Decisions among time saving options: when intuition is strong and wrong

When people judge the time that can be saved by increasing the speed of an activity, they are often victims of a time saving bias. That is, they overestimate the time that can be saved by increasing the speed. Judgments of time savings following speed increase when driving follow the Proportion heuristic [Svenson, O. (1970). A functional measurement approach to intuitive estimation as exemplified by estimated time savings. Journal of Experimental Psychology, 86, 204-210]. In a choice between time saving options, this heuristic simplifies to the Ratio rule. The first study tested this rule and found that the Ratio rule predicted incorrect decisions when planning to save traveling time in road traffic. The second study showed that the time saving bias was also present in planning of health care; to specify, in decisions about which one of two clinics to reorganize to save more of the doctors' time for personal contacts with patients. To further test the Ratio rule, Study 3 used a matching procedure in which two decision alternatives were made equal by the participants. The results supported the Ratio rule. Practical implications of the results are discussed including the Planning fallacy. In conclusion, the present set of studies have illustrated a time saving bias and provided evidence explaining why people make systematic errors when judging and deciding about time saved following a speed increase.     

Driving speed changes and subjective estimates of time savings,accident risks and braking

Participants made decisions between two road improvements to increase mean speed. Time saved when speed increased from a higher driving speed was overestimated in relation to time saved from increases from lower speeds. In Study 2, participants matched pairs of speed increases so that they would give the same time saving and repeated the bias. The increase in risk of an accident with person injury was underestimated and the increase in risk of a fatal accident grossly underestimated when speed increased. The increase of stopping distance when speed increased was systematically underestimated. In Study 3, the tasks and results of Study 2 were repeated with engineering students. When forming opinions about speed limits and traffic planning, drivers, the public, politicians and others who do not collect the proper facts are liable to the same biases as those demonstrated in the present study. Copyright © 2008 John Wiley & Sons, Ltd.     

Predecision conflict and different patterns of postdecision attractiveness restructuring: empirical illustrations from an important real-life decision

This study presents different postdecision consolidation patterns following decisions made under value conflicts. The different patterns were illustrated by case studies of real-life decisions concerning university programs. There were five program alternatives each of which branched into a different professional area. These decisions were very important to the students. The subjects were followed during a year, from a couple of months before they made their choice of program and during several months after the start of the programs. Different postdecision strategies for consolidating a prior decision were derived from Differentiation and Consolidation Theory (Svenson, 1992). The strategies involved the following postdecision attractiveness restructuring patterns. (1) Reversing an attractiveness disadvantage into an advantage on a conflict attribute, (2) Compensating for a disadvantage through increase of an advantage of another attribute, (3) Reversing disadvantage on a conflict and decreasing advantage on non-conflict attribute(s), and (4) Increasing advantage for chosen alternative on all attributes. In addition, (5) downgrading of importance of the conflict attribute or a complete elimination of this attribute is also a possible way of consolidating the prior decision. The results illustrated the above consolidation patterns. A comparison with subjects who made the same decisions but with no value conflict indicated that postdecision consolidation was largely driven by value conflicts at the time of decision in conjunction with the outcome of the decision.     

Perception of the head transversal plane and the subjective horizontal during gondola centrifugation

The subjective visual horizontal (SVH) and the subjective head transversal plane (STP) were measured by means of an adjustable luminous line in darkness during centrifuging. Subjects (N = 10) were seated upright, facing forward in a swing-out gondola. After acceleration of the centrifuge to 2G (vectorial sum of the earth's gravity and the centrifugal force; gondola inclination 60 degrees), subjects had to set the line either so that it was perceived as gravitoinertially horizontal (SVH) or so that it was perceived as parallel with the transversal ("horizontal") plane of the head (STP). Initially after acceleration, the SVH was tilted with respect to the gravitoinertial horizontal of the gondola (M = 16.6 degrees). This tilt was compensatory with respect to the gondola inclination. However, the STP was tilted in the opposite direction (M = 12.4 degrees), which might suggest a vestibular-induced distortion of the mental representation of one's own body. Similar results were obtained when measuring the subjective visual vertical (SVV) and the subjective midsagittal plane (SSP) in 5 subjects. The perceived roll angle (obtained as SVH-STP or SVV-SSP) was considerably larger than had previously been reported. Time constants for exponential decay of the tilt of the SVH or SVV were often 2-3 min, indicating a memory for semicircular canal information on changes in head orientation--a position-storage mechanism.     

Cognitive strategies in a complex judgment task: Analyses of concurrent verbal reports and judgments of cumulated risk over different exposure times

Subjects judged the cumulated risk of dying during a year for a set of persons or cases each characterized by the risks during three different periods of risk exposure during the year (e.g., 18 weeks with 2.3 deaths per thousand persons per year of exposure, 28 weeks with 2.5 deaths and 6 weeks with 16.0 deaths per thousand per year). Three main strategies were used for solving the problems: (1) addition of the risk levels, (2) computing the mean of the risk levels, and (3) the most frequently used anchoring and adjustment strategy most closely approximating the normatively correct risk over the year. The first two strategies do not use all relevant information because they neglect the importance of different exposure times. The anchoring and adjustment strategy used all information and was executed in a first stage in which an initial anchor or reference risk was selected followed by a second stage in which this anchor was adjusted according to the remaining information. The process for finding the first anchor was quite flexible, using different principles (e.g., extreme values or similarity) depending on the pattern of cues characterizing each case. Biases in relation to normative theory originated from subjects misunderstanding or simplifying the problem (Strategies (1) and (2)) or the characteristics of the anchoring and adjustment process which resulted in relative overestimation of short-time, high-risk cases. A few subjects, however, all of whom used sequential anchoring and adjustment, succeeded in giving quite accurate estimates.     

