A method for quantifying focused versus overview behavior in AOI sequences

We present a new measure for evaluating focused versus overview eye movement behavior in a stimulus divided by areas of interest. The measure can be used for overall data, as well as data over time. Using data from an ongoing project with mathematical problem solving, we describe how to calculate the measure and how to carry out a statistical evaluation of the results.     

A simple method using a single video camera to determine the three-dimensional position of a fish

In the present paper, we describe a method for recording the coordinates of a fish in an aquarium in a three-dimensional space, using a single video camera and a mirror. We use photogrammetic equations for this, considering the image obtained in the mirror as a virtual image obtained by a second camera. A transformation of the coordinate system is required to express the obtained coordinates in anx,y,z system defined by the edges of the aquarium. The accuracy of the proposed method was estimated, and errors in extreme conditions were found to be 0.8% to 1.2 %, compared with the dimensions of the aquarium used in the test.     

A graphic measure for game-theoretic robustness

Robustness has long been recognized as an important parameter for evaluating game-theoretic results, but talk of ‘robustness’ generally remains vague. What we offer here is a graphic measure for a particular kind of robustness (‘matrix robustness’), using a three-dimensional display of the universe of 2 ×  2 game theory. In such a measure specific games appear as specific volumes (Prisoner’s Dilemma, Stag Hunt, etc.), allowing a graphic image of the extent of particular game-theoretic effects in terms of those games. The measure also allows for an easy comparison between different effects in terms of matrix robustness. Here we use the measure to compare the robustness of Tit for Tat’s well-known success in spatialized games (Axelrod, R. (1984). The evolution of cooperation. New York: Basic Books; Grim, P. et al. (1998). The philosophical computer: Exploratory essays in philosophical computer modeling. Cambridge, Mass: MIT Press) with the robustness of a recent game-theoretic model of the contact hypothesis regarding prejudice reduction (Grim et al. 2005. Public Affairs Quarterly, 19, 95–125).     

Proposal for a new body sway evaluation method

This study is aimed at examining body sway factors for 1107 healthy people aged 16 to 69 years and to propose a practical body sway evaluation method. The center of foot pressure measurement was carried out twice for 1 min. with a 1-min. rest. 30 parameters with high reliability selected from 6 domains (distance, distribution of amplitude, area, velocity, power spectrum, and body sway vector) were summarized objectively into 4 body sway factors (unit time sway, front-back sway, left-right sway, and high frequency band power). Factor scores were calculated by the estimate equation and the total standard scores of parameters with high factor loadings. Considering this result, a total standard score for each factor was classified into 4 percentile categories based on percentile rank. Using this classification criteria, body sway scores for each individual were classified into any of the above 4 domains for each factor. It was confirmed that young adults mainly belong to percentile Categories A and B and the elderly mainly belong to percentile Categories C and D. It was found that a great effect on body sway occurred when an individual's conscious condition changed (contracting a cold or after exercise). In conclusion, the body sway of healthy people can be explained by these 4 sway factors. An evaluation of the body sway pattern using the 4 sway factors may enable us to concretely understand individuals' disorders and abnormal states in addition to changes in body sway that occur with aging.     

Psychological norms for simple three-line graphic shapes

There is a longstanding tradition in psychological research for norming lists of words that are used in experimental studies. The present study extends this practice to graphic imagery by obtaining norming data on 24 simple abstract graphic shapes composed of three straight-line segments. The attributes obtained in the norming procedure were the shapes' familiarity, describability, associability, availability, and potential for word association. Results from rating data indicate significantly different, yet reliable, responses by participants to the various shape configurations. Multidimensional scaling analysis of shape ratings identified two underlying dimensions of perceived differences: the continuity of a shape's linear direction and the consistency or regularity of its interior angles. By contrast, performance in generating word associations for figures appeared to be linguistically driven, with initial responses related to the similarity of shapes to letters of the alphabet. The norms and the computer program used to collect them can be downloaded from www.psychonomic.org/archive.     

The interaction of visual and motor memory for graphic forms following tracing

Memory for series of abstract graphic forms was tested using a recognition/ reconstruction procedure in two experiments with 8-9-year-old children. The children either looked at the forms and traced around each of them in turn (VT condition), or looked at the forms for an equivalent length of time and pointed to them (V condition). Memory for the forms, but not their order was improved by tracing. The mechanism responsible for this was investigated by comparing the effects of motor and visual interference interpolated between stimulus presentation and recognition testing. Motor interference was most disruptive in the VT condition while visual interference tended to be most disruptive in the V condition. These results support the proposal that tracing produces a distinct motor memory trace and that this additional source of information aids visual recognition.     

