The role of priming in conjunctive visual search

To assess the role of priming in conjunctive visual search tasks, we systematically varied the consistency of the target and distractor identity between different conditions. Search was fastest in the standard conjunctive search paradigm where identities remained constant. Search was slowest when potential target identity varied predictably for each successive trial (the 'switch' condition). The role of priming was also demonstrated on a trial-by-trial basis in a 'streak' condition where target and distractor identity was unpredictable yet was consistent within streaks. When the target to be found was the same for a few trials in a row, search performance became similar to that when the potential target was the same on all trials. A similar pattern was found for the target absent trials, suggesting that priming is based on the whole search array rather than just the target in each case. Further analysis indicated that the effects of priming are sufficiently strong to account for the advantage seen for the conjunctive search task. We conclude that the role of priming in visual search is underestimated in current theories of visual search and that differences in search times often attributed to top-down guidance may instead reflect the benefits of priming.     

Association between serotonin transporter gene polymorphism and family history of attempted and completed suicide

The purpose of this study was to examine the association of the serotonin transporter gene to family history of suicidality. Forty-seven volunteers responded to questionnaires about family history of suicide, and provided buccal swabs for analysis of the polymorphism. Allelic homozygocity (the short variant) was associated with family history of suicidality. These data, to be interpreted with the study's limitations in mind, suggest a link between the serotonin transporter gene polymorphism and suicide-related variables, which should be the focus of future research.     

Self-control in honeybees

Self-control means choosing a large delayed reward over a small immediate reward; impulsiveness is its opposite. The metabolic hypothesis states that the amount of self-control across species correlates negatively with metabolic rate (Tobin & Logue, 1994). Foraging honeybees have high metabolic rates; the metabolic hypothesis would predict little self-control in bees. But foraging bees work for the longterm good of their hive, conditions that seem to require self-control. In three experiments, we gave bees the choice between (1) a sweeter delayed reward and a less sweet immediate reward and (2) a large delayed reward and a small immediate reward. Bees showed much self-control, inconsistent with the metabolic hypothesis.     

Irrelevance: Strengthening the Bayesian requirements

Bayesians standardly identify irrelevance with probabilistic irrelevance. However, there are cases where e is probabilistically irrelevant to h but intuitively e is relevant to h. For instance, ‘Die A came up 1 and die B came up 1, 3, 5 or 6’ is probabilistically irrelevant to ‘Die A came up odd and die B came up even’, yet, intuitively, it is not, irrelevant to that claim, in the sense that ‘Sydney has a harbour Bridge’ is irrelevant to it. In the context of decision making this notion of irrelevance combined with such rules as ‘Do not expend resources on irrelevant evidence’ leads to bad results. A stronger notion of irrelevance fitting our intuitions and the contexts of decision making is proposed: e is irrelevant to h if and only if every part of e is probabilistically irrelevant to every part of h. However, we need to take care in determining what counts as part of a statement.     

Visual short-term memory benefit for objects on different 3-D surfaces

Visual short-term memory (VSTM) plays an important role in visual cognition. Although objects are located on different 3-dimensional (3-D) surfaces in the real world, how VSTM capacity may be influenced by the presence of multiple 3-D surfaces has never been examined. By manipulating binocular disparities of visual displays, the authors found that more colored objects could be held in VSTM when they were placed on 2 rather than on 1 planar 3-D surfaces. This between-surface benefit in VSTM was present only when binding of objects' colors to their 3-D locations was required (i.e., when observers needed to remember which color appeared where). When binding was not required, no between-surface benefit in VSTM was observed. This benefit in VSTM could not be attributed to the number of spatial locations attended within a given surface. It was not due to a general perceptual grouping effect either, because grouping by motion and grouping by different regions of the same surface did not yield the same benefit. This increment in capacity indicates that VSTM benefits from the placement of objects in a 3-D scene.     

