Priming of Pop-Out Does not Affect the Shooting Line Illusion

We combined a shooting-line illusion with a visual search pop-out task in an effort to determine whether priming of pop-out was due to acceleratcd processing of visual information in the primed dimension. While the priming effect and the line-motion percept were replicated, the visual search task showed no influence on the perceived direction of line motion. These results indicate that the priming effect does not accelerate early visual processing.National Institutes of Health-National Eye Institute (EY05087, 49620-93-1-0407

Target absent trials in configural contextual cuing

In contextual cueing (CC), reaction times to find targets in repeated displays are faster than in displays that have never been seen before. This has been demonstrated using target-distractor configurations, global background colors, naturalistic scenes and the co-variation of target with distractors. The majority of CC studies have used displays where the target is always present. This paper investigates what happens when the target is sometimes absent. Experiment 1 shows that, although configural CC occurs in displays when the target is always present, there is no CC when the target is always absent. Experiment 2 shows that there is no CC when the same spatial layout can be both target present and target absent on different trials. The presence of distractors in locations that contain targets on other trials appears to interfere with CC and even disrupts the expression of previously learned contexts (Experiments 3-5). The results show that it is the target-distractor associations that are important in producing CC and, consistent with a response selection account, changing the response type from an orientation task to a detection task removes the CC effect

Michigan’s Medical Marihuana Act—Parting the Haze

Article published in the Michigan State University School of Law Student Scholarship Collection

Kill Zones and Their Use During the American Civil War: An Archaeological Review of The Battle of Pickett’s Mill

While not well known in the list of battles during the Atlanta Campaign late in the American Civil War, it is marked as an overwhelming Confederate victory in the face of looming defeat in the war itself. With the Union suffering nearly two thousand casualties, the tactics and strategies used by the Confederate army no doubt aided in their victory. During the battle, Union soldiers were drawn into a ravine where Confederate soldiers could easily fire down on them. The Union men followed the ravine up into a flat area where they were then fired on again with accurate rifle and cannon fire. This research will review the areas of concentrated fire by Confederate troops and whether these occurred out of circumstance, or if they had been planned in advanced as pre-designated areas of fire, otherwise known as “kill zones”. The archaeological data from previous research will be reviewed to determine concentrations of Confederate fired ammunition as well as lines of entrenchment to gather evidence of premeditated fields of fire to create a kill zone. This research will also review historical texts and accounts to determine if this was intentional and whether this strategy was used elsewhere in battles during the Civil War. It will also review that if these areas of concentrated fire were only by coincidence, then what were the mistakes made by the Union that lead to such a high number of casualties when they heavily outnumbered Confederate forces

Time to guide: evidence for delayed attentional guidance in contextual cueing

Contextual cueing experiments show that, when displays are repeated, reaction times (RTs) to find a target decrease over time even when the observers are not aware of the repetition. Recent evidence suggests that this benefit in standard contextual cueing tasks is not likely to be due to an improvement in attentional guidance (Kunar, Flusberg, Horowitz, & Wolfe, 2007). Nevertheless, we ask whether guidance can help participants find the target in a repeated display, if they are given sufficient time to encode the display. In Experiment 1 we increased the display complexity so that it took participants longer to find the target. Here we found a larger effect of guidance than in a condition with shorter RTs. Experiment 2 gave participants prior exposure to the display context. The data again showed that with more time participants could implement guidance to help find the target, provided that there was something in the search stimuli locations to guide attention to. The data suggest that, although the benefit in a standard contextual cueing task is unlikely to be a result of guidance, guidance can play a role if it is given time to develop

Coarse guidance by numerosity in visual search

In five experiments, we examined whether the number of items can guide visual focal attention. Observers searched for the target area with the largest (or smallest) number of dots (squares in Experiment 4 and "checkerboards” in Experiment 5) among distractor areas with a smaller (or larger) number of dots. Results of Experiments 1 and 2 show that search efficiency is determined by target to distractor dot ratios. In searches where target items contained more dots than did distractor items, ratios over 1.5:1 yielded efficient search. Searches for targets where target items contained fewer dots than distractor items were harder. Here, ratios needed to be lower than 1:2 to yield efficient search. When the areas of the dots and of the squares containing them were fixed, as they were in Experiments 1 and 2, dot density and total dot area increased as dot number increased. Experiment 3 removed the density and area cues by allowing dot size and total dot area to vary. This produced a marked decline in search performance. Efficient search now required ratios of above 3:1 or below 1:3. By using more realistic and isoluminant stimuli, Experiments 4 and 5 show that guidance by numerosity is fragile. As is found with other features that guide focal attention (e.g., color, orientation, size), the numerosity differences that are able to guide attention by bottom-up signals are much coarser than the differences that can be detected in attended stimul

Cre/lox generation of a novel whole-body Kiss1r KO mouse line recapitulates a hypogonadal, obese, and metabolically-impaired phenotype.

Kisspeptin and its receptor, Kiss1r, act centrally to stimulate reproduction. Recent evidence indicates that kisspeptin is also important for body weight and metabolism, as whole-body Kiss1r KO mice, developed with gene trap technology, display obesity and reduced metabolism. Kiss1r is expressed in brain and multiple peripheral tissues, but it is unknown which is responsible for the metabolic phenotype. Here, we sought to confirm that 1) the metabolic phenotype of the gene trap Kiss1r KOs is due to disruption of kisspeptin signaling and not off-target effects of viral mutagenesis, and 2) the Kiss1r flox line is suitable for creating conditional KOs to study the metabolic phenotype. We used Cre/lox technology (Zp3-Cre/Kiss1r flox) to develop a new global Kiss1r KO ("Kiss1r gKO") to compare with the original gene trap KO phenotype. We confirmed that deleting exon 2 of Kiss1r from the entire body induces hypogonadism in both sexes. Moreover, global deletion of Kiss1r induced obesity in females, but not males, along with increased adiposity and impaired glucose tolerance, similar to the gene trap Kiss1r KOs. Likewise, Kiss1r gKO females had decreased VO2 and VCO2, likely underlying their obesity. These findings support that our previous results in gene trap Kiss1r KOs are due to disrupted kisspeptin signaling, and further highlight a role for Kiss1r signaling in energy expenditure and metabolism besides controlling reproduction. Moreover, given Kiss1r expression in multiple cell-types, our findings indicate that the Kiss1r flox line is viable for future investigations to isolate specific target cells of kisspeptin's metabolic effects

Everything is Foreseen, Yet Free will is Given (Mishna Avot 3:15)

Jan Theeuwes’ review of visual selection shines a useful spotlight on the role of selection history in determining subsequent deployments of attention. However, he blurs an important distinction between volition and top-down guidance of attention and he underplays the role of both of those factors in the control of attention