What type of interests are characterized by excessive focus on unusual objects?

The correct answer is highly restricted interests. This term is associated with individuals who exhibit a strong and intense focus on specific topics or objects that may be unusual. These interests can be highly detailed and consuming, often leading individuals to engage in extensive discussions or activities related to their specific interest, often to the exclusion of other topics or activities.

In the context of autism spectrum disorders, highly restricted interests are one of the hallmark features, distinguishing them from other behaviors. These interests may not only be unusual but can be pursued with a level of passion and intensity that may seem atypical to those around them. This can also reflect not only their knowledge depth about the interest but also a way for them to find comfort and stability in their environment.

The other options describe different behaviors and characteristics related to various forms of engagement with the environment and social interactions but do not specifically refer to the intense focus on unusual objects and topics that defines highly restricted interests. Hyper or hyporeactivity pertains more to sensory responses, stereotyped or repetitive behavior refers to repetitive actions or movements, and insistence on sameness involves a preference for routine and predictability in activities or environments rather than a concentrated interest in specific objects.