Fish cognition: a primate's eye view

We provide selected examples from the fish literature of phenomena found in fish that are currently being examined in discussions of cognitive abilities and evolution of neocortex size in primates. In the context of social intelligence, we looked at living in individualised groups and corresponding social strategies, social learning and tradition, and co-operative hunting. Regarding environmental intelligence, we searched for examples concerning special foraging skills, tool use, cognitive maps, memory, anti-predator behaviour, and the manipulation of the environment. Most phenomena of interest for primatologists are found in fish as well. We therefore conclude that more detailed studies on decision rules and mechanisms are necessary to test for differences between the cognitive abilities of primates and other taxa. Cognitive research can benefit from future fish studies in three ways: first, as fish are highly variable in their ecology, they can be used to determine the specific ecological factors that select for the evolution of specific cognitive abilities. Second, for the same reason they can be used to investigate the link between cognitive abilities and the enlargement of specific brain areas. Third, decision rules used by fish could be used as 'null-hypotheses' for primatologists looking at how monkeys might make their decisions. Finally, we propose a variety of fish species that we think are most promising as study objects. Accepted after revision: 6 September 2001 Electronic Publication     

Increases in manic symptoms after life events involving goal attainment

Bipolar disorder has been conceptualized as an outcome of dysregulation in the behavioral activation system (BAS), a brain system that regulates goal-directed activity. On the basis of the BAS model, the authors hypothesized that life events involving goal attainment would promote manic symptoms in bipolar individuals. The authors followed 43 bipolar I individuals monthly with standardized symptom severity assessments (the Modified Hamilton Rating Scale for Depression and the Bech-Rafaelsen Mania Rating Scale). Life events were assessed using the Goal Attainment and Positivity scales of the Life Events and Difficulties Schedule. As hypothesized, manic symptoms increased in the 2 months following goal-attainment events, but depressed symptoms were not changed following goal-attainment events. These results are congruent with a series of recent polarity-specific findings.     

On the science of Rorschach research

Wood et al.'s (1999b) article contained several general points that are quite sound. Conducting research with an extreme groups design does produce effect sizes that are larger than those observed in an unselected population. Appropriate control groups are important for any study that wishes to shed light on the characteristics of a targeted experimental group and experimental validity is enhanced when researchers collect data from both groups simultaneously. Diagnostic efficiency statistics--or any summary measures of test validity--should be trusted more when they are drawn from multiple studies conducted by different investigators across numerous settings rather than from a single investigator's work. There should be no question that these points are correct. However, I have pointed out numerous problems with specific aspects of Wood et al.'s (1999b) article. Wood et al. gave improper citations that claimed researchers found or said things that they did not. Wood et al. indicated my data set did not support the incremental validity of the Rorschach over the MMPI-2 when, in fact, my study never reported such an analysis and my data actually reveal that the opposite conclusion is warranted. Wood et al. asserted there was only one proper way to conduct incremental validity analyses even though experts have described how their recommended procedure can lead to significant complications. Wood et al. cited a section of Cohen and Cohen (1983) to bolster their claim that hierarchical and step-wise regression procedures were incompatible and to criticize Burns and Viglione's (1996) regression analysis. However, that section of Cohen and Cohen's text actually contradicted Wood et al.'s argument. Wood et al. tried to convince readers that Burns and Viglione used improper alpha levels and drew improper conclusions from their regression data although Burns and Viglione had followed the research evidence on this topic and the expert recommendations provided in Hosmer and Lemeshow's (1989) classic text. Wood et al. oversimplified issues associated with extreme group research designs and erroneously suggested that diagnostic studies were immune from interpretive confounds that can be associated with this type of design. Wood et al. ignored or dismissed the valid reasons why Burns and Viglione used an extreme groups design, and they never mentioned how Burns and Viglione used a homogeneous sample that actually was likely to find smaller than normal effect sizes. Wood et al. also overlooked the fact that Burns and Viglione identified their results as applying to female nonpatients; they never suggested their findings would characterize those obtained from a clinical sample. Wood et al. criticized composite measures although some of the most important and classic findings in the history of research on personality recommend composite measures as a way to minimize error and maximize validity. Wood et al. also were mistaken about the elements that constitute an optimal composite measure. Wood et al. apparently ignored the factor-analytic evidence that demonstrated how Burns and Viglione created a reasonable composite scale, and Wood et al. similarly ignored the clear evidence that supported the content and criterion related validity of the EMRF. With respect to the HEV, Wood et al. created a z-score formula that used the wrong means and standard deviations. They continued to use this formula despite being informed that it was incorrect. Subsequently, Wood et al. told readers that their faulty z-score formula was "incompatible" with the proper weighted formula and asserted that the two formulas "do not yield identical results" and "do not yield HEV scores that are identical or even very close." These published claims were made even though Wood et al. had seen the results from eight large samples, all of which demonstrated that their wrong formula had correlations greater than .998 with the correct formula. At worst, it seems that Wood et al. (199     

Geometrical illusions can affect time-to-contact estimation and mimed prehension

Results indicate that under some conditions the Sander parallelogram illusion can affect time-to-contact (TTC) estimation in a prediction-motion (PM) task and in an interceptive action (IA). The illusion also affected mimed manual prehension. The implication is that the timing of responses in the PM and IA tasks may involve an estimate of TTC that is based on the perceived dimensions of the environment. Further research is warranted in the development of models of perceived collision and of visually guided actions.     

Structural influences on the resolution of lexical ambiguity: an analysis of hemispheric asymmetries

Structural influences on lexical ambiguity resolution in the two cerebral hemispheres was investigated using a divided visual field procedure. Participants were presented with auditory Wh- sentences containing an ambiguous word, where the grammatical role of the word was apparent only at a sentence-final verb (e.g., "Which BANK did the woman see?"). Following a sentence, either immediately or after 600 ms, a target word was presented in either the right or left visual field. Targets were related to the ambiguous word's dominant meaning (MONEY), the subordinate meaning (RIVER), or were unrelated. With left visual field presentation, priming occurred for both dominant- and subordinate-related targets at a 0 ms delay, but only for dominant-related targets at 600 ms. With left visual field presentation, priming occurred for subordinate-related targets only at both delays. The results suggest that grammatical assignment triggers the selection of meaning in the left hemisphere, whereas processing in the right hemisphere operates independently of structural analyses.     

Prejudice,social stress,and mental health in lesbian,gay, and bisexual populations: conceptual issues and research evidence

In this article the author reviews research evidence on the prevalence of mental disorders in lesbians, gay men, and bisexuals (LGBs) and shows, using meta-analyses, that LGBs have a higher prevalence of mental disorders than heterosexuals. The author offers a conceptual framework for understanding this excess in prevalence of disorder in terms of minority stress--explaining that stigma, prejudice, and discrimination create a hostile and stressful social environment that causes mental health problems. The model describes stress processes, including the experience of prejudice events, expectations of rejection, hiding and concealing, internalized homophobia, and ameliorative coping processes. This conceptual framework is the basis for the review of research evidence, suggestions for future research directions, and exploration of public policy implications.