Contextual Adaptation of Cognitive Flexibility is driven by Task- and Item-Level Learning

Adaptive behavior requires finding, and adjusting, an optimal tradeoff between focusing on a current task-set (cognitive stability) and updating that task-set when the environment changes (cognitive flexibility). Such dynamic adjustments of cognitive flexibility are observed in cued task-switching paradigms, where switch costs tend to decrease as the proportion of switch trials over blocks increases. However, the learning mechanisms underlying this phenomenon, here referred to as the list-wide proportion switch effect (LWPSE), are currently unknown.We addressed this question across four behavioral experiments. Experiment 1 replicated the basic LWPSE reported in previous studies. Having participants switch between three instead of two tasks, Experiment 2 demonstrated that the LWPSE is preserved even when the specific alternate task to switch to cannot be anticipated. Experiments 3a and 3b tested for the generalization of list-wide switch-readiness to an unbiased “transfer task,” presented equally often as switch and repeat trials, by intermixing the transfertask with biased tasks. Despite the list-wide bias, the LWPSE was only found for biased tasks, suggesting that the modulations of switch costs are task set and/or task stimulus (item)-specific. To evaluate these two possibilities, Experiment 4 employed biased versus unbiased stimuli within biased task sets and found switch-cost modulations for both stimuli sets. These results establish how people adapt their stability-flexibility tradeoff to different contexts. Specifically, our findings show that people learn to associate context appropriate levels of switch readiness with switch-predictive cues, provided by task sets as well as specific task stimuli.

Forced-Choice Assessment of Work-Related Maladaptive Personality Traits: Preliminary Evidence From an Application of Thurstonian Item Response Modeling

This article describes an investigation of whether Thurstonian item response modeling is a viable method for assessment of maladaptive traits. Forced-choice responses from 420 working adults to a broad-range personality inventory assessing six maladaptive traits were considered. The Thurstonian item response model’s fit to the forced-choice data was adequate, while the fit of a counterpart item response model to responses to the same items but arranged in a single-stimulus design was poor. Monotrait heteromethod correlations indicated corresponding traits in the two formats overlapped substantially, although they did not measure equivalent constructs. A better goodness of fit and higher factor loadings for the Thurstonian item response model, coupled with a clearer conceptual alignment to the theoretical trait definitions, suggested that the single-stimulus item responses were influenced by biases that the independent clusters measurement model did not account for. Researchers may wish to consider forced-choice designs and appropriate item response modeling techniques such as Thurstonian item response modeling for personality questionnaire applications in industrial psychology, especially when assessing maladaptive traits. We recommend further investigation of this approach in actual selection situations and with different assessment instruments.

Knowing about People and Naming Them: Can Alzheimer's Disease Patients Do One without the Other?

It has recently been suggested that patients with semantic breakdown may show the phenomenon of so-called “naming without semantics”. If substantiated, this finding would clearly have a major impact on theories of face and object processing, all of which assume that access to semantic knowledge is a prerequisite for successful naming. In order to investigate this issue, we studied recognition, identification (the ability to provide accurate information), and naming of 50 famous faces by 24 patients with mild to moderate dementia of Alzheimer type (DA T) and 30 age-matched controls. The DA T group was impaired in all three conditions. An analysis of the concordance between identification and naming by each patient, for each stimulus item, established that naming a famous face was possible only with semantic knowledge sufficient to identify the person. Our data support the hypothesis that naming is not possible unless semantic information associated with the target is available. Naming without semantics, therefore, did not occur in patients with DAT. By contrast, there were 206 instances (17% of the total responses) in which the patients were able to provide detailed, accurate identifying information yet were unable to name the person represented. The implication of these findings for models of face identification and naming are discussed.

Acoustical Characteristics of Intended Syllabic Stress in Excellent Esophageal Speakers

The ability of excellent esophageal speakers to manipulate acoustical characteristics associated with intended syllabic stress was studied. Five excellent esophageal speakers and five sex- and age-matched normals produced 10 sentence pairs, each containing a bisyllabic stimulus item differing only in primary stress placement. The mean fundamental frequency, sound pressure level, and duration of the stressed and unstressed vowel nuclei were analyzed. Although some differences in absolute levels were apparent, only sound pressure level differences reached statistical significance. For both groups, intended primary stress was associated with a comparable pattern of increased fundamental frequency, sound pressure level, and duration. The present findings suggest that excellent esophageal speakers are capable of producing some correlates of primary syllabic stress in a fashion remarkably similar to but somewhat less consistent than normals. The implications of these data for long-range clinical planning are discussed.

The effect of a narrative context on the verbal style of middle-class and lower-class children

ABSTRACTThe verbal style of middle-class and lower-class ten-year-old children was assessed in a descriptive communication task using three different types of stimulus items: standard visual, tactual, and items embedded in a narrative. In a partial replication of Heider's (1971) work it was found that lower-class children used a global descriptive style to communicate information about standard visual (abstract) stimuli, whereas middle-class children used an analytic style. Group differences also were observed with tactually input stimuli, although the lower-class responses shifted toward an analytic style. However, both middle-class and lower-class children used an analytic style to describe stimulus items when they were embedded in a narrative context. In addition, order effects were observed, suggesting that lower-class children use an analytic style with standard visual stimuli if they perceive this style as situationally appropriate. Social class differences in verbal style are not only a function of type of stimulus item, but are also a function of strategies applied in the communicative situation.

Appendix: Simple Measures of Variation in Lexical Fields

This appendix suggests a number of measures which may be readily calculated in respect of data on lexical usage to provide an indication of the degree of variation in such usage. It introduces and briefly discusses five straightforward measures of variation or consensus which apply to the case where any informant has been constrained to give only one response per stimulus item. None of these measures is, strictly speaking, a statistical measure, although p is almost so in terms of its logic and the D-measures have a form familiar to that of a wide class of elementary statistics. Each measure in fact generates a numerical index which relates to an arithmetical property of the data in question: the measures are not in general estimates of population parameters. The use is heuristic, exploratory and comparative: by systematically reducing the information which comprises the data, the measures should help the investigator to become more aware of the salient characteristics of the data to hand.

Variables Influencing Performance on Speech-Sound Discrimination Tests

Stimulus items were presented in three different contexts and under two different listening conditions to a total of 72 nursery, kindergarten, and first-grade children divided into equally sized groups on the basis of age. Results indicated that both the context of stimulus item presentation and the presence of background noise affected accuracy of performance. Children in all three groups consistently made more errors in the context using limited grammatical and phonetic cues. Noise disrupted performance in all contexts, but the greatest disruption occurred in the paired-comparison context. It appeared that contexts employing grammatical cues were more resistant to disruption from background noise. The results of this investigation also indicated that the performance of young children may have been affected by factors other than their ability to discriminate speech sounds.