Error patterns in a chord keyboard response task

Errors in a serial choice-reaction time experiment employing two-finger chord responses to alphabetic stimuli are shown to be distributed in a significantly non-random fashion. Two factors are postulated which are relevant to prediction of the error response. These are the presence or absence of a common finger, and the difference in finger separation, between the actual and the required response. It is suggested that the chord response is coded in terms of a pattern (the distance between the two response components). Responses which mirror the correct response about the centre of the hand are also shown to be significantly more frequent.     

Encoding and memory for verbal and pictorial stimuli

Memory for visually presented verbal and pictorial material was compared using stimuli chosen to minimize non-essential differences between the two types of material. Experiment I required retention of a short list; verbal and pictorial stimuli were remembered equally well. Experiment II required recall of single items after 30 s of backwards counting; recall was much superior for pictorial stimuli. The type of task appeared to affect encoding, with verbal encoding reported to be predominant in Experiment I and visual encoding, or imagery, common in Experiment II.     

A comparison of leverpress and head-poke discriminated Sidman avoidance

A discriminated Sidman avoidance procedure used by Forgione (1970) was replicated using a head-poke response instead of a leverpress as the avoidance operant. The resultant data were described in terms of the five dependent measures reported by Forgione. Head-poke avoidance was found to be more efficient than its leverpress counterpart and compared very favorably with the lever-disabling (or shock-timer-on) procedure used by Forgione to break up inefficient leverpress behavior patterns.     

FREE RECALL OF REPEATED WORDS AS A FUNCTION OF INTRALIST VARIABILITY

von W right J. M. Free recall of repeated words as a function of intralist variability. Scand. J. Psychol ., 1972, 13 , 39–42.—Five "critical" words were repeated 4 times each in constant positions within lists of 80 items. The number of different filler words, and the order of the repeated filler words, was varied between lists. In free recall tests total recall was approximately constant, but the recall of the critical words was significantly better the greater the variation in the intralist context of these words, especially the greater the number of different filler words. The results are interpreted in terms of the encoding variability hypothesis.     

Retinal locus and the letter-span error function

The effect of retinal locus on the letter-span error function was investigated by requiring Ss to fixate at the left, middle, or right of lines of letters presented for 100 msec. Stimulus presentations consisted of lines of eight letters presented across the visual field, and lines of four letters presented alternately in the left and right visual hemifields. Locus of fixation and relative letter position were found to be significantly related to whether or not a letter was correctly localized. A significant interaction between locus of fixation and letter position was observed.     

Visual information processing of sequentially presented inputs: III. Further effects of list length and interstimulus interval values on sub-span storage and retrieval mechanisms

Two experiments were carried out, employing a computer-based cathode-ray tube display system, to study further the effects of sub-span Hst length, i.e., two, three, four, and five decimal digits, and relatively small interstimulus interval (ISI) values, i.e., 20, 40, 60, 80, and 100 msec, on visual information processing, storage, and retrieval mechanisms. The results of the first experiment confirmed the compttcated intenctions found in two earlier studies between Hst length and ISI values, but with much smaller ISI values than employed preriousfy. The results of the second experiment, in which unequal ISI values were employed within the same length input string, showed little effect resulting from this parameter, but it was suggested that a wider distribution of different ISI values within the same length input string would produce very strong effects.     

Limits on the applicability of signal detection theories

Two auditory signals were presented in random sequences in which the more intense signal came on.2, .5, or.8a/the trials. Each trial began with an intermediate tone which was identified in the instructions as either the standard for comparison or simply as a warning tone. Half the Os were instructed to discriminate whether the signal was “louder” or “softer” than the standard, the other half to recognize which signal had been presented. For both discrimination and recognition tasks, the total proportion of ldlouder” judgments was independent of the presentation probabilities, accuracy for each signal varying inversely with its probability of presentation. These results suggest strict limitations on the response optimization posited by theories of signal detection.