ARIS: A computer-assisted instruction system

The automated real-time instructional system (ARIS) is a small computer-assisted instructional system written to run under the UNIX operating system on a PDP-11/34A machine. ARIS is a tool used to provide highly individualized instruction and, at the same time, to study the process of learning by keeping detailed records of students’ actions. Currently, the system is used to teach logic and set theory. This paper describes the general philosophy, operation, and implementation of ARIS.     

Stereotype Threat,Social Class,Gender, and Academic Under-Achievement: When Our Reputation Catches Up to Us and Takes Over

According to Steele (1997), negative stereotypes about intellectual abilities can act as a threat that disrupts the performance of students targeted by bad reputations. Previous research on stereotype threat has showed that on a stereotype-relevant test, stigmatized group members (e.g., African Americans) performed worse than others on an intellectual verbal task. However, when the instructions accompanying the test did not create stereotype threat, stigmatized group members' performance was equal to that of other participants. In this paper, we present studies documenting the effect of stereotype threat and discuss ways to counter it. Two strategies derived from Self-Categorization Theory (Turner & Oakes, 1989) and Self-Affirmation Theory (Steele, 1988) are presented, tested, and discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Sensitivity of the brain to loss aversion during risky gambles

Little is known about the neural systems that subserve human loss aversion. A recent neuroimaging study by Tom, Poldrack and colleagues reports that this pattern of behaviour is directly tied to the greater sensitivity of the brain to potential losses compared with potential gains and uncovers a brain network whose activity increases with potential gains and decreases with potential losses. These results challenge the common view that loss aversion engages a distinct emotion-related brain network (e.g. amygdala and insula).     

Electrofisiología y eficiencia intelectual

Resumen

La investigación de índices fisiológicos correlativos de la eficiencia intelectual, ha sido la preocupación constante de numerosos psicofisiólogos.

El análisis del EEG, el análisis de los potenciales evocados de niños defifientes mentales y de niños normales conducen a resultados contradictorios.

El descubrimiento del sueño paradójico ha sido el origen de un nuevo enfoque de la eficiencia intelectual. Numerosos trabajos con resultados convergentes, muestran una correlación positiva entre tasa de sueño paradójico y deficiencia mental.

¿Puede generalizarse esta relación a todos los tipos etiológicos y a todos los niveles intelectuales? ¿Qué mecanismos entran en juego? Se propone una interpretación que hace intervenir la memoria como variable intermediaria.     

Difference measurement and simple scalability with restricted solvability

Let A, B be two sets, with B ? A × A, and ≤ a binary relation on B. The problem analyzed here is that of the existence of a mapping u: A → R, satisfying:

$\text{(a,b) ? (}\text{a}\text{?}\text{,}\text{b}\text{?}\text{)}\text{iff}\text{∨∧ μ(b) ? μ(a) ? μ(}\text{b}\text{?}\text{) ? μ(}\text{a}\text{?}\text{)}$

whenever (a, b), (a′, b′) ∈ B. In earlier discussions of this problem, it is usually assumed that B is connected on A. Here, we only assume that B satisfies a certain convexity property. The resulting system provides an appropriate axiomatization of Fechner's scaling procedures. The independence of axioms is discussed. A more general representation is also analyzed:

$\text{(a,b) ? (}\text{a}\text{?}\text{,}\text{b}\text{?}\text{)}\text{iff}\text{∨∧ F[μ(b), μ(a)] ? F[μ}\text{b}\text{?}\text{]}$

, where F is strictly increasing in the first argument, and strictly decreasing in the second. Sufficient conditions are presented, and a proof of the representation theorem is given.     

Sufficient conditions for an ordered-ring isomorphism onto a positive subinterval: A lemma for polynomial measurement

This paper discusses a sufficient set of conditions for a structure to be ordered-ring isomorphic to a positive subinterval of the real numbers. It extends our previous results concerning bounded versions of Hölder's Theorem (Falmagne, 1971). The main result can serve as a basic lemma for establishing representation theorems in polynomial conjoint measurement when the empirical sets contain neither large elements nor ones close to the natural zero.     

Conjoint Weber laws and additivity

This paper investigates the mathematical consequences of a number of related empirical laws, exemplified by

$\text{P}{}_{\mathrm{ax;by}}\text{= P(ξa)(ξx);(ξb)(ξy)}$

where a, x, b, y, and ξ are real numbers, and P_ax;by is the probability of choosing the two-dimensional object (a, x) in the set {(a, x), (b, y)}. A variety of results is derived showing that, in the presence of such laws, the class of feasible models for choice data is considerably reduced. In particular, it is shown that the above law, together with the “additive conjoint” form

$\text{P}{}_{\mathrm{ax;by}}\text{= F[l(a) + r(x), l(b) + r(y)]}$

(where F, l, and r are unspecified except for continuity and monotonicity properties), requires the choice probabilities to possess one of the following three analytic forms:

$\text{P}{}_{\mathrm{ax;by}}\text{= G}\text{a}{}^{\mathrm{\beta }}\text{+ δx}{}^{\mathrm{\beta }}\text{b}{}^{\mathrm{\beta }}\text{+ δy}{}^{\mathrm{\beta }}\text{, β ≠ 0}$

;

$\text{P}{}_{\mathrm{ax;by}}\text{= G(a}{}^{\mathrm{\beta }}\text{x}{}^{\mathrm{\gamma }}\text{/b}{}^{\mathrm{\beta }}\text{y}{}^{\mathrm{\gamma }}\text{), β + γ ≠ 0}$

;

$\text{P}{}_{\mathrm{ax;by}}\text{= Q}{}_0\text{(a/x, b/y)}$

.