A diffusion model analysis of the effects of aging in the lexical-decision task

The effects of aging on response time (RT) are examined in 2 lexical-decision experiments with young and older subjects (age 60-75). The results show that the older subjects were slower than the young subjects, but more accurate. R. Ratcliff s (1978) diffusion model provided a good account of RTs, their distributions, and response accuracy. The fits show an 80-100-ms slowing of the nondecision components of RT for older subjects relative to young subjects and more conservative decision criterion settings for older subjects than for young subjects. The rates of accumulation of evidence were not significantly different for older compared with young subjects (less than 2% and 5% higher for older subjects relative to young subjects in the 2 experiments).     

Assessing model mimicry using the parametric bootstrap

We present a general sampling procedure to quantify model mimicry, defined as the ability of a model to account for data generated by a competing model. This sampling procedure, called the parametric bootstrap cross-fitting method (PBCM; cf. Williams (J. R. Statist. Soc. B 32 (1970) 350; Biometrics 26 (1970) 23)), generates distributions of differences in goodness-of-fit expected under each of the competing models. In the data informed version of the PBCM, the generating models have specific parameter values obtained by fitting the experimental data under consideration. The data informed difference distributions can be compared to the observed difference in goodness-of-fit to allow a quantification of model adequacy. In the data uninformed version of the PBCM, the generating models have a relatively broad range of parameter values based on prior knowledge. Application of both the data informed and the data uninformed PBCM is illustrated with several examples.     

Naive optics: Predicting and perceiving reflections in mirrors

Undergraduate students predicted what would be made visible by a planar mirror. A paper-and-pencil task confirmed previous findings that when approaching a mirror from the side, participants expected to see their reflection in the mirror earlier than they actually would. This early response was found for all mirrors when the observer moved horizontally--even when the mirror was placed on the floor or the ceiling--but not when the observer moved vertically (in a lift). The data support the hypothesis that many people imagine the world in the mirror as rotated around the vertical axis. When participants had to judge manipulated mirror reflections according to their naturalness, a high degree of tolerance was found. In contrast to the prediction task, a rotation around the vertical axis was judged to be less natural than other distortions. The authors conclude that perceptual knowledge and predictive knowledge lead to different patterns of errors. ((c) 2003 APA, all rights reserved)     

Experimental tests of an attitudinal theory of the gender gap in voting

This research examined the hypothesis that gender gaps in voting stem from differences in the extent to which men and women agree with candidates' issue stances. Two initial experiments portraying candidates by their sex and attitudes and a third experiment that also included information about political party produced the predicted attitudinal gender-congeniality effect: Participants of each sex reported greater likelihood, compared with participants of the other sex, of voting for the candidate who endorsed positions typically favored more by their own sex than the other sex. In addition, this gender-congeniality effect was present among Republican and independent participants but absent among Democratic participants because Democratic men as well as women favored candidates who advocated the positions typically favored by women. Interpretation invoked the importance of group interest based on gender as an influence on women's voting.     

Mental verb input for promoting children's theory of mind: A training study

An experimental study investigated the effect of the type of mental verb input (i.e., input with think, know, and remember) on preschoolers’ theory of mind development. Preschoolers (n = 72) heard 128 mental verb utterances presented in video format across four sessions over two weeks. The training conditions differed only in the way the mental verbs were presented: the form (statement or question), the referent (first person or other person), and the interaction style (overheard or interactive). Children who overheard the characters discussing the mental states of someone else, either in statement or question form, significantly improved in their false belief understanding. These experimental findings demonstrate mental verb utterances about other people, even when not directed to the child, scaffold children's attention to differing perspectives, thus more efficiently promoting some aspects of their ToM development.     

