A task-difficulty artifact in subliminal priming

Subliminal priming is said to occur when a subliminal prime influences the classification of a subsequent target. Most subliminal-priming claims are based on separate target- and prime-classification tasks. Because primes are intended to be subliminal, the prime-classification task is difficult, and the target-classification task is easy. To assess whether this task-difficulty difference accounts for previous claims of subliminal priming, we manipulated the ease of the prime-classification task by intermixing long-duration (visible) primes with short-duration (near liminal) ones. In Experiment 1, this strategy of intermixing long-duration primes raised classification of the shortduration ones. In Experiments 2 and 3, prime duration was lowered in such a way that prime classification was at chance in intermixed presentations. Under these conditions, we failed to observe any priming effects; hence, previous demonstrations of subliminal priming may simply have reflected a task-difficulty artifact.     

A possible artifact in serial response behaviour

Using 12 subjects who worked for 12 min on a self-paced 5-choice serial response task, it was hypothesised that external events inserted by computer program in accordance with a random sequence of time intervals would bisect a greater proportion of long response times, and thus that the parameters of the resulting distributing would be greater than the parameters of the parent distribution or of a distribution in which responses were selected at random. The results confirmed the hypothesis and it was concluded that the Waiting Time Paradox as described by Feller (1966), is applicable to situations involving serial response tasks.     

A low-cost research-oriented biofeedback thermometer with digital readout

The construction of a research-oriented biofeedback thermometer with digital readout is described. The device uses recently developed low-cost integrated circuits and has a liquid crystal readout with capability of .1° and .01°F display. Internal calibration circuitry enables precision monitoring of overall performance stability. The basic thermometer design has potential application as a general instrument for behavioral and physiological research.     

A detector of sonic and ultrasonic vocalizations with frequency readout

An electronic apparatus to detect vocalizations between 4 and 50 kHz and to provide frequency readout is described. A frequency-to-voltage converter changes vocalizations to their analog. A peak-and-hold circuit retains and gates the maximal value of this analog voltage while it is accessed by a chart recorder or computer. Provision is made to lock out noise by inhibiting the device’s response to all signals lower than those associated with a selectable cutoff frequency. In preliminary tests of the apparatus, vocal signals of two rats in a common cage were recorded while the animals were subjected to a brief, intermittent bout of faradic shock to the feet. All recorded vocalizations occurred at frequencies below 26 kHz.     

On sending artifact in search of artifact: reply to Mcdonald, Harris, and Maher

Two studies are reported that show the McDonald, Harris, and Maher critique of our earlier experiment to be mistaken. In the first study, arousal-induced attention to self was demonstrated in a field setting devoid of any of the artifactual covariates of arousal induction suggested by these researchers. In the second study, a replication of the McDonald et al. experiment was conducted in which a crucial manipulation check that they failed to make was included. This check on the unusualness and embarrassment-producing properties of the manipulations revealed that their study was burdened by the very artifact they claimed might exist in ours. Although their slow-running manipulation was superficially similar to our fast-running manipulation, slow running created self-focus through unusualness and embarrassment, whereas fast running led to self-focus via arousal.     

Improved calibration of color video projectors by means of computer animation

A computer animation for the calibration of color video projectors is described. The animation facilitates the calibration procedure and can be readily programmed on almost any graphics computer or played from a videotape.     

Potential artifact in dichoptic backward masking.

Under some conditions a dark interval in the target eye may be concomitant with presentation of a dichoptic mask. Results show that this monoptic dark interval contributes to the over-all observed dichoptic masking effect.     

Inference and coherence in causal-based artifact categorization

In four experiments, we tested conditions under which artifact concepts support inference and coherence in causal categorization. In all four experiments, participants categorized scenarios in which we systematically varied information about artifacts’ associated design history, physical structure, user intention, user action and functional outcome, and where each property could be specified as intact, compromised or not observed. Consistently across experiments, when participants received complete information (i.e., when all properties were observed), they categorized based on individual properties and did not show evidence of using coherence to categorize. In contrast, when the state of some property was not observed, participants gave evidence of using available information to infer the state of the unobserved property, which increased the value of the available information for categorization. Our data offers answers to longstanding questions regarding artifact categorization, such as whether there are underlying causal models for artifacts, which properties are part of them, whether design history is an artifact’s causal essence, and whether physical appearance or functional outcome is the most central artifact property.     

Essentialism and graded membership in animal and artifact categories

A number of studies have argued that people view membership in animal and artifact categories as a matter of degree. These studies have generally failed to distinguish between the issues of typicality and category membership. Thus, data which have been taken to demonstrate that membership is a matter of degree may only demonstrate that typicality is graded. Partly on the basis of these findings, it has been argued that some categories are organized around an underlying essence. The essence determines membership absolutely. The present paper reports a series of studies that reexamine the question of graded membership. In the first study, subjects were asked to rate both typicality and category membership for the same stimuli as a way of distinguishing the two questions. A second method relied on the intuition that disagreements about membership in all-or-none and graded categories may have different qualities. Results from both studies suggest some support for claims that membership in animai and artifact categories is a matter of degree. A third study explored the possibility that graded responses were due to conflicting, or ambiguous, sets of criteria. A task focusing on biological features did not lead to more absolute categorization. These results contradict essentialist predictions.