Reconsolidation and memory infidelity in Lymnaea

Lymnaea stagnalis were operantly conditioned to not perform aerial respiratory behaviour in a specific context (i.e. context-1). The memory for this learned response was reactivated 3 days later in context-1. During the 1 h reconsolidation period following memory reactivation, randomly picked snails were either maintained in context-1 or exposed to a new context (i.e. context-2). One hour later in the post-reconsolidation period, snails in context-1 were placed for 1 h in context-2 and vice-versa. In neither the hypoxic reconsolidation nor the post reconsolidation periods did snails receive a reinforcing stimulus when they opened their pneumostome. All snails were blindly tested for memory 24 h later period in context-2. Only those snails that had been exposed to context-2 during the reconsolidation period exhibited 'memory' for context-2. That is, memory infidelity was observed. Snails exposed to context-2 in only the post-reconsolidation period did not show memory for context-2. The immediate cooling of snails after their exposure to the new context in the reconsolidation period blocked the formation the implanted memory. Snails trained in context-1 and exposed to context-2 in the consolidation period only, also did not have memory for context-2. However, the memory for context-1 could still be recalled following successful implantation of the 'new' memory. All data presented here are consistent with the notion that during the reconsolidation process memory can be updated.     

Methods for the Behavioral,Educational, and Social Sciences: An R package

Methods for the Behavioral, Educational, and Social Sciences (MBESS; Kelley, 2007b) is an open source package for R (R Development Core Team, 2007b), an open source statistical programming language and environment. MBESS implements methods that are not widely available elsewhere, yet are especially helpful for the idiosyncratic techniques used within the behavioral, educational, and social sciences. The major categories of functions are those that relate to confidence interval formation for noncentral t, F, and chi2 parameters, confidence intervals for standardized effect sizes (which require noncentral distributions), and sample size planning issues from the power analytic and accuracy in parameter estimation perspectives. In addition, MBESS contains collections of other functions that should be helpful to substantive researchers and methodologists. MBESS is a long-term project that will continue to be updated and expanded so that important methods can continue to be made available to researchers in the behavioral, educational, and social sciences.     

Memory search following valid and invalid abrupt-onset cues

The impact of abrupt-onset cues on memory search was investigated, where the abrupt-onset cue was a valid (Experiment 1), random (Experiment 2), or irrelevant (Experiment 3) predictor of the location containing the test probe. In Experiment 4, the abrupt-onset cue either preceded or followed the test probe. Sternberg-like functions were obtained in Experiments 1 and 2, with the effects of the abrupt-onset cue localized primarily in the intercept rather than the slope. Experiment 3 demonstrated that a spatially separated and irrelevant abrupt-onset cue increased latency even when all memory probes occurred at the fixation point. In Experiment 4, the robust impact of an abrupt-onset cue vanished, regardless of stimulus onset asynchrony, when it followed the target. We concluded that abrupt-onset cues captured attention regardless of their predictability, manifested as a delaying of search. However, once attention was captured by the target, a subsequent abrupt-onset stimulus had no effect. These results were discussed in terms of diffuse attention and contingent capture models of attention.     

Remembering the forgotten: psychotherapy groups for the nursing home resident

The mental health needs of the long-term nursing home resident receive little attention. It is especially difficult for the more cognitively intact resident to obtain psychological help. An integrated group psychotherapy model that incorporates developmental, cognitive-behavioral, and psychodynamic approaches is described, based on the author's clinical experience in developing and co-leading four groups in three long-term care facilities over a period of ten years. The technical and countertransference challenges of working with this unique population and in this format are described, along with clinical material to illustrate common themes. The success of the groups in improving the morale, sense of community, and quality of life for group members is demonstrated.     

Determinants of Depression Severity and Duration in Canadian Adults: The Moderating Effects of Gender and Social Support

This study examined the effects of 4 subtypes of social support (tangible, affective, positive social interaction, and emotional/informational) and gender on the severity and duration of depressive symptoms within the general adult Canadian population. Data were collected from the Canadian Community Health Survey (CCHS; Statistics Canada, 2002 ). Upon meeting predetermined criteria, 6,316 participants were included in the study. The findings suggest that, overall, positive social interaction was significantly associated with decreases in depression severity; while emotional/informational support was significantly associated with increases in depression severity. Positive social interaction and emotional/informational support appeared to significantly decrease the duration of depression. Interesting gender differences also emerged among the 4 subtypes of social support. Implications of the findings are discussed.