Partner aggression in high-risk families from birth to age 3 years: associations with harsh parenting and child maladjustment

Aggression between partners represents a potential guiding force in family dynamics. However, research examining the influence of partner aggression (physically and psychologically aggressive acts by both partners) on harsh parenting and young child adjustment has been limited by a frequent focus on low-risk samples and by the examination of partner aggression at a single time point. Especially in the context of multiple risk factors and around transitions such as childbirth, partner aggression might be better understood as a dynamic process. In the present study, longitudinal trajectories of partner aggression from birth to age 3 years in a large, high-risk, and ethnically diverse sample (N = 461) were examined. Specific risk factors were tested as predictors of aggression over time, and the longitudinal effects of partner aggression on maternal harsh parenting and child maladjustment were examined. Partner aggression decreased over time, with higher maternal depression and lower maternal age predicting greater decreases in partner aggression. While taking into account contextual and psychosocial risk factors, higher partner aggression measured at birth and a smaller decrease over time independently predicted higher levels of maternal harsh parenting at age 3 years. Initial level of partner aggression and change over time predicted child maladjustment indirectly (via maternal harsh parenting). The implications of understanding change in partner aggression over time as a path to harsh parenting and young children's maladjustment in the context of multiple risk factors are discussed.     

Does power magnify the expression of dispositions?

Conventional wisdom holds that power holders act more in line with their dispositions than do people who lack power. Drawing on principles of construct accessibility, we propose that this is the case only when no alternative constructs are activated. In three experiments, we assessed participants' chronic dispositions and subsequently manipulated participants' degree of power. Participants then either were or were not primed with alternative (i.e., inaccessible or counterdispositional) constructs. When no alternatives were activated, the responses of power holders--perceptions of other people (Experiment 1), preferences for charitable donations (Experiment 2), and strategies in an economic game (Experiment 3)--were more in line with their chronically accessible constructs than were the responses of low-power participants. However, when alternatives had been activated, power holders' responses were no longer more congruent with their dispositions than were the responses of low-power participants. We propose a single mechanism according to which power increases reliance on accessible constructs--that is, constructs that easily come to mind-regardless of whether these constructs are chronically or temporarily accessible.     

Rats build and update topological representations through exploration

Although rats are able to build complex spatial representations of their surroundings during exploration, the nature of the encoded information is still a matter for debate. In particular, it is not well established if rats can process the topological structure of the environment in such a way that they are aware of the connections existing between remote places. Here, rats were first exposed for four 5-min trials to a complex environment divided into several sectors that were separated by doors allowing either unrestricted or restricted access to other sectors. In the fifth test trial, we measured the behavior of the animals while they explored the same environment in which, however, they faced changes that either altered or did not alter the topological structure of the environment. In experiment 1, closing previously opened doors prevented the rat from having direct access between corresponding sectors. In experiment 2, opening previously closed doors allowed direct access between sectors that had not been directly accessible. In each experiment, control doors allowed us to discard the mere influence of door manipulation. We compared the rats’ exploratory behavior in response to door manipulations that either strongly altered or did not alter the ability to commute between sectors and found evidence that the animals displayed differential reactions to the two types of door manipulations. This implies that during exploration rats build a precise map of the connectivity of space that can be flexibly updated and used for efficient navigation.     

Pathways to vocational services: factors affecting entry by veterans enrolled in Veterans Health Administration mental health services

The current study provides naturalistic data documenting the pathways-to-care to vocational services for 155 veterans who were receiving some form of mental health care from the Veterans Health Administration and had a vocational need but were not currently enrolled in vocational services. Of the participants, 94.2% had recognized their vocational need, 80.6% reported that they or someone else had sought help to alleviate the need, and 77.4% had previously received some form of vocational services. The median length of the participants' vocational need was more than 4.2 years. Delays associated with recognition, help-seeking, and treatment entry all contributed to the overall delay in entering appropriate care. Filtering factors associated with quicker recognition, seeking help, and receiving services included diagnosis, level of disability, type of vocational need, and support from primary providers, family, and friends. The results provide information for designing interventions to improve service entry by adults with mental health problems and vocational needs.     

EFFECTS OF PREFERENCE AND REINFORCER VARIATION ON WITHIN-SESSION PATTERNS OF RESPONDING

We examined correspondence between preference assessment outcome and within‐session patterns of responding in one subject with autism. Responding maintained by a single highly preferred item resulted in a greater total number of responses, a slower decline in within‐session response rates, and a greater proportion of short interresponse times compared to responding maintained by varied moderately preferred (MP) stimuli. Presenting varied MP stimuli within the same session produced greater levels and more sustained responding than presenting those same stimuli individually.