The foreperiod effect revisited: conditioning as a basis for nonspecific preparation

The foreperiod (FP) is the interval between a warning stimulus and the imperative stimulus. It is a classical finding that both the duration and the intertrial variability of FP considerably affects response time. These effects are invariably attributed to the participant's state of nonspecific preparation at the moment the imperative stimulus is presented. In this article, we examined a proposal by Los, S. A. (1996) [On the origin of mixing costs: exploring information processing in pure and mixed blocks of trials. Acta Psychologica, 94, 145-188] that the real-time development of nonspecific preparation during FP relies on the same principle as trace conditioning. To this end, we adjusted the formal conditioning model developed by Machado, A. (1997) [Learning the temporal dynamics of behavior. Psychological Review, 104 (2), 241-265], and fitted this model to a representative data set we obtained from nine participants. Although the model accounted for only a moderate proportion of the variance, it accurately reproduced several key features of the data. We therefore concluded that the model is a promising first step toward a theory of nonspecific preparation.     

Simple reaction time as a function of response complexity: memory drum theory revisited

The prediction emanating from memory drum theory (Henry & Rogers, 1960') that simple reaction time (SRT) increases as a response becomes more complex (i.e., increases in number of movement parts) was investigated. Experiments 1 (N = 20) and 3 (N = 16) indicated that SRT was longer for responses consisting of two and three parts than it was for a one-part response and this may be interpreted as support for the prediction. Failing to support the prediction, however, was the finding that SRT was essentially the same for responses consisting of two and three parts. This may not be too damaging to the theory because it could simply be reflecting an upper limit in terms of numbers of parts or response duration for causing an increase in SRT. Experiments 2 (N = 20) and 3 revealed an SRT effect between two responses that were supposed to be equal in complexity. At first, this finding appeared to be contrary to the prediction, but it may be interpreted as support for it because one of the responses defined as having one movement part could actually have had two     

Self-reported visual function and academic success: Cattell revisited

To test the hypothesis that visual deficits might hamper college students' academic success, we examined the relationship between a reliable self-report measure of visual function and semester grades. The correlation between the Everyday Vision Questionnaire scores and the grades of 331 college students was .01, which replicates and extends the historical findings of Cattell and others.     

Robust nonorthogonal analyses revisited: An update based on trimmed means

Three approaches to the analysis of main and interaction effect hypotheses in nonorthogonal designs were compared in a 2×2 design for data that was neither normal in form nor equal in variance. The approaches involved either least squares or robust estimators of central tendency and variability and/or a test statistic that either pools or does not pool sources of variance. Specifically, we compared the ANOVA F test which used trimmed means and Winsorized variances, the Welch-James test with the usual least squares estimators for central tendency and variability and the Welch-James test using trimmed means and Winsorized variances. As hypothesized, we found that the latter approach provided excellent Type I error control, whereas the former two did not.Financial support for this research was provided by grants to the first author from the National Sciences and Engineering Research Council of Canada (#OGP0015855) and the Social Sciences and Humanities Research Council (#410-95-0006). The authors would like to express their appreciation to the Associate Editor as well as the reviewers who provided valuable comments on an earlier version of this paper.     

Recency judgments as a function of word frequency: A framing effect and frequency misattributions

The effects of word frequency on judgments of recency of item presentation were examined in two experiments. Subjects in Experiment 1 were presented two mixed lists of high- and low-frequency words followed by a list assignment task for recognized items. It was found that subjects were biased toward assigning low-frequency words to the more recently presented list. Subjects in Experiment 2 were presented a single mixed list of high- and low-frequency words followed by either a relative recency of presentation judgment task or a relative primacy of presentation judgment task. Each word pair on the tests contained one high-frequency word and one low-frequency word. It was found that, for the recency judgment task, subjects were biased to select the low-frequency item as having been presented more recently. However, on the parallel primacy judgment task, there were no effects of word frequency; moreover, overall accuracy levels were higher with primacy than with recency instructions. We interpret the effects of word frequency on recency judgments in Experiments 1 and 2 in terms of a misattribution of frequency-related differences in recollection-based recognition. The finding that recency and primacy instructions produced different patterns of results provides further evidence (Flexser & Bower, 1974) for an effect on performance of the way in which the temporal judgment task was framed.     

Not only encoding and retrieval: The enactment effect as a function of task preparation

Three experiments examined the implications of adding a fourth preparation stage to the encoding-retention-retrieval stage analysis of memory. Action memory was selected as the research domain. The results demonstrated that systematic variation of the preparation stage yields new insights about enactment effects in memory. Together with effects of enactment in the preparatory stage, enactment was also shown to give differential effects in encoding and retrieval, with interactions between these three factors. The experimental results were discussed in relation to a strategy processing interpretation of action memory.     

Colavita dominance effect revisited: the effect of semantic congruity

To investigate the effect of semantic congruity on audiovisual target responses, participants detected a semantic concept that was embedded in a series of rapidly presented stimuli. The target concept appeared as a picture, an environmental sound, or both; and in bimodal trials, the audiovisual events were either consistent or inconsistent in their representation of a semantic concept. The results showed faster detection latencies to bimodal than to unimodal targets and a higher rate of missed targets when visual distractors were presented together with auditory targets, in comparison to auditory targets presented alone. The findings of Experiment 2 showed a cross-modal asymmetry, such that visual distractors were found to interfere with the accuracy of auditory target detection, but auditory distractors had no effect on either the speed or the accuracy of visual target detection. The biased-competition theory of attention (Desimone & Duncan Annual Review of Neuroscience 18: 1995; Duncan, Humphreys, & Ward Current Opinion in Neurobiology 7: 255–261 1997) was used to explain the findings because, when the saliency of the visual stimuli was reduced by the addition of a noise filter in Experiment 4, visual interference on auditory target detection was diminished. Additionally, the results showed faster and more accurate target detection when semantic concepts were represented in a visual rather than an auditory format.     

