Mark Hurlstone

Temporal grouping effects in verbal and spatial serial recall suggest that the representation of serial order in verbal and spatial short-term memory (STM) incorporates positional information. However, not all effects of grouping are created equal in the verbal and spatial domains. Although grouping a sequence of verbal items engenders an increase in between-group transpositions that maintain their within-group position, grouping a sequence of spatial items does not engender an increase in these so-called interposition errors. Here I present experimental and computational modeling evidence which suggests that positional information is represented in subtly different ways in verbal and spatial STM. Specifically, the findings indicate that in verbal STM, groups are coded for their position in a sequence and items are coded for their position in a group. By contrast, in spatial STM groups are coded for their position in a sequence, but items are coded for their position in a sequence, rather than in a group. Findings support the notion that positional information in verbal and spatial STM is represented by modality-specific mechanisms rather than a domain-general system.

Current research shows that emotions can motivate climate engagement and action, but precisely how has received scant attention. We propose that strong emotional responses to climate change result from perceiving one’s “objects of care” as threatened by climate change, which motivates caring about climate change itself, and in turn predicts behaviour. In two studies, we find that climate scientists (N = 44) experience greater emotional intensity about climate change than do students (N = 94) and the general population (N = 205), and that patterns of emotional responses explain differences in support for climate change policy. Scientists tied their emotional responses to concern about consequences of climate change to future generations and the planet, as well as personal identities associated with responsibility to act. Our findings suggest that “objects of care” that link people to climate change may be crucial to understanding why some people feel more strongly about the issue than others, and how emotions can prompt action.

How is the serial order of a spatial sequence represented in short-term memory? Previous research by Farrell and Lewandowsky (Farrell & Lewandowsky, 2004; Lewandowsky & Farrell, 2008) has shown that five alternative mechanisms for the representation of serial order can be distinguished on the basis of their predictions concerning the response times accompanying transposition errors. We report three experiments involving the output-timed serial recall of sequences of seen spatial locations that tested these predictions. The results of all three revealed that transposition latencies are a negative function of transposition displacement, but with a reduction in the slope of the function for postponement, compared to anticipation errors. This empirical pattern is consistent with that observed in serial recall of verbal sequences reported by Farrell and Lewandowsky (2004) and with the predictions of a competitive queuing mechanism within which serial order is represented via a primacy gradient of activations over items combined with associations between items and positional markers, and with suppression of items following recall. The results provide the first clear evidence that spatial and verbal short-term memory rely on some common mechanisms and principles for the representation of serial order.