Assessing the accuracy of conflicting autobiographical memories

We examined criteria that rememberers and neutral audiences use to validate conflicting memories. In Experiment 1, rememberers described an incident that they recalled differently from someone else from their own and the other person’s perspective. Rememberers and audiences then evaluated the accuracy of statements in both accounts, explained their accuracy ratings, and appraised the qualities of the memories. In Experiment 2, dyads who possessed conflicting memories of a shared past episode evaluated each other’s recollections. In both studies, rememberers rated their own recollections as more accurate than other people’s and based their judgments primarily on the internal coherence of the memories. Rememberers used consensus more frequently and sensory detail less often to evaluate other people’s memories than their own. Audiences (Experiment 1) reported examining the consistency between the accounts and their own experiences; they also used consensus and normative behavior to a greater extent than rememberers. In both studies, rememberers judged their own accounts to be more detailed and coherent. Their ratings of detail and coherence predicted their ratings of accuracy.     

Patterning,partial reinforcement,and N-length effects at spaced trials as a function of reinstatement of retrieval cues

Four experiments are reported which demonstrate the importance of the reinstatement of retrieval cues in partial-reinforcement experiments using spaced trials. Reinstatement occurs when the goalbox and startbox are of the same brightness (gray). Nonreinstatement occurs when the goalbox and startbox are of different brightnesses (black-and-white striped vs gray). Under reinstatement conditions, both a partial-reinforcement effect (PRE) and N-length effects were observed whether small reward or large reward was used. Under nonreinstatement conditions, a PRE was observed when large reward was used but not when small reward was used; N-length effects were not observed either with large or small reward. Finally, using a 24-hr intertrial interval, single alternation patterning was found only with a group receiving large reward, a long nonreward confinement duration, and reinstatement. These results are not consistent with the notion that massed and spaced trials are governed by separate mechanisms, and support an explanation of both massed and spaced trials based on E. J. Capaldi's sequential theory.     

Spatio-temporal probing of apparent rotational movement

A visual bar alternately presented in vertical and horizontal orientations appeared to rotate 90° through one of two pairs of opposite quadrants. Subjects judged whether a probe dot, interjected at some delay and angular deviation from the vertical bar, appeared before or after the bar “passed through” the corresponding angular orientation. When the motion was perceived in the probed quadrant, percent “before” responses dropped abruptly from near 100% to near 0% as delay increased, and the drop occurred at longer delays for probes at larger angular deviations. Under physically identical conditions, when the motion was perceived in an unprobed quadrant, percent “before” responses varied much less with delay and insignificantly with angular position. The accuracy of the judgments in the first case suggests the internal generation of an ordered sequence of intermediate representations during each apparent rotation.     

Interocular Delay Produces Depth in Subjectively Moving Noise Patterns

Brief apparent motion sequences were introduced into a dynamic visual dot display by spatially shifting selected dots between successive frames. This causes the display to look as if it is drifting continuously in one direction. When such a display is observed with an interocular delay the drifting dots appear to be displaced in depth, even though there is no conventional retinal disparity in the display. We found that the magnitude of this depth shift increased with the duration of the apparent motion sequences. With sequences of five or more frames duration the depth effect was very similar to that which would have been predicted with a continuously moving target. With briefer sequences the size of the depth effect decreased rapidly. We suggest that apparent motion cascades form the basis of Tyler's dynamic visual noise stereophenomenon, and we question his “random spatial disparity” hypothesis.     

A systems approach to decision making on student services

It is argued that student services in higher education need to be made more accountable. A systems approach to planning and evaluation is outlined, and problems of resource allocation and of performance measurement are discussed. Some research problems are also indicated. It is suggested that a system of the kind proposed will enable wider use to be made of limited resources.     

Monotone mapping of similarities into a general metric space

A method of “maximum variance nondimensional scaling” is described and tested that transforms similarity measures into distances that meet just three conditions: (C1) they exactly satisfy the metric axioms, (C2) they are, as nearly as possible, monotonically related to the similarity measures, (C3) they have maximum variance possible under the two preceding conditions. By achieving an appropriate balance between the last two conditions, one can determine the true underlying distances and the form of the unknown monotone function relating the similarity measures to those distances without assuming that the underlying space has any particular Euclidean, Minkowskian, or even dimensional strucutre. The method appears to have potential applications, e.g., to studies of stimulus generalization and the structure and processing of semantic information.     

Use of the conditional reflex to assess the temporal characteristics of curarization effects on heart rate responding

A Pavlovian methodological counterpart to the use of druginduced changes in operant rates of responding was used to assess the temporal characteristics of d-tubocurarine chloride effects on the heart rate conditional reflex in rats. After a stable conditional reflex had been established, the base heart rate, as well as the unconditional and conditional reflex, was monitored during administration of the drug. A sizable behavioral effect was reflected in all three measures, including a temporary abolition of the conditional and unconditional reflexes. An interpretation of these results was discussed, and further development and application of this specific methodology was explored.     

Pair discrimination for a continuum of synthetic voiced stops with and without first and third formants

Phoneme labeling and discrimination experiments were conducted with a continuum of voiced stops produced by a Terminal Analog Speech Synthesizer. The stops ranged from |b| to |d|. Only second formant (F₂) transitions changed from one sound to another. (A formant is energy concentrated in a narrow frequency range.) In the labeling experiment conducted to locate the phoneme boundary, subjects identified the individual stimuli as |b| and |d|. In discrimination, difference and identity pairs were presented, with alternative responses of same and different. This allows separate consideration of discrimination (different/Different) and recognition (same/Identity) hits, and also analysis of the data in accordance with the theory of signal detectibility. The sounds were discriminated with and without F ₁ and F ₃ which contained no discriminatory information, but are responsible for perceived similarity to speech. With F ₁ F ₃ , sensitivity (d) was highest at the |b-d| boundary, but without F ₁ F ₃ this was not true. Spectral analysis of the sounds both with and without F ₁ F ₃ revealed a phonemic energy discontinuity for the 1/3 octave around the F ₂ steady-state frequency (1250 Hz). It therefore seems probable that subjects listened to frequencies which contained phonemic information when F ₁ F ₃ were included, but not when they were omitted. In spite of the high sensitivity at the |b-d| boundary, recognition hits (same /Identity) were lowest the boundary had to sound less like a difference to be called different than a pair away from the boundary.Indications, then, are quite strong that auditory-frequency selection helps the perception of speech, and it is clear that a strategy of criterion lowering helps it.     

Studies in group decision I: Social space,patterns of communication and group concensus

The discovery of the effects of risky shift focusses the interest on the study of decision processes. Nevertheless the researches carried on until now have always shown confusion between the theoretical and experimental analysis of these processes and the risk-related behavior. In the first part of the article the authors try to clear this confusion as well as to define the conditions of a systematic study of the mechanisms of decision leading either to an averaging or to a polarization of individual views. The authors insist on the necessity to compare groups rather than individuals to groups. To start with, one hypothesis concerning the effects of group organization on the degree of polarization of views is proposed. The experiment described in the second part of the article confirms the hypothesis: A group in which individuals have the possibility to communicate with each other and to interact directly take more extreme decisions than a group deprived of this possibility. It is presumptuous and inexact to state that groups take more extreme risk than individuals whereas it is right to say that certain groups take risks when circumstances are favorable.