Search PubMed⌕ Search

Biomedical subjects

B P Allen

Publications and source records attributed to B P Allen.

14 recordsLinked to original sources
PubMed2001

Lighting position and judgments of distance of shadow-casting objects.

Participants recruited on the web performed in two experiments in which they viewed eight pictures of the same two rods in the exact same positions with shadows generated by a light source located at eight positions around the rods. In Exp. 1, participants judged how much shadows projected to the front, back, and sides of the rods facilitated the correct perception of the actual distance of the rods relative to each other. In Exp. 1 (n: 52), frontal lighting facilitated judgments more than lighting from the rear, but frontal and side lighting did not differ in facilitative effects. In Exp. 2 (n: 72), judgments of rods depicted with shadows were relative to a judgment of the rods depicted without shadows (raw scores were the value of the judgment of the shadowless rods subtracted from the value of the judgment of each of the eight sets of rods). Again, frontal lighting was more facilitative than rear lighting and frontal lighting did not differ from side lighting. However, when the average of each participant's backlighting judgments was compared with his judgment of the shadowless rods, shadows generated by backlighting were more facilitative than none.

Distance Perception↗
PubMed2000

Angles of shadows as cues for judging the distance of shadow casting objects.

40 participants were presented the six possible comparisons of four pictures of cylinders and their shadows. For each comparison, each participant was to decide which cylinder was most distant from a reference point. Overall 15 of the participants got all six judgments correct, an outcome that is exceedingly unlikely by chance.

Adult↗
PubMed1999

Shadows as sources of cues for distance of shadow-casting objects.

Shadows are neglected sources of information about shadow-casting objects' distance (location). In an experiment using real shadows, participants judged the distance of two rods, either with shadows (illumination from the left) or without shadows. Without shadows, a thin rod raised slightly above the surface was incorrectly judged to be more distant than a thick rod, but with shadows the thin rod was accurately judged to be closer. For judgments to be correct, shadows had to overwhelm competing height and stimulus-size cues. Exp. II involved nonoverlapping shadows produced by a light placed in front of the rods. Again, without shadows the thin-elevated rod was incorrectly judged to be more distant, but with shadows it was correctly judged to be closer. Exp. III involved two sets of thick and thin elevated rods and frontal lighting. Judgments were accurate when shadows were present but inaccurate when shadows were absent. Experiments conducted through the American Psychological Society Web-research site replicated results of Exp. I, II, and III. A final Web experiment replicated results of the others, but with shadows produced by illumination from the right. Three properties of shadows--angles, interposition, and positioning--are possible sources of distance information associated with cast shadows.

Cues↗
PubMed1993

Frightening information and extraneous arousal: changing cognitions and behavior regarding nuclear war.

An experiment was designed to demonstrate that fear creates changes, that extraneous arousal modulates the effect of frightening information, and that Janis's (1967) theory may explain these effects. American students watched either a videotape depicting a nuclear attack or a nonfrightening videotape unrelated to nuclear war and were required to perform 10, 20, 35, or 100 jumping jacks. The results of the experiment demonstrated that fear was effective, especially at moderate levels of extraneous arousal, but high levels of arousal eliminated or reversed the effects.

Adult↗
PubMed1987

Youth suicide.

The literature on youth suicide (ages 15-24) is surveyed for the period 1980-1985. Emphasis is placed on general determinants of suicide, predictors in the form of psychological tests, precipitating events (immediate causes), and signs--clues that may signify impending attempts at self-destruction. Suggestions for prevention, and limitations of research on suicide are offered.

Adolescent↗
PubMed1984

Inattention to history yields faulty conceptions of Nazi leaders.

Harrower (1976) as well as Miale and Seizer (1975) partly base their analyses of the Nazi leadership on the contention that Hjalmar Schacht, Minister of Economics for the Third Reich, was a typical Nazi. Those analyses are called into question by the contention that Schacht was not a Nazi at all. Further, it is argued that the failure to understand Schacht is not the only misjudgment made by the two sets of authors. The same literature that suggests Schacht was not a Nazi indicates that the theses of Harrower and Miale-Selzer are too simple.

Journal Article↗