Marc M. Sebrechts

Stimulus-specific processing consequences of pattern goodness

Two issues concerning the effects of visual pattern goodness on information processing time were investigated: the role of memory vs. encoding and the role of individual stimulus goodness vs. stimulus similarity. A sequential “same-different” task was used to provide differentiation of target item or memory effects from display item or encoding effects. Experiment 1 used four alternative stimuli in each block of trials. The results showed that good patterns were processed faster than poor patterns for both “same” and “different” responses. Furthermore, the goodness of the target item had a greater effect on reaction time than did the goodness of the display item, indicating that memory is more important than encoding in producing faster processing of good stimuli. Effects of interstimulus similarity on processing time were minimal, although isolation of good stimuli in a similarity space could explain many of the results. Experiment 2 replicated the results of Experiment 1, despite the fact that differences in similarity space had been minimized by using only two alternative stimuli in each block. In addition, the speed of processing a “same” pair was essentially independent of the particular alternative stimulus in a block. These results suggest that in this task, there is a processing advantage for good stimuli that is stimulus specific, with the effect operating primarily in memory.

An invited article Facilitating human–computer communication

Basic cognitive psychology can provide guidelines for how to design computer systems that are easy for people to use. Prior knowledge of the real world and natural language affect the way people use computers, so computer systems that are consistent with this prior knowledge are easier for people to use. Providing users with mental models for a computer system will allow them to solve more complex problems and understand sequences of commands better. Computer systems should be flexible to accommodate the individual differences between users, but the complexity of understandable computer systems is constrained by the limited information processing capacity of users. The domain of human–computer communication promises to be a fertile domain for applied tests of cognitive theories.

A diagrammatic approach to computer instruction for the naive user

There are inherent difficulties with text as an instructional format. This research presents the development of a diagrammatic representation that overcomes some of those difficulties. A simple “language” is presented that includes both procedural and model information. This approach is applied to the instruction of word processing/text-editing skills. An experimental methodology is presented and preliminary results are reported that suggest that the diagrammatic approach results in improvements in both the amount of word processing accomplished and the speed with which modifications are made.

Lateralized affective priming of lateralized affectively valued target words

Abstract Four experiments analyzed the effects of lateralized affective prime stimuli (either faces or words) on judgements of the affective value of visually lateralized verbal target stimuli. Right visual field affective primes decreased the speed and accuracy of judgments of right visual field targets. Left visual field affective prime stimuli tended to increase the speed and accuracy of judgments of left visual field targets. There was also evidence for asymmetric priming effects where primes and targets were presented to different visual fields. The results supported a model of right hemisphere involvement in the processing of affective stimuli.

Secondary memory and very rapid forgetting.

Studies of recall in the absence of expectancy (e. g., Muter, 1980) have suggested that forgetting from primary memory is much more rapid than previously assumed. Two experiments examined the role of secondary memory, as reflected by encoding strategies, in determining this rate of forgetting. Experiment 1 demonstrated that the type of encoding specified by orienting tasks can influence recall in a traditional Brown-Peterson task. Experiment 2 demonstrated a similar pattern of effects of orienting task in the Muter task when recall was not expected, despite much more rapid forgetting. The type of encoding engaged by the orienting tasks did not account for Muter-s results. Expectancy and orienting task appear to have separable influences on resource allocation during encoding. The presence of secondary memory influences at even the shortest retention interval indicates that forgetting from primary memory may be even more rapid than has been proposed.

How you tell your computer what you mean: Ostension in interactive systems

An important part of communication is being able to point to an object without referring to its components or to the area surrounding it. How to do this is the problem of ostension. We observed many ostension errors in novices learning to use a full-screen text editor. Specifically, the novices erroneously tried to use keys that are appropriate for pointing when using a typewriter but incorrect in screen editors (e.g., space bar, backspace key, etc.), they frequently missed the location they intended by one character, they inadvertently pointed to the wrong occurrcnce of a string using a FIND command, they incorrectly specified boundaries by forgetting about “invisible” characters (e.g., formatting characters), and they mistakenly attempted to point to non-typing areas of the screen that were off-limits.

Tracing the evolution of knowledge structures

The goal of the research described here is to understand the evolution of knowledge structures as novices learn to use text editors. Two groups of individuals were trained to use one of two text editing systems: the IBM Displaywriter and UCSD-Pascal. Individuals rated the similarity among pairs of editing commands before and after training. Before training, subjects’ similarity ratings are characterized by heavy reliance on natural language denotations of command names. After training, subjects’ similarity ratings are explainable in terms of a small set of identifiable properties of underlying knowledge structures that are typical of experts’ knowledge about a text editor. These properties reflect functional features of command actions, and the psychological salience of a property for a given individual is related to editing performance.

Accessing Associative Strength in Cued Recall and Pair Recognition

A series of experiments was conducted to investigate the uniqueness effect (i.e., better memory performance with unique cues than shared cues) in cued recall and cue-target recognition and to determine whether a simple model based on associative strength could account for the phenomenon. After replicating the effect in Experiment 1, Experiments 2 and 3 sought to eliminate it through repetition of the shared stimuli. Three presentations eliminated the cue uniqueness effect in pair recognition but not in cued recall. An associative link-strength model failed to account for these data. Enhancing this model by taking into account differences in the way associative strength is accessed in pair recognition and cued recall provided one way to account for the phenomenon and is consistent with recent models for the fan effect.

Variations on active learning

Although current theories of memory emphasize the fact that learning is an active process, there is little consensus on the role of active learning. This paper attempts to provide a more precise characterization of active learning in the acquisition of computer skills. The analysis of verbal protocols suggests that active learning varies on at least two dimensions: schema orientation and learning strategy. Schema orientation refers to the type of information the learner is acquiring and varies from relational information to procedural information. Learning strategy describes how the information is acquired. Some people prefer to be internally driven and form their own plans for learning. Others are externally driven and allow the instructional materials to guide their learning. These differences need to be taken into account in describing learning and in designing instructional materials.

Remembering computer command names: effects of subject generation versus experimenter imposition

Two experiments analyzed the effectiveness of goal statements in aiding recall of self-generated as opposed to experimenter-imposed command names. Subjects were presented with a series of before-after pairs representing the computer states before and after a command was executed. In Experiment 1, during study, one group of subjects generated a command name in response to each pair; a second group generated a goal statement describing the goal to be accomplished in addition to generating a command name. During recall, half of each group was required to recall the name, whereas the other half was required to describe the goal before attempting to recall the name. In Experiment 2, during study, command names (and goals for those subjects in the goal condition) were imposed by the experimenter rather than generated by the subject. Subjects who generated goals and names recalled more command names than did those who generated only names or who received imposed goals and/or names. Generation of an appropriate goal at study improved encoding by helping subjects to select more appropriate command names; generation of an appropriate goal at test improved retrieval for appropriate names only, presumably by activating a relevant subset of names. Even in the relatively simple task of naming and remembering command names, having an appropriate model of the domain through the use of specific goal statements substantially improved performance.