Normative beliefs supporting aggression of Arab children in an intergroup conflict

Based on the social knowledge theory (Heusmann), this study investigated normative beliefs supporting aggression (NOBAG), empathy, and intergroup anxiety of Arab children in Israel. The study proposed that ethnicity of the target person (within subject variable) and participant's sex (between subject variable) will differ between respondents' level of NOBAG and empathy: Higher NOBAG and lower empathy toward an outgroup member were expected. Sex differences were expected on all variables, as well as intercorrelations among them. Measures included the Revised Normative Beliefs Measure (NOBAG: general and specific), The Index of Empathy for Children and Adolescents (general and specific), and the Intergroup Anxiety Scale. The study population included 186 elementary‐school children from two Arab schools in Israel. Results indicated that all participants support an aggressive reaction to a child of an outgroup more than to one of their own group and exhibit a greater degree of empathy toward the latter. Sex differences were found on all variables except on specific NOBAG. Correlation coefficients suggest sex differences in relations between variables. Results of a Logistic regression for the prediction of NOBAG toward ingroup/outgroup person indicated that empathy toward Jews predicted NOBAG in both sexes while intergroup anxiety predicted NOBAG in a different way for boys and girls. The discussion refers to the need for peace education to reduce anxiety and promote empathy. Aggr. Behav. 00:000–000, 2005. © 2005 Wiley‐Liss, Inc.     

Relationships between cognitive and behavioral measures of executive function in children with brain disease.

This study addressed the clinical and construct validity of the Behavior Rating Inventory of Executive Function. (BRIEF: Gioia, Isquith, Guy, & Kenworthy, 2000), a questionnaire designed to tap behavioral aspects of executive functions in children. BRIEF profiles in early treated phenylketonuria (PKU; n=44), early treated hydrocephalus (n=45), frontal focal lesions (n=20) and controls (n=80) were examined. Clinical validity was supported through significant between-group comparisons, especially between the frontal focal lesion group and other groups. To examine construct validity, raw scores on cognitive executive function measures including the Contingency Naming Test (CNT), Rey Complex Figure (RCF), Tower of London (TOL), and Controlled Oral Word Association Test (COWAT), were correlated with BRIEF scale scores. Few significant correlations were found, indicating cognitive and behavioral measures appear to tap different constructs within the executive function domain. A dissociation was found between behavioral and cognitive impairments in the frontal as opposed to PKU and hydrocephalus groups. This is discussed in relation to underlying pathology, the cognitive measures used, and possible limitations in the BRIEF's usefulness for measuring behavioral executive dysfunction in groups only mildly affected by neurological compromise.     

Different corticostriatal patterns of L-DOPA utilization in patients with untreated schizophrenia and patients treated with classical antipsychotics or clozapine

Positron emission tomography (PET) has been shown to be of great importance in elucidating the mechanism of action of antipsychotic drugs. In psychotic patients L-[11C]DOPA PET has been used to demonstrate some differences in dopaminergic activity compared with that in healthy volunteers. Ten healthy volunteers were investigated with PET and L-[11C]DOPA. Ten drug-free patients with psychosis, nine stable schizophrenics treated with clozapine, and nine stable patients treated with classical antipsychotics were also investigated with L-[11C]DOPA. Principal-component analysis was employed for the analysis of L-[11C]DOPA Ki values across a number of corticostriatal brain regions. These data revealed a significant three-component model with clear-cut separation between healthy controls and patients with unmedicated schizophrenia. Stable optimal treatment with either classical neuroleptics or clozapine partially, albeit differentially, reversed the aberrant patterns seen in drug-free schizophrenia. It can thus be concluded that schizophrenia is associated with abnormal patterns of L-[11C]DOPA utilization in corticostriatal systems. Treatment with clozapine or classical neuroleptics induces partial, albeit differential, normalization of the abnormal patterns seen in untreated schizophrenia.     

Cognitive abnormalities and cerebral perfusion defects in a community-dwelling cohort of elderly men with MMSE within the normal range

Objectives: Mini Mental State Examination’s (MMSE’s) sensitivity in its upper level is questioned, hence we investigated cognitive abnormalities and defects in regional cerebral blood flow (rCBF) in elderly with MMSE scores ≥24.

Methods: One hundred and four men at age 81 with MMSE scores ≥24 (mean 28.4 ± 1.7), no dementia or stroke, were examined with neuropsychological test battery, and their rCBF was estimated using ^99mTc-HMPAO SPECT.

Results: MMSE was very sparsely correlated with rCBF. Instead, visuo-spatial tests were correlated with rCBF in parietal and occipital lobe, verbal tests with rCBF in frontal and temporal-parietal lobes, and most of all between Digit Symbol and all rCBF regions, especially in subcortical gray and white matter. In a cluster of low achievers, test of Synonyms, followed by Digit Symbol and Benton test, had highest discriminatory importance. Low achievers had generalized rCBF changes especially in subcortical areas. Only lower scores on two MMSE items, figure drawing and calculation, could discriminate the clusters.

Conclusion: A substantial number of octogenarian men with MMSE ≥ 24p have widespread rCBF changes corresponding to a decreased speeded performance and verbal capacity.