary tasks that onset with the preview disrupted the preview benefit irrespective of their modality. Only visual secondary tasks disrupted the benefit in the delayed condition. These selective interference effects suggest that the preview benefit can be fractionated into 2 components: an initialization component that involves modality-independent resources and a maintenance component that depends on visual resources. Results are discussed in relation to theoretical accounts of the preview benefit in search.

Adult↗

PubMed2002

Loci of signal probability effects and of the attentional blink bottleneck.

To investigate the locus of signal probability effects and the influence of stimulus quality on this locus, the authors manipulated probability in Task 2 of a psychological refractory period (PRP) paradigm. The effect was additive with stimulus onset asynchrony (SOA) when the target was not masked but underadditive with decreasing SOA when the target was masked. Even with masking, however, a range of probabilities had effects additive with SOA. The results suggest loci of stimulus probability before the PRP bottleneck as well as at or after the bottleneck. A second issue addressed was the locus of interference in the attentional blink (AB). The AB was larger when the probability of the first of 2 targets was lower. The results lead to the conclusion that one cause of the AB effect is a locus at least as late as the PRP bottleneck.

Attention↗

PubMed2002

Does size rescaling require central attention?

The goal of the present experiment was to determine if object size rescaling in the shape-matching task requires central resources. Two polygons were presented side by side as the second task in a psychological refractory period paradigm. The polygons could be the same as each other or mirror images of each other and the size ratio between the two polygons was varied. In the first task, subjects were required to make a speeded response to the pitch of a tone. The polygon task followed at varying SOAs and the subjects then made a speeded same/mirror image judgement on the polygons. The size ratio effect was additive with SOA indicating that size rescaling is capacity demanding and that it requires central attention.

Attention↗

PubMed2002

Blinded by headlights.

Target identification is impaired when targets are presented during the planning or execution of a compatible response (e.g., right-pointing arrow during a right keypress) relative to an incompatible response (Müsseler & Hommel, 1997 a, b). Examinations of this blindness to response-compatible stimuli have typically used arrowheads as targets ("<" and ">"). The importance of the target symbol was examined by manipulating subjects' interpretation of that symbol (i.e., ">" interpreted as a right-pointing arrow or as a headlight shining to the left). Targets were presented at varying times during the planning or execution of a response in order to examine the time-course of the effect. Results showed that the interpretation, and not the physical identity, of the target was important for the blindness effect. Although the blindness effect was largest during the planning and execution of a response, it was not always confined to that temporal interval.

Adult↗