Learning under stress: the inverted-U-shape function revisited

Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze (RAWM). Variations in stress intensity were induced using different water temperatures (25°C, 19°C, and 16°C), which elicited increased plasma corticosterone levels. During spatial training over three consecutive days, an inverted-U shape was found, with animals trained at 19°C making fewer errors than animals trained at either higher (16°C) or lower (25°C) stress conditions. Interestingly, this function was already observed by the last trial of day 1 and maintained on the first day trial of day 2. A long-term recall probe test administered under equal temperature conditions (20°C) revealed differences in performance according to the animals' former training conditions; i.e., platform searching for rats trained at 25°C was less accurate than for rats trained at either 16°C or 19°C. In reversal learning, groups trained at both 19°C and 25°C showed better performance than the 16°C group. We also found an interaction between anxiety and exploration traits on how individuals were affected by stressors during spatial learning. In summary, our findings confirm, for the first time, the existence of an inverted-U-shape memory function according to stressor intensity during the early learning and memory phases in a hippocampus-dependent task, and indicate the existence of individual differences related to personality-like profiles for performance at either high or low stress conditions.     

Item selection by means of a maximizing function

A new item selection technique is presented which takes into account the intercorrelations of the items as well as their correlations with the criterion. The technique is regarded as superior to comparable techniques in that it is considered to achieve greater economy of time, greater objectivity of procedure, higher validity, and higher reliability. The mathematical theory underlying the method is developed. An approximate solution of the mathematical equations is suggested. An approximation procedure for the complete item selection technique is presented, based on the mathematical solution, but much simpler in procedure. The clerical operations involved in the approximation procedure are outlined and illustrated on a sample worksheet.     

Color change as a causal agent revisited

Michotte (1946/1963, p. 235) concluded that color "has no bearing whatever on the question of qualitative causality". Surprisingly, this claim has received little empirical investigation in the 60 years since its publication. In 2 experiments, 2 balls struck a cylinder and changed color (either continuously or in a stepped progression) for 2 s. After the 2-s interval, the cylinder disgorged a purple substance. Participants chose which of the 2 balls was most likely to have caused the disgorging effect. An object that changed color was favored as the cause much more often than one that did not, and participants generally preferred an object that reached its terminal color immediately before the effect over objects that reached their terminal colors earlier. When participants performed a causal ratings task, color change produced moderate judgments of causation, with little response differentiation as a function of color dynamics.     

Susceptibility to retroactive interference: The effect of context as a function of age and cognition

Previous studies have shown that contextual cues improve memory performance and reduce interference in younger adults. However, it is not clear whether middle-aged and older adults can also benefit from contextual cues, or if this ability diminishes with ageing and cognitive decline. In order to test this question, we tested 69 middle-aged adults (aged 30–50 years) and 65 older adults (aged 65–85). Participants completed a retroactive interference paradigm with or without contextual cues. Cognitive functioning of older adults was assessed using the Montreal Cognitive Assessment, which is a sensitive and highly validated tool to detect cognitive decline in older age. The results showed that while middle-aged adults were able to benefit from context to improve recognition and reduce interference, older adults were not able to benefit from it. However, when we compared older adults with lower (<26) and higher (≥26) scores on the Montreal Cognitive Assessment, we found that older adults with high cognitive functioning could benefit from context advantage at retrieval to improve recognition compared to those with lower cognitive functioning. Yet, similar to older adults with lower cognitive functioning, they could not benefit from context advantage at encoding and hence were still susceptible to interference.     

Visual dominance and attention: the Colavita effect revisited

Under many conditions, humans display a robust tendency to rely more on visual information than on other forms of sensory information. Colavita (1974) illustrated this visual dominance effect by showing that naive observers typically fail to respond to clearly suprathreshold tones if these are presented simultaneously with a visual target flash. In the present study, we demonstrate that visual dominance influences performance under more complex stimulation conditions and address the role played by attention in mediating this effect. In Experiment 1, we show the Colavita effect in the simple speeded detection of line drawings and naturalistic sounds, whereas in Experiment 2 we demonstrate visual dominance when the task targets (auditory, visual, or bimodal combinations) are embedded among continuous streams of irrelevant distractors. In Experiments 3-5, we address the consequences of varying the probability of occurrence of targets in each sensory modality. In Experiment 6, we further investigate the role played by attention on visual dominance by manipulating perceptual load in either the visual or the auditory modality. Our results demonstrate that selective attention to a particular sensory modality can modulate--although not completely reverse--visual dominance as illustrated by the Colavita effect.     

Discovery as a means to understanding

Two experiments were conducted to determine whether the discovery of a conditional rule from its instances facilitated a test of its truth from partially concealed information, compared with a situation in which the rule was presented directly. In the first experiment the subjects who discovered the rule expressed it in their own words. The results showed that they tested it significantly better than a control group who were presented with the rule, as expressed by the subjects in the experimental group. In the second experiment the subjects in the experimental group were compelled to express the rule in the form of a conditional sentence. The results showed again that they performed significantly better than those in a corresponding control group.