An efficient adaptive procedure for psychophysical discrimination experiments

We present an adaptive procedure to conduct psychophysical discrimination experiments. In a discrimination experiment, an observer senses (sees, hears, feels, etc.) two stimuli (separated in space or time) and is asked to order these stimuli with respect to a particular parameter (say,s). Under the usual assumption of a locally linear internal representation ofs, perturbed by additive Gaussian noise, the probabilityP(s ₂)—of judging test stimuluss ₂ “larger” than a reference stimuluss ₁—is an error function (a cumulative normal distribution). Such an error function,Erf [(s ₂μ)/σ], is parametrized by two parameters: μand σ. The parameter μ is the value for whichP(s ₂) = 50% and is related to possible bias effects in the internal representation of the observer. The parameter σ is √2 times the standard deviation of the noise distribution and is generally called thediscrimination threshold. In this paper, we present (1) an algorithm to estimate μ and σ given the data generated by such an observer, (2) an analysis of the efficiency of a stimulus presentation with respect to the estimation of μ and σ , and (3) a method that controls the specific choice of stimulus values during an experiment so that an optimal estimation of μ and σ is obtained.     

Mastery pleasure versus mere ownership: A quasi-experimental cross-cultural and cross-alphabetical test of the name letter effect

Four studies test both the alternative explanation advanced by Hoorens and Todorova (1988) for Nuttin's (1984, 1985, 1987) name letter effect (NLE), and two interpretations for an unexplained finding of the former authors. Flemish, Hungarian and Thai children show an increasing rather than a decreasing NLE over primary school grades (studies 1, 2 and 4). Thai university students and school children prefer own name letters in their ‘mother’ alphabet (Thai) but also in their second (Roman) alphabet (studies 3 and 4). All these results contradict the primacy of own name writing or mastery pleasure hypothesis. Independently of the time interval between the acquisition of both alphabets, a stronger NLE is found in the subjects ‘mother’ alphabet than in their second alphabet, contradicting a mitigated mastery pleasure explanation for the stronger NLE in one's ‘mother’ alphabet (Hoorens and Todorova, 1988). All the data are consistent with Nuttin's interpretation of the NLE in terms of the affective consequences of ‘mere ownership’. Finally, the striking generality of the NLE over languages, alphabets, and cultures is again demonstrated.     

ACQUISITION AND CROSS-SETTING GENERALIZATION OF MANUAL SIGNS WITH SEVERELY RETARDED INDIVIDUALS

In this study, we assessed the effect of a transfer of stimulus control procedure on the acquisition and cross-setting generalization of manual signs with four profoundly retarded individuals. Two individuals were trained to produce appropriate signs to verbal instructions, whereas the other two were trained until manual signs were controlled by visual stimuli (objects). Data obtained from three probe situations (two for one individual) constituted the dependent variables of the investigation. The results, gathered within a multiple-baseline design across signs showed that (a) individuals acquired the trained signs and (b) maintenance and generalization across settings (classroom, ward) and persons (teachers, ward staff) occurred, but was highly variable between and within individuals.     

Assertiveness,self-actualization,and locus of control in women

An intervention program designed to facilitate psychological growth in middle-aged women was implemented and evaluated. Specifically, the study examined the program's effects on the participants in the areas of assertiveness, externality, and self-actualization at the end of the program and five months later. The results showed significant increases in assertiveness and self-actualization in the women at the posttest and five months later. There was no change in locus of control; most of the women were internally oriented at the pretest and remained the same over time.     

The effects of spatial,temporal, and control variables on the free-recall serial position curve of retardates and equal-MA normals

Memory & Cognition - In Experiment I seven pictures were sequentially illuminated at a 3-see rate through seven translucent windows. A different window provided the starting point for each of...     

Self-disclosure: an attributional perspective.

This experiment examined the effect of timing of an intimate disclosure and assignment of responsibility for the event disclosed on interpersonal attraction. Subjects were induced to interact with a confederate who in all cases revealed something quite personal about himself. The disclosure occurred either early or near the end of a 10-minute conversation. The confederate accepted responsibility for the event disclosed, did not mention responsibility, or assigned responsibility to external factors. Negative traits were assigned to the early disclosure, and he was liked significantly less than the late discloser. The results are explained in terms of differential attributions made to early and late disclosures. The results for the assignment of responsibility variable were surprising: The confederate who accepted responsibility for the event disclosed elicited more negative reactions than the confederate who blamed other factors or who did not mention responsibility. Some possible reasons for this unexpected finding are discussed.     

Clause structure of sentences and speech processing

Listeners heard narrative stories in segments 20-60 sec long, and wrote their immediate recall for the most recent speech in each segment. Segments ended in four ways: there was a main clause alone, a subordinate clause alone, a main clause preceding a subordinate clause, or a subordinate clause preceding a main clause. Only these final sentences were well recalled. Of these, single-clause sentences were recalled best and two-clause sentences with main-subordinate clause order were recalled worst. An interaction obtained between clause position and function suggests that processing may be delayed when sentences fall to begin with main clauses.     

A new illusion: The underestimation of distance during pursuit eye movements

A new visual illusion is reported. The apparent distance through which a displaced target appears to move is significantly shorter when pursuit tracked than when that same distance is observed by means of a saccadic eye movement. This misperception of distance seems to be related to the Aubert-Fleischl paradox, the underestimation of the velocity of a tracked target, and to reveal a consistent characteristic of the pursuit eye movement system.