Many tests of significance: new methods for controlling type I errors

There have been many discussions of how Type I errors should be controlled when many hypotheses are tested (e.g., all possible comparisons of means, correlations, proportions, the coefficients in hierarchical models, etc.). By and large, researchers have adopted familywise (FWER) control, though this practice certainly is not universal. Familywise control is intended to deal with the multiplicity issue of computing many tests of significance, yet such control is conservative--that is, less powerful--compared to per test/hypothesis control. The purpose of our article is to introduce the readership, particularly those readers familiar with issues related to controlling Type I errors when many tests of significance are computed, to newer methods that provide protection from the effects of multiple testing, yet are more powerful than familywise controlling methods. Specifically, we introduce a number of procedures that control the k-FWER. These methods--say, 2-FWER instead of 1-FWER (i.e., FWER)--are equivalent to specifying that the probability of 2 or more false rejections is controlled at .05, whereas FWER controls the probability of any (i.e., 1 or more) false rejections at .05. 2-FWER implicitly tolerates 1 false rejection and makes no explicit attempt to control the probability of its occurrence, unlike FWER, which tolerates no false rejections at all. More generally, k-FWER tolerates k - 1 false rejections, but controls the probability of k or more false rejections at α =.05. We demonstrate with two published data sets how more hypotheses can be rejected with k-FWER methods compared to FWER control.     

Dietary restraint moderates genetic risk for binge eating

Dietary restraint is a prospective risk factor for the development of binge eating and bulimia nervosa. Although many women engage in dietary restraint, relatively few develop binge eating. Dietary restraint may increase susceptibility for binge eating only in individuals who are at genetic risk. Specifically, dietary restraint may be a behavioral exposure factor that activates genetic predispositions for binge eating. We investigated this possibility in 1,678 young adolescent and adult same-sex female twins from the Minnesota Twin Family Study and the Michigan State University Twin Registry. Twin moderation models were used to examine whether levels of dietary restraint moderate genetic and environmental influences on binge eating. Results indicated that genetic and nonshared environmental factors for binge eating increased at higher levels of dietary restraint. These effects were present after controlling for age, body mass index, and genetic and environmental overlap among dietary restraint and binge eating. Results suggest that dietary restraint may be most important for individuals at genetic risk for binge eating and that the combination of these factors could enhance individual differences in risk for binge eating.     

The Relationship between Parent-Child Conflict and Adolescent Antisocial Behavior: Confirming Shared Environmental Mediation

Prior studies have indicated that the relationship between parent-child conflict and adolescent antisocial behavior is at least partially shared environmental in origin. However, all available research on this topic (to our knowledge) relies exclusively on parent and/or adolescent informant-reports, both of which are subject to various forms of rater bias. As the presence of significant shared environmental effects has often been attributed to rater bias in the past (Baker et al. Journal of Abnormal Psychology 16:219–235, 2007; Bartels et al. Journal of the American Academy of Child and Adolescent Psychiatry 42:1351–1359, 2003, Twin Research 7:162–175, 2004; Hewitt et al. Behavior Genetics 22:293–317, 1992), it would be important to confirm that findings of shared environmental mediation persist when even examining (presumably more objective) observer-ratings of these constructs. The current study thus examined the origins of the relationship between parent-child conflict and adolescent acting-out behavior, as measured using both observer-ratings and various informant-reports. Participants included 1,199 adopted and non-adopted adolescents in 610 families from the Sibling Interaction and Behavior Study (SIBS). Results indicated that parent-child conflict consistently predicts acting-out behavior in adopted adolescents, and moreover, that this association is equivalent to that in biologically-related adolescents. Most importantly, these findings did not vary across parent- and adolescent-reported or observer-ratings of parent-child conflict and acting-out behavior. Such findings argue strongly against rater bias as a primary explanation of shared environmental mediation of the association between parent-child conflict and adolescent antisocial behavior.     

Second-order autoshaped key pecking based on an auditory stimulus.

In Experiment 1, pigeons were exposed either to paired or to unpaired presentations of a tone and grain, and then to paired presentations of a keylight with the tone. Substantial second-order conditioned pecking to the keylight was produced in the birds that had received paired presentations of tone and grain. In Experiment 2, second-order pecking to the keylight increased in probability across four groups that had received, respectively, 20, 80, 140, or 200 paired presentations of tone and grain. In Experiment 3, the amount of pecking directed towards a keylight which predicted the first-order, tone CS was as substantial in birds without a prior history of key pecking as in birds with such a history. A further experiment failed to discover any significant differences in the levels of second-order pecking to a keylight paired with a first-order tone CS or with a first-order keylight CS. Thus, an auditory signal that does not itself support pecking may enable a localized visual stimulus to evoke key pecking.     

Associative priming in color naming: interference and facilitation

In Experiment 1, color-naming interference for target stimuli following associated primes was greater in a group making a lexical decision to the prime than in a group reading the prime silently. High-frequency targets were responded to more quickly than low-frequency targets. In Experiment 2, with subjects naming the prime, there was evidence of associative interference when the prime and the target were grouped temporally but not when the intertrial interval was comparable with the prime-target interval. Associative primes presented at a short (120-msec) prime-target stimulus onset asynchrony facilitated color naming in Experiment 3. Taken together, the results suggest that the effect of faster processing of the base word in a color-naming task is facilitatory and that color-naming priming interference arises when associative prime processing increases conflict between word and color responses by enhancing phonological or articulatory activation of the base word.     

Developing of an English Version of the Aggressive Driving Behavior Test (AVIS). Improving the Construct Validity of Aggressive Driving

The research investigated the psychometric properties and the discriminant validity of the English version of the Questionnaire for the Assessment of Aggressive Driving Behavior (AVIS). Study 1 assessed the psychometric properties of the instrument. Internal consistency ranged from 0.77 to 0.92. Exploratory factor analysis did not support the original five factor structure, Instrumental Aggression and Acting Out being unified in a single factor. Following the confirmatory factor analysis a version with 26 items and 3 factors was obtained. Inter-scale correlations showed that the dimensions of the AVIS are inter-correlated. Study 2 verified the discriminant validity of the English version of the AVIS by testing the relationships between the AVIS dimensions and the DAX (Driving Anger Expression Inventory) dimensions. The results showed good discriminant validity, the dimensions of the two instruments being uncorrelated. In conclusion, the findings contribute to the development of the driving aggression construct by adding new dimensions to it.     

Media’s Influence on Self-Image and Romantic Relationship Decision-Making in College-Age Clients: What Mental Health Counselors Should Know

Research indicates that media-influenced decisions potentially assist in leading college-aged students to make negative interpersonal choices, resulting in poor intimate relationships (Storey and McDonald, 2013). However, many mental health counselors inadvertently ignore the effect of media when they work with college-aged clients. To speak to the need for mental health counselors to become aware of the issue, this study examined the phenomenological perspective of eight students. This qualitative study’s results indicate that media portrayal of successful couples and unrealistic expectations affect intimate relationship decision-making.