APL functions for interactive data analysis: Graphics and labels

APL functions designed to provide labeled plots and histograms are described. Support functions that augment a data file with necessary information to label output and to maintain a common plotting scale are also described. APL code and illustrative output are presented.     

Binocular interaction of orientation and spatial frequency channels: Evoked potentials and observer sensitivity

The interaction between size and orientation feature processing in the human visual system was investigated. Both observer sensitivity (d’ss) and the visual evoked potential (VEP) to test gratings flashed to one eye were investigated as a function of the nature of a continuously presented suppressing grating viewed either by that same eye or the opposite eye. The test and suppressing gratings were varied both in bar width (9′ss vs. 36′ss) and orientation (vertical vs. horizontal). The continuous grating intra- and interocularly suppressed the monocular VEPs to the flashed grating, the specificity of the suppression depending on the latency at which VEP amplitude was measured. VEP amplitude measured at early latencies (100–125 msec) was suppressed primarily when the flashed and continuous gratings were the same orientation, regardless of size. Starting at about 200 msec, and thereafter, VEP amplitudes were suppressed when the continuous bars were either the same orientationor size as the flashed bars. Late latencies, starting at 220 msec, and thereafter, were suppressed primarily when the bars in the two gratings were the same orientation and size. The reduction in observer sensitivity (d′ss) paralleled the changes found in the late VEP measures. These effects were evident under both the intraocular and interocular suppressing conditions. This pattern of VEP suppression, measured across eight points in the VEP waveform, was interpreted as indicating the existence of a sequence of channels that are specific first to a particular grating orientation, then to either a particular grating spatial frequency or orientation, and finally to the conjunction of a particular orientation and spatial frequency. Both sequential and parallel feature processing appears to take place in the human visual cortex, with grating orientation being encoded earlier than grating size.     

Figural goodness and internal structure in perceptual discrimination

The time required for 24 Ss to sort four decks of cards composed of 5-dot figures (Garner & Clement, 1963) was measured. A deck consisted of 32 cards: 4 each of 8 patterns. There were 4 sets of figures: Sets AI and A2 had identical amount and form of redundancy; so also did BI and 82. Sets BI and B2, having more uncertainty in simple contingencies and having negative interaction terms, required significantly more time to sort than Sets AI and A2, All sets differed in mean ratings of figural goodness, (Garner & Clement, 1963). Even when amount and form of redundancy are held constant, the figural goodness of the individual figures constituting the set influence the discriminability, Sets consisting of good or simpler figures are easier to sort.     

Effect of Person

The role of the experimenter in the behavioral study, although recognized by Darwin, Pavlov, psychiatrists and others, has not been adequately evaluated in terms of the quantitative measures of the CR. Our study in this paper concerns especially the cardiac changes induced by “Person” in normal and pathological animals—monkey, dog, cat, opossum, guinea pig and rabbit. Owing to the greater sensitivity of the cardiovascular and respiratory systems, these are more reliable and delicate measures than the usual somatic muscular ones. The Person can be used as an unconditional stimulus on the basis of which conditional reflexes are formed. Person has an especially pronounced effect on neurotic animals—shown often in a more pronounced way in the cardiorespiratory responses than in the more superficial behavioral ones. This Effect of Person may provide insights into the production of neurosis as well as some of the beneficial effects of therapy, e.g., the personal factor of the therapist.     

Figural goodness and internal structure in perceptual discrimination

The time required for 24 Ss to sort four decks of cards composed of 5-dot figures (Garner & Clement, 1963) was measured. A deck consisted of 32 cards: 4 each of 8 patterns. There were 4 sets of figures: Sets A1 and A2 had identical amount and form of redundancy; so also did B1 and B2. Sets B1 and B2, having more uncertainty in simple contingencies and having negative interaction terms, required significantly more time to sort than Sets A1 and A2. All sets differed in mean ratings of figural goodness, (Garner & Clement, 1963). Even when amount and form of redundancy are held constant, the figural goodness of the individual figures constituting the set influence the discriminability. Sets consisting of good or simpler figures are easier to sort.     

Disentangling behavioral intention and behavioral expectation

Social psychologists have extensively researched behavioral intention and its relation to future behavior, usually within the framework of M. Fishbein and I. Ajzen's (1975, Belief, attitude, intention and behavior: An introduction to theory and research, Reading, MA: Addison-Wesley) theory of reasoned action. However, the field has confounded two separate constructs while investigating intention: behavioral intention (BI) and what P. R. Warshaw, B. H. Sheppard, and J. Hartwick (in press, in R. Bagozzi (Ed.), Advances in marketing communication, Greenwich, CT: JAI Press) have coined behavioral expectation (BE), which is the individual's self-prediction of his or her future behavior. In this paper we define both constructs and explain how they differ in terms of the processes by which they are formed, their roles in determining behavior, and their utilities as behavioral predictors. We propose that behavioral expectation is the more accurate overall predictor since many common behaviors are unreasoned (i.e., mindless or habitual) behaviors, goal-type actions, or behaviors where the individual expects his or her intention to change in a foresseable manner. These are all cases where present intention (BI) is not the direct determinant of behavior but where the individual may be capable of appraising whatever additional determinants exist and of including them within his or her behavioral expectation. A study (N = 197) is reported in which student subjects received either a BE (n = 113) or a BI (n = 84) version of a questionnaire pertaining to their performance of 18 common behaviors. Overall, behavioral expectation was the better predictor of self-reported performance.