Anxiety and the allocation of attention to threat

Using a probe detection technique we have recently demonstrated that anxious subjects consistently deploy attention towards threat-related stimuli, whereas non-anxious controls tend to move attention away from such material (MacLeod, Mathews, & Tata, 1986).

The current study employed the same paradigm but attempted to distinguish the role of trait and state anxiety by testing high- and low-trait students when state anxiety was relatively low (12 weeks before a major examination) and again when it was relatively high (one week before this examination). High-trait subjects alone tended to shift attention towards generally threatening material on both test occasions. Results for examination-related stimuli were more complex. Increased proximity to the examination was associated with an increase in attentional bias towards such threat stimuli in high-trait subjects, but with increased attentional avoidance of such stimuli in low-trait subjects. It is suggested that the attentional response to currently relevant stress-related stimuli may be associated with neither trait nor state anxiety alone, but with an interactive function involving both these variables. These results are discussed in relation to existing models of emotion and cognition, and alternative interpretations of the findings are considered.     

Cross-domain semantic priming in normal subjects and a prosopagnosic patient

Cross-domain semantic priming of person recognition (from face primes to name targets at 500msecs SOA) is investigated in normal subjects and a brain-injured patient (PH) with a very severe impairment of overt face recognition ability. Experiment 1 demonstrates equivalent semantic priming effects for normal subjects from face primes to name targets (cross-domain priming) and from name primes to name targets (within-domain priming). Experiment 2 demonstrates cross-domain semantic priming effects from face primes that PH cannot recognize overtly. Experiment 3 shows that cross-domain semantic priming effects can be found for normal subjects when target names are repeated across all conditions. This (repeated targets) method is then used in Experiment 4 to establish that PH shows equivalent semantic priming to normal subjects from face primes which he is very poor at identifying overtly and from name primes which he can identify overtly. These findings demonstrate that automatic aspects of face recognition can remain intact even when all sense of overt recognition has been lost.     

Accessing stored information about familiar people

Summary Two experiments investigating access to occupations and names of familiar people are reported, in which the response requirements of occupation and name-categorization tasks were made equivalent. In Experiment 1 matching tasks were used, in which subjects were required to determine whether simultaneously presented pairs of faces, surnames, or full names were those of people with the same or different occupations (politician or nonpolitician) or with same or different first names (Michael or David). Experiment 2 required binary classification of individual faces or surnames in terms of the bearer's occupation (politician or nonpolitician) or first name (Michael or David). In both experiments responses to faces were faster in tasks involving access to occupations than in tasks involving access to first names, whereas for surnames there was no difference in reaction times between occupations and first names in matching or classification tasks. These findings are consistent with the idea that identity-specific semantic codes and name codes are accessed sequentially from faces, but in parallel from written names.     

Effects of Control on the Stress Reactions of Commuters1

The effects of morning, rush hour commuting were examined in a quasi-experimental field study involving government-employed commuters (single and carpool drivers). Commuting stress was measured as a response to variations in how difficult it was for commuters to move from home to work. The mediation of these effects by two sources of control in the commuting situation also were assessed. Control was operationalized as control over the internal environment of the car (single versus carpool driver) and choice over routes taken to get to work. Among commuters with a high impedance route, driving to work was associated with significant increases in systolic and diastolic blood pressure and decreases in behavioral performance. The stress of commuting under high impedance conditions was reduced for single drivers relative to carpoolers. Under similar conditions of high impedance, however, having the option to select more than one route to get to work seemed to be more stressful than having only one route. The practical implications of these results are discussed.     

Stimulus-response compatibility in the programming of speech

Subjects chose between sequences of one syllable (e.g.,/gi/vs./bi/), two syllables (e.g.,/gibi/ vs./gubu/), and three syllables (e.g.,/gibidi/ vs. gubudu/), when/i/sequences were signaled by high-pitched tones and/u] sequences were signaled by low-pitched tones (high compatibility), or the reverse (low compatibility). Choice times were additively affected by sequence length and compatibility. A second experiment showed attenuated compatibility effects for sequences with different vowels in the first and second syllables. These results replicate previously reported results for choices between finger sequences, which suggests that the same programming methods are used in both output domains. Evidently, choices between response sequences can be achieved by selecting a distinguishing parameter and assigning it in a serial fashion to partially prepared motor subprograms.     

