Melanie S. Weaver

Psychology’s contemporary and all-time notables: Student, faculty, and chairperson viewpoints

Chairpersons of graduate psychology departments were surveyed to determine which psychologists this group viewed as having achieved contemporary and all-time importance. The results of this survey were compared with similar data gathered in 1966. To provide a basis for additional comparisons, all psychology students and faculty at a regional midwestern university were administered similar surveys.

Taste Preference of the Adult Rat as a Function of Prenatal Exposure to Ethanol

Two groups of pregnant rats (n = 10) received exposure to either 10% ethanol or water. All male offspring (n = 43) received a six-day preference test (ethanol vs water) at 90 days of age. Fluid consumption scores indicated a significant preference for water by all Ss. However, those animals receiving prenatal ethanol exposure consumed significantly more ethanol during preference testing than did the animals receiving prenatal water exposure.

Defensive Burying: The Effects of Multiple Stimulus Presentation and Extinction

Two groups of rats served in an evaluation of the effects of multiple aversive-stimulus presentations and extinction upon defensive burying responding. The results indicate that multiple shock presentations resulted in significantly more burying than did a single shock. A significant reduction in responding was shown by both groups by the second extinction session.

A preliminary investigation into the source of odor-cue production

Rats received a daily eight-trial double-alternation sequence of reward/nonreward in a straight runway during three phases of an experiment designed to investigate the source of reward/nonreward odor cues. Appropriately patterned responding was strongly established during the first (control, feet uncovered) phase, heightened during the second phase, when odors emanating from the feet were precluded, and returned to the original Phase 1 level during the third phase (feet uncovered). Even though the foot sweat pads do not appear to be a source for reward/nonreward odor, the present data do suggest that they may be a possible source of odors that compete with reward/nonreward odor cues.

Odor-Based Runway Performance of Rats as A Function of Type of Reinforcer and Multiple Deprivation Conditions

Two experiments examining the development of odor-based double-alternation patterning under concurrent food and water deprivation, but food versus water reinforcement, are reported. In both experiments patterning was established only by animals receiving food reinforcement. Shifting type of reinforcer (i.e., food to water, and vice versa) resulted in an immediate and pronounced change in performance (Experiment 1). Increasing the duration of water deprivation (Experiment 2) produced an increase in general performance level, but did not result in the development of patterning by water-reinforced animals. These results would appear to be supportive of an ethologically based interpretation, such as optimal foraging theory.

Odor-based runway performance as a function of deprivation state, squad size, and subject-rotation procedures

The results of a two-phase experiment investigating odor-based alleyway performance of rats are reported. During both phases, two squads (n = 8) received daily double-alternation training. Each squad was composed of two subgroups (n = 4), one food deprived and one water deprived. The water-deprived animals were tested first in one squad, whereas the food-deprived animals were tested first in the second squad. During Phase 2, a daily subject-rotation procedure, under which the last subject in each of the second subgroups was rotated to the initial position in that subgroup, was implemented. Odor-based patterning was developed in Phase 1 only by the subgroup run last within each of the larger squads. Phase 2 rotation failed to disrupt patterned responding in the rotated animals. The results of this experiment support the contention that, even though specific deprivation conditions may have a bearing upon the use of odors as discriminative stimuli, such constraints are certainly not absolute.

Odor-mediated patterned responding as a function of delay of reinforcement but not reward-magnitude contrast

A two-phase experiment examining the production and utilization of odors under conditions of delay of reinforcement (Phases 1 and 2) but not reward-magnitude contrast (Phase 1) is presented. Appropriate odor-based patterning was shown only when animals entered an empty goalbox and reinforcement was subsequently delivered. Reducing reinforcement on selected trials (Phase 2) failed to result in the development of patterning by subjects entering a preloaded goalbox and did not significantly influence patterned responding that had already been established by those animals that entered an empty goalbox.

Shock-Elicited Aggression as a Function of Early Ethanol Exposure

Upon reaching maturity the offspring (N = 88) of animals exposed during pregnancy to ethanol and plain water, respectively, served as Ss in a shock-elicited aggression test. Significantly higher levels of aggression were shown by those animals that had received prenatal ethanol exposure. Several ethanol-related birth effects were also noted.

Odor based double alternation responding and retention as a function of naloxone injection

A two-phase experiment designed to investigate the effects of naloxone injection upon odor-based double-alternation performance is reported. Two groups of rat subjects received a daily eight-trial sequence of reward/nonreward in a straight runway during both phases of the experiment. Subjects in Group N received an injection of naloxone on each of the last 2 days of Phase 1. Subjects in Group S received an injection of isotonic saline on these 2 days. Phase 1 performance was not significantly influenced by the naloxone treatment. However, Group N displayed significantly superior retention of double-alternation patterning on Day 1 of Phase 2, begun 2 weeks after the completion of Phase 1.

Utilization of odor cues as a function of reward-magnitude contrast and delay of reinforcement.

An experiment manipulating both reward-magnitude contrast and delay of reinforcement is reported. The results indicated that odor cues are produced under conditions of delayed large-reward versus nonreward contrast but not under large- versus small-reward contrast. Additional magnitude and delay manipulations that resulted in the elimination of odor-based double-alternation patterning in the straight runway are presented.