Alzheimer’s disease (AD) is a progressive form of dementia marked by decline in cognitive functioning and memory loss due to protein abnormalities in the brain. One early cognitive deficit seen in AD is a contextual acquisition deficit. However, evidence suggests that deficits in contextual extinction learning may present earlier than acquisition deficits. Extinction is a type of learning process by which the brain acquires information inconsistent with information it had previously learned, and gradually begins to accept this new information instead of the old. As psychological stress has been linked with increased Alzheimer’s markers, it is important to explore the interaction between stress and contextual learning.
In our first experiment, male C57BL/6J mice were divided into three groups – unpredictable stress (US), isolation, and group housed (controls). All three groups were trained in a contextual fear conditioning. After training, the animals in the isolation and US groups were isolated in individual cages for seven days. In addition to living in isolation, the US group underwent seven days of variable, unpredictable stressors which include 2 hours of wet bedding, cage tilted at 45 degrees for 30 minutes, 30 minutes of restraint stress, 5 minutes of forced swimming in warm water, placement in an empty cage for one hour, and nesting material removal overnight. These stressors were applied in a random order every day for 7 days. On the eighth day, acquisition learning was assessed. Animals in the US group showed significant deficits in acquisition of contextual fear conditioning compared to isolated animals and group housed controls. Extinction learning was assessed on days nine through twelve. There was no effect of US on extinction learning, as there was likely a floor effect due to impaired acquisition. In the second experiment, animals were divided into US and a group housed control group. The US animals underwent the same series of stressors listed previously for six days. On the seventh day, all animals received one 250mg/kg injection of LPS, a bacterial mimetic, to determine how stress impacted the immune challenge. Four hours later, the hippocampus was collected for cytokine and HMGB1 mRNA analysis. As the elderly face surmounting odds of AD, along with significant stress, research on how these interact and early diagnostic signs is especially relevant.

Reinforcer devaluation involves pairing an appetitive stimulus (e.g., food) with an aversive event (e.g., illness), which disrupts the ability of the stimulus to elicit behavior (Adamson & Dickinson, 1981). The effect of reinforcer devaluation could be the result of the stimulus signaling the aversive event. Alternatively, exposure to the stimulus and aversive event together may result in a hedonic shift, or change in the affective unconditional properties of the stimulus. The two accounts make different predictions regarding the effect of reexposure to the devalued stimulus. The hedonic shift account describes reexposure to the stimulus as necessary to experience the changed value of the stimulus, but a signaling account can explain devaluation after one pairing. Balleiene & Dickinson (1991) found that reexposure to food paired with illness was necessary to observe a devaluation effect. The current experiment investigated the devaluation of a conditioned reinforcer. Rats were initially trained with pairings of an audiovisual (light and tone) stimulus with sugar water (sucrose). In the next phase, acquisition of a new behavior, lever pressing, was supported by presenting the stimulus (conditioned reinforcer) following a lever press. During devaluation, the experimental group received one trial of the stimulus paired with a shock, whereas the control group received the stimulus and shock, but separated in time (i.e., unpaired). In Test 1, all rats were given the opportunity to press the lever with no nominal consequences (e.g., no stimulus or shock). Then, all rats were re-exposed to the audiovisual stimulus without the lever or shock. In Test 2, lever pressing was measured as in Test 1. The data will be discussed in terms of the role of reexposure in devaluation.

References

Adams and Dickinson (1981). Instrumental responding following reinforce devaluation. The Quarterly Journal of Experimental Psychology Section B: Comparative and Physiological Psychology, 33 (2), 109-121.

Balleine, B., & Dickinson, A. (1991). Instrumental performance following reinforcer devaluation depends upon incentive learning. The Quarterly Journal of Experimental Psychology, 43(3), 279-296.

There is empirical evidence that there is an association between nostalgia, or a sentimental longing for the past, and one’s psychological and social well-being. Additional research has shown that nostalgic reverie leads not only to increased optimism and positive attitudes towards preventative health behaviors, but also actual increased health behaviors. This study extends the research on nostalgia and health into the realm of college athletics and explores how collegiate athletes’ performance is correlated with nostalgic tendencies, in addition to various measures of well-being, optimism, meaning in life, vitality, and life satisfaction. A positive correlation is expected, such that higher performing athletes are also more nostalgia prone. This study will serve as a foundation to explore the direct benefits for athletes of nostalgic thought, the advantages of which are firmly supported in other contexts.

Covert echoing has been hypothesized to play a role in the emergence of stimulus control over vocal naming after a person is exposed to contiguous presentation of a novel object and its name. However, experimental evidence is weak. This study examined the effects of blocking echoic responses during exposure to name-object presentations on later vocal naming. Preschool-age children were exposed to pictures of national flags and heard the associated country names. In the echoic condition, participants were instructed to echo the country name presented in each trial. In the interference condition, they were instructed to name the background color on which the flag was presented in each trial, which was presumed to interfere with echoic responding. In the no-response-requirement (NRR) condition, participants were not instructed to make any responses. Flag naming was probed after each session. Only 3 of the 5 participants showed a tendency to name the flags vocally even after repeated exposure. Of these three, only one demonstrated poorer performance in the interference condition relative to the echoic and NRR conditions. These results fail to provide support for the echoic hypothesis and are consistent with other data from our lab.

Student evaluations of teaching (SETs) are a tool commonly employed at universities for assessing faculty members’ teaching performance and even eligibility for promotions. Survey items often ask students to make judgments about the professor’s knowledgeability, teaching style, and class difficulty. Fair and consistent review of SETs is critical for faculty members as they seek to improve their teaching skills and gain professional recognition. The present study investigates the novel question of how judgments of completed SETs are made. Undergraduate students (n = 160) and faculty participants were shown and asked to make judgments about a fictional SET. The four conditions varied in whether the fictional professor being evaluated was rated lower or higher than average, and whether or not the professor gave in-class quizzes. Follow-up questions had participants evaluate why they made certain judgments about the professor. This research helps explicate the factors that contribute to faculty members’ interpretations of and students’ responses on SETs.