Cognitive functioning and anxiety

Summary Various possible differences in cognitive functioning between those high and low in trait anxiety are considered. Particular emphasis is paid to the hypothesis that individuals high in trait anxiety tend to approach threatening stimuli, whereas those low in trait anxiety tend to avoid such stimuli. The evidence indicates that there are such differences in the processing of threatening stimuli as a function of trait anxiety. However, these differences are found only under certain conditions, for example, when threatening and nonthreatening stimuli are presented concurrently, and when minor rather than major threat is involved.The differences between those high and low in trait anxiety encompass pre-attentive, attentional, and interpretative mechanisms. As a consequence, any adequate theory of trait anxiety must take proper account of cognitive mechanisms and functioning.     

Motor response information influence on CNV shape and resolution time

This study systematically investigates changes in CNV waveform shape and resolution time that result from the presentation of facilitatory, inhibitory, or no motor response (MR) information simultaneously with the warning (S1) or imperative (S2) stimulus of the S1-S2-MR CNV paradigm. Analyses indicate that the simultaneous presentation of S1 and information to produce or inhibit a MR attenuates initial CNV development. Further, when the S1 information is inhibitive, CNV development is retarded throughout. The contribution of an inhibitory psychological process during CNV development is proposed. The data also indicate that CNV resolution time is not dependent on the presence of a motor response. It is suggested that CNV resolution time is indicative of psychological completion or closure.     

Ego-involvement leads to positive self-schema activation and to a positivity bias in information processing

Study 1 examined the hypothesis that ego-involvement leads to positive self-schema activation. Ego-involvement was induced by having experimental subjects anticipate a difficult test of intelligence. Noninvolved control subjects did not anticipate the test. All subjects completed a depth-of-processing task, following which incidental recall was assessed. Ego-involved relative to noninvolved subjects tended to recall a greater number of positive and fewer negative words at both the self-referent and semantic processing levels. Study 2 was conducted to address further the self-schema hypothesis and to address the hypothesis suggested by the results of Study 1 that ego-involvement leads to a positivity bias in information processing. The design of Study 2 was similar to that of Study 1. Results revealed that the self-favorability of negative words recalled at the self-referent level was greater for ego-involved than for noninvolved subjects, suggesting positive self-schema activation. In addition, ego-involved subjects recalled a greater number of positive words at the semantic level, suggesting a positivity bias in information processing.Study 2 was conducted by Andrew Howell in partial fulfillment of the requirements of a Master of Arts degree at Concordia University, under the supervision of Michael Conway. The authors thank Karin Stiefenhofer for her work on the project. The research was supported by the Social Sciences and Humanities Research Council of Canada and the Fonds pour la Formation de Chercheurs et l'Aide à la Recherche du Québec grants to Michael Conway.     

Memory deficits before and after temporal lobectomy: Effect of laterality and age of onset

Laterality and age of onset effects on semantic and figural memory were evaluated in 30 right-handed, left speech dominant (amobarbital test) patients with epilepsy before and after temporal lobectomy. There were no effects of focus on WAIS-R IQ scores. Early onset (less than or equal to 5 years) was associated with lower IQ and memory (WMS). Left Temporal (LT) patients showed worse semantic than figural memory preoperatively. Unexpectedly, early onset LT had marked postoperative decline of figural memory, whereas late onset LT patients showed the previously reported worsening of semantic memory. Right Temporal (RT) lobectomy patients, in contrast, improved in both semantic and figural memory regardless of age of onset. A "crowding effect" was suggested by the decline in figural memory following surgery in the early onset LT patients who remained stable or improved in semantic memory. Results indicate the need to incorporate age of onset of seizures into laterality models of memory function following unilateral temporal-hippocampal resection.     

The component awareness and accuracy of dual- and single-jointed actions

The accuracy with which people execute wrist and elbow movements were measured using three main conditions: (i) single-jointed (wrist or elbow) movements to targets, (ii) dual-jointed (wrist and elbow) movements to targets, and (iii) components of dual-jointed movements to targets, when the task for the subject was to perform the elbow or wrist constituent of the action in isolation, without displacing the second joint. Elbow precision was significantly worse under component than dual conditions, which is compatible with the notion that wrist and elbow activity are conjugately, rather than independently, programmed when a dual-jointed action is performed. The pattern of wrist accuracy was divergent, but possible reasons for this were discussed. In all cases, error was measured in terms of deviation from perfect posture; using this index, the hypothesis that incorporating more moving joints into an action serves to increase movement complexity and jeopardise precision was tested, but the results were ambiguous. Discussion also centered on the problems of using performance data to infer changes in motor programming, and the need for rigorous conceptualisation and research in this area.