Evaluating evidence of psychological adaptation: how do we know one when we see one?

Evolutionary psychologists argue that human nature contains many discrete psychological adaptations. Each adaptation is theorized to have been functional in humans' ancestral past, and empirical evidence that an attribute is an adaptation can come from showing it possesses complexity, efficiency, universality, and other features of special design. In this article, we present a tutorial review of the evidentiary forms that evolutionary psychologists commonly use to document the existence of human adaptations. We also present a heuristic framework for integrating and evaluating cross-disciplinary evidence of adaptation. Pregnancy sickness, incest avoidance, men's desires for multiple sex partners, and an easily learned fear of snakes are evaluated as possible human adaptations using this framework. We conclude that future research and teaching in evolutionary psychology would benefit from more fully utilizing cross-disciplinary frameworks to evaluate evidence of human adaptation.     

Stability in autobiographical memories

A total of 30 undergraduates recalled the same 20 autobiographical memories at two sessions separated by 2 weeks. At each session they dated their memories and rated them on 18 properties commonly studied in autobiographical memory experiments. Individuals showed moderate stability in their ratings on the 18 scales (r approximately .5), with consistency of dating being much higher (r = .96). There was more stability in the individuals' average rating on each scale (r approximately .8), even when the averages were calculated on different memories in the different sessions. The results are consistent with a constructive view of autobiographical memory, in which stable individual differences in cognitive style are important.     

Dietary ethyl-eicosapentaenoic acid but not soybean oil reverses central interleukin-1-induced changes in behavior, corticosterone and immune response in rats

Omega (n)-3 and n-6 fatty acids are important membrane components of neurons and immune cells, and related to psychiatric and inflammatory diseases. Increased ratio of n-6/n-3 in the blood has been reported in depressed patients and in students following stress exposure. The n-3 fatty acid, eicosapentaenoic acid (ethyl-EPA) suppresses inflammation and has antidepressant properties. Interleukin (IL)-1beta can stimulate corticosterone secretion, induce anxiety and stress-like behavior and inflammatory responses. This study was to evaluate the effect of diets enriched with coconut oil, ethyl-EPA and soybean oil on central IL-1beta induced stress and anxiety-like behavior, induced changes in the concentration of prostaglandin (PG) E2 and corticosterone and the release of IL-10. Groups of rats were fed with either 5% coconut oil (as control diet), 0.2% EPA with 4.8% coconut oil or 1% EPA with 4% coconut oil and 5% soybean oil for 7 weeks. The central administration of IL-1beta induced sickness, stress and anxiety-like behavior as indicated by a reduction in body weight, decreased time spent, and the number of entries, into the open arms of the elevated plus maze and decreased exploration and entry into the central zone of the "open field" apparatus. IL-1beta also increased PGE2 and corticosterone concentrations and decreased the release of IL-10 from leucocytes. Food enriched with ethyl-EPA but not soybean oil, significantly attenuated most of these changes. These results demonstrate that ethyl-EPA has anti-inflammatory, anti-stress and anti-anxiety effects in rats.     

Factor validation of the addiction severity index scale structure in persons with concurrent disorders

Confirmatory factor analysis was used to test the scale structure of the Addiction Severity Index (ASI) in a sample of 1,802 substance abusers (43% alcohol dependent) with a concurrent psychiatric disorder (46% with mood disorders). The fit of the original composite score model based on the work of P. L. McGahan, J. A. Griffith, R. Parente, and A. T. McLellan (1990) was compared with the evaluation indices (EIs) developed by A. I. Alterman et al. (1998). The 5-dimensional model based on the EIs was an overall better fit to the data. Internal consistency (Cronbach's alpha) for the EIs ranged from.66 (family domain) to.75 (legal domain). The 5 EIs were moderately correlated (rs =.42-.72) with the interviewer severity ratings from the ASI. Evaluation studies involving concurrent disordered substance abusers should use the EIs as summary measures of change.     

Development and psychometric properties of the disability application appraisal inventory

This article describes the development and psychometric properties of an inventory to assess cognitive appraisal of the Department of Veterans Affairs (VA) disability application process, the Disability Application Appraisal Inventory (DAAI). Participants were 439 veterans seeking disability status for posttraumatic stress disorder through the VA and subgroups from that sample. The 3 DAAI scales assess (a) understanding of the disability application process (Knowledge scale) (b) expectations specific to the process (Negative Expectations scale) and (c) investment in obtaining disability status (Importance scale). The scales are internally consistent and largely uncorrelated. Test-retest correlations are adequate for the Negative Expectations and Importance scales. Evidence of factorial and construct validity is presented.     

More information from fewer questions: the factor structure and item properties of the original and brief fear of negative evaluation scale

Statistical methods designed for categorical data were used to perform confirmatory factor analyses and item response theory (IRT) analyses of the Fear of Negative Evaluation scale (FNE; D. Watson & R. Friend, 1969) and the Brief FNE (BFNE; M. R. Leary, 1983). Results suggested that a 2-factor model fit the data better for both the FNE and the BFNE, although the evidence was less strong for the FNE. The IRT analyses indicated that although both measures had items with good discrimination, the FNE items discriminated only at lower levels of the underlying construct, whereas the BFNE items discriminated across a wider range. Convergent validity analyses indicated that the straightforwardly-worded items on each scale had significantly stronger relationships with theoretically related measures than did the reverse-worded items. On the basis of all analyses, usage of the straightforwardly-worded BFNE factor is recommended for the assessment of fear of negative evaluation.     

The closer we are,the more we are alike: The effect of self-other merging on depersonalized self-perception

The present study examined whether or not the extent to which people include other group members in the self, influences depersonalized self-perception (i.e., perceiving self and others as similar in terms of group characteristics). The results revealed that self-other merging positively influenced feelings of belongingness and identification with the in-group. Furthermore, a strong experience of self-other merging was shown to lead to depersonalized self-perception as measured by a self-assimilation and an in-group homogeneity index. Finally, results also revealed that feelings of belongingness and group identification mediated, at least partly, the effect of self-other merging on depersonalized self-perception. The findings are discussed in light of the literature on self-expansion.     

Extinction-induced immobility in the water maze and its neurochemical concomitants in aged and adult rats: a possible model for depression?

Extinction of escape behavior in the water maze due to the removal of the platform, was hypothesized to induce a negative state, including the development of immobility, which is held to reflect a state of "despair" when measured in the forced swimming test. 27 aged and 8 adult animals (26 and 3 months old Wistar rats, respectively) were tested in the water maze during nine days with a platform hidden, followed by 7 days of extinction trials with the platform absent. As expected, both age groups developed immobility over the extinction trials, with the aged showing more than the adults. To examine whether the age difference in immobility was related to performance differences during acquisition, the aged were subdivided into superior, intermediate and inferior learners (n = 9 per group) on the basis of overall times to platform during acquisition, and compared with each other and the adults. Results showed that the aged inferior learners displayed the highest levels of immobility among the aged. Immobility scores were then correlated with post-mortem neurotransmitter contents in the hippocampus and ventral striatum. In the ventral striatum, levels of immobility were correlated with levels of acetylcholine, dopamine and the metabolite dihydroxyphenylacetic acid in the aged, and with norepinephrine in the adults. The data support the hypothesis that multiple extinction trials in the water maze result in immobility that may indicate "behavioral despair," and that striatal neurotransmitter systems correlate with the degree of its expression. The concept of extinction-induced despair is held to provide the promise of a conceptual and empirical model of human depression that is the consequence of loss of reinforcers.