Nonverbal measurement of affect: The graphic differential

The measurement of affective meaning (Osgood's three universal factors) is easily accomplished via the semantic differential. However, the verbal nature of this instrument prevents its use with many subject groups in which the measurement of affective meaning would be the most interesting: members of illiterate cultures, verbally damaged individuals such as anomic aphasics and thought-disordered schizophrenics, and children younger than 6 years. For these purposes, the present study describes the development of a nonverbal alternative to the semantic differential and assesses the statistical comparability of scores resulting from the use of the two instruments.This research was supported by Grant NSF GS 2012x to Professors Charles E. Osgood and William H. May.     

A technique for quantifying and analyzing evoked responses

Two computer programs are discussed. One is used in the analog-to-digital conversion of and averaging of the responses; the other employs fuil-wave rectification and numerical integration as a method of comparing waveforms.     

Choosing among techniques for quantifying single-case intervention effectiveness

If single-case experimental designs are to be used to establish guidelines for evidence-based interventions in clinical and educational settings, numerical values that reflect treatment effect sizes are required. The present study compares four recently developed procedures for quantifying the magnitude of intervention effect using data with known characteristics. Monte Carlo methods were used to generate AB designs data with potential confounding variables (serial dependence, linear and curvilinear trend, and heteroscedasticity between phases) and two types of treatment effect (level and slope change). The results suggest that data features are important for choosing the appropriate procedure and, thus, inspecting the graphed data visually is a necessary initial stage. In the presence of serial dependence or a change in data variability, the nonoverlap of all pairs (NAP) and the slope and level change (SLC) were the only techniques of the four examined that performed adequately. Introducing a data correction step in NAP renders it unaffected by linear trend, as is also the case for the percentage of nonoverlapping corrected data and SLC. The performance of these techniques indicates that professionals' judgments concerning treatment effectiveness can be readily complemented by both visual and statistical analyses. A flowchart to guide selection of techniques according to the data characteristics identified by visual inspection is provided.     

Effect of visual surrounding motion on body sway in a three-dimensional environment

Unidirectional motion of a uniplanar background induces a codirectional postural sway. It has been shown recently that fixation of a stationary foreground object induces a sway response in the opposite direction (Bronstein & Buckwell, 1997) when the background moves transiently. The present study investigated factors determining this contradirectional postural response. In the experiments presented, center of foot pressure and head displacements were recorded from normal subjects. The subjects faced a visual background of 2 x 3 m, at a distance of 1.5 m, which could be moved parallel to the interaural axis. Results showed that when the visual scene consisted solely of a moving background, the conventional codirectional postural response was elicited. When subjects were asked to fixate an earth-fixed foreground (window frame) placed between them and the moving background, a consistent postural response in the opposite direction to background motion was observed. In addition, we showed that this contradirectional postural response was not transient but was sustained for the 11 sec of background motion. We investigated whether this contradirectional postural response was the consequence of the induced movement of the foreground by background motion. Although induced movement was verbally reported by subjects when viewing an earth-fixed target projected onto the moving background, the contradirectional sway did not occur. These results indicate that foreground-background separation in depth was necessary for the contradirectional postural response to occur rather than induced movement. Another experiment showed that, when the fixated foreground was attached to the head of the observer, the contradirectional sway was not observed and was therefore unrelated to vergence. Finally, results showed that the contradirectional postural response was, in the main, monocularly mediated. We conclude that the direction of the postural sway produced by a moving background in a three-dimensional environment is determined primarily by motion parallax.     

The development of context sensitivity in children's graphic copying strategies

The authors report on a series of 5 experiments in which 462 5- to 10-year-old children and 109 adults were required to copy geometric figures either with no constraints or following prior exposure to primes consisting of different parsings of the figures. The analysis focused on the graphic strategies adopted by the participants to copy the models. Three developmental steps were revealed in the baseline copying condition. Priming experiments demonstrated that the age-developmental step correspondence varied as a function of the type of prime used. However, the impact of priming differed according to age. It was limited at 6 years, whereas its size was noticeable at the other ages. These results are discussed in the light of developmental models that hypothesize a major role either for endogeneous factors in cognitive development or for exogeneous and contextual factors.     

High-power graphic computers for visual simulation: A real-time-rendering revolution

Advances in high-end graphics computers in the past decade have made it possible to render visual scenes of incredible complexity and realism in real time. These new capabilities make it possible to manipulate and investigate the interactions of observers with their visual world in ways once only dreamed of. This paper reviews how these developments have affected two preexisting domains of behavioral research (flight simulation and motion perception) and have created a new domain (virtual environment research) which provides tools and challenges for the perceptual psychologist. Finally, the current limitations of these technologies are considered, with an eye toward how perceptual psychologists might